Name: in situ high pressure hydrogen tribological testing of common polymer materials used in the hydrogen delivery infrastructure
Uploaded: 2018-03-31T14:00:00
Description: Watch this Scientific Journal Video about In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure at JoVE.com

This research was performed at the Pacific Northwest National Laboratory (PNNL), which is operated by Battelle Memorial Institute for the Department of Energy (DOE) under Contract No. DE-AC05-76RL01830.

The experiment described here requires the use of hydrogen gas which is odorless, colorless, and thus undetectable by human senses. Hydrogen is highly flammable and burns with a nearly invisible blue flame and can form explosive mixtures in the presence of oxygen. High pressures in excess of 6.9 MPa add additional explosion hazards that must be appropriately planned for in preparation for any testing. This amount of stored energy represents a serious safety hazard and therefore due diligence, planning, and a safety evalu...

<ol>
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Energy. 35, 7633-7640 (2010).</li><li>Theiler, G., Gradt, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tribological+characteristics+of+polyimide+composites+in+Hydrogen+environment.">Tribological characteristics of polyimide composites in Hydrogen environment.</a> Tribol. Int. 92, 162-171 (2015).</li><li>Sawae, Y., 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=Friction+and+wear+of+bronze+filled+PTFE+and+graphite+filled+PTFE+in+40+MPA+hydrogen+gas.">Friction and wear of bronze filled PTFE and graphite filled PTFE in 40 MPA hydrogen gas.</a> Proceed. , 249-251 (2011).</li><li>Fujiwara, H., Ono, H., Nishimura, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Degradation+behavior+of+acrylonitrile+butadiene+rubber+after+cyclic+high-pressure+hydrogen+exposure.">Degradation behavior of acrylonitrile butadiene rubber after cyclic high-pressure hydrogen exposure.</a> Int. J. 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Hydrogen Energy. 38 (14), 5989-6001 (2013).</li><li>Papavinasam, 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> Corrosion control in the oil and gas industry. , (2013).</li><li>Yamamoto, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen+Embrittlement+of+Nuclear+Power+Plant+Materials.">Hydrogen Embrittlement of Nuclear Power Plant Materials.</a> Mat. Trans. 45 (8), 2647-2649 (2004).</li><li>Rymuza, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tribology+of+polymers.">Tribology of polymers.</a> Arch. Civ. Mech. Eng. 7 (4), 177-184 (2007).</li><li>Mckeen, L. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 1 Introduction to Fatigue and Tribology of Plastics and Elastomers. , (2010).</li><li>Lorge, O., Briscoe, B. J., Dang, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gas+induced+damage+in+poly(vinylidene+fluoride)+exposed+to+decompression.">Gas induced damage in poly(vinylidene fluoride) exposed to decompression.</a> Polymer. 40, 2981-2991 (1999).</li><li>Sawae, Y., Yamaguchi, A., Nakashima, K., Murakami, T., Sugimura, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+Hydrogen+Atmosphere+on+Wear+Behavior+of+PTFE+Sliding+Against+Austenitic+Stainless+Steel.">Effects of Hydrogen Atmosphere on Wear Behavior of PTFE Sliding Against Austenitic Stainless Steel.</a> Proceed. , 1-3 (2008).</li><li>Sawae, Y., Nakashima, K., Doi, S., Murakami, T., Sugimura, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+high+pressure+hydrogen+on+wear+of+PTFE+and+PTFE+composite.">Effects of high pressure hydrogen on wear of PTFE and PTFE composite.</a> Proceed. , 233-235 (2010).</li><li>Duranty, E., 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=An+in+situ+tribometer+for+measuring+friction+and+wear+of+polymers+in+a+high+pressure+hydrogen+environment.">An in situ tribometer for measuring friction and wear of polymers in a high pressure hydrogen environment.</a> Rev. 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Current ex situ techniques for tribological testing of polymer materials require samples to be exposed to high pressure hydrogen which are then depressurized before being tested using a commercial tribometer.15,24,25 The test methodology in this protocol was designed to permit testing of the tribological properties of polymer samples in a high pressure environment in situ. By testing polymer materials such as t...

