Abstract: Zirconia thermal barrier coatings were obtained on copper by a 5kW CO2 laser, and dense coatings without porosity and with metallurgical bond to substrates were produced. Al2O3 intermediate layer is found at the interface between NiCoCrAlY layer and ZrO2 ceramic layer. NiCoCrAlY bond coatings are composed of cells, cellular dendrites and dendrites, and the precipitation of γ′ and β phases increases the microhardness values. TiO2-Al dopants can avoid cracks, so the chemical reaction mechanism in ceramic coatings at elevated temperature, and adhesion mechanism by titanium additive diffusion among the grain boundary were proposed.
Laser cladding of thermal barrier coatings on copper
Abstract:
Zirconia thermal barrier coatings were obtained on copper by a 5 kW CO2 laser, and dense coatings without porosity and with metallurgical bond to substrates were produced. Al2O3 intermediate layer is found at the interface between NiCoCrAlY layer and ZrO2 ceramic layer. NiCoCrAlY bond coatings are composed of cells, cellular dendrites and dendrites, and the precipitation of γ′ and β phases increases the microhardness values. TiO2Al dopants can avoid cracks, so the chemical reaction mechanism in ceramic coatings at elevated temperature, and adhesion mechanism by titanium additive diffusion among the grain boundary were proposed.
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