FRAMEWORKS FOR DIRECT BONDING

The spontaneous formation of a direct bond between materials - a phenomenon sometimes encountered in mechanics and optics - was considered inconvenient at first. It was some time before the advantages of the possibility of realizing direct bonds were realized: direct bonds obviated the need for intermediate adhesive layers. A good deal of research had to be done into the required pretreatment of the material parts and the aftertreatment for bond tightening before direct bonding could be used as a technology. Geometrical, mechanical, chemical and physical properties of the materials involved all play a part in the formation of a direct bond; they are collectively referred to as the physiognomic properties. This chapter will describe a number of examples demonstrating the wide variety of materials (both inorganic and organic) that can be directly bonded, after which some magnetic, electric and electromagnetic advantages of directly bonded, electromagnetically active materials will be briefly outlined.