Bonding of alumina to steel using copper interlayer

The experiments carried out show that multilayer bonding by using thin and very plastic material interlayer is a good solution of the problem of making alumina - st joints with large dimensions. Using ct this type interlayer allows for relaxation of stresses generated during bonding cycle. It was concluded that copper material interlayer is suitable for this purpose. Direct bonding using active products of reduction reaction of CuO (Cu2O, O-2) can be the adequate process of bonding joints with copper interlayer, Using this method, we can partly to foe the relation between the quality of the bond (homogenious microstructure at the whole bonding surface) and a protective atmosphere. This paper contains the conditions of alumina - steel joining process and results of strength tests. Another part of this work are microstructure examinations, showing the homogenity of bonds. The elaborated method can be used for joining alumina to copper and copper to steel in one thermal cycle. Such bonded joints have high mechanical strength and homogenous microstructure. Comparing to other joining methods this process does not need to use any special joining conditions (following bonding features - low bonding temperature similar to 1340K, protective atmosphere of N-2 containing below 40 ppm O-2, bonding time similar to 90 minutes).