RESIDUAL-STRESS IN PROTECTIVE ZRO2 COATINGS PRODUCED BY MAGNETRON SPUTTERING

Residual stress in protective coatings, which can be caused by a misma tch of thermal expansion coefficients of substrate and coating or be i ntrinsic to the deposition technique, is a key phenomena for all appli cations. A voiding any tensile stress, especially at high working temp eratures, is a crucial condition for most protective ceramic coatings. We controlled the development of the residual stress in ZrO2 coatings , partially stabilized by yttria during the sputter deposition on stee l substrates. The information gained from in situ stress measurements allows thermal and intrinsic stress to be distinguished. Furthermore, the stress measurements allow coating stress and thermal properties of the coating to be tailored by varying the deposition conditions. We s how that a compressive 'pre'-stress of about 1.7 x 10(9) Nm(-2) at roo m temperature is sufficient to prevent high-temperature corrosion of I nconel 600 at 1000 degrees C.