Interfacial Reaction between SiC Ceramics and Cu-Mn Alloy (Report 2)

Abstract

A reactive bonding method of Cu foil to sintered SiC ceramics using Cu-Mn liquid insert alloy was reported previously (Report 1).
Solid-state and liquid-state reactions of Cu-Mn/SiC were investigated in this report at heating temperatures of 500-700°C for 1 min and 900°C for-60 min using EPMA, AES and XRD. Results obtained are summarized as follows.
1) Mn concentrates to the Cu-Mn/SiC interface at heating above 600°C (Cu-Mn is in solid state). Depth profile analysis with AES revealed that Mn reacts to SiC and releases the C, forming Mn-silicides such as Mn₅Si₃ and Mn₅Si₂. While the released C diffuses into the Mn layer.
2) Any reaction layer, except C rich layer, couldnt be observed at liquid Cu-Mn/SiC interface by heating even at a high temperature for long time (900°C, 60 min). But a phenomenon of separating and flouting into the liquid of sintered SiC grains was observed, which is considered to be caused by the preferential diffusion of Mn into grain-boundarys of sintered SiC.