Name: measurement of outgassing rates of steels
Uploaded: 2016-12-13T15:00:00
Description: Watch this Scientific Journal Video about Measurement of Outgassing Rates of Steels at JoVE.com

This work was supported jointly by the Converging Research Center Program through the Ministry of Science, ICT and Future Planning, Korea (NRF-2014M3C1A8048817) and R&amp;D Convergence Program of NST (National Research Council of Science and Technology) of Republic of Korea (CAP-14-3-KRISS).

Caution: Please follow all appropriate safety practices while assembling the equipment and sample chambers. Please wear personal protective equipment (safety glasses, gloves, safety shoes, etc.).
1. Fabrication of a Sample Vacuum Chamber
<ol>
	<li>Design and fabrication of the vacuum chamber
	<ol>
		<li>Prepare and submit design drawings to a commercial vendor or an in-house machine shop for manufacturing the sample vacuum chamber. A representative example of the de...

<ol>
	<li>Mamun, M. A., Elmustafa, A. A., Stutzman, M. L., Adderley, P. A., Poelker, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+heat+treatments+and+coatings+on+the+outgassing+rate+of+stainless+steel+chambers.">Effect of heat treatments and coatings on the outgassing rate of stainless steel chambers.</a> J. Vac. Sci. Technol. A. 32 (2), 021604 (2014).</li><li>Sasaki, Y. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reducing+SS+304/316+hydrogen+outgassing+to+2x10&#8722;15+torr+l+/cm2+s.">Reducing SS 304/316 hydrogen outgassing to 2x10&#8722;15 torr l /cm2 s.</a> J. Vac. Sci. Technol. A. 25 (4), 1309-1311 (2007).</li><li>He, P., Hseuh, H. C., Mapes, M., Todd, R., Weiss, D., Wilson, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Outgassing+properties+of+the+spallation+neutron+source+ring+vacuum+chambers+coated+with+titanium+nitride.">Outgassing properties of the spallation neutron source ring vacuum chambers coated with titanium nitride.</a> J. Vac. Sci. Technol. A. 22 (3), 705-710 (2004).</li><li>Bernardini, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Air+bake-out+to+reduce+hydrogen+outgassing+from+stainless+steel.">Air bake-out to reduce hydrogen outgassing from stainless steel.</a> J. Vac. Sci. Technol. A. 16 (1), 188-193 (1998).</li><li>Park, C., Chung, S., Liu, X., Li, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+in+hydrogen+outgassing+from+stainless+steels+by+a+medium-temperature+heat+treatment.">Reduction in hydrogen outgassing from stainless steels by a medium-temperature heat treatment.</a> J. Vac. Sci. Technol. A. 26 (5), 1166-1171 (2008).</li><li>Kamiya, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vacuum+chamber+made+of+soft+magnetic+material+with+high+Permeability.">Vacuum chamber made of soft magnetic material with high Permeability.</a> Vacuum. 98, 12-17 (2013).</li><li>Park, C., Ha, T., Cho, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+outgassing+rates+of+low-carbon+steels.">Thermal outgassing rates of low-carbon steels.</a> J. Vac. Sci. Technol. A. 34 (2), 021601 (2016).</li><li>Battes, K., Day, C., Hauer, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Outgassing+rate+measurements+of+stainless+steel+and+polymers+using+the+difference+Method.">Outgassing rate measurements of stainless steel and polymers using the difference Method.</a> J. Vac. Sci. Technol. A. 33 (2), 021603 (2015).</li><li>Jousten, K., Putzke, S., Buthig, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Partial+pressure+measurement+standard+for+characterizing+partial+pressure+analyzers+and+measuring+outgassing+rates.">Partial pressure measurement standard for characterizing partial pressure analyzers and measuring outgassing rates.</a> J. Vac. Sci. Technol. A. 33 (6), 061603 (2015).</li><li>Redhead, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recommended+practices+for+measuring+and+reporting+outgassing+data.">Recommended practices for measuring and reporting outgassing data.</a> J. Vac. Sci. Technol. A. 20 (5), 1667-1675 (2002).</li><li>Jousten, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calibration+of+total+pressure+gauges+in+the+UHV+and+XHV+regions.">Calibration of total pressure gauges in the UHV and XHV regions.</a> J. Vac. Soc. Jpn. 37 (9), 678-685 (1994).</li><li>Nemanic, V., Setina, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Outgassing+in+thin+wall+stainless+steel+cells.">Outgassing in thin wall stainless steel cells.</a> J. Vac. Sci. Technol. A. 17 (3), 1040-1046 (1999).</li><li>Nemanic, V., Setina, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+study+of+thermal+treatment+procedures+to+reduce+hydrogen+outgassing+rate+in+thin+wall+stainless+steel+cells.">A study of thermal treatment procedures to reduce hydrogen outgassing rate in thin wall stainless steel cells.</a> Vacuum. 53, 277-280 (1999).</li><li>Berg, R. F., Fedchak, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NIST+Calibration+Services+for+Spinning+Rotor+Gauge+Calibrations.">NIST Calibration Services for Spinning Rotor Gauge Calibrations.</a> Natl. Inst. Stand. Technol. Spec. Publ. , 250-293 (2015).</li><li>Kou, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Welding Metallurgy. , 13-16 (2003).</li><li>Fruehan, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Vacuum Degassing of Steel. , (1990).</li><li>Fedchak, J. A., Scherschligt, J., Sefa, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+Build+a+Vacuum+Spring-transport+Package+for+Spinning+Rotor+Gauges.">How to Build a Vacuum Spring-transport Package for Spinning Rotor Gauges.</a> J. Vis. Exp. (110), e53937 (2016).</li><li>Saitoh, M., Shimura, K., Iwata, T., Momose, T., Ishimaru, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+vacuum+gauges+on+outgassing+rate+measurements.">Influence of vacuum gauges on outgassing rate measurements.</a> J. Vac. Sci. Technol. A. 11 (5), 2816-2821 (1993).</li><li>Calder, R., Lewin, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+of+stainless-steel+outgassing+in+ultra-high+vacuum.">Reduction of stainless-steel outgassing in ultra-high vacuum.</a> Brit. J. Appl. Phys. 18, 1459-1472 (1967).</li></ol>

