Name: negative additive manufacturing of complex shaped boron carbides
Uploaded: 2018-09-18T14:45:00
Description: Watch this Scientific Journal Video about Negative Additive Manufacturing of Complex Shaped Boron Carbides at JoVE.com

这项工作是在美国能源部的赞助下, 劳伦斯国家实验室根据合同 DE-AC52-07NA27344 进行的。我释放 LLNL-JRNL-750634。

注意事项: 请与所有材料的安全数据表 (SDS) 进行协商, 在浇注和固化前, 应佩戴适当的防护设备 (PPE)。间苯二酚和聚乙烯胺被称为有毒。甲醛是有毒和致癌的20。陶瓷悬浮剂的制备应在化学油烟罩或其它通风良好的工作环境中进行。
1. 负添加剂制造
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120毫升两部分悬浮液的制备 注: 两部分悬架将准备在铸造前帮助延长悬浮液的保质期。一...

<ol>
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该协议中描述的负添加剂制造方法允许在2290摄氏度的最佳温度烧结后, 在接近全密度下生产复杂形状的碳化硼零件。与制备和铸造有关的前几个步骤是产生高质量铸件的最关键的环节, 其缺陷极小。如果悬浮液的粘度过高, 混合就会发生不良。烧结件的孔隙度也受到影响, 因为粘度的增加阻碍了气泡的去除。如果最后悬架在混合和脱气后闲置太久, 粘度的增加将会给在不规则形状的3维印刷模具中填?...

碳化硼 (B4C), 其硬度约为 38 GPa, 被称为第三个最难商用的材料, 仅次于钻石 (115 gpa) 和立方氮化硼 (~ 48 gpa)。这个特殊的属性, 连同低密度 (2.52 克/厘米3), 使它具有吸引力的防御应用, 如装甲1。B4C 还具有高熔点、优异的耐磨性和高中子吸收截面2、3、4。然而, 这些有利的机械性能的利用通常要求 B4C 被烧结到高密度。热压是将 B4C 完全致密化的常规方法。这种技术通常仅限于具有有限曲率和相当均匀厚度的简单几何。昂贵和劳动密集型加工与多晶金刚石工具或激光切割需要引入更精细或更复杂的特点。
另外, 采用无压烧结的胶体成形技术可以产生接近全密度的零件, 需要最小化加工。由于在固结过程中缺乏外部压力, 烧结助剂通常添加到陶瓷介质中, 以提高常压烧结的效果。碳通常用作烧结助剂, 用于 B4C5、6、7。可以使用各种碳源, 如纳米颗粒粉末或热解的碳化有机物。碳烧结助剂沿晶界均匀分布是获得 B4C 均匀烧结的重要因素。因此, 碳浓度和 B4C 颗粒尺寸也是烧结件到高密度8的重要和相关因素。
注凝成型是获得复杂形状陶瓷零件最有前景的胶体成形技术之一。这项技术包括把一个有机单体的陶瓷悬浮液铸造成一个模子, 聚合原位作为凝胶9,10,11。该凝胶作为粘合剂, 形成一个绿色的身体形状的模具, 是足够强大, 可以处理, 而不破损的后续处理步骤。以前不可能的3D 模具几何现在可以通过低成本的聚合物基添加剂制造 (AM) 技术 (光固化成形) 和熔融沉积建模 (有限差分)12来生产。最近3D 打印机的可用性为设计具有高度复杂几何的陶瓷开辟了新的可能性。
负添加剂制造是一种将注凝成型与牺牲 3 d 印刷模具相结合的技术。陶瓷零件的复杂性直接关系到模具设计的复杂性。模具设计现在可以令人难以置信的复杂与高分辨率塑料3D 打印机的问世。例如, 3D 扫描工具可用于捕获个人的轮廓并被合并到模具中。通过使用负 AM, 可以创建适合个人体型和形状的轻型陶瓷装甲。这样的设计自定义可以提供更轻的重量装甲, 增强了用户的机动性。
其他常见的陶瓷技术, 如直接墨写 (DIW), 选择性激光烧结 (SLS) 和粘结剂喷射 (BJ) 也有效地生产复杂形状的陶瓷零件。然而, 这些技术中的大多数仅用于生产细孔结构, 并且在扩展到大零件时效率不高, 如装甲应用13、14、15、16、17. 此外, 由于费用高昂, 这些技术大多无法用于高产量的生产。因此, 负 AM 是工业级大型零件生产的首选和相对低廉的途径。
用于注凝成型的 B4C 悬浮液必须低粘度, 并含有凝胶剂和烧结助剂。间苯二酚和甲醛的选择是因为他们有能力进行缩聚反应, 形成一个中和甲醛 (RF) 网络, 这有助于将 B4C 粒子结合在一起。传统的水凝胶用于注凝成型是有限的模具与空心芯由于高内收缩经验在干燥过程中18。由于射频通常用作气凝胶, 几乎没有收缩, 这允许使用更复杂的形状模具。使用 RF 的另一个优点是, 通过改变悬浮液的 pH 值可以控制胶凝速率 (图 3)。此外, 含有间苯二酚或甲醛的悬浮液可以提前制备并单独储存, 直到它们准备好浇铸。最重要的是, 射频凝胶可以热解留下 50 wt% 碳19。这种高度均匀的碳分布可以帮助在烧结过程中将 B4C 致密化为接近全密度。15 wt% 的射频相对于碳化硼被用于配方的悬浮, 提供 7.5 wt% 的碳后的铸造件热解。
这项工作的总目标是结合传统的注凝成型技术与廉价的3D 印刷能力和独特的凝胶剂, 以获得接近全密度的碳化硼零件与高度复杂的几何。除陶瓷外, 负极也可应用于其它材料领域, 创造出全新的多材质系统几何形状。这里介绍的方法扩展了在 Lu等方面的工作。8 , 目的是为重现这些结果提供更详细的协议。

