Metal-Ceramic Joining, an Important Key to Ceramic Materials Development

Abstract

Ceramic to metal bonding is a very old process dating back to when Egyptians first used it to cover their jewels with enamels several centuries B.C. Although coating techniques such as flame and plasma spraying are quite wide-spread in the industry, new needs to join bulky materials have emerged over the past couple of decades. In each case the problems stem mainly from the differences between the intrinsic properties of each material, such as:

• atomic structure

• physical properties

• mechanical behaviour

• chemical properties

In order to produce reliable joinings, it is necessary to solve several problems due to new interface formations such as:

• bad wetting of ceramics by molten metals

• achievement of good contact between the surfaces

• poor reactivity between materials at low temperature

• residual stress in the materials...

This tutorial does not claim to explain all the bonding mechanisms, since the interface creation engenders problems such as flaws, internai stress..., but proposes an approach of the principles to establish a valuable study of metal-ceramic joining.