Numerous methods for the measurement of outgassing rates have been reported in the literature. Experimental methods include the throughput, conductance modulation, two-path, RoR, and variations of these methods. However, no one method is ideal for obtaining the necessary outgassing data.10 The RoR method using SRG, however, became the method of choice for measurement of low outgassing materials.11-13 SRG17 is often used as a secondary standard in high vacuum systems without erroneous pump...

Steels are routinely used in construction because of their good mechanical properties. Certain steels (ferrous steels, in particular) are preferred materials for applications involving vacuum. Depending on the type and grade, these steels have sufficiently low outgassing rates essential for high vacuum (HV, 10&#8722;7 &#60; p &#60; 10&#8722;5 Pa) or ultrahigh vacuum (UHV, 10&#8722;10 &#60; p &#60; 10&#8722;7 Pa) systems. Further, extensive research has been conducted toward the development of special pretreatment procedures that reduce outgassing1-3. The pretreatment measures are designed to minimize the pumping investment or to improve the vacuum from HV to UHV or from UHV to extreme-high vacuum (p &#60; 10&#8722;10 Pa).
Although many practical methods have been proposed to reduce the outgassing rate of ferrous steels, recent methods are focused on reducing the time and temperature required to obtain a lower outgassing rate. Heat treatment at 350 &#176;C-450 &#176;C rather than vacuum firing at 800 &#176;C-950 &#176;C, is a good example of this approach.1,4,5 Furthermore, choosing the ideal material for a specific vacuum application is critical; for example, selecting a ferritic material with a very low outgassing rate for use in magnetic field shielding.6,7
During such investigations, precise measurement of the outgassing rate is a prerequisite for the screening of candidate materials or verifying the effectiveness of various pretreatment procedures.8,9 The most common experimental techniques used for the measurement of outgassing are the throughput and rate-of-pressure rise methods.10 Recently, various experiments have been conducted to measure the hydrogen outgassing rate based on the RoR method using spinning rotor gauge (SRG).1, 11-13 The RoR method using SRG is highly suitable for measuring very low hydrogen outgassing rates that often limit the lowest pressure achievable in a vacuum system made of steel. This is because the SRG has negligible pumping or outgassing action. Further, the SRG also has excellent accuracy and good linearity in high vacuum and ultra-high vacuum range.14
Given that the published literature on RoR experiments is limited, it is worthwhile to describe the experimental details to develop a deeper understanding of the method. In this video article, we describe in detail the process of setting up the experiment and provide detailed instructions to perform outgassing measurements using the RoR method. To demonstrate the efficacy of the method, the outgassing rates of two commonly used steels (stainless steel 304 and mild steel S20C) were measured before and after a preheat treatment to reduce the hydrogen outgassing rate. The pre- and post-treatment values were compared. Typical experimental results using a rather simple setup are presented to demonstrate the efficacy of the method optimized for evaluating low hydrogen degassing rates.

