High-Strength Bauxite Porcelain - New Results and the Special Impact of Reducing Firing Atmosphere

摘要

For the first time, in latest development works, in which sintered bauxite was used as A12O3 carrier, the detrimental residual quartz was dissolved nearly fully by aggressive early eutectic melt phases [1], The Fig, 1 a-c show the microstructure of this novel material, which is free from residual quartz [2-3]. To improve the mechanical properties, a maximum amount of the A12O3 should be corundum, and the mullite needles should be as small as possible. This goal was achieved with the microstructure shown in the Figures 1 a-c. With regard to the options for the development of a high-strength technical porcelain without addition of alumina, the following results and statements, which comprise suggestions for novel solutions, were obtained [1]: o A high-strength technical porcelain can be produced without use of alumina if low- iron calcinated bauxites containing >85 % of A1,O3 are introduced instead of alumina. For this purpose, the added amount of bauxite must be higher than 50 mass-% if bending strength values of the material specimens above 200 MPa are to be attained.