Keramikverbundwerkstoff und seine Verwendung

摘要

A ceramic composite material consists of a carbon fiber-reinforced SiC+C matrix coated with a lower protective layer of one or more compounds of Si, C, B and O, a middle protective layer based on transition metal borides and/or silicides and an upper protective layer of one or more of SiC, SiO2, MoSi2, Mo3Si, Mo5Si3, ZrB, ZrB2, ZrB12, Si3N4, ZrO2, Y2O3, Al2O3, Al2O3-SiO2 mixed oxide and SiOC. A ceramic composite material, for use at up to 1600 degrees C, consists of a basic material which comprises 30-60 vol.% C fibers, 10-55 vol.% matrix of SiC and C in a wt. ratio of 2-20:1 and 5-40 vol.% porosity and which is coated with (a) a 20-150 mu thick lower protective layer of one or more compounds of Si, C, B and O; (b) a 50-250 mu thick middle protective layer of transition metal borides and/or silicides in combination with SiC, SiO2 or SiOC; and (c) a 20-250 mu thick upper protective layer of one or more of SiC, SiO2, MoSi2, Mo3Si, Mo5Si3, ZrB, ZrB2, ZrB12, Si3N4, ZrO2, Y2O3, Al2O3, Al2O3-SiO2 mixed oxide and SiOC. Independent claims are also included for (i) increasing the effectiveness of the oxidation protection system of the above ceramic composite material by an oxidative pretreatment at 900-1400 degrees C to activate the crack sealing mechanisms before use; and (ii) production of the coating layers (a), (b) and (c) by applying slips of inorganic fillers, organic binder and solvent and firing such that the organic binder is converted into inorganic components of the layers.