<table border="0" cellpadding="0" cellspacing="0" width="869">
	<tbody>
		<tr height="33">
			<td colspan="4" height="33" style="height:34px;width:869px;">Sample chamber</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Stainless steel, 304</td>
			<td style="width:169px;">POSCO&#160;&#160;&#160;&#160;&#160; (www.posco.co.kr)</td>
			<td style="width:131px;"></td>
			<td></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Mild steel, D3752</td>
			<td style="width:169px;">Xiangtan Iron&#38;Steel co.,LTD (http://www.hnxg.com)</td>
			<td style="width:131px;"></td>
			<td style="width:355px;"></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Mild steel, D3752</td>
			<td style="width:169px;">SeAh Besteel (www.seahbesteel.co.kr)</td>
			<td style="width:131px;"></td>
			<td style="width:355px;"></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Name</td>
			<td style="width:169px;">Company</td>
			<td style="width:131px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="33">
			<td colspan="4" height="33" style="height:34px;width:869px;">Cleaning</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Cleaning bath</td>
			<td style="width:169px;">Samill IDS</td>
			<td></td>
			<td style="width:355px;">Ultrasonic cleaning, heating, timer, concentration control&#160;</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Acetone</td>
			<td style="width:169px;">Samchun Chemical (www.samchun.com)</td>
			<td style="width:131px;">A1759</td>
			<td style="width:355px;">HPLC GRADE (99.7%)</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Tekusolv</td>
			<td style="width:169px;">NCH Co.&#160;&#160;&#160;&#160;&#160;&#160;&#160; (www.nch.com)</td>
			<td style="width:131px;">0368-0058J</td>
			<td style="width:355px;">Solvents</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">BN cleaner</td>
			<td style="width:169px;">Henkel surface technologies (na.henkel-adhesives.com)</td>
			<td style="width:131px;">6610263775</td>
			<td style="width:355px;">Akkaline, pH 13</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Ethanol</td>
			<td style="width:169px;">Fisher Scientific (www.fishersci.com)</td>
			<td style="width:131px;">A995-4</td>
			<td style="width:355px;">HPLC Reagent(99.9%)</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Deionized water (Electro deionizer SYSTEM)</td>
			<td style="width:169px;">A.T.A&#160;&#160;&#160;&#160;&#160;&#160;&#160; (www.atagroup.co)</td>
			<td style="width:131px;">EDI SYSTEM</td>
			<td style="width:355px;"></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Liquid N2 gas</td>
			<td style="width:169px;">Hanyoung (www.gasmaster.co.kr)</td>
			<td style="width:131px;">B/T 176 L</td>
			<td style="width:355px;">LN2 dewar, purity 99.999%</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Name</td>
			<td style="width:169px;">Company</td>
			<td style="width:131px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="33">
			<td colspan="4" height="33" style="height:34px;">Welding</td>
		</tr>
		<tr height="68">
			<td height="68" style="height:68px;">Tungsten Inert Gas wedling machine</td>
			<td style="width:169px;">Thermal Arc (www.victortechnologies.com/thermalarc)</td>
			<td>400GTSW</td>
			<td>Ar gas prefllow&#38;postflow 8 liter/min, backflow 5 liter/min</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">turning jig</td>
			<td style="width:169px;">Vactron&#160;&#160;&#160; (www.vactron.co.kr)</td>
			<td style="width:131px;">Made to order</td>
			<td>Made to order</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Ar gas</td>
			<td style="width:169px;">Lindekorea (www.lindekorea.com)</td>
			<td></td>
			<td>Purity 99.999%</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Name</td>
			<td style="width:169px;">Company</td>
			<td style="width:131px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="33">
			<td colspan="4" height="33" style="height:34px;">Leak test</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Leak detector</td>
			<td style="width:169px;">Adixen&#160;&#160;&#160;&#160; (www.adixen.fr/en/)</td>
			<td style="width:131px;">ASM380</td>
			<td>Pumping Speed(air): 9.7 l/s</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">He gas</td>
			<td style="width:169px;">Lindekorea (www.lindekorea.com)</td>
			<td></td>
			<td>Purity 99.999%</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Name</td>
