A method of manufacturing synthetic quartz used for supporting and placing a wafer with a focus ring or edge ring ceramic member which is used during a semiconductor manufacturing process, and the present invention is directed to providing a method of manufacturing cylindrical synthetic quartz which is capable of improving a yield by minimizing temporal loss and quantitative loss and significantly increasing the rate of synthetic quartz production.

Tubular ceramic structures, e.g., anode components of tubular fuel cells, are manufactured by applying ceramic-forming composition to the external surface of the heat shrinkable polymeric tubular mandrel component of a rotating mandrel-spindle assembly, removing the spindle from the assembly after a predetermined thickness of tubular ceramic structure has been built up on the mandrel and thereafter heat shrinking the mandrel to cause the mandrel to separate from the tubular ceramic structure.

Tubular ceramic structures, e.g., anode components of tubular fuel cells, are manufactured by applying ceramic-forming composition to the external surface of the heat shrinkable polymeric tubular mandrel component of a rotating mandrel-spindle assembly, removing the spindle from the assembly after a predetermined thickness of tubular ceramic structure has been built up on the mandrel and thereafter heat shrinking the mandrel to cause the mandrel to separate from the tubular ceramic structure.

A sprayed article is prepared by thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto an outer or inner surface of a cylindrical carbon substrate to form a sprayed coating, and burning out the carbon substrate, thus leaving the ceramic or metal-base sprayed coating of cylindrical shape having a wall thickness of 0.5-5 mm.

A sprayed article is prepared by thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto an outer or inner surface of a cylindrical carbon substrate to form a sprayed coating, and burning out the carbon substrate, thus leaving the ceramic or metal-base sprayed coating of cylindrical shape having a wall thickness of 0.5-5 mm.

A sprayed article is prepared by thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto an outer or inner surface of a cylindrical carbon substrate to form a sprayed coating, and burning out the carbon substrate, thus leaving the ceramic or metal-base sprayed coating of cylindrical shape having a wall thickness of 0.5-5 mm.

A sprayed article is prepared by thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto an outer or inner surface of a cylindrical carbon substrate to form a sprayed coating, and burning out the carbon substrate, thus leaving the ceramic or metal-base sprayed coating of cylindrical shape having a wall thickness of 0.5-5 mm.

A sprayed article is prepared by thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto an outer or inner surface of a cylindrical carbon substrate to form a sprayed coating, and burning out the carbon substrate, thus leaving the ceramic or metal-base sprayed coating of cylindrical shape having a wall thickness of 0.5-5 mm.

A sprayed article is prepared by thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto an outer or inner surface of a cylindrical carbon substrate to form a sprayed coating, and burning out the carbon substrate, thus leaving the ceramic or metal-base sprayed coating of cylindrical shape having a wall thickness of 0.5-5 mm.