Wetting of laser-textured tungsten substrate by molten tin

Abstract

In the new generation of nuclear reactors, plasma facing components tend to be designed as Sn/W composite components. Considering the combination of tin and tungsten, the wettability evaluation of Sn/W system and its influencing factors are urgent work. Wetting experiments of Sn/W system were carried out in high vacuum by using modified sessile drop method. The results show that after vacuum annealing at 1100℃, good wettability (∼ 48° intrinsic contact angle) can be obtained quickly at 900℃ below the critical temperature of 1050℃. After laser surface texturing, the greater the roughness of the tungsten substrate surface, the better the wettability can be obtained. In essence, this correspondence is closely related to the geometric parameters of the grooves formed by laser etching, which corresponds to the predicted results in Wenzel model. The phenomenon of pinning and depinning of triple lines in the later stage of spreading is related to the spreading of liquid in the groove, and the spreading rate of the latter is faster than that of macro triple line, which leads to this phenomenon.