			<td style="width:169px;">Company</td>
			<td style="width:131px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="33">
			<td colspan="4" height="33" style="height:34px;width:869px;">Vacuum equipment</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Spinning rotor gauge&#160;</td>
			<td style="width:169px;">MKS Instruments (www.mks.com)</td>
			<td style="width:131px;">SRG-3</td>
			<td style="width:355px;">Controller, head, and thimble set</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Industrial level meter</td>
			<td style="width:169px;">MKS Instruments (www.mks.com)</td>
			<td style="width:131px;">SRG-3</td>
			<td>For SRG assemble &#177; 1&#730;</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Oscilloscope</td>
			<td style="width:169px;">Tektronix&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; (www.tek.com)</td>
			<td>TDS2012B</td>
			<td></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Residulal gas analyser</td>
			<td style="width:169px;">Balzers</td>
			<td style="width:131px;">QMA200</td>
			<td>m/e 0-100&#160;</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">TMP(HiPace 80)</td>
			<td style="width:169px;">Pfeiffer Vacuum (www.pfeiffer-vacuum.com)</td>
			<td style="width:131px;">PMP03941</td>
			<td style="width:355px;">Pumping Speed(N2): 67 l/s</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Scroll pump</td>
			<td style="width:169px;">Anest Iwata&#160;&#160;&#160;&#160;&#160;&#160;&#160; (www.anest-iwata.co.jp)</td>
			<td style="width:131px;">ISP 90</td>
			<td>Pumping Speed(Air): 1.8 l/s</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">All-metall easy close angle valve(CF35)</td>
			<td style="width:169px;">VAT Inc.&#160; (www.vatvalve.com)</td>
			<td style="width:131px;">54032-GE02-0002</td>
			<td style="width:355px;">Rotatable flange</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Angle valve(KF25)</td>
			<td style="width:169px;">MDC Vacuum Inc. (www.mdcvacuum.com)</td>
			<td style="width:131px;">KAV-100</td>
			<td style="width:355px;"></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Five-Way Crosses&#160;&#160;&#160;&#160;</td>
			<td style="width:169px;">MDC&#160;</td>
			<td style="width:131px;">Made to order</td>
			<td style="width:355px;">CF4-1/2 Spool-rotatable 1-way to CF2-3/4 Nipple 3ea, Vacuum degassed at 400&#8451; for 3 days</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Reducing Tees&#160;</td>
			<td style="width:169px;">MDC</td>
			<td style="width:131px;">Made to order</td>
			<td style="width:355px;">CF4-1/2 Flange to CF2-3/4 Tees(Half flange), Vacuum degassed at 400&#8451; for 3 days</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;width:215px;">Name</td>
			<td style="width:169px;">Company</td>
			<td style="width:131px;">Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="33">
			<td colspan="4" height="33" style="height:34px;">Temperature control&#160;</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Chiller</td>
			<td style="width:169px;">JEIO Tech&#160;&#160; (www.jeiotech.com)</td>
			<td>RW-2025G</td>
			<td></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Cooling line</td>
			<td style="width:169px;">LS Metal&#160;&#160;&#160;&#160; (www.lsmetal.biz)</td>
			<td style="width:131px;">C1100</td>
			<td style="width:355px;">Level Wound Coil, Diameter 10mm</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Heater controllers</td>
			<td style="width:169px;">HMT</td>
			<td style="width:131px;">Made to order</td>
			<td style="width:355px;">Bakeout program controller</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Electrical heater tapes</td>
			<td style="width:169px;">Brisk heat (www.briskheat.com)</td>
			<td>BIH101080L</td>
			<td></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Thermocouple(K type)</td>
			<td style="width:169px;">miraesensor (www.miraesensor.com)</td>
			<td>MR-2290</td>
			<td></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Handheld multimeter</td>
			<td style="width:169px;">Saehan&#160;&#160;&#160;&#160; (www.saehan.co.kr)</td>
			<td>3234</td>
			<td></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:46px;">Data recorder(Temp.)</td>
			<td style="width:169px;">Yokogawa (www.yokogawa.com)</td>
			<td>GP10-1E1F-UC10</td>
			<td></td>
		</tr>
	</tbody>
</table>