<table border="0" cellpadding="0" cellspacing="0" style="width:1045px;" width="1044">
	<tbody>
		<tr height="19">
			<td height="19" style="height:19px;width:215px;">Boron carbide powder 1250F</td>
			<td style="width:253px;">Tetrabor Ceramics</td>
			<td style="width:215px;">Lot 211M419</td>
			<td style="width:363px;">&#62;96% purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Boron carbide powder 1500F</td>
			<td style="width:253px;">Tetrabor Ceramics</td>
			<td style="width:215px;">Lot 209M102/9</td>
			<td>&#62;96% purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Boron carbide powder 3000F</td>
			<td style="width:253px;">Tetrabor Ceramics</td>
			<td>Lot 111m53/9&#160;</td>
			<td>&#62;96% purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Polyethylene Imine (PEI)</td>
			<td style="width:253px;">Sigma Aldrich</td>
			<td style="width:215px;">MKBP3417V</td>
			<td>Averaged MW ~25,000 by L.S.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Resorcinol</td>
			<td style="width:253px;">Sigma Aldrich</td>
			<td style="width:215px;">MKBG6751V</td>
			<td>BioXtra, &#8805;99%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Formaldehyde</td>
			<td style="width:253px;">Fisher Scientific</td>
			<td style="width:215px;">F79-1</td>
			<td>37% by weight; Stabilized with 10-15% Methanol</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Acetic Acid</td>
			<td style="width:253px;">Sigma Aldrich</td>
			<td style="width:215px;">SKU 695092</td>
			<td>Glacial &#8805;99.7%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Acetone</td>
			<td style="width:253px;">Sigma Aldrich</td>
			<td>SKU 179124</td>
			<td>ACS Reagent Grade &#8805;99.5%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Water</td>
			<td style="width:253px;">LLNL In-house (Milli-Q)</td>
			<td style="width:215px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Planetary Mixer</td>
			<td style="width:253px;">Thinky</td>
			<td style="width:215px;">AR-250</td>
			<td>Fits 150mL and 300mL Thinky containers</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Acrylonitrile butadiene styrene (ABS) plastic filament</td>
			<td style="width:253px;">eSUN</td>
			<td style="width:215px;"></td>
			<td>Natural color</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Taz 6 (3D printer)</td>
			<td style="width:253px;">Lulzbot</td>
			<td style="width:215px;"></td>
			<td>FDM 3D printer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">4%H2/96%Ar gas</td>
			<td style="width:253px;">Air Gas</td>
			<td style="width:215px;">UHP</td>
			<td>4% Hydrogen, balanced Argon</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Helium gas</td>
			<td style="width:253px;">Air Gas</td>
			<td style="width:215px;">UHP</td>
			<td>Helium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Heating oven</td>
			<td style="width:253px;">Neytech</td>
			<td style="width:215px;">Vulcan 9493308</td>
			<td>Oven for 80 &#176;C curing</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Quartz tube furnace</td>
			<td style="width:253px;">Applied Test Systems, Inc.&#160;</td>
			<td style="width:215px;">LEA 05-000075</td>
			<td>Furnace for 1050 &#176;C carbonization</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Graphite furnace</td>
			<td style="width:253px;">Thermal Technology LLC</td>
			<td style="width:215px;"></td>
			<td>Sintering furnace</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Scanning Electron Microscope (SEM)</td>
			<td style="width:253px;">Jeol</td>
			<td style="width:215px;">JSM-7401F</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">pH meter</td>
			<td style="width:253px;">Thermo Scientific</td>
			<td style="width:215px;">Orion 4 Star</td>
			<td>calibrated with buffer standards</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Rheometer</td>
			<td style="width:253px;">TA Instrument</td>
			<td style="width:215px;">AR2000ex</td>
			<td>For measurement of viscosity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">X-ray Diffractometer (XRD)</td>
			<td style="width:253px;">Bruker</td>
			<td style="width:215px;">AX D8 Advanced</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Analytical balance</td>
			<td style="width:253px;">Mettler Toledo</td>
			<td style="width:215px;">XS104</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bruker EVA&#160;</td>
			<td style="width:253px;"></td>
			<td style="width:215px;"></td>
			<td>XRD Analysis Software</td>
		</tr>
	</tbody>
</table>

