Abstract: The contact angle of liquid Ag with solid W and its temperature dependance were examined by sessile drop method under various atmospheres,e.g.vacuum,Ar,H_2 and carcked NH_3.The O_2 partial pressure in the atmosphere is found to be the major factor. An obvious improvement on the wettability may be made by a trace amount of Ni,Cu or Ce added to liquid Ag,The contact angle near M.P.is then narrowed from 69 to about 10—20 deg.

Key words: contact angle, Ag, W, atmosphere, wettability