Fabrication of functionally graded ZrO2/NiCrAlY composites by plasma activated sintering using tape casting and itʹs thermal barrier property

Green sheets for ZrO2/NiCrAlY functionally graded material (FGM) were prepared using tape casting in order to control thickness and layer design in FGM. The prepared green sheets were stacked and then sintered by plasma activated sintering (PAS) at 1300 °C for 2 min under the pressure of 30 MPa in vacuum. The sintered parts were used for thermal barrier tests. The effect of thickness of the ZrO2 layer on thermal barrier property of FGM was studied. The effects of micro-cracks and pores in ZrO2 layer on thermal barrier property of FGM were studied in FGMs prepared with the mixed composition of partially stabilized zirconia (PSZ) and monoclinic zirconia (m-ZrO2) in ZrO2 layer. After maintaining the surface temperature of ZrO2 layer at 1500 °C for 20 min, the surface temperature of NiCrAlY layer was measured with thermocouple, indicating that thermal difference (ΔT) between two surfaces was about 760 °C. Thickness variation, micro-cracks and pores in ZrO2 layer did not affect thermal barrier property. However, micro-cracks and pores in ZrO2 layer showed the release of stress concentration in ZrO2 layer. After thermal barrier tests, new type of crack was not investigated in FGM.