negative additive manufacturing of complex shaped boron carbides

碳化硼 (B4C) 是目前存在的最难的材料之一。然而, 这种诱人的物产也限制了它的 machineability 成复杂形状为高磨损, 高硬度和轻量级材料应用例如盔甲。为克服这一挑战, 采用负添加剂制造 (AM), 在不同长度的尺度上产生硼碳化物的复杂几何形状。负首先涉及注凝成型一个 3 d 印刷塑料模具的悬浮。模子然后溶化, 留下一个绿色身体作为消极拷贝。间苯二酚-甲醛 (RF) 作为一种新型的凝胶剂, 因为不像传统的水凝胶, 几乎没有收缩, 这使得非常复杂的模具使用。此外, 这种凝胶剂可以热解留下 50 wt% 碳, 这是一个高效的烧结援助 b4c 由于这种高度均匀分布的原位碳在 b4C 矩阵, 小于2% 孔隙度可在烧结后实现。本协议详细介绍了在具有高度复杂几何的近完全致密碳化硼零件上创建的方法。

在概述的过程 (图 1), 复杂形状的碳化硼零件与碳 (B4c/c) 可以被烧结多达 97.6, 0.4% 的理论最大密度与 Vicker 的硬度 23.0 @ 1.8 GPa8。演示了几种可能的烧结 B4c/c 零件的例子 (图 2)。这些例子显示了注凝成型技术可以复制的精细纹理特征。这有利于创建需要精确中尺度特性的部件。针对不同的小灵通, ...

Watch this Scientific Journal Video about Negative Additive Manufacturing of Complex Shaped Boron Carbides at JoVE.com

Negative Additive Manufacturing of Complex Shaped Boron Carbides

复合型碳化硼的负添加剂制造

一种称为负添加剂制造的方法, 用于生产接近完全致密的不同长度鳞片的复合型碳化硼零件。这种技术是可能的, 通过制定一个新的悬浮液, 涉及间苯二酚甲醛作为一个独特的凝胶剂, 留下一个均匀的碳烧结后, 热解后的援助。

Boron carbide (B4C) is one of the hardest materials in existence. However, this attractive property also limits its machineability into complex shapes for ...

