Sintec Keramik Gmbh & Co Kg

Rainer Hegermann

Ulrich Goetz

The invention concerns a piston of finest grain carbon, having a bending strength of at least 100 MPa, a bending elongation >0.8%, an average interlayer distance c/2<0.35 nm, an average crystallite size in the c direction >5 nm and a heat conductivity of at least 10 W/mK, and a method for its production comprising: a) compacting of a polyaromatic mesophase powder to almost its final shape; b) heating of the green product at ambient pressure under a non-oxidizing atmosphere to a temperature of between 900 to 1300&deg; C. and maintenance at this temperature; c) high-temperature treatment, thereby heating up to a temperature between 1400 and 2400&deg; C. and holding this temperature for between 2 and 20 hours; d) cooling down of the shaped form to an ambient temperature at less than 4 K/min, and a polyaromatic mesophase powder for the production of such a piston, characterized by a) a portion of quinoline-insoluble components of &gE;85 weight %; b) a portion of toluene-insoluble components of &gE;90 weight %; wherein c) a shaped form produced from the powder after sintering up to 1000&deg; C. has a mass residue of more than 90 weight % of the mass before sintering.

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Rosshaupten, Germany

Rainer Hegermann