Vacuum bonding techniques to set up joints between ceramics and metals and between composite materials and alloys

Today the industrial use of assemblies involving joints between ceramics and metal, cermets and steel, composite materials and alloys is developing in various fields such as the designing of better cutting tools or the realization of thermal shields. 2 techniques of joining are mainly used. The in-oven vacuum brazing where the bonds are set during the liquid phase and the thermo-compression which involves only solid phases. The physico-chemical processes and the mechanical interactions that occurred at the joining interface are presented. The different parameters and factors that intervene in the quality of the metallurgical bonds are analysed. The theoretical study of the basic phenomena allows to explain the formation of defects, to determine control means and testing methods and to optimize operating modes. (A.C.)