负增材制造（AM）是一种经济高效的方法，用于将超硬、致密的陶瓷部件制成复杂形状，这是传统铸造方法所无法实现的方法。在这项技术中使用气凝胶是独一无二的。它既用作凝胶剂，在铸造过程中几乎没有收缩，也是热解后烧结的分散碳源。将凝胶铸造成 3D 打印模具是一种多功能技术，可扩展到其他材料。甲醛凝胶剂最适合碳轴承系统。首先，准备两部分悬架，以帮助延长悬架的保质期，然后再铸造。为此，使用行星混合器在 25.00 克水中溶解 0.88 克聚乙烯胺，创建 R 混合物。要创建单独的 F 混合物，使用行星混合器将 0.88 克聚乙烯胺溶解在 16.83 克水中。现在，将12.60克的雷索西诺粉溶解到R混合物中。在完全溶解混合粉末后，溶液应从浑浊的白色转向透明溶液。此外，在f混合物中加入17.03克甲醛溶液，并确保完全混合。此时，将 5.25 克碳化碳化物粉分别加入 R 混合物和 F 混合物中。然后，在R混合物和F混合物中加入6.50克醋酸，并确保每个混合物完全混合。要准备铸造模具，请使用熔融沉积建模 3D 打印机打印模具，并采用丙烯酸二苯二烯苯乙烯或 ABS 灯丝。彻底搅拌悬架后，结合 R 混合和 F 混合以获得最终悬架。铸造前，将真空混合到最终悬浮液混合物上约10分钟，在不沸腾水的情况下清除气泡。这可以通过使用 200 到 300 RPM 的搅拌板（带真空罐）来完成。以下步骤是最关键的，因为凝胶剂将开始反应，并导致悬浮液的粘度迅速增加。意识到这一时间敏感步骤对于获得最佳结果至关重要。立即将去空悬浮液倒入 3D 打印模具中，并密封玻璃容器。将模具放在可密封的玻璃容器内，以防止在固化过程中水分流失。将带模具的密封容器放入 60 至 80 摄氏度的烤箱中，以启动固化过程。对于长度为数厘米的零件，允许铸件固化至少 8 小时。八小时后，将带霉菌的密封容器从烤箱中取出，并冷却至室温。转移到一个新的容器，然后添加足够的丙酮，直到模具完全淹没。此过程可能需要两到四天，具体取决于需要溶解的体积量。极小的丙酮浴的搅拌，或稍微加热到40摄氏度，可能有助于加快过程。在ABS塑料溶解后，从丙酮浴中提取自由的绿色身体。将绿色身体放在烤箱中，温度为 80 摄氏度，以确保完全干燥和去除所有水分。干燥后，将每个绿色身体放在一个两英寸的石英管内衬石墨箔。将石英管放入250 SCCM的流气炉中，由4个重量百分比的氢气和96%的砷气组成，在热解处理过程中产生还原的大气。将炉内的绿色主体以每分钟5摄氏度的速度加热，直到1050摄氏度，并坚持3小时。确保绿色主体的颜色均匀较深，表示热解处理中是否存在碳。现在，将碳化部件放在石墨炉中，用真空回填流动氦气进行烧结。加热炉2，290摄氏度，并举行一小时，以实现零件的最佳密度化。一小时后取出。悬架的粘度针对 pH 2.8 的凝胶cast进行了优化，以提供显著凝胶化发生前最长的工作时间。有大约 20 分钟，直到粘度 1.0 帕斯卡秒。扫描电子显微镜图像显示在二甲醛热解后在碳化氢颗粒上形成的空间均匀碳网络的证据。样品的X射线衍射，在不同处理阶段，也证实了热解后石墨峰的生长。横截面样品的附加显微镜显示最终产品在2，280摄氏度烧结后的低孔隙度。不要忘记甲醛是致癌的，使用甲醛可能极其危险。因此，在处理悬挂时，必须穿戴适当的个人防护装备，并在通风良好的区域工作。看完这个视频后，希望你现在熟悉负添加剂制造工艺，并可以成功地凝胶化碳化钙质合金悬浮液到复杂形状的绿色身体，然后烧结到他们的全部密度。

Research

JoVE Journal

Chemistry

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria

隔离和脂质A的化学表征革兰氏阴性菌

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS ...

科研

化学

Manufacturing of Three-dimensionally Microstructured Nanocomposites through Microfluidic Infiltration

通过微流体渗透制备三维微结构纳米复合材料的制造

Microstructured composite beams reinforced with complex three-dimensionally (3D) patterned nanocomposite microfilaments are fabricated via nanocomposite ...

Atomically Defined Templates for Epitaxial Growth of Complex Oxide Thin Films

原子定义模板复合氧化物薄膜的外延生长

Atomically defined substrate surfaces are prerequisite for the epitaxial growth of complex oxide thin films. In this protocol, two approaches to obtain ...

Self-assembly of Complex Two-dimensional Shapes from Single-stranded DNA Tiles

复杂的二维形状的从单链DNA的瓷砖自组装

Current methods in DNA nano-architecture have successfully engineered a variety of 2D and 3D structures using principles of self-assembly. In this ...

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

掺硼金刚石电极质量和应用，以评估<em&gt;原位</em&gt;本地pH值通过水电改造

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended ...

Synthesis and Characterization of Supramolecular Colloids

超分子胶体的合成与表征

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes

在线含硫化合物在复杂油气矩阵氮分析

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The ...

Investigations on the Ga(III) Complex of EOB-DTPA and Its 68Ga Radiolabeled Analogue

Investigations on the GaIII Complex of EOB-DTPA and Its 68Ga Radiolabeled Analogue

在EOB-DTPA和镓（三）复杂的调查其<sup&gt; 68</sup&gt;嘎放射性标记模拟

We demonstrate a method for the isolation of EOB-DTPA (3,6,9-triaza-3,6,9-tris(carboxymethyl)-4-(ethoxybenzyl)-undecanedioic acid) from its Gd(III) ...

Synthesis of a Water-soluble Metal&#8211;Organic Complex Array

Synthesis of a Water-soluble MetalÃƒÆ’Ã‚Â¢ÃƒÂ¢Ã¢â‚¬Å¡Ã‚Â¬ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œOrganic Complex Array

一个水溶性金属 - 有机络合物阵列合成

We demonstrate a method for the synthesis of a water-soluble multimetallic peptidic array containing a predetermined sequence of metal centers such as ...