Proportioning requirements for tungsten - copper alloy phase sintering method

Tungsten-copper alloy phase sintering method is to mix copper powder and tungsten powder and sintering at liquid phase temperature. The process is simple and easy to operate, but the sintering temperature is often very high, and the density of tungsten-copper composite material prepared by liquid phase sintering method is not high, which can only reach 90%~95% of the theoretical density. If the density is to be improved, Complex processes such as hot forging and hot pressing are also needed for tungsten and copper composites. The activated liquid phase sintering method is based on the liquid phase sintering method to add Ni, Pb, Co and other elements, can improve the solubility of tungsten, make its relative density increase, sintering densification temperature decrease, so as to reduce the cost of products, but the addition of activated elements has an impact on the conductive properties of tungsten and copper composites.

The high performance tungsten and copper composites for electrodes were prepared by activated liquid sintering method. Ni and Co activated elements were added respectively, and the skeleton sintering temperature was 1250℃. The research shows that the performance of tungsten and copper composites can be improved by adding Ni and Co. The density of W-Cu composites increases from 14.9g/cm3 to about 17.0g/cm3. However, due to the addition of Ni or Co, the electrical conductivity of W-Cu composites decreases by about 17%IACS. Therefore, activated liquid sintering method is generally used to prepare W-Cu composites with low electrical conductivity requirements. At present, it is the most extensive method to prepare tungsten and copper composites, which is mainly divided into two parts: prefiring skeleton and copper infiltration. The core is to prepare tungsten skeleton with a certain porosity, which is generally achieved by controlling the density of the compact [13-16]. The w-10cu composite prepared by the infiltration method has good sintering performance, but the surface of the material needs to be turned after the infiltration, which increases the cost of the product. W-10cu composite was prepared by the infiltration method, and the tungsten skeleton with a porosity of 19.74% was prepared by bidirectional pressing, and then the tungsten skeleton was melted at 1300℃ for 120min. The results show that, The microstructure distribution of W-10Cu composite is uniform, the relative density is 97.14%, and the electrical conductivity is 39.9%IACS, which meets the requirements of national standard.