AE ANALYSIS OF DESTRUCTION BEHAVIOR DURING THERMAL CYCLING ON FLAME SPRAY COATINGS

Abstract Acoustic emission characterization (AE) is receiving considerable attention from the industries, due primarily to the current progress in advanced materials for using under severe environmental conditions. Recently much application has been done on wear and corrosion resistant coatings for aeroplane turbine engines, boiler tubes and so on. Especially high toughness chromium carbide coating containing nickel and chromium matrix is widely used for seals in compressors, turbines and bores of hydraulic cylinders. Till now, the coating has been performed with D-gun (detonation gun) and plasma spraying for high temperature seal. With the development of high velocity flame spraying (600m/sec. particle velocity), it has become important to compare its coating characterization with D-gun under wear and thermal cycle uses. We have used METCO DIAMOND-JET system gun to compare with D-gun system. For high velocity flame spraying, propylene as fuel and oxygen mixed gases were used. Movable electric furnace with sensor which could adjust moving velocity was used. AE signals of each and total thermal cycling were measured. Also amplitude distribution analysis was carried on. Result obtained by high velocity flame coating was better than those by D-gun on thermal cycle use.