SEPARATION MECHANISM OF CU CERAMICS MA CO MPOSITE POWDERS IN DC PLASMA SPRAYING/

The separation phenomena of ceramic phase from metal phase have been o ften recognized in the DC plasma spraying of uniformely mixed mechanic ally alloyed (MA) metal-ceramic powders. The separation mechanism of t he MA composite powder materials during plasma spraying was mainly inv estigated in this work. Some methods for restrain the separation were also applied. The results obtained are summarized as follows. (1) The wettability between metal and ceramic material, surface tension of eac h material melted as well as the accelaration force of the plasma to t he molten particles have affected this separation phenomena. (2) Separ ation was recognized even in the Cu/TiC MA powder material system, whi ch had good wettability between metal and ceramic materials. (3) Separ ation was well restrained by both the application of the CuO/alumina p ower materials system and spraying in the low power plasma conditions.