| 摘要 |
PCT No. PCT/DE87/00285 Sec. 371 Date Feb. 27, 1989 Sec. 102(e) Date Feb. 27, 1989 PCT Filed Jun. 24, 1987 PCT Pub. No. WO88/01610 PCT Pub. Date Mar. 10, 1988.A ceramic consisting substantially of Al2O3 as ceramic support, ceramic cover layer and/or ceramic supporting structure for heating conductors is described, which is electrochemically stable, which, in other words, does not decompose on application of a heating voltage, even in long-term operation at temperatures above 600 DEG . Such a ceramic exhibits a very small alkali metal content, of less than 0.2% by weight Na2O and K2O respectively. Particularly favorable processing, in particular pressing properties are exhibited by such a ceramic if it has 2.5 to 10% by weight of barium silicate or strontium silicate fluxes, the proportions of Na2O, K2O, CaO and MgO together make up less than 1% by weight, and the BaO or SrO:SiO2 molar ratio is between 2:1 and 1:12.5. Such a ceramic with a BaO:SiO2 ratio of 2.6:1 parts by weight is electrochemically stable up to approximately 1400 DEG C., and at 1300 DEG C. still exhibits a bending strength of approximately 300 N/mm2.
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