High purity powders

摘要

This invention relates to high purity yttria or ytterbia stabilized zirconia powders comprising from about 0 to about 0.15 weight percent impurity oxides, from about 0 to about 2 weight percent hafnium oxide (hafnia), from about 6 to about 25 weight percent yttrium oxide (yttria) or from about 10 to about 36 weight percent ytterbium oxide (ytterbia), and the balance zirconium oxide (zirconia). Thermal barrier coatings for protecting a component such as blades, vanes and seal surfaces of gas turbine engines, made from the high purity yttria or ytterbia stabilized zirconia powders, have a density greater than 88% of the theoretical density with a plurality of verticalzA macrocracks homogeneously dispersed throughout the coating to improve its thermal fatigue resistance.

主权项

1. A high purity yttria or ytterbia stabilized zirconia powder comprising a blend of two or more high purity yttria or ytterbia stabilized zirconia powders; wherein the blend comprises from about 55 to about 80 volume percent of a first high purity yttria or ytterbia partially stabilized zirconia powder having from about 0 to about 0.15 weight percent impurity oxides, from about 0 to about 2 weight percent hafnium oxide (hafnia), from about 6 to about 8 weight percent yttrium oxide (yttria) or from about 10 to about 14 weight percent ytterbium oxide (ytterbia), and the balance zirconium oxide (zirconia), and from about 20 to about 45 volume percent of a second high purity yttria or ytterbia fully stabilized zirconia powder having from about 0 to about 0.15 weight percent impurity oxides, from about 0 to about 2 weight percent hafnium oxide (hafnia), from about 16 to about 22 weight percent yttrium oxide (yttria) or from about 25 to about 33 weight percent ytterbium oxide (ytterbia), and the balance zirconium oxide (zirconia).