“壳-核”纳米钼铜复合粉末的低温制备及其致密化扩散机理研究

Mo-Cu composites, which combine the refractory properties of Mo with the high conductivity of Cu, are of special interest because of their excellent physical, mechanical and electronic properties, such as high thermal and electrical conductivity, low and alterable thermal expansion coefficient, nonmagnetic, well high-temperature behavior and fair plasticity. These properties render Mo–Cu alloys widespread applications in electronic packaging devices, heat sink materials, vacuum technology (electrical contact), aerospace field and so on. In order to realize process simplifying and energy saving, simple microwave-assisted synthesis is conducted to prepare well-dispersed core-shell Mo-Cu nano-powders with high sintering activity at low temperature in this project. Moreover, novel Mo-Cu composites with high properties are functionally designed. Chemical activation sintering process is used to study the effects of transition metals (Ag) on microstructure and performance of Mo-Cu composites. The distribution of additives in the sintering composites and diffusion mechanism of multiple metal powders system during densification are also explored. Consequently, this project is of great theoretical and practical significance in providing the technical prototype and theory evidence for the development of high-performance (high thermal and electrical conductivity, low thermal expansion coefficient) Mo-Cu composites and further motivating their low-energy production and large-scale applications in broader fields.

钼铜复合材料综合了钼和铜各自的特性，具有优异的物理性能和力学性能，如高导电导热性、低且可控的热膨胀系数、无磁性、较高的高温强度及一定的塑性，被广泛应用于电子封装、热沉、真空领域（如真空电触头）及航空航天领域。从简化工艺及节约能源的角度出发，本项目采用简单的微波辅助法在低温下制备高烧结活性的“壳-核”结构纳米钼铜复合粉末，实现粉末的均匀弥散制备。同时，本项目对钼铜复合材料进行功能化设计，利用化学元素活化烧结法研究添加银元素对钼铜复合材料组织性能的影响，探明添加元素在烧结体中的分布情况及多元金属粉末在致密化过程中的扩散机理，实现钼铜复合材料的性能可控制备。本项目的顺利开展，为高性能（高致密度、高导电导热、低热膨胀系数）钼铜复合材料的研发提供了技术原型及理论依据，有助于推动钼铜复合材料的低能耗生产及其规模化应用，具有重要的理论和实践意义。

钼铜复合材料综合了钼和铜各自的特性，具有优异的物理性能和力学性能，如高导电导热性、低且可控的热膨胀系数、无磁性、较高的高温强度及一定的塑性，被广泛应用于电子封装、热沉、真空领域及（如真空电触头）及航空航天领域。从简化工艺及节约能源的角度出发，本项目对钼铜复合材料进行功能化设计，采用简单的微波辅助法在低温下制备高烧结活性的“壳-核”结构纳米钼铜复合粉末，实现粉末的均匀弥散制备。同时，利用传统的粉末烧结工艺实现粉末的致密化，研究烧结工艺对钼铜复合材料组织性能的影响，探明钼铜两相在烧结体中的分布情况及粉末在致密化过程中的扩散机理，实现钼铜复合材料的结构、性能可控制备。研究结果发现，微波辅助法有助于在较低温度下获得钼铜复合粉末，但是包覆完整的“壳-核”结构仍需在较高温度下获得。本项目所制备的包覆结构能有效地阻碍粉末在液相烧结过程中铜的渗出，从而使烧结体最大限度的保持设计成分。采用这种粉末制备的钼铜烧结体具有较好的综合性能。最后建立了钼铜复合粉末的主烧结曲线，并通过大量实验数据验证了期有效性及准确性。本项目的顺利开展及完成，为高性能（高致密度、高导电导热、低热膨胀系数）钼铜复合材料的研发提供了技术原型及理论依据，有助于推动钼铜复合材料的低能耗生产及其规模化应用，具有重要的理论和实践意义。