Wetting Behaviors of Nickel-Based Alloys on Sintered Silicon Carbide Ceramics

Abstract

Wetting behaviors of pure nickel and nickel-based alloys on sintered silicon carbide ceramics and their interfacial microstructures were investigated in this presentation. The nickel-based alloys were mainly the commercial nickel-molybdenum-chromium products. The wetting and spreading properties were observed by a real-time thermal optical measurement system under flowing argon-5%hydrogen atmosphere. As temperature increased, the pure nickel cylinder sample had few changes before 1356°C except for the thermal expansion in size and changed to liquid drop-shape when the temperature reached 1366°C. The contact angle was about 90o. And nickel could not contact sintered silicon carbide ceramics well. However, the introduction of molybdenum and/or chromium in the pure nickel was good for the wetting properties of pure nickel on sintered silicon carbide ceramics. The contact angles of nickel-based alloys (B-1, C-1 and C-2) on sintered silicon carbide ceramics after holding 15min at 1400°C were 25o, 12.5o, 11.5o, respectively. And they hardly reduced as temperature increased. The SEM images indicated that the interfacial microstructures of B-1 and C-1 on sintered silicon carbide ceramic substrates were uniform and the dissolved interface near silicon carbide ceramics indicated that they had a good bonding. At the same time, the reciprocal diffusion was clear in the intermediate layer. Besides that, the introduction of chromium was supposed to reduce the diffusion rate of molybdenum from the alloy to the ceramic substrate.