Ceramic compositions for low conductivity thermal barrier coatings

摘要

Zirconia-containing ceramic compositions having a c/a ratio of the zirconia lattice in the range of from 1.005 to 1.016. These compositions comprise a stabilizing amount up to 10 mole % of the composition of a stabilizer component which comprises: (1) a first metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of from 1.5 to 6 mole % of the composition of; (2) a second metal oxide selected from the group consisting of lanthana, neodymia and mixtures thereof in an amount of from 0.5 to 4 mole % of the composition; and (3) optionally ytterbia in an amount of from 0.5 to 4 mole % of the composition. These compositions further comprise hafnia in an amount of from 0.5 to 15 mole % of the composition; and optionally tantala in an amount of from 0.5 to 1.5 mole % of the composition. These compositions are useful in preparing thermal barrier coatings (22) having a balance of reduced thermal conductivity with good producibility, spallation resistance and erosion/impact resistance for an underlying metal substrate (14) of articles (10) that operate at, or are exposed to, high temperatures.