Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
185 words
A method for manufacturing a high strength, noncorrosive, electronically conductive polycrystalline titanium dioxide ceramic member exhibiting high resistance to thermal shock and uniform grain size with an average size of less than about 25 micrometers and consisting of titanium dioxide in the rutile crystallographic form doped with a homogeneously distributed ionic metal species selected from tantalum and niobium, comprising: (A) Dissolving in a solvent selected from water and aliphatic alcohols the pentafluoride salt of said metal species in an amount adapted to provide from about 0.01 to about 8 atomic percent of said metal species in said ceramic member; (B) Adding titanium dioxide powder is either the rutile or anatase form to the solution of (A) to produce a mixed slurry; (C) Drying said slurry to powder form at a temperature adapted to avoid evaporation of said metal species; (D) Green forming said powder to the desired shape; (E) Heating the shaped green body to about 350° C. at a rate of at least about 10° C. per minute; and (F) Sintering said shaped green body at a temperature of at least about 1330° C.
Claim 2
Independent Claim
185 words
A method for manufacturing a high strength, noncorrosive, electronically conductive polycrystalline titanium dioxide ceramic member exhibiting high resistance to thermal shock and uniform grain size with an average size of less than about 25 micrometers and consisting of titanium dioxide in the rutile crystallographic form doped with a homogeneously distributed ionic metal species selected from tantalum and niobium, comprising: (A) Dissolving in a solvent selected from water and aliphatic alcohols the pentafluoride salt of said metal species in an amount adapted to provide from about 0.01 to about 8 atomic percent of said metal species in said ceramic member; (B) Adding titanium dioxide powder is either the rutile or anatase form to the solution of (A) to produce a mixed slurry; (C) Drying said slurry to powder form at a temperature adapted to avoid evaporation of said metal species; (D) Green forming said powder to the desired shape; (E) Heating the shaped green body to about 350° C. at a rate of at least about 10° C. per minute; and (F) Sintering said shaped green body at a temperature of at least about 1330° C.
Claim 3
Dependent Claim
56 words
A method as devised in claim 1, further comprising an annealing step wherein said sintered shaped body is annealed in a reducing atmosphere having an oxygen partial pressure of about 10 -5 to about 10 -25 atmospheres at a temperature of about 850° C. to about 1400° C. to increase the conductivity of said ceramic member.
Claim 4
Dependent Claim
34 words
A method in accordance with claim 1 wherein said pentafluoride salt is employed in amounts sufficient to provide from about 0.1 to about 3 atomic percent of said metal species in said ceramic body.
Claim 5
Dependent Claim
28 words
A method in accordance with claim 1 wherein said shaped green body is sintered at a temperature in the range of about 1380° C. to about 1440° C.
Claim 6
Dependent Claim
133 words
A method in accordance with claim 2 wherein (1) said pentafluoride salt is employed in amounts sufficient to provide from about 0.1 to about 3 atomic weight percent of said metal species in said ceramic body. (ii) said shaped green body is sintered at a temperature of about 1400° C., and (iii) said oxygen partial pressure range during annealing comprises the values within the union of two graphic regions defined by the following limits: (A) a range of oxygen partial pressures from about 10 -5 to about 10 -15 atmospheres for an annealing temperature range of about 850° C. to about 1250° C.; and (B) a range of oxygen partial pressures from about 10 -10 to about 10 -20 atmospheres for an annealing temperature range of about 1250° C. to about 1400° C.
Claim 7
Dependent Claim
12 words
A ceramic member prepared in accordance with the method of claim 1.
Claim 8
Independent Claim
176 words
A method for manufacturing a high strength, noncorrosive electronically conductive polycrystalline titanium dioxide ceramic member exhibiting high resistance to thermal shock and uniform grain size with an average size of less than about 25 micrometers and consisting of titanium dioxide in the rutile crystallographic form doped with a homogeneously distributed ionic metal species from tantalum and niobium, comprising: (A) dispersing a mixture of a pentachloride-diethyletherate 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 provide from about 0.01 to about 8 atomic weight percent of said metal species in said ceramic member; (B) Drying said slurry to powder form at a temperature adapted to avoid evaporation of said metal species: (C) Green forming said powder to the desired shape; (D) Heating the shaped green body to about 500° C. at a rate of at least about 40° C. per minute; and (E) Sintering said shaped green body at a temperature of at least about 1330° C.
Claim 9
Independent Claim
176 words
A method for manufacturing a high strength, noncorrosive electronically conductive polycrystalline titanium dioxide ceramic member exhibiting high resistance to thermal shock and uniform grain size with an average size of less than about 25 micrometers and consisting of titanium dioxide in the rutile crystallographic form doped with a homogeneously distributed ionic metal species from tantalum and niobium, comprising: (A) dispersing a mixture of a pentachloride-diethyletherate 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 provide from about 0.01 to about 8 atomic weight percent of said metal species in said ceramic member; (B) Drying said slurry to powder form at a temperature adapted to avoid evaporation of said metal species: (C) Green forming said powder to the desired shape; (D) Heating the shaped green body to about 500° C. at a rate of at least about 40° C. per minute; and (E) Sintering said shaped green body at a temperature of at least about 1330° C.
Claim 10
Dependent Claim
56 words
A method as defined in claim 7, further comprising an annealing step wherein said sintered shaped body is annealed in a reducing atmosphere having an oxygen partial pressure of about 10 -5 to about 10 -25 atmospheres at a temperature of from about 850° C. to about 1400° C. to increase conductivity of said ceramic member.
Claim 11
Dependent Claim
31 words
A method in accordance with claim 7 wherein said pentachloridediethyletherate complex of said metal species is prepared by adding a pentachloride salt of said metal species to an excess of diethylether.
Claim 12
Dependent Claim
37 words
A method in accordance with claim 7 wherein the components of said slurry are included in amounts adapted to provide from about 0.1 to about 3 atomic weight percent of said metal species in said ceramic body.
Claim 13
Dependent Claim
28 words
A method in accordance with claim 7 wherein said shaped green body is sintered at a temperature in the range of about 1380° C. to about 1440° C.
Claim 14
Dependent Claim
133 words
A method in accordance with claim 7 wherein (i) said slurry components are employed in amounts sufficient to provide from about 0.1 to about 3 atomic weight percent of said metal species in said ceramic body, (ii) said shaped green body is sintered at a temperature of about 1400° C., and (iii) said oxygen partial pressure range during annealing comprises the values within the union of two graphic regions defined by the following limits: (A) a range of oxygen partial pressures from about 10 -5 to about 10 -15 atmospheres for an annealing temperature range of about 850° C. to about 1250° C., and (B) a range of oxygen partial pressures from about 10 -10 to about 10 -20 atmospheres for an annealing temperature range of about 1250° C. to about 1400° C.