Nano-structure Tungsten Copper Composite Material Development

Compared with conventional crystalline materials, nano-structure tungsten copper composite material has different specific properties, such as higher density, higher strength, better hermeticity and thermal and electrical conductivity. So it has attracted wide concern of the researchers around the world. Through different preparation process of tungsten copper nano composite powders, the powder granularity has been greatly refined and dispersion improved, which can effectively improve the sintering characteristics of W-Cu system and it beneficial for tungsten copper composite material get the fully densification.

At present, the focus of nano-structure tungsten copper composite material includes the manufacturing process and sintering characteristics. There are some manufacturing processes studied, such as MA (Mechanical Alloying), Mechanical Thermo-chemical Process, Spray Drying Method, Sol-Gel Method and so on. Some studies have shown that a total reduction of tungsten copper oxide powder in a highly dispersed state, only rely on capillary action can cause the rearrangement of particles so as to achieve full densification. By spray drying combustion combined nanostructure tungsten-copper composite powders prepared by the subsequent reduction treatment, the content of Cu is 20%-40%, by 1250 ℃ insulation 1h sintered density can be obtained more than 98%; combined mechanical thermo-chemical method with liquid-phase sintering can manufacture W grains 1μm in average grain size without adding sintering additives; by mechanical alloying method, at lower temperature (1100 ℃) liquid phase sintering performance can be effectively enhanced sintering powders. It is for the reason that the interaction between same types of W-W particles and different types of W-Cu particle in tungsten copper pseudo alloy. In addition, from the sintering characteristics, since nano grain is fine (usually less than 100nm in granularity), has larger specific surface area, stronger surface activity, the larger contact area of the powders and higher sintering driving force, the required sintering temperature is lower and the speed of densification improved.

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