Effects of simplified pretreatment process on the morphology of W-Cu composite powder prepared by electroless plating and its sintering characterization

摘要

Tungsten-copper (W-Cu) composite powder was prepared by electroless plating with a simplified pretreatment. Morphologies and coposition of the original W, simply pretreated W, W-Cu composite powder, and sintered W-Cu samples were analyzed by field emission scanning electron microscopy (FE-SEM), and energy dispersion spectrometry (EDS). Cold compaction was carried out under the pressure of 400 MPa while sintering at 1200 ℃. The relative density and electrical conductivity of the sintered samples were investigated. The results show that 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 electroless 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 °C and 400 MPa, the sintered specimen exhibited optimum performance, with the relative density reaching as high as 95.04% and superior electrical conductivity of IACS at 53.24%, which doubles the national average of 26.77%.