PREPARATION AND PROPERTIES OF ALCON (AL28C6O21N6) CERAMICS

The synthesis of Al28C6O21N6 powder (ALCON), starting from the binary compounds is described. The powder is resistant to oxidation in air up to 760 degrees C. From the prepared powder, fully dense ceramics have successfully been prepared using hot pressing. The as-prepared cerami cs had a thermal conductivity of 20Wm(-1)K(-1). Experiments showed tha t it is also possible to prepare ALCON ceramics by reactive hot-pressi ng, starting from Al2O3, AIN and Al4C3. Further optimization is expect ed to raise the thermal conductivity significantly. The strength, abou t 300 MPa, is similar to that of AIN. The thermal expansion coefficien t of 4.8 x 10(-6)K(-1) closely matches that of silicon, making applica tion of ALCON ceramics as heat sinks an interesting possibility.