measurement of outgassing rates of steels

Steels are commonly used materials in the fabrication of vacuum systems because of their good mechanical, corrosion, and vacuum properties. A variety of steels meet the criterion of low outgassing required for high or ultrahigh vacuum applications. However, a given material can present different outgassing rates depending on its manufacturing process or the various pretreatment processes involved during the fabrication. Thus, the measurement of outgassing rates is highly desirable for a specific vacuum application. For this reason, the rate-of-pressure rise (RoR) method is often used to measure the outgassing of hydrogen after bakeout. In this article, a detailed description of the design and execution of the experimental protocol involved in the RoR method is provided. The RoR method uses a spinning rotor gauge to minimize errors that stem from outgassing or the pumping action of a vacuum gauge. The outgassing rates of two ordinary steels (stainless steel and mild steel) were measured. The measurements were made before and after the heat pretreatment of the steels. The heat pretreatment of steels was performed to reduce the outgassing. Extremely low rates of outgassing (on the order of 10&#8722;11 Pa m3 sec&#8722;1 m&#8722;2) can be routinely measured using relatively small samples.

As expected, the residual gas after the bakeout was mostly hydrogen.7 The pressure rise measured using the SRG was linear over a long period of time (Figure 5). Thus, the readsorption effect might be negligible and the intrinsic outgassing rate (q) for the steels tested in this study can be evaluated using the RoR method.10 The measured pressure rise data was analyzed using the linear least squares fitting method. The outgassing rates of the...

Watch this Scientific Journal Video about Measurement of Outgassing Rates of Steels at JoVE.com

Measurement of Outgassing Rates of Steels

A protocol for the measurement of outgassing rates of hydrogen from ordinary steel vacuum chambers using the rate-of-pressure rise method is presented.

Steels are commonly used materials in the fabrication of vacuum systems because of their good mechanical, corrosion, and vacuum properties. A variety of ...

The overall goal of this procedure is to measure the outgassing rate of hydrogen from vacuum chambers using the rate of pressure rise method. This method can help answer key questions in the vacuum measurement field, such as measurement of the outgassing rate of very low outgassing materials. The main advantage of this technique is that the outgassing rate can be systematically measured even from extremely low outgassing materials, or relatively small samples.Demonstrating the procedure will be Se-Hyun Kim, a grad student from my laboratory. First, assemble the vacuum components of the experimental apparatus sequentially, using copper gaskets from the pump side to the sample side. Using a wrench, tighten all the flange joints face to face with a copper gasket, except the joint between the sample chamber and the chamber isolation valve.Using a level meter, adjust the spinning rotor gauge, or SRG flange assembly, and the sample chamber, so that the axis of the SRG head is vertical. Tighten the flange joint between the sample chamber and the chamber isolation valve face to face, while maintaining the SRG flange's level. Next, connect the roughing pump and the helium leak detector or HLD with isolating valves to the clamp flange port of the exhaust end of the turbomolecular pump, or TMP.To perform a leak test, turn on the HLD. Once the detector is ready, open the HLD valve, and close the roughing pump valve. Pump down the setup using the HLD, waiting for approximately 30 minutes to pump out the residual helium gas.Ensure that the helium level is within the minimum detectable limit of the HLD. Spray helium gas through the leak test groove on the flanges. Then, measure any change in the helium level ensuring that the chamber is leak tight.If not leaks are detected, stop the leak test, and vent the vacuum system. Then, open the roughing pump valve and close the HLD valve. Pump down the vacuum system by switching on the TMP and the roughing pump at the same time.For bake-out, remove the SRG head from the flange assembly, wrap the vacuum components between the SRG flange assembly and the inlet flange of the TMP and band heaters. Following this, check that there is no electrical short circuit between the heaters and the vacuum parts using a handheld multimeter. Next, connect the heaters to the extension cable, then to their respective heater controllers.Afterwards, wrap the chamber in aluminum foil. Now, raise the temperature of the chamber to 150 degrees celsius, at a ramp rate of one to two degrees celsius per minute. Maintain the temperature of the residual gas analyzer, or RGA electronics, under 50 degrees celsius, using a cooling fan.At this point, de-gas each of the RGA filaments by electron bombardment for at least five minutes. Measure the RGA spectrum from a one to 50 mass to charge ratio, to ensure that the water peak is less than one half of the hydrogen peak. Allow the system to cool down to room temperature at a ramp rate of one to two degrees celsius per minute.Check for leaks referring to the RGA spectrum measured during the cooldown. Next, analyze the residual gas in the sample chamber and measure the RGA spectrum. After closing the chamber isolation valve, measure the RGA spectrum again.Verify that the sum of all impurity gasses, such as water, carbon monoxide, and carbon dioxide is below five percent. Following this, assemble the SRG head on the SRG flange assembly. Using a level meter for reference, ensure that the axis of the SRG head is within plus or minus two degrees max.Start the SRG, and wait for stabilization of the residual drag, which usually takes a few hours. Enter the proper input parameters such as gas, temperature, and measurement interval. While waiting for the signal to stabilize, stabilize the temperature of the sample by switching on the chiller to run cool water through the system.Then, set the fluid temperature to 15 degrees celsius. Following this, start the heater controller for the sample, and set the target temperature to 24 degrees celsius. After closing the oven door, wait for the temperature to stabilize within plus or minus 0.1 degrees celsius.Now, verify that the variation of the offset value of the signal is within plus or minus one times 10 to the minus nine Pascal per second. Check the signal level provided by the SRG controller, which should be at least minus 10 decibels, and ideally between zero and six decibels. Next, check the damping level provided by the SRG controller which should be between minus 35 and minus 60 decibels, and is normally satisfied in the system using the TMP and scroll pump, that is laid on a rubber pad.Gently close the all metal angle valve to start the pressure build up being careful not to subject the SRG to mechanical shock. After closing the door of the oven, acquire pressure data for eight to 24 hours using a computer. Pre-check the measured data to verify that the variation in temperature is within plus or minus 0.1 degrees celsius after stabilization, and that the pressure rise is linear with 10 percent error.Continue to measure data until the pressure rise becomes linear within 10 percent error for at least 16 hours. Finally, turn off all equipment. The residual gas after the bake-out was mostly hydrogen, and the pressure rise was linear over a long period of time.Thus, the reabsorption effect might be negligible, and the intrinsic outgassing rate for the steels tested in this study can be evaluated using the rate of pressure rise method. The measured outgassing rate for untreated STS 304 steel was consistent with reported values, and an approximately 22 fold reduction in outgassing was achieved with the medium temperature heat pre-treatment. While the outgassing rates for untreated mild steels were very low, the outgassing rates were second to the rates of stainless steels after intensive heat treatment.In addition, the outgassing rate for mild steel decreased by only 66 percent following heat treatment, and no significant reduction in outgassing was observed. These measurements strongly suggest that the difference in outgassing between stainless steels and mild steels can be attributed to the differences in the steel making processes, and in particular, the secondary metallurgy processes during which impurity gasses are extracted. Once mastered, this technique can be done in five days, if it is performed properly.While attempting this procedure, it is important to remember to check if there are leaks and to maintain the temperature of the system precisely. After watching this video, you should have a good understanding of how to build the outgassing rate measurement system, and how to measure the outgassing rate systematically, using the rate of pressure rise method.

