Wetting of silicon carbide by chromium containing alloys

We have studied the wetting behaviour of Cu-Cr, Cu-Ni-Cr, Cu-Si-Cr and Cu-Ni-Si-Cr alloys on sintered β-SiC. The addition of Cr to liquid Cu or Cu-Ni alloys significantly improves their wettability on SiC. The reactions between the Cu-Cr or Cu-Ni-Cr alloys and SiC lead to the formation of a duplex layer containing Cr3C2 and a mixture of Cu and C phases. The formation of this duplex layer can be suppressed by the addition of sufficient Si to the Cu-Cr alloys and the addition of Si does not significantly alter their behaviour. Cu-Ni-Si-Cr alloys also suppressed the formation of the duplex layer below some critical Cr concentration. A thermodynamic model developed for metal/oxide systems can be used to explain the behaviour of their alloys on SiC and also their behaviour on Si3N4. © 1998 Acta Metallurgica Inc.