JOINING OF GLASSY CARBON WITH A C/C-SIC COMPOSITE BY BRAZING FOR AN INNOVATIVE HIGH TEMPERATURE SENSOR

A novel temperature sensor based on thermal field emission in a vacuum requires the development of an adapted protective system composed of a protective tube and a shutter. The requirements of the protective tube are complex. The tube has to be temperature resistant, thermal shock resistant, thermally conductive, corrosion resistant, fracture resistant and gas tight. A new approach is a coated hybrid composite, which is made of glassy carbon and a C/C-SiC composite. The final manufacturing step is the integration of the temperature sensor. Thus, thermal joining of the protective tube with the shutter appears to be necessary. The joint has to be temperature resistant, gas tight and mechanically stable. The article discusses the development of a suitable active brazing method by means of titanium-containing brazing alloys to join the mentioned components: especially glassy carbon with glassy carbon, Si3N4 and C/C-SiC. Finally, the joints are characterized by scanning electron microscopy. The mechanical properties of the joints are determined by the four point bending test.