In the recent years, there has been great interest in hydrogen as a potential zero emission or near-zero emission fuel in vehicles and stationary power sources. Since hydrogen exists as a low density gas at room temperature, most applications use some form of compressed hydrogen for fuel.1,2 A potential drawback of using compressed, high pressure hydrogen gas is incompatibility with many materials found within infrastructure2,3,4 and vehicular applications5 where compatibility issues are combined with repeated pressure and temperature cycling. A pure hydrogen environment is known to damage metal components including certain steels and titanium through different mechanisms including hydride formation, swelling, surface blistering, and embrittlement.2,6,7,8 Non-metallic components such as lead zirconate titanate (PZT) used in piezoelectric ceramics have also proven susceptible to degradation due to hydrogen incompatibility effect such as surface blistering and lead migration.9,10,11,12 While these examples of damage due to hydrogen exposure have been previously studied, the compatibility of polymer components within hydrogen environments has only recently become of interest.13,14,15,16 This is largely a result of metallic components providing structural integrity in nuclear and oil and gas applications whereas the polymer components usually act as barriers or seals.17,18,19,20 As a result, the friction and wear properties of polymer materials within components such as polytetrafluoroethylene (PTFE) valve seats and nitrile butadiene rubber (NBR) O-rings become important factors in their ability to function.
In the case of the hydrogen infrastructure, components such as valves, compressors, and storage tanks contain polymer materials that are in contact with metallic surfaces. The frictional interaction between the polymer and metallic surfaces results in wear of each of the surfaces. The science of the relationship between the friction and wear of two interacting surfaces is known as tribology. Polymers tend to have lower elastic moduli and strength than metallic, therefore the tribological properties of polymer materials differ greatly from metallic materials. As a result, polymer surfaces tend to exhibit greater wear and damage after frictional contact with a metallic surface.21,22 In a hydrogen infrastructure application, rapid pressure and temperature cycling causes repeated interaction between the polymer and metallic surfaces, increasing the likelihood of friction and wear on the polymer component. Quantifying this damage can be challenging ex situ due to possible explosive decompression of the polymer sample after depressurization which may cause non-tribological damage.23 Additionally, many commercial polymer products contain many fillers and additives such as magnesium oxide (MgO) that may interact negatively with hydrogen gas through hydriding, further complicating ex situ analysis of wear in these materials.24,25
Due to the complexity of differentiating between damage to the polymer material caused during depressurization and damage due to tribological wear ex situ, there is a need to directly study the frictional properties of non-metallic materials in situ within a high-pressure hydrogen environment that is likely to exist within the hydrogen delivery infrastructure. In this protocol, we demonstrate a test methodology developed to quantify the friction and wear properties of polymer materials in a high-pressure hydrogen environment utilizing a purpose-built in situ tribometer.26 We also present representative data acquired using the in situ tribometer and ethylene propylene diene monomer (EPDM) rubber, a common polymer sealing and barrier material. The EPDM material for which representative data was generated using the protocol below was purchased in 60.96 cm square sheets with a 0.3175 cm thickness and was reported by the vendor to have a 60A hardness rating.

