Troisiéme Conférence Européenne sur les Matériaux et les Procédés Avancés
J. Phys. IV France 03 (1993) C7-1293-C7-1298
Silicon carbonitrides - A novel class of materialsH. SCHÖNFELDER1, F. ALDINGER1 and R. RIEDEL2
1 Max-Planck-Institute of Metals Research, Laboratory for Powder Metallurgy, Institute of Materials Science, Heisenbergstr. 5, 7000 Stuttgart 80, Germany
2 University of Darmstadt, Institute of Materials Science, Hilpertstr. 31, PTZ, Building D, 6100 Darmstadt, Germany
Silicon carbonitride monoliths derived from polymer powder compacts via polymer pyrolysis represent a new class of structural ceramic materials due to the complete coalescence of the powder particles during polymer decomposition and the formation of a uniform ceramic matrix free from any grain boundaries or secondary phases. The submicron pore channel system penetrating the material can be minimized in volume by infiltration of liquid polysilazane solution or by post-HIPing so that relative densities of 96 % can be reached. The monoliths are oxidation resistant up to 1600°C in air due to the formation of a highly pure silica oxidation layer and they exhibit a creep rate of 1.10-6 s-1 at 1650°C and 30 MPa load. Initially x-ray amorphous silicon carbonitride can be crystallized in nitrogen or in air to form Si3N4/SiC or Si3N4/SiC/C nanocomposites.
© EDP Sciences 1993