Laser joining of silicon carbide - a new technology for ultra-high temperature resistant joints

High performance ceramics, e.g., silicon carbide (SiC), can widely be used in the nuclear sector because of their excellent thermo chemical and radiological properties. However, it has not been possible to utilise this great potential since the technologies for high temperature resistant joining of these ceramic materials are not yet satisfying. This paper describes an innovative laser joining technology that allows the firm vacuum gas tight binding between any shaped bodies made of these ceramic materials. The joints obtained are temperature resistant at 1600 degreesC and above. The method is based on a solder that is specially made from Al2O3, Y2O3 and SiO2 and melted locally in the joining zone by use of laser radiation. The paper discusses the influence of the laser beam wave length, the seam geometry and the solder composition on the quality of the braze joint. The advantages of this new method are illustrated by means of laser brazed SiC capsules and other parts and compared with conventional joining methods. (C) 2004 Elsevier B.V. All rights reserved.