76 / 2021-06-30 14:28:28

A Novel Spraying Strategy to Improve the Thermal Insulation of Thermal Barrier Coatings

thermal barrier coating,atmospheric plasma spraying,deposition strategy,thermal conductivity

Thermal barrier coatings prepared through atmospheric plasma spraying are often deposited with spray gun perpendicular to the substrate and traversed in a certain direction with a certain step width, which will form a cross-sectional lamilar structure in the TBCs. In the lamilar structure, there were many bonded and unbonded interfaces among the deposited powders during the preparation of TBCs. The unbonded interfaces can insulate the heat transfer, which will decrease the thermal conductivity of TBCs furtherly. In this work, a new deposition strategy was proposed to lower the thermal conductivity of TBCs. During deposition of the ceramic coatings in TBCs, each ceramic layer was deposited in an intersection angle of 30^o, 60^o and 90^o with the pre-deposited traverse direction. The thermal conductivity of the TBCs prepared with new deposition strategies were simulated through finite element calculation and tested by laser flash heating method, respectively. Results showed that the TBCs prepared with new deposition strategies had lower thermal conductivity than that of the common deposited one. New deposition strategy brought out more unbonded interfaces among the deposited ceramic powders which would be helpful to insulate heat transfer and lower the thermal conductivity. The preferred deposition strategy was an intersection angle of 90^o with the pre-deposited traverse direction to lower the thermal conductivity of the TBCs.