クロムメタライズ法によるSiCセラミックスと金属との銀ろう付(第1報)
1988 年 6 巻 2 号 p. 226-232
詳細
1988 年 6 巻 2 号 p. 226-232
A new chromium (Cr) metallization process was developed for brazing or soldering of SiC ceramic to metal. This report describes the characteristics of Cr metallization, bond strength and helium leak rate of the silver brazed layer.
SiC ceramics used in the experiments was hotpress-sintered material containing a small amount of BeO. It has a high thermal conductivity (270 W/m.K) and also a high electrical resistivity (1014Ω.m). Silver brazing of SiC ceramics to metal was carried out at 1073K using eutectic alloy of 72wt% Ag-28 wt% Cu.
The results of this study are as follows,
(1) Cr metallization was achieved by printing Cr paste on the surface of SiC ceramics, and then heating the ceramics at a temperature between 1173K and 1273K for 1.8ks in Ar atmosphere.
(2) The thickness of Cr metallized layer did not depend on the thickness of printed Cr paste under the same heating condition.
(3) The bending strength of the SiC/SiC and SiC/WC-Co hard alloy, brazed layer were 320MPa and 360MPa respectively at 723K and fractured through SiC. The fracture remained in the brazed layer at temperatures above 773K.
(4) The helium leak rate of the silver brazed layer (combination: SiC/A1203, SiC/kovar, SiC/WC-Co) was less than 1.2×10-10 atm.cc/s even after the thermal cycle testing.
