中文摘要：

利用包埋渗法在新型铌基超高温合金表面制备了铝改性的硅化物抗氧化涂层,分析了涂层的相组成、结构及其组织形成过程。涂层制备采用先在1150℃包埋渗硅4h,然后再于800-1000℃包埋渗铝4h的方法。结果表明：渗硅后涂层的相组成为（Nb,X）Si2（X代表Ti,Cr和Hf元素）;再于各温度包埋渗铝后,（Nb,X）Si2层中的平均铝含量随包埋渗铝温度的升高而增加,最高可达10.84at%;当包埋渗铝温度为860-1000℃时会在渗硅层与基体间形成新的铌铝金属间化合物层,且渗入（Nb,X）Si2层中的铝会在局部形成Nb3Si5Al2相。

英文摘要：

Al-modified silicide coatings were prepared by pack cementation process on a Nb-based ultrahigh temperature alloy.The structure,phase constituents and formation process of the coatings were studied.The coatings were prepared in a twostage process： firstly pack siliconized at 1150℃ for 4h and then pack aluminized at 800～1000℃ for 4h,respectively.The main phase of the pack siliconized coating is（Nb,X）Si2（X represents Ti,Cr and Hf）.The average content of Al in the （Nb,X）Si2 layer increases with increase of aluminizing temperature,and the maximam is about 10.84at%.When the aluminizing temperature is higher than 860℃,small Nb3Si5Al2 particles are found to exist in the（Nb,X）Si2 layer,furthermore an niobium-aluminide layer forms between the pack siliconized layers and the matrix.