Tungsten Copper Contact HIP Process

Tungsten copper contact has excellent electrical, thermal conductivity and chemical stability, but the problem in densification is always a barrier in its developing way. And this incomplete densification will have an bad influence on the hardness, the strength, wear resistance and arc ablation resistance conversely. So the relevant researchers propose that pressure sintering, a total reduction of chemical and explosive compaction method special process to improve the density of tungsten copper contact material. However, there are some defects in these processes, such as high operation and maintenance costs, be suitable for the parts with small size and so on.

In order to improve the properties of tungsten copper contacts, we combine tungsten copper contact used in high voltage circuit breakers to study HIP process for tungsten copper material impact, and its elimination of the porosity, densification mechanism and related factors. HIP (Hot Isostatic Pressing), it places the product into a closed container, which is applied to each peer pressure while applying heat, under the action of high temperature and pressure, the product can be sintered and densified. HIP has many advantages, such as combines the advantages of hot pressing with isostatic pressing, lower molding temperature, excellent densification and performance, which is essential for high-performance material manufacturing; now, in the United States, Japan and Europe to achieve the industrial, marine, aviation, aerospace, automotive and other fields have been widely used.

Before HIP process, tungsten powder mixed with a certain amount of copper, cold isostatic pressing, low temperature pre-sintered to give semi-finished copper by infiltration. It uses argon (Ar) as pressure transmission medium, temperature control (tungsten-rhenium thermocouple measurement), pressure, dwell time and other relevant parameters, before and after the HIP process copper tungsten contact material hardness, density, bending strength and conductivity of comparative measurements. The density uses conventional Archimedes drainage method; the hardness uses Rockwell hardness HRB and refers to Brinell hardness HB; flexural strength is measured by GB electrical contact material basic performance; electrical conductivity is measured by eddy current conductivity tester.

The experimental result shows that HIP densification mechanism of tungsten copper contacts is similar to the cast alloy, which removes internal defects by deformation - closed - diffusion under high temperature and high pressure and achieves completely densification. Therefore, it requires after-infiltrated material should have good closure, all internal defects, osteoporosis and so can not in communication with the outer surface. If all the defects can not be guaranteed enclosed inside the blank in the process of infiltration, the density after HIP process changes little, even no change. In addition, HIP treatment effect is also related to the content of copper. When the HIP temperature reaches a temperature close to the melting point of copper, its surface will be leaking copper beads phenomenon. Overall, HIP process can promote tungsten copper contact completely densification, which remarkably improves the mechanical and physical properties, and effectively solves dispersion and reliability.

If you have any interest in our tungsten copper alloy products, please do not hesitated to contact us by Email:sales@chinatungsten.comor by telephone:86 592 5129696, we are at your service.