Use of laser beam to form gas-tight connection with high temperature resistance between ceramic moldings, employs glass- or glass ceramic solder

摘要

The first molding (1) includes a recess or continuous passage through it. It is made from semi-transparent oxide ceramic. The second molding (2) is an oxide ceramic, non-oxide ceramic, and/or metal. They (1, 2) are bonded using a glass solder and/or a glass ceramic solder (3). For this purpose, the surfaces to be joined are provided with the solder. The surfaces are raised at least to the melting point of the solder, by irradiation through the semi-transparent oxide ceramic. Provision with solder, implies its arrangement inside the recess or opening. It is alternatively placed in a reservoir at the inlet of an access opening into the zone where faces of the moldings are to be bonded. On heating the bonding zone, capillary effect causes solder to flow into the intermediate space between the moldings. Relative movement is caused between moldings and beam, by rotation or movement of: the moldings, a moveable laser beam and/or at least one moveable laser. The oxide ceramic is partially-transparent to wavelengths of 300 nm to 3 mu m, especially in the waveband 800 nm to 1100 nm. The ceramic is an oxide or is oxide-based, being selected from zirconates, aluminates, silicates, titanates and/or their mixtures. It is selected especially from zirconia, alumina, MgAl 2O 4, silica, Mg 2SiO 4, cordierite, mullite, titania, Al 2TiO 5and/or their mixtures. The metal has a coefficient of thermal expansion in the range 8.5 x 10 - 6/K to 10 x 10 - 6. The metal is preferably selected from Cu, Ti, Fe, Ni, Co, Cr, Zr, W, Mo, Al, V, Si and/or their alloys and/or mixtures. The melting point of the solder is preferably in the range 900-1200[deg] C. The laser beam (or beams) is guided without reaching an end point in the plane of incidence, i.e. to avoid end point overheating. It may be led on a circular, oval or elliptic path. Continuous laser radiation is used. The rotary speed of the moldings is preferably 50-80 rpm. The laser is a diode laser and/or a Nd:YAG laser.