The Synthesis of Graded Thermal Barrier Coatings on Nickel Substrates by Laser Induced Thermite Reactions

Abstract

AI2O3 and ZrO2Al2O3 bearing coatings were synthesized onto nickel substrates by laser induced thermite reactions. The oxide coatings were produced via thermite reactions between NiO and Al powders with and without the addition of Y2O 3-stabilised ZrO2 (YSZ), respectively. In the case where no YSZ was added, a graded coating with a top layer of AI2O 3 was produced. Whereas, when YSZ was added, the coating essentially comprised Zr02 dendrites with the interdendritic regions filled with the ZrO2-Al2O3 eutectic phase. The formation process of the coatings is described. © 2009 The Japan Institute of Metals.