Ni-56Si合金对SiC陶瓷的润湿和铺展

采用座滴法考察了不同温度和气氛下Ni-56Si合金对SiC陶瓷的润湿和铺展行为。分析了固化后的液滴/SiC衬底界面和液滴表面的微结构和相组成。结果表明:该润湿体系于1350℃下在真空、1个大气压的静态或流动的Ar+5%(体积分数)H2的混合气3种气氛中均可获得优良的润湿性。在真空条件下,其铺展最快达到平衡,1350℃时的润湿性明显优于1100℃和1200℃,且在1100℃时的铺展过程与1350℃和1200℃有显著不同,即存在2种不同的铺展机制,这与SiC表面的润湿壁垒(SiO2层)的消除动力学有关。界面微结构分析进一步证实该系统的非反应润湿特性。

WETTING AND SPREADING OF Ni-56Si ALLOY ON SiC CERAMIC

The wetting and spreading of Ni-56Si alloy on SiC ceramic were performed under different temperatures and atmospheres by the sessile drop technique. The microstructure and phase compositions of solidified sessile drop/SiC substrate interface and drop surface were analyzed by scanning electron microscopy and energy dispersive spectroscopy. The results show that good wettability can be obtained in the Ni-56Si/SiC system at 1 350 ℃ under a high vacuum,static or flowing atmosphere of Ar ＋ 5% in volume H2 atmospheres,respectively,and the fastest spreading equilibrium can be achieved under vacuum. The wettability at 1 350 ℃ is clearly better than those at 1 100 and 1 200 ℃ in vacuum. The spreading process at 1 100 ℃ is different from those at 1 200 and 1 350 ℃ in vacuum,and two different spreading mechanisms are present at the three different temperatures,which can be attributed to the kinetics of removing the wetting barriers （SiO2 layer） on SiC surface. The non-reactive wetting characteristics are further confirmed by the interface microstructure in this Ni-Si/SiC system.