TiB2对Ta-W合金氧化行为的影响

采用热压烧结制备Ta-W合金和Ta-W-TiB₂合金，研究两种合金在700、800和900℃的高温氧化行为，通过X射线衍射分析、扫描电子显微镜观察和能谱分析对合金的氧化层组分和组织形貌进行分析。结果表明:两种合金经热压烧结后的相对密度均达到97%以上，可以实现致密化。在氧化温度范围内所有合金的氧化动力学曲线都遵循直线规律，氧化温度升高氧化速率逐渐增大。Ta-W合金的氧化产物为Ta₂O₅固溶体，Ta-W-TiB₂合金的氧化产物为Ta₂O₅固溶体和TiO₂氧化物。在700~800℃下，稳定的TiO₂提高了Ta-W-TiB₂合金的抗氧化能力，但在900℃时，TiO₂的破坏大大减弱了氧化层对基体的保护能力。

Effect of TiB2 on the oxidation behavior of Ta-W alloy

Ta-W and Ta-W-TiB₂ alloys were prepared by hot pressing sintering. The oxidation behavior of Ta-W and Ta-W-TiB₂ alloys at the temperature of 700, 800, and 900℃ were studied. The composition and morphology structure of the oxide layer were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy spectrum analysis (EDS). The results show that, the relative density of Ta-W and Ta-W-TiB₂ alloys prepared by hot pressing sintering is beyond 97%. In the oxidation temperature range, the oxidation kinetics curves of all alloys follow the linear rate law, and the oxidation rate increases with the increase of oxidation temperature. The oxidation products of Ta-W alloys are the Ta₂O₅ solid solution, and the oxidation products of Ta-W-TiB₂ alloys are the Ta₂O₅ solid solution and TiO₂. The stable TiO₂ improves the antioxidant capacity of the alloy at 700~800℃. However, the destrvuction of TiO₂ at 900℃ greatly weakens the protection ability of oxide layer to protect the substrate.