Brazing of micrograin-filled quartz fiber reinforced silica composites and Invar using Ag-21Cu-4.5Ti alloy

Abstract

Brazing of quartz fiber reinforced silica composites (QFSC) to Invar alloy was carried out in a vacuum at 1173 K for 10 min using Ag-21Cu-4.5Ti metal filler. Experiments indicated that composites prefilled with CaCO 3 micrograins had good wettability. The CaCO 3 decomposed to CaO during brazing. After brazing, a joint of structure QFSC/3CaO·2SiO 2+Ti 3O 5+Fe 2Ti+NiTi+Ag(s,s)+ Cu(s,s)/Invar was established. The shear strength of the brazed joint reached 11.6 MPa at room temperature, which is about five times the shear strength of that obtained without surface filling. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.