Study On Preparation Of W-Cu Composite Powder Using Electroless Plating And Its Sintering Properties

W-Cu composite materials possess excellent properties such as high strength, excellent electric conductivity, low thermal expansion and high-temperature oxidation resistance. These features make the W-Cu composite a very attractive material which has been widely used as heavy-duty electronic contactors, circuit breakers and thermal management devices, and so on. With the rapid development of the electronic information industry and the high-tech fields of defense industry, there are several new directions of development and requirements on high performance W-Cu composites. However, due to their relatively large difference in properties between W and Cu, the preparation process of these composites require higher requirement. The preparation of the superfine/nano W-Cu composite powder is the one of methods to prepare the W-Cu composite materials with well performance. Electroless plating is an autocatalytic method in which the reduction of the metallic ions in the solution and the film deposition can be performed by the oxidation of chemical compound present in the solution itself. Electroless plating produces high-purity composite powders with even phase dispersion. In this paper, W-30Cu/(0,0.25,0.5,1,2) wt.%TiN composite materials were prepared by electroless plating with simplified pretreatment and powder metallurgy. And the technic parameters of process, optimal design and properties of those composites were analyzed, investigated a new approach in the preparation of W-Cu composite materials with high performance. The following conclusions could be drawn:(1)W-Cu composite powder was prepared by electroless plating with a simplified pretreatment. The defect formed on the surface of the simply treated W powder favors the adsorption, nucleation, and growth of Cu grain in subsequent electroless copper plating. Cellular projection at the same conditions on the surface of the simply treated W powder increased with the increase in HF content up to a certain range. The W-Cu composite powder obtained after electroless copper plating became more even, however, continued increase in HF content to a certain value caused the decrease in the number of defects that formed on the surface of pretreated W powder as well as the decrease in the amount of Cu grains adsorbed on the surface of W powder during electro less copper plating, but the number of free and not be adsorbed Cu grains were increased. Lastly, the obtained evenness degree of the W-Cu composite powder was reduced. At 1200℃ and 400 MPa, the sintered specimen exhibited optimum performance, with the relative density reaching as high as 95.04% and superior electrical conductivity of I ACS at 53.24%, which doubles the national average of 26.77%.(2)Dense W-30Cu composites can be obtained by electroless plating and powder metallurgy. With different sintering processes, the maximum relative density is 95.04% at 400MPa compaction pressure and 1200℃ sintering.(3)The W-30Cu composite materials supplemented with different TiN contents have been successfully fabricated by electroless plating with simplified pretreatment and powder metallurgy. The addition of TiN nanoparticles significantly affected the micro structure and properties of W-30Cu composite materials. A good combination of the compressive strength and hardness of the W-30Cu composite material can be obtained with the incorporation of TiN additive at 0.25 wt%. However, the relative density and electric conductivity slightly decreased.