METHODS FOR PREPARING THERMAL BARRIER COATINGS WITH HIGH FRACTURE TOUGHNESS INNER LAYER FOR IMPROVED IMPACT RESISTANCE

摘要

Method for preparing reduced thermal conductivity thermal barrier coating having improved impact resistance for an underlying substrate for high temperature applications. An exemplary method includes depositing a first zirconia-containing ceramic composition having a c/a ratio of about 1.011 to about 1.016 and stabilized in the tetragonal phase by yttria, calcia, ceria, scandia, magnesia, india, lanthana, gadolinia, neodymia, samaria, dysprosia, erbia, ytterbia, europia, praseodymia, and mixtures thereof, and including about 0.3 to about 0.5% by weight lanthana, neodymia, gadolinia, and mixtures thereof The first material forms a high fracture toughness inner layer having a fraction of porosity of about 0.20 or less, and a thickness in the range of from about 0.5 to about 2 mils. The method includes depositing a ceramic material forming an outer thermal insulating layer overlying the inner layer and having a greater fraction of porosity than the inner layer.