化学沉积法制备W-Cu复合粉体及其烧结性能研究

发布时间：2018-05-27 20:54

  本文选题：简化预处理 + 化学沉积　； 参考：《合肥工业大学》2015年硕士论文

【摘要】：W-Cu复合材料因具有高的强度、良好的导电导热性,低的热膨胀系数、良好的高温抗氧化性等诸多的优良性能而被广泛用作电接触器、真空断路器、热沉材料等功能和结构器件。现代电子信息工业和国防工业高尖端领域的快速发展对W-Cu复合材料提出了新的发展方向和要求。由于W、Cu之间较大的性能差异,一直以来W-Cu复合材料的制备工艺都是该领域的研究热点。制备超细/纳米W-Cu复合粉末是获得高性能W-Cu复合材料的方法之一,值得探索。化学沉积是在水溶液中可控的自催化氧化还原反应,不需要提供电流,对基体没有形状和类型的限制,采用这种方法可以制备相分散均匀、纯度高的复合粉体。本文采用简化预处理的化学沉积与粉末冶金相结合的方法制备了W-30Cu/(0,0.25,0.5,1,2) wt.% TiN复合材料,并对其工艺,优化设计及性能等方面进行研究,探索制备高性能的W-Cu复合材料的新途径。主要研究结果如下：(1)通过对简化预处理工艺参数HF浓度的调整,制备具有表面缺陷的W粉,采用超声波辅助化学沉积制备W-30Cu复合粉末。经过简化预处理的W粉表面形成缺陷,有利于后续化学沉积过程中Cu颗粒的吸附、形核、长大,且在其他条件相同的情况下,一定范围内随着HF浓度的增加,简化预处理后的W粉表面胞状凸起物数量增多,化学沉积后所得的W-Cu复合粉末沉积层越均匀：但是当HF浓度继续增大至一定值后,简化预处理后W粉表面所形成的缺陷数量减少,化学沉积过程中所吸附的Cu颗粒减少,最后所得的W-Cu复合粉末沉积层均匀度减少。当HF溶度为60mL、L时,复合粉末在400MPa压制,1200℃烧结后烧结体试样的相对密度高达95.04%,导电率高达53.24% IACS,高于国标26.77%。(2)采用最优简化预处理工艺制备W-Cu复合粉末,发现当压制压力为400MPa,烧结温度为1200℃时,制备的W-30Cu复合材料组织结构均匀且综合性能优良(具有最高的相对密度为95.04%;导电率为53.24% IACS,高于国标26.77%)(3)纳米TN的添加显著影响了W-30Cu复合材料的组织结构及性能,当TiN的添加量为0.25wt%时,尽管W-30Cu复合材料的相对密度和导电性稍微下降了,但是具有较好的综合性能。
[Abstract]:W-Cu composites are widely used as electrical contactors, vacuum circuit breakers, heat sink materials and other functional and structural devices because of their high strength, good thermal conductivity, low thermal expansion coefficient, good high temperature oxidation resistance and many other excellent properties. The rapid development of modern electronic information industry and national defense industry puts forward new directions and requirements for the development of W-Cu composites. The preparation process of W-Cu composites has been a hot topic in this field due to the large difference in properties between WCU and Cu. The preparation of ultrafine / nano W-Cu composite powder is one of the methods to obtain high performance W-Cu composites, which is worth exploring. Chemical deposition is a controllable autocatalytic redox reaction in aqueous solution, which does not need to provide current and has no restrictions on the shape and type of matrix. This method can be used to prepare composite powders with uniform phase dispersion and high purity. In this paper, W-30Cu / O / 0 / 0.25% TiN composites were prepared by combining chemical deposition with powder metallurgy with simplified pretreatment. The process, optimization design and properties of W-30Cu / O / 0.25% W-Cu composites were studied in order to explore a new way to prepare high performance W-Cu composites. The main results are as follows: (1) W powder with surface defects was prepared by adjusting the concentration of HF, a simplified pretreatment process parameter, and W-30Cu composite powder was prepared by ultrasonic assisted chemical deposition. The formation of defects on the surface of W powder after simplified pretreatment is beneficial to the adsorption, nucleation and growth of Cu particles in the subsequent chemical deposition process, and with the increase of HF concentration in a certain range under the same other conditions. After simplified pretreatment, the number of cellular protrusions on the surface of W powder increased, and the W-Cu composite powder deposited by chemical deposition became more uniform: however, when HF concentration continued to increase to a certain value, After simplified pretreatment, the number of defects formed on the surface of W powder was reduced, the Cu particles adsorbed in the chemical deposition process were decreased, and the uniformity of the resulting W-Cu composite powder deposit layer was reduced. When the solubility of HF is 60 mL / L, the relative density of the sintered sample sintered at 1200 鈩，

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