<table border="0" cellpadding="0" cellspacing="0" width="597">
	<tbody>
		<tr height="79">
			<td height="79" style="height:79px;width:201px;">EPDM Polymer Stock Sheet</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:117px;">8525T68</td>
			<td style="width:156px;">24&#34; x 24&#34;, 1/8&#34; Thick</td>
		</tr>
		<tr height="49">
			<td height="49" style="height:49px;width:201px;">Pressure Vessel, Autoclave</td>
			<td style="width:123px;">Fluitron Inc.</td>
			<td style="width:117px;">8308-1788-U</td>
			<td style="width:156px;">5&#34; diameter, 1&#39; height</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:201px;">High Purity Hydrogen Gas</td>
			<td style="width:123px;">Praxair</td>
			<td style="width:117px;">HY4.5</td>
			<td style="width:156px;">Grade 4.5, 5ppm O2, 5 ppm H20</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:201px;">O2 Sensor</td>
			<td style="width:123px;">Advanced Micro Instruments</td>
			<td style="width:117px;">T2</td>
			<td style="width:156px;">0-5ppm min. range, 10,0000ppm max.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:201px;">Pre-purified Argon Gas</td>
			<td style="width:123px;">Oxarc</td>
			<td style="width:117px;">LCCO-HP818</td>
			<td style="width:156px;">High-purity, 99.998%</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:201px;">Liquid Dishwashing Detergent</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:117px;">98365T89</td>
			<td style="width:156px;">32 oz pour bottle, lemon scented</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:201px;">Mildew Resistant Sponge</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:117px;">7309T1</td>
			<td style="width:156px;">6&#34; long x 3 -1/2&#34; Wide x 1&#34; High, yellow</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:201px;">PTFE Pipe Thread Sealant Tape</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:117px;">4591K12</td>
			<td style="width:156px;">1/2&#34; wide, white color</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:201px;">Gas Tube Fittings</td>
			<td style="width:123px;">Swagelok</td>
			<td style="width:117px;">SS-400-1-4</td>
			<td style="width:156px;">1/4&#34; OD, stainless steel, male NPT threading</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:201px;">Hammer Driven Die</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:117px;">3427A22</td>
			<td style="width:156px;">7/8&#34; Hammer driven hole punch</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:201px;">Linear Variable Differential Transformer</td>
			<td style="width:123px;">Omega</td>
			<td style="width:117px;">LD320-2.5&#160;</td>
			<td style="width:156px;">2.5mm, AC output, guided w/spring</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:201px;">Autoclave O-ring Seal</td>
			<td style="width:123px;">Fluitron Inc.</td>
			<td style="width:117px;">A-4511</td>
			<td style="width:156px;">Hastelloy C-276, 5-3/4&#34; OD x 5&#34; ID x 3/8&#34;</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:201px;">Torque Wrench</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:117px;">85555A422</td>
			<td style="width:156px;">Adjustable Torque-Limiting Wrench, Quick-Release, 1/2&#34; Square Drive, 50-250 ft.-lbs. Torque</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:201px;">Mallet</td>
			<td style="width:123px;">McMaster-Carr</td>
			<td style="width:117px;">5939A11</td>
			<td style="width:156px;">Hard and Extra-Hard Rubber Hammer, 2-1/4 lbs.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:201px;">iLoad Mini Capacitive Load Sensor</td>
			<td style="width:123px;">Loadstar Sensors</td>
			<td style="width:117px;">MFM-050-050-S*C03</td>
			<td style="width:156px;">50 lb, U Calibration, 0.5% Accuracy, Steel</td>
		</tr>
	</tbody>
</table>

in situ high pressure hydrogen tribological testing of common polymer materials used in the hydrogen delivery infrastructure

High pressure hydrogen gas is known to adversely affect metallic components of compressors, valves, hoses, and actuators. However, relatively little is known about the effects of high pressure hydrogen on the polymer sealing and barrier materials also found within these components. More study is required in order to determine the compatibility of common polymer materials found in the components of the hydrogen fuel delivery infrastructure with high pressure hydrogen. As a result, it is important to consider the changes in physical properties such as friction and wear in situ while the polymer is exposed to high pressure hydrogen. In this protocol, we present a method for testing the friction and wear properties of ethylene propylene diene monomer (EPDM) elastomer samples in a 28 MPa high pressure hydrogen environment using a custom-built in situ pin-on-flat linear reciprocating tribometer. Representative results from this testing are presented which indicate that the coefficient of friction between the EPDM sample coupon and steel counter surface is increased in high pressure hydrogen as compared to the coefficient of friction similarly measured in ambient air.

Using the methodology presented, the coefficient of kinetic friction and wear factor for an elastomeric sample can be measured while in a high-pressure hydrogen environment. The representative data presented in Figure 1 show that in a high-pressure hydrogen environment greater force is required to move EPDM polymer samples under the steel counter surface. Using the relationship between the normal force FN and the frictional force FK the ...

Watch this Scientific Journal Video about In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure at JoVE.com

In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure

A test methodology for quantifying tribological properties of polymers used in hydrogen infrastructure service is demonstrated and characteristic results for a common elastomer are discussed.

In Situ High Pressure Hydrogen Tribological Testing of Common Polymer Materials Used in the Hydrogen Delivery Infrastructure

High pressure hydrogen gas is known to adversely affect metallic components of compressors, valves, hoses, and actuators. However, relatively little is ...

