Joining of alumina and steel by a laser supported brazing process

A laser supported method to join ceramic materials with metals has been studied. Using a CO2-laser and an active braze filler material, Al2O3-ceramics have been brazed to steel. The microstructure of the interface has been examined and also the mechanical strength of the brazed joint using bending tests. Typical processing times are of the order of several minutes, which is faster than furnace brazing. The results of the mechanical tests show that the failure of the brazed metal–ceramic joint occurs within the ceramic close to the interface between the braze filler metal and the ceramic part. Thermally induced stresses may lead to cracks within the ceramic, which initiates the failure under mechanical loading. The typical bending strength varies between 40 and 80 MPa with a Weibull modulus ranging from 4.3 to 6.1.