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Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA&#39;s mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects &#8212; both important for efficient heat transfer from the medium to be cooled.
The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the material properties.

Experimental methods for investigation of solid state cooling processes and characterization of elastocaloric material properties of Shape Memory Alloys (SMA) are presented. A custom-built test rig has been designed for controlling and comprehensive monitoring of elastocaloric cooling processes. Furthermore, it provides a validation platform for thermomechanically coupled modeling approaches.

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor ...

Optical Trap Loading of Dielectric Microparticles In Air

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly scattered dielectric microparticles adhered to a glass substrate are momentarily detached using ultrasonic vibrations generated by a piezoelectric transducer (PZT). Then, the optical beam focused on a selected particle lifts it up to the optical trap while the vibrationally excited microparticles fall back to the substrate. A particle may be trapped at the nominal focus of the trapping beam or at a position above the focus (referred to here as the levitation position) where gravity provides the restoring force. After the measurement, the trapped particle can be placed at a desired position on the substrate in a controlled manner. 
In this protocol, an experimental procedure for selective optical trap loading in air is outlined. First, the experimental setup is briefly introduced. Second, the design and fabrication of a PZT holder and a sample enclosure are illustrated in detail. The optical trap loading of a selected microparticle is then demonstrated with step-by-step instructions including sample preparation, launching into the trap, and use of electrostatic force to excite particle motion in the trap and measure charge. Finally, we present recorded particle trajectories of Brownian and ballistic motions of a trapped microparticle in air. These trajectories can be used to measure stiffness or to verify optical alignment through time domain and frequency domain analysis. Selective trap loading enables optical tweezers to track a particle and its changes over repeated trap loadings in a reversible manner, thereby enabling studies of particle-surface interaction.

A protocol for launching and stably trapping selected dielectric microparticles in air is presented.

We demonstrate a method to trap a selected dielectric microparticle in air using radiation pressure from a single-beam gradient optical trap. Randomly ...