Hydrogen gas is a promising potential fuel for use in near zero emissions vehicles. In order to realize the hydrogen economy, a refueling infrastructure is needed. Typical components within infrastructure include compressors, actuators, valves, regulators and hoses.Many of which include some combination of metal and polymer materials. While the majority of metals used in these components have been heavily studied for their compatibility and high pressure hydrogen environments, there has been relatively little work studying the impact of high pressure hydrogen on polymer compatibility. Friction and wear properties of polymers under high pressure hydrogen are potentially very important to understand when designing dynamic seals and components.Effects from hydrogen may be greater than those in metals due to a polymer's lower density and susceptibility to small molecule diffusion. In this video we will describe an in situ test methodology that we have developed to measure the wear and friction properties of polymers under a high pressure hydrogen gas environment up to 4000 psi. A note of warning.This experiment requires the use of hydrogen gas under high pressures and requires extreme caution. Hydrogen gas is odorless, colorless and thus undetectable by human senses. Hydrogen is highly flammable and burns with a nearly invisible blue flame and can form explosive mixtures in the presence of oxygen.High pressures in excess of 1, 000 psi add additional explosion hazards that must be appropriately planned for in preparation for any testing. This amount of stored energy represents a serious safety hazard. Therefore, due diligence, planning and safety evaluation must be performed before starting such an experiment to ensure that these hazards are mitigated.The experiment presented here is performed in accordance with the appropriate safety precautions in an ASME-certified pressure vessel with a burst disk set to 5, 000 psi with proper ventilation. In order to analyze the friction and wear of the elastomers within a high pressure hydrogen environment we have designed an unique in situ tribometer operable in a sealed pressure vessel at 4, 000 psi. The tribometer measures the in situ frictional force required to move the elastomer sample in a linear reciprocating fashion against a vertically loaded steel pin in contact with the sample.Additionally, a linear variable differential transformer or LVDT, measures the extent of the in situ indentation of the steel ball into the polymer surface during testing. To prepare the elastomer samples, we clean the stock polymer sheet by removing oils and talc powder applied during the manufacturing process. And then wash the polymer sheet with soap and water using a non-abrasive sponge.To drive off any remaining water from the washing process dry the polymer strip in a drying oven set to approximately 85%of the material's maximum working temperature for approximately 72 hours. Then allow the sample to cool to room temperature. Store the washed and dried polymer strips in a humidity controlled environment near 25%relative humidity prior to tribological testing.Now that the polymer strip is prepared, while wearing powder-free gloves mark one end of the polymer strip with a one-sided arrow. In a space about an inch from the first mark make a second arrow in the same direction as the first. These marks will ensure consistent sample orientation during the mounting process.Now place an 7/8 inch circular dye around the second arrow and use the dye to cut a sample coupon from the polymer strip. Loosen the hex cap screws, securing the sample clamp on the in situ tribometer. Remove the screw and precision spring from the near corner of the sample clamp.Taking care to ensure the arrow marked on the sample coupon is pointing to the back of the in situ tribometer slide the sample coupon into the sample clamp. Reinsert the precision spring and hex cap screw to the near corner slot. Insert a 0.113 inch gauge block in the gap between the top and bottom of the sample clamp and tighten the hex cap screws until the clamp is tightened around the gauge block, ensuring a 10%compression of the sample with the gauge block.After ensuring power to the tribometer is off, to set the initial position of the sample stage, place a 0.95 inch gauge block along the wall of the in situ tribometer under the drive screw. Using the drive chain, back the sample stage along the drive screw until the stage is snug with the gauge block. To prepare the in situ tribometer for the experiment, first clean the surface of the steel ball with a soft cloth and an appropriate and an appropriate solvent, in this case acetone, to remove any potential polymer transfer film from the ball.Slide the bronze ball carrier onto the rail perpendicular to the sample sled allowing the counter ball to slide into