CrN/Cr涂层对Ti22Al26Nb合金的高温防护研究

采用电弧离子镀技术在O相Ti22Al26Nb合金表面镀覆CrN以及CrN/Cr涂层并研究了其在800和900℃空气中的等温氧化行为,结果显示O相钛合金表面施加单一的CrN涂层后,涂层表面在氧化时形成了保护性的氧化膜Cr2O3层,因此合金受到了良好的高温防护,但是涂层和基体合金之间发生了明显的互扩散;在CrN涂层和钛合金基体之间施加纯Cr扩散障层后形成的CrN/Cr涂层,其表面除了象单一CrN涂层那样氧化后形成了一层连续、致密、结合良好的保护性氧化膜Cr2O3层外,还能有效的抑制涂层与基体合金之间的互扩散,此外扩散障Cr层的存在使得靠近其基体的晶粒也出现了长大现象。

Investigation of high temperature protection of CrN/Cr coating on Ti22Al26Nb alloy

Arc ion plating （AIP） was employed to deposit CrN and CrN/Cr coatings on Ti22A126Nb alloy and high temperature oxidation behaviors of the coating were investigated at 800 ℃ and 900 ℃ in air respectively. The results show that the substrate Ti alloy is protected by CrN coating because a protective, good-binding Cr2 O3 layer is formed on the surface of coating during high temperature oxidation. However, an inter-diffusion layer is formed between the coating and the substrate. After a Cr diffusion barrier coating is deposited between the coating and the suhstrate, the inter-diffusions between the CrN coating and Ti22Al26Nb alloy are effectively inhabited for 5 mm thickness of the pure Cr diffusion barrier coating besides a continuous, compact, and protective Cr2O3 layer is formed on the CrN/Cr coating during both two cases of temperature oxidations. Furthermore, there is appearance crystal grain growth for the substrate Ti22AL26Nh alloy near to the Cr diffusion barrier coating.