Standardized Method for Measuring Collection Efficiency from Wipe-sampling of Trace Explosives

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency are needed to evaluate and optimize sampling protocols. The approach described here is designed to provide this measurement infrastructure, and controls most of the factors known to be relevant to wipe-sampling. Three critical factors (the applied force, travel distance, and travel speed) are controlled using an automated device. Test surfaces are chosen based on similarity to the screening environment, and the wipes can be made from any material considered for use in wipe-sampling. Particle samples of the explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) are applied in a fixed location on the surface using a dry-transfer technique. The particle samples, recently developed to simulate residues made after handling explosives, are produced by inkjet printing of RDX solutions onto polytetrafluoroethylene (PTFE) substrates. Collection efficiency is measured by extracting collected explosive from the wipe, and then related to critical sampling factors and the selection of wipe material and test surface. These measurements are meant to guide the development of sampling protocols at screening venues, where speed and throughput are primary considerations.

Optimized sampling protocols and the development of new wipe materials can be facilitated by standardized measurements of collection efficiency from wipe-sampling. Our approach for sampling trace explosives uses an automated device to control speed, force, and distance during wipe-sampling followed by extraction of collected explosives.

One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common ...

Micro/Nano-scale Strain Distribution Measurement from Sampling Moir&#233; Fringes

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. The developed technique can be performed in two ways: using the reconstructed multiplication moir&#233; method or the spatial phase-shifting sampling moir&#233; method. When the specimen grid pitch is around 2 pixels, 2-pixel sampling moir&#233; fringes are generated to reconstruct a multiplication moir&#233; pattern for a deformation measurement. Both the displacement and strain sensitivities are twice as high as in the traditional scanning moir&#233; method in the same wide field of view. When the specimen grid pitch is around or greater than 3 pixels, multi-pixel sampling moir&#233; fringes are generated, and a spatial phase-shifting technique is combined for a full-field deformation measurement. The strain measurement accuracy is significantly improved, and automatic batch measurement is easily achievable. Both methods can measure the two-dimensional (2D) strain distributions from a single-shot grid image without rotating the specimen or scanning lines, as in traditional moir&#233; techniques. As examples, the 2D displacement and strain distributions, including the shear strains of two carbon fiber-reinforced plastic specimens, were measured in three-point bending tests. The proposed technique is expected to play an important role in the non-destructive quantitative evaluations of mechanical properties, crack occurrences, and residual stresses of a variety of materials.

Micro/Nano-scale Strain Distribution Measurement from Sampling Moir&amp;#233; Fringes

A sampling moir&#233; technique featuring 2-pixel and multi-pixel sampling methods for high-accuracy strain distribution measurements at the micro/nano-scale is presented here.

This work describes the measurement procedure and principles of a sampling moir&#233; technique for full-field micro/nano-scale deformation measurements. ...

Determination of the Excitation and Coupling Rates Between Light Emitters and Surface Plasmon Polaritons

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising from metallic periodic arrays without involving time-resolved techniques. We have formulated the rates by quantities that can be measured by simple optical measurements. The instrumentation based on angle- and polarization-resolved reflectivity and photoluminescence spectroscopy will be described in detail here. Our approach is intriguing due to its simplicity, which requires routine optics and several mechanical stages, and thus is highly affordable to most of the research laboratories.

This protocol describes the instrumentation for determining the excitation and coupling rates between light emitters and Bloch-like surface plasmon polaritons arising from periodic arrays.

We have developed a unique method to measure the excitation and coupling rates between the light emitters and surface plasmon polaritons (SPPs) arising ...

Generation of Size-controlled Poly (ethylene Glycol) Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. This paper proposes a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation. The polydimethylsiloxane (PDMS) chip was fabricated using the multi-layer soft lithography method. Hexadecane containing surfactant was used as the continuous phase, and PEGDA with the ultraviolet (UV) photo-initiator was the dispersed phase. Surfactants allowed the local surface tension to drop and formed a more cusped tip which promoted breaking into tiny micro-droplets. As the pressure of dispersed phase was constant, the size of droplets became smaller with increasing continuous phase pressure before dispersed phase flow was broken off. As a result, droplets with size variation from 1 &#181;m to 80 &#181;m in diameter could be selectively achieved by changing the pressure ratio in two inlet channels, and the average coefficient of variation was estimated to be below 7%. Furthermore, droplets could turn into micro-beads by UV exposure for photo-polymerization. Conjugating biomolecules on such micro-beads surface have many potential applications in the fields of biology and chemistry.

Generation of Size-controlled Poly ethylene Glycol Diacrylate Droplets via Semi-3-Dimensional Flow Focusing Microfluidic Devices

Here, we present a protocol to illustrate the fabrication processes and verifying experiments of a semi-three-dimensional (semi-3D) flow-focusing microfluidic chip for droplet formation.

Uniform and size-controllable poly (ethylene glycol) diacrylate (PEGDA) droplets could be produced via the flow focusing process in a microfluidic device. ...

