基于YSZ的电镀Pt复合涂层红外发射率探究

Exploration of Infrared Emissivity of Electroplated Pt Composite Coating Based on YSZ

摘要:

红外隐身性能是新一代战斗机高温部件设计中的关键指标。高温部件通常采用热障涂层作为面层，通过表面涂覆红外低发射率涂层实现红外隐身。研究了不同涂层制备工艺对复合涂层性能的影响。采用等离子喷涂-物理气相沉积（PS-PVD）技术和大气等离子喷涂（APS）技术，以DZ40M高温合金为基体，通过PS-PVD或APS制备不同厚度的7YSZ陶瓷层，随用电弧离子镀沉积Al中间层以提升表面导电性，并通过电镀法形成Pt红外低发射率层。研究表明，Al层在真空热处理过程中与YSZ发生原位反应生成致密α-Al?O?层，显著增强涂层间结合强度。当采用APS工艺制备YSZ层，Al/Pt的厚度比接近1∶1时，复合涂层在真空热处理后红外发射率可低至0.21，结合强度达41 MPa，通过优化Al/Pt层的厚度比，结合强度可进一步提升至53 MPa。若Al层过薄，Pt层会出现微观翘起，若Al层过厚，则会导致Pt层微观层面产生起伏与空洞，这两种情况均会对复合涂层的红外性能与结合强度造成影响。当采用PS-PVD工艺制备YSZ层，复合涂层在真空热处理后红外发射率低至0.27，结合强度达到68 MPa。为高性能红外隐身涂层的设计与工艺优化提供了重要理论依据。

Abstract:

Infrared stealth has become a critical consideration for new generation of fighter aircraft. To address the demands of high-temperature operating environments， thermal barrier coatings （TBCs） are typically employed as surface layers for high-temperature components. Infrared stealth is often achieved through the application of infrared low-emissivity coatings. In this study， composite coatings were prepared using plasma spraying-physical vapor deposition （PS-PVD） and atmospheric plasma spraying （APS） techniques. 7YSZ ceramic layers of varying thickness were deposited on DZ40M high-temperature alloy substrate. Subsequently， Al layers of different thicknesses were applied using arc ion plating technology to enhance the surface’s conductivity for subsequent plating and to improve the overall bonding strength of the coatings after vacuum heat treatment. Finally， a Pt metal layer was electroplated onto the surface to serve as the infrared low-emissivity layer. The results revealed that the bonding strength of the composite coatings was significantly enhanced by the incorporation of an Al interlayer， ， which facilitated the connection between the plated Pt layer and the YSZ thermal barrier layer. When the thickness ratio of Al/Pt was approximately 1∶1 and the YSZ layer was prepared via the APS process， the infrared emissivity of the composite coating reached as low as 0.21 after vacuum heat treatment. Under these conditions， the bonding strength achieved 41 MPa， which could be further increased to 53 MPa by optimizing the thickness ratio of the Al/Pt layers. However， an excessively thin Al layer led to warping of the Pt layer on the microscopic level， while an excessively thick Al layer resulted in undulations and voids within the Pt layer after heat treatment. Both conditions negatively impacted the infrared emissivity and bonding strength of the composite coatings. When the YSZ layer was prepared by the PS-PVD process， the infrared emissivity of the composite coatings could be as low as 0.27 and the bonding strength could be as high as 68 MPa after the vacuum heat treatment. These findings highlight the importance of controlling the thickness of the Al and Pt layers as well as the choice of the YSZ deposition method to optimize the infrared stealth performance and bonding strength of composite coatings for high-temperature applications.