the keyhole and rest onto the polymer sample. Place the copper stationary weight on the bronze carrier. Using a hex key and two bronze screws, reattach the LVDT measurement arm to the bronze carrier, such that freely floating cylinder of the LVDT rests on the arm.Adjust the clamp holding the LVDT in place, such that the LVDT is measuring near at zero point. Lower the tribometer assembly into the pressure vessel, ensuring that the thermal well on the top flange of the vessel will lower into the gap between the tribometer and the wall of the vessel. Wrap the hastelloy o-ring with two and a half layers of PTFE tape and place the o-ring in the groove in the lip of the pressure vessel.Reconnect the five power wires for the tribometer motor, the four data wires for the load cell, and the five data wires for the LVDT. Now, to seal the pressure vessel, lower the top flange of the pressure vessel to close it, taking care to lower the top gently onto the PTFE-wrapped o-ring. While lowering, be aware of the position of the data and power wires, such that they are not pinched between the lid and the lens ring.Insert the bolts into the numbered holes on the top flange in ascending order until they are finger tight. Using a hex key tort the flange bolts in ascending order to hand tight and repeat until the bolts can no longer be tightened. Starting at 90 foot pounds and increasing in thirty foot pound increments, use a torque wrench to torque the flange bolts in ascending order until they are torqued to 200 foot pounds.This portion of the experiment requires the use of high pressure hydrogen. It is critical that the full safety evaluation and appropriate safety factors are considered when using flammable and high pressure gas. Connect the swagelok gas fittings to the autoclave lid and flush the pressure vessel with low pressure around 80 psi Argon gas for approximately an hour until the oxygen content of the vessel drops below 10 ppm.Once the oxygen levels are safe, slowly, at less than 40 psi per second, flush the vessel with 99.995%purity hydrogen gas up to 1000 psi, then slowly vent the gas. Repeat the flushing process two more times. After flushing the pressure vessel, slowly fill the pressure vessel with hydrogen gas up to 2, 000 psi and allow the vessel to rest for 10 minutes, such that the temperature of the gas within the vessel equilibrates to room temperature.Continue to fill the vessel with high pressure hydrogen gas, this time up to 3, 000 psi and then wait another 10 minutes. Finally bring the vessel up to the target 4, 000 psi with hydrogen gas and close off all valves. Allow the polymer sample to soak for approximately 12 hours in the hydrogen gas before starting the experiment.The experiment is performed for one hour of linear motion, which translates to 120 linear reciprocating cycles of the sample stage. During the experiment, the load cell measures the amount of force required to slide the surface of the elastomer sample coupon across the loaded steel ball. Additionally, the LVDT measures the penetration depth of the steel ball into the elastomer sample as a function of time.Once the experiment has completed, slowly depressurize the system at a rate below 50 psi per second to prevent possible explosive decompression and thereby damage to the polymer sample surface not representative of any friction or wear mechanisms. From the frictional force measured by the load cell called F of k, and the normal force exerted by the steel ball, called F of n, the kinetic coefficient of friction mu can be calculated. Using the LVDT penetration depth data x, and the pressure, volume and time, the wear factor, the material's resistance to wear, can be calculated.These plots contain representative data gathered using the test methodology described in this video, while testing EPDM rubber and high pressure hydrogen gas, the blue data, and an ambient pressure air, the black data. In the data set shown here, the coefficient of friction for the steel ball on the EPDM polymer sample was increased in high pressure hydrogen gas as compared to ambient air. However, the wear resistance of the EPDM sample was lower in high pressure hydrogen than in ambient pressure air.This is most likely due to the increased density of the pressurized samples. The hydrogen fuel delivery infrastructure is expanding quickly to meet the needs of new alternative fuel vehicles. The safety and reliability of this infrastructure will rely on understanding soft material's compatibility with high pressure hydrogen.Here we have demonstrated a test methodology for measuring the tribological properties of polymer materials in a high pressure hydrogen environment using an unique in situ tribometer. This test methodology can be used to assess the fitness of polymer materials for service in the hydrogen infrastructure.

