To improve the high-temperature oxidation resistance, Al₂O₃-Nb₂O₅/NbAl₃ composite coating with or without TiO₂ particles was prepared on Nb-based alloy through a two-step method of halide activated pack cementation (HAPC) and micro arc oxidation (MAO). NbAl₃ layer was firstly formed on the substrate by HAPC treatment. Then, TiO₂ was introduced into the Al₂O₃-Nb₂O₅ coating on NbAl₃ by hydrolysis reaction of K₂TiF₆ during MAO process. In this paper, the effect of TiO₂ on the morphology and formation of the MAO coating was studied. Furthermore, the oxidation resistances of the TiO₂-Al₂O₃-Nb₂O₅/NbAl₃ and Al₂O₃-Nb₂O₅/NbAl₃ composite coated Nb alloy were investigated. The results showed that the addition of K₂TiF₆ could promote the growth of MAO coating and increase the density. After oxidation at 1200 °C for 100 h, a dense protective oxides scale was found on the TiO₂-Al₂O₃-Nb₂O₅/NbAl₃ coating sample, and the weight gain was only 4.75 mg/cm², which was significantly lower than the coated sample without TiO₂. The mechanism of oxidation resistance enhancement of coating with TiO₂ should be ascribed to the formation of a dense TiO₂ + Al₂O₃ scale, which could effectually prevent the diffusion of O and suppress the formation of Nb₂O₅.

为提高抗高温氧化性能，采用卤化物活化填充胶结（HAPC）两步法在Nb基合金上制备了含或不含TiO _{2颗粒的Al 2} O ₃ -Nb ₂ O ₅ /NbAl _{3复合涂层。}和微弧氧化（MAO）。首先通过HAPC处理在衬底上形成NbAl _3层。然后，通过K ₂ TiF ₆的水解反应将TiO ₂引入到NbAl _{3上的Al 2} O ₃ -Nb ₂ O ₅涂层中。在 MAO 过程中。本文研究了TiO ₂对MAO涂层形貌和形成的影响。此外，研究了TiO ₂ -Al ₂ O ₃ -Nb ₂ O ₅ /NbAl ₃和Al ₂ O ₃ -Nb ₂ O ₅ /NbAl ₃复合包覆Nb合金的抗氧化性。结果表明，K ₂ TiF ₆的加入可以促进MAO涂层的生长，增加其致密度。在 1200 ℃ 氧化 100 h 后，在 TiO _{2上发现了一层致密的保护性氧化皮。}-Al ₂ O ₃ -Nb ₂ O ₅ /NbAl ₃涂层样品，增重仅为4.75 mg/cm ²，明显低于不含TiO ₂的涂层样品。_{TiO 2}涂层抗氧化性增强的机理应归因于形成致密的TiO ₂  + Al ₂ O ₃氧化皮，有效地阻止了O的扩散，抑制了Nb ₂ O ₅的形成。