Texture of EB-PVD thermal barrier coatings under variable deposition conditions

The texture of electron-beam physical vapour deposited thermal barrier coatings was investigated by pole figure measurements. Only minor influence of various surface preparations and diverse substrates on texture of partially yttria stabilized zirconia coatings was found. A fourfold symmetry with {100} planes nearly parallel to the surface must be considered for all samples that have been rotated during deposition. Position of texture components depends on the angle of vapour incidence. Substrate temperature was found to influence the sharpness of the preferred orientation. Results were correlated to vapour phase growth models and to crystal bonding energies with special emphasis on periodical bond chains. A model for texture origin of EB-PVD thermal barrier coatings is proposed. (orig.)