Performance study of a complex thermal barrier functional coating with an electro-spark deposited burn-resistant layer

It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of " titanium fire” which is easily happened. MTU Aero Engines GmbH has developed a complex functional coating which has great performance of burn resistant and sealing, the coatings has already been applied on compressor blades and casing for aero-engines and showed great performance. In this study, the complex functional coating which is composed of an electro-spark deposited amorphous Ti₄₀Zr₂₅Ni₃ burn-resistant layer and a high-energy plasma spraying prepared YSZ thermal barrier layer was prepared on titanium alloys surface. Then the heat insulation ability, burn resistant performance and the bonding strength were investigated. The experimental results showed that the interface between the coating and the matrix was typical metallurgical bonded, and the average bonding strength was 36.335 MPa; when the temperature of the flame on the one side of the specimen reached 600 ℃, the average insulated temperature of the coating samples was 70.67 ℃; when the flame temperature was 350 ℃, the titanium samples without the complex functional coatings were burned, while the samples with the coating showed great performance of burn resistant even when the temperature was 750 ℃. This indicates that the new functional coating has good heat-insulating and burn-resistant performance.