PRODUCTION OF POLYCRYSTALLINE TITANIUM DIOXIDE CERAMIC

摘要

Polycrystalline titanium dioxide ceramic members are obtained by (A) forming a slurry comprising titanium dioxide and said metal species, said metal species being present in an amount to provide from 0.01 to 8 atomic percent of said metal species in said ceramic member, said slurry being formed either (i) by dissolving in a solvent selected from water and aliphatic alcohols the pentafluoride salt of said metal species in an amount adapted to provide from .01 to 8 atomic percent of said metal species in said ceramic member and then adding titanium dioxide powder in either the rutile or anatase form to the solution to produce a slurry; or (ii) dispersing a mixture of a pentachloridediethyletherate complex of said metal species and titanium dioxide powder in either the rutile or anatase form to form a slurry, said slurry components being included in amounts adapted to provided from .01 to about 8 atomic percent of said metal species in said ceramic member; (B) Drying said slurry to powder form at a temperature at which evaporation of said metal species is avoided; (C) Green forming said powder to the desired shape; (D) Heating the shaped green body to 350.degree.C. at a rate of at least 10.degree.C. per minute; or in the case where slurry of step A is formed using the pentachloride dietherate complex heating to 500.degree.C. at a rate at least 40.degree.C. per minute; (E) Sintering said shaped green body at a temperature of at least 1330.degree.C.; and optionally (F) Annealing said sintered shaped body in a reducing atmosphere having an oxygen partial pressure of 10-5 to 10-25 atmospheres at a temperature of from about 850.degree.C. to 1400.degree.C. to increase the conductivity of said ceramic member.