Fabrication of novel thermal barrier coating on polymer composites via the combined sol-gel/sealing treatment process

摘要

Thermal barrier coating on the polyimide matrix composites was successfully fabricated at 400 ℃ via the combined sol-gel/sealing treatment process. In this approach, zirconia coating was firstly deposited onto substrate by sol-gel process, followed by penetration of aluminum phosphate into the final coating. Sealing mechanisms of phosphate sealant were based on the adhesive binding of phosphates and the I chemical bonding. After thermal cycling at 400 ℃ for 135 cycles, no apparent delaminations and spal-lations appeared in the ZrO_2 /phosphates dual coating, and the average bonding strength was 5.83 MPa. Thermal oxidation of substrate coated with the ZrO_2 /phosphates dual coating could be retarded at about 900 ℃.