EFFECTS OF ATMOSPHERE AND TRACE ELEMENT ON THE WETTABILITY OF SOLID W BY LIQUID Ag

The contact angle of liquid Ag with solid W and its temperature dependance wereexamined by sessile drop method under various atmospheres,e.g.vacuum,Ar,H_2 andcarcked 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 orCe added to liquid Ag,The contact angle near M.P.is then narrowed from 69 to about10—20 deg.