Cutting Procedures, Tensile Testing, and Ageing of Flexible Unidirectional Composite Laminates

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, where the yarns in each layer are oriented parallel to each other and held in place using binder resins and thin polymer films. The armor is constructed by stacking the unidirectional layers in different orientations. To date, only very preliminary work has been performed to characterize the ageing of the binder resins used in unidirectional laminates and the effects on their performance. For example, during the development of the conditioning protocol used in the National Institute of Justice Standard-0101.06, UD laminates showed visual signs of delamination and reductions in V50, which is the velocity at which half of the projectiles are expected to perforate the armor, after ageing. A better understanding of the material property changes in UD laminates is necessary to comprehend the long-term performance of armors constructed from these materials. There are no current standards recommended for mechanically interrogating unidirectional (UD) laminate materials. This study explores methods and best practices for accurately testing the mechanical properties of these materials and proposes a new test methodology for these materials. Best practices for ageing these materials are also described.

The goal of the study was to develop protocols to prepare consistent specimens for accurate mechanical testing of high-strength aramid or ultra-high-molar-mass polyethylene-based flexible unidirectional composite laminate materials and to describe protocols for performing artificial ageing on these materials.

Many body armor designs incorporate unidirectional (UD) laminates. UD laminates are constructed of thin (&#60;0.05 mm) layers of high-performance yarns, ...

Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of data that can be obtained from an individual sample and renders it difficult to produce statistically relevant data for unique and rare materials. Resonant cavity dielectric spectroscopy is a non-destructive, contactless technique which can simultaneously interrogate both sides of a sheeted material and provide measurements which are suitable for statistical interpretations. This offers analysts the ability to quickly discriminate between sheeted materials based on composition and storage history. In this methodology article, we demonstrate how contactless resonant cavity dielectric spectroscopy may be used to differentiate between paper analytes of varying fiber species compositions, to determine the relative age of the paper, and to detect and quantify the amount of post-consumer waste (PCW) recycled fiber content in manufactured office paper.

A protocol for the non-destructive analysis of the fiber content and relative age of paper.

The current analytical techniques for characterizing printing and graphic arts substrates are largely ex situ and destructive. This limits the amount of ...

Measuring Sub-23 Nanometer Real Driving Particle Number Emissions Using the Portable DownToTen Sampling System

The current particle size threshold of the European Particle Number (PN) emission standards is 23 nm. This threshold could change because future combustion engine vehicle technology may emit large amounts of sub-23 nm particles. The Horizon 2020 funded project DownToTen (DTT) developed a sampling and measurement method to characterize particle emissions in this currently unregulated size range. A PN measurement system was developed based on an extensive review of the literature and laboratory experiments testing a variety of PN measurement and sampling approaches. The measurement system developed is characterized by high particle penetration and versatility, which enables the assessment of primary particles, delayed primary particles, and secondary aerosols, starting from a few nanometers in diameter. This paper provides instruction on how to install and operate this Portable Emission Measurement System (PEMS) for Real Drive Emissions (RDE) measurements and assess particle number emissions below the current legislative limit of 23 nm.

Presented here is the DownToTen (DTT) portable emission measurement system to assess real driving automotive emissions of sub-23 nm particles.

The current particle size threshold of the European Particle Number (PN) emission standards is 23 nm. This threshold could change because future ...

Calibration Procedures for Orthogonal Superposition Rheology

Orthogonal superposition (OSP) rheology is an advanced rheological technique that involves superimposing a small-amplitude oscillatory shear deformation orthogonal to a primary shear flow. This technique allows the measurement of structural dynamics of complex fluids under non-linear flow conditions, which is important for the understanding and prediction of the performance of a wide range of complex fluids. The OSP rheological technique has a long history of development since the 1960s, mainly through the custom-built devices that highlighted the power of this technique. The OSP technique is now commercially available to the rheology community. Given the complicated design of the OSP geometry and the non-ideal flow field, users should understand the magnitude and sources of measurement error. This study presents calibration procedures using Newtonian fluids that includes recommendations for best practices to reduce measurement errors. Specifically, detailed information on the end-effect factor determination method, sample filling procedure, and identification of the appropriate measurement range (e.g., shear rate, frequency, etc.) are provided.

We present a detailed calibration protocol for a commercial orthogonal superposition rheology technique using Newtonian fluids including end-effect correction factor determination methods and recommendations for best practices to reduce experimental error.

Orthogonal superposition (OSP) rheology is an advanced rheological technique that involves superimposing a small-amplitude oscillatory shear deformation ...