Process for applying a protective layer to shaped carbon bodies

A process for applying a protective layer to shaped carbon bodies within a reactor, comprising the steps of:

• heating the shaped carbon bodies to a temperature of 1250.degree. to 1350.degree. C.;
• depositing by vapor deposition the reaction products of a gaseous admixture containing a carrier gas and a member selected from the group consisting of (a) a silicon- and carbon-containing gaseous compound and (b) a gaseous admixture including a silicon-containing gaseous compound and a carbon-containing gaseous compound onto the surface of the shaped carbon bodies so as to produce a silicon carbide layer;
• lowering the temperature of the carbon bodies to between 1000.degree. and 1200.degree. C.;
• and
• subsequently depositing by chemical vapor deposition from a carrier gas onto the shaped carbon body, the reaction product of a gaseous organosilicon compound and ammonia so as to produce a silicon nitride layer.