in-situ-high-pressure-hydrogen-tribological-testing-common-polymer

Research

JoVE Journal

Engineering

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a 15N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the 1H isotope in depths up to about 2 &#956;m from the target surface. Surface H coverages are measured with a sensitivity in the order of ~1013 cm-2 (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~1018 cm-3 (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal 15N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, 1H(15N,&#945;&#947;)12C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of 15N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

We illustrate the application of 1H(15N,&#945;&#947;)12C resonant nuclear reaction analysis (NRA) to quantitatively evaluate the density of hydrogen atoms on the surface, in the volume, and at an interfacial layer of solid materials. The near-surface hydrogen depth profiling of a Pd(110) single crystal and of SiO2/Si(100) stacks is described.

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and ...

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices have used devices prepared by spin coating, a process that is not amenable to large-scale fabrication. This mismatch in device fabrication makes it difficult to translate quantitative results obtained in the laboratory to the commercial level, making optimization difficult. Using a mini-slot die coater, this mismatch can be resolved by translating the commercial process to the laboratory and characterizing the structure formation in the active layer of the device in real time and in situ as films are coated onto a substrate. The evolution of the morphology was characterized under different conditions, allowing us to propose a mechanism by which the structures form and grow. This mini-slot die coater offers a simple, convenient, material efficient route by which the morphology in the active layer can be optimized under industrially relevant conditions. The goal of this protocol is to show experimental details of how a solar cell device is fabricated using a mini-slot die coater and technical details of running in situ structure characterization using the mini-slot die coater.

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Here, we present a protocol to fabricate organic thin film solar cells using a mini-slot die coater and related in-line structure characterizations using synchrotron scattering techniques.

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices ...

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, &#960;-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (&#181;-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, &#181;-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

Protocols for the synthesis of microspheres from polymers, the manipulation of microspheres, and micro-photoluminescence measurements are presented.

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, ...

Detecting the Water-soluble Chloride Distribution of Cement Paste in a High-precision Way

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a high-precision chloride profile. Firstly, paste specimens are molded, cured, and exposed to cyclic wet-dry conditions. Then, powder samples at different specimen depths are grinded when the exposure age is reached. Finally, the water-soluble chloride content is detected using a silver nitrate titration method, and chloride profiles are plotted. The key to improving the accuracy of the chloride distribution along the depth is to exclude the error in the powderization, which is the most critical step for testing the distribution of chloride. Based on the above concept, the grinding method in this protocol can be used to grind powder samples automatically layer by layer from the surface inward, and it should be noted that a very thin grinding thickness (less than 0.5 mm) with a minimum error less than 0.04 mm can be obtained. The chloride profile obtained by this method better reflects the chloride distribution in specimens, which helps researchers to capture the distribution features that are often overlooked. Furthermore, this method can be applied to studies in the field of cement-based materials, which require high chloride distribution accuracy.

A protocol for obtaining a water-soluble chloride profile by using a high precision milling method is presented.

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a ...

Ultrasonic Fatigue Testing in the Tension-Compression Mode

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on exposing the specimen to longitudinal vibrations on its resonance frequency close to 20 kHz. With use of this method, it is possible to significantly decrease the time required for the test, when compared to conventional testing devices usually working at frequencies under 200 Hz. It is also used to simulate loading of material during operation in high speed conditions, such as those experienced by components of jet engines or car turbo pumps. It is necessary to operate only in the high and ultra-high cycle region, due to the possibility of extremely high deformation rates, which can have a significant influence on the test results. Specimen shape and dimensions have to be carefully selected and calculated to fulfill the resonance condition of the ultrasonic system; thus, it is not possible to test the full components or specimens of arbitrary shape. Before each test, it is necessary to harmonize the specimen with the frequency of the ultrasonic system to compensate for deviations of the real shape from the ideal one. It is not possible to run a test until a total fracture of the specimen, since the test is automatically terminated after initiation and propagation of the crack to a certain length, when the stiffness of the system changes enough to shift the system out of the resonance frequency. This manuscript describes the process of evaluation of materials' fatigue properties at high-frequency ultrasonic fatigue loading with use of mechanical resonance at a frequency close to 20 kHz. The protocol includes a detailed description of all steps required for a correct test, including specimen design, stress calculation, harmonizing with the resonance frequency, performing the test, and final static fracture.

A protocol for ultrasonic fatigue testing in the high and ultra-high cycle region in axial tension-compression loading mode.

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on ...

