Oxidation behavior of laser remelted plasma sprayed NiCrAlY and NiCrAlY-Al2O3 coatings

Two types of plasma sprayed coatings (NiCrAlY and NiCrAlY-Al2O3) were remel ted by continuous wave CO2 laser. A homogeneous dense remelted layer withou t voids, cavities, unmelted particles and microcracks was formed. As a resu lt of isothermal oxidation tests at 1000 degreesC, the weight gains of lase r remelted coatings, especially laser remelted NiCrAlY-Al2O3 coatings, were obviously lower than plasma sprayed coatings. The effects of both laser re melting and incorporation of Al2O3 second phase in NiCiAlY matrix on high t emperature oxidation resistance of plasma sprayed coatings was discussed. ( C) 2001 Elsevier Science B.V. All rights reserved.