Ceramic material for high temperature service

Abstract

A high purity yttria or ytterbia stabilized zirconia powder wherein a purity of the zirconia is at least 99.5 weight percent purity and with a maximum amount of specified oxide impurities.

What is claimed: 
     
         1 . A ceramic powder comprising:
 a primary stabilizer oxide comprising 4-20 weight percent and oxide impurities up to a maximum of 0.15 weight percent; and   a first material comprising a balance of the ceramic powder, wherein the first material is partially stabilized by the primary stabilizer oxide into a first partially stabilized material;   wherein the oxide impurities, when combined with each other or with the first partially stabilized material, form phases with melting temperatures at least 100° C. lower than the melting temperature of the first material.   
     
     
         2 . The ceramic powder according to  claim 1 , wherein the first material comprises at least one of zirconia or hafnia; and
 the primary stabilizer oxide comprises at least one of a yttria or a ytterbia stabilizer.   
     
     
         3 . The ceramic power according to  claim 2 , wherein the oxide impurities comprise:
 less than 0.005 weight percent SiO 2 ;   less than 0.015 weight percent Al 2 O 3 ;   less than 0.002 weight percent TiO 2 ; and   less than 0.002 weight percent MgO.   
     
     
         4 . The powder of  claim 3 , wherein the oxide impurities further comprise:
 less than 0.04 weight percent Fe 2 O 3 ;   less than 0.02 weight percent CaO;   less than 0.001 weight percent Cr 2 O 3 ; and   less than 0.002 weight percent Na 2 O.   
     
     
         5 . The powder of  claim 1 , wherein the powder is a thermal sprayable powder. 
     
     
         6 . The powder of  claim 1  has a high purity of at least 99.5 weight percent purity. 
     
     
         7 . The powder of  claim 1 , wherein said powder has a particle size of from about 5 to 150 microns. 
     
     
         8 . A blended ceramic powder comprising:
 a first material composition comprising:
 a first primary stabilizer oxide comprising 4-16 weight percent and first oxide impurities up to a maximum of 0.15 weight percent; and 
 a first material comprising a balance of the first material composition, wherein the first material is partially stabilized by the first primary stabilizer oxide into a first partially stabilized material; 
 wherein the first oxide impurities, when combined with each other or with the first partially stabilized material, form phases with melting temperatures at least 100° C. lower than the melting temperature of the first material; and 
   a second material composition comprising:
 a second primary stabilizer oxide comprising 4-20 weight percent and second oxide impurities up to a maximum of 0.15 weight percent; and 
 a second material comprising a balance of the second material composition, wherein the second material is partially stabilized by the second primary stabilizer oxide into a second partially stabilized material; 
 wherein the second oxide impurities, when combined with each other or with the second partially stabilized material, form phases with melting temperatures at least 100° C. lower than the melting temperature of the second material. 
   
     
     
         9 . The blended ceramic powder according to  claim 8 , wherein the first material comprises at least one of zirconia or hafnia, the first primary stabilizer oxide comprises 4-12 weight percent of a yttria stabilizer, and a fraction of the first material in the blended powder is 5-50 weight percent, and
 wherein the second material comprises at least one of zirconia or hafnia, the second primary stabilizer oxide comprises 4-16 weight percent of a ytterbia stabilizer, and a fraction of the second material in the blended powder is 50-95 weight percent.   
     
     
         10 . The blended ceramic powder according to  claim 9 , further comprising a third material composition comprising:
 a third primary stabilizer oxide comprising 4-20 weight percent and second oxide impurities up to a maximum of 0.15 weight percent,   a third material comprising a balance of the third material composition, wherein the third material is partially stabilized by the third primary stabilizer oxide into a second partially stabilized material,   wherein the third first oxide impurities, when combined with each other or with the third partially stabilized material, form phases with melting temperatures at least 100° C. lower than the melting temperature of the third material.   
     
     
         11 . The blended ceramic powder according to  claim 10 , wherein the third material composition comprises at least one of zirconia or hafnia, the third primary stabilizer oxide comprises at least one of 4-16 weight percent of a neodymium stabilizer or 4-20 weight percent Europa stabilizer,
 wherein the fraction of the first material in the blended powder is 10-90 weight percent,   wherein the fraction of the second material in the blended powder is 5-45 weight percent and   wherein the fraction of the third material in the blended powder is 5-45 weight percent.   
     
     
         12 . The blended ceramic powder according to  claim 8 , wherein the first material comprises at least one of zirconia or hafnia, the first primary stabilizer oxide comprises 4-16 weight percent of a ytterbia stabilizer, and the first material fraction of the blended powder is 5-50 weight percent, and
 wherein the second material comprises at least one of zirconia or hafnia, the second primary stabilizer oxide comprises at least one of 4-16 weight percent of a neodymium stabilizer or 4-20 weight percent Europa stabilizer, and the second material fraction of the blended powder is 50-95 weight percent.   
     
     
         13 . The blended ceramic powder according to  claim 8 , wherein the first material comprises at least one of zirconia or hafnia, the first primary stabilizer oxide comprises 4-12 weight percent of a yttria stabilizer, and the first material fraction of the blended powder is 50-95 weight percent, and
 wherein the second material comprises at least one of zirconia or hafnia, the second primary stabilizer oxide comprises at least one of 4-16 weight percent of a neodymium stabilizer or 4-20 weight percent Europa stabilizer, and the second material fraction of the blended powder is 5-50 weight percent.   
     
     
         14 . The blended ceramic powder according to  claim 8 , wherein at least one of the first, second and third oxide impurities comprise:
 less than 0.005 weight percent SiO 2 ;   less than 0.015 weight percent Al 2 O 3 ;   less than 0.002 weight percent TiO 2 ; and   less than 0.002 weight percent MgO.   
     
     
         15 . The blended ceramic powder of  claim 14 , wherein the at least one of the first, second or third oxide impurities further comprises:
 less than 0.04 weight percent Fe 2 O 3 ;   less than 0.02 weight percent CaO;   less than 0.001 weight percent Cr 2 O 3 ; and   less than 0.002 weight percent Na 2 O.   
     
     
         16 . The blended ceramic powder of  claim 8  is a thermal sprayable powder. 
     
     
         17 . The blended ceramic powder of  claim 8  has a particle size of from about 5 to 150 microns. 
     
     
         18 . The blended ceramic powder of  claim 8  has a high purity of at least 99.5 weight percent purity.