ＳｉＣセラミックスと銅との接合及びその接合体の熱的特性 セラミックスと金属との接合 １

Abstract

A new bonding technique of copper and SiC ceramics having high thermal conductivity was developed, and thermal characteristics of the bonded elements were evaluated.SiC ceramics used in the experiments were hotpress-sintered material containing a small amount of BeO. It has high thermal conductivity (270W/m·k) and also high electrical resistivity (1013Ω·cm or above).It was concluded from this study that, (1) 50 mm×50 mm square SiC blocks were successfully bonded to copper blocks within 20 second without cracking by using both Cu-35wt%Mn foil as a brazing material and the copper-35vol% carbon fiber composite material of 2 mm in thickness as the compliant material to relieve the thermal stress.(2) Manganese silicides (Mn6Si) and manganese carbides (Mn23C6) were observed in the SiC/Cu bonded zone by using Cu-35wt% Mn brazing foil.(3) Peel strength between a SiC block and 100μm thick copper foil was above 2 kgf/mm and fracture occurred in copper foil.(4) Tensile strength of a bonded element of SiC block/Cu-35vol% carbon fiber compliant material/ copper block was about 2 kgf/mm2. Fracture occurred in the composite material. The element can be heat resistant and used up to 300°C.(5) Thermal reliability of the bonded element (using a 35 mm square SiC block) was evaluated by normal thermal cycle test and rapid thermal cycle test using a 1.5 MW splash test machine. Maximu allowable heat fluxes were about 500 W/cm2 and 400 W/cm2 respectively.