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic glasses (MGs). Despite their amorphous nature, the identification of hyperfine interactions unveils faint structural modifications. For this purpose, we have employed two techniques that utilize nuclear resonance among nuclear levels of a stable 57Fe isotope, namely M&#246;ssbauer spectrometry and nuclear forward scattering (NFS) of synchrotron radiation. The effects of heat treatment upon (Fe2.85Co1)77Mo8Cu1B14 MG are discussed using the results of ex situ and in situ experiments, respectively. As both methods are sensitive to hyperfine interactions, information on structural arrangement as well as on magnetic microstructure is readily available. M&#246;ssbauer spectrometry performed ex situ describes how the structural arrangement and magnetic microstructure appears at room temperature after the annealing under certain conditions (temperature, time), and thus this technique inspects steady states. On the other hand, NFS data are recorded in situ during dynamically changing temperature and NFS examines transient states. The use of both techniques provides complementary information. In general, they can be applied to any suitable system in which it is important to know its steady state but also transient states.

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

Here, we present a protocol to describe ex situ and in situ investigations of structural transformations in metallic glasses. We employed nuclear-based analytical methods which inspect hyperfine interactions. We demonstrate the applicability of M&#246;ssbauer spectrometry and nuclear forward scattering of synchrotron radiation during temperature-driven experiments.

We demonstrate the use of two nuclear-based analytical methods that can follow the modifications of microstructural arrangement of iron-based metallic ...

Determination of Aggregate Surface Morphology at the Interfacial Transition Zone (ITZ)

Here, we present a comprehensive method to illustrate the uneven distribution of the interfacial transition zone (ITZ) around the aggregate and the effect of aggregate surface morphology on the formation of ITZ. First, a model concrete sample is prepared with a spherical ceramic particle in roughly the central part of the cement matrix, acting as a coarse aggregate used in common concrete/mortar. After curing until the designed age, the sample is scanned by X-ray computed tomography to determine the relative location of the ceramic particle inside the cement matrix. Three locations of the ITZ are chosen: above the aggregate, on the side of the aggregate, and below the aggregate. After a series of treatments, the samples are scanned with a SEM-BSE detector. The resultant images were further processed using a digital image processing method (DIP) to obtain quantitative characteristics of the ITZ. The surface morphology is characterized at the pixel level based on the digital image. Thereafter, K-means clustering method is used to illustrate the effect of surface roughness on ITZ formation.

Determination of Aggregate Surface Morphology at the Interfacial Transition Zone ITZ

Hereby, we proposed a protocol to illustrate the effect of aggregate surface morphology on the ITZ microstructure. The SEM-BSE image were quantitatively analyzed to obtain ITZ's porosity gradient via digital image processing and a K-means clustering algorithm was further employed to establish a relationship between porosity gradient and surface roughness.

Here, we present a comprehensive method to illustrate the uneven distribution of the interfacial transition zone (ITZ) around the aggregate and the effect ...

Hydrogen Charging of Aluminum using Friction in Water

A new method of hydrogen charging of aluminum was developed by means of a friction in water (FW) procedure. This procedure can easily introduce high amounts of hydrogen into aluminum based on the chemical reaction between water and non-oxide coated aluminum.

In order to introduce high amounts of hydrogen in aluminum and aluminum alloys, a new method of hydrogen charging was developed, called the friction in water procedure.

A new method of hydrogen charging of aluminum was developed by means of a friction in water (FW) procedure. This procedure can easily introduce high ...

Determining the Mechanical Strength of Ultra-Fine-Grained Metals

The mechanical strengthening of metals is the long-standing challenge and popular topic of materials science in industries and academia. The size dependence of the strength of the nanometals has been attracting a lot of interest. However, characterizing the strength of materials at the lower nanometer scale has been a big challenge because the traditional techniques become no longer effective and reliable, such as nano-indentation, micropillar compression, tensile, etc. The current protocol employs radial diamond-anvil cell (rDAC) X-ray diffraction (XRD) techniques to track differential stress changes and determine the strength of ultrafine metals. It is found that ultrafine nickel particles have more significant yield strength than coarser particles, and the size strengthening of nickel continues down to 3 nm. This vital finding immensely depends on effective and reliable characterizing techniques. The rDAC XRD method is expected to play a significant role in studying and exploring nanomaterial mechanics.

The protocol presented here describes the high-pressure radial diamond-anvil-cell experiments and analyzing the related data, which are essential for obtaining the mechanical strength of the nanomaterials with a significant breakthrough to the traditional approach.