一种高铪Ni3Al基合金的抗氧化性能

Oxidation Resistance of a High-Hf-content Ni3Al-based Alloy

开展了高铪(1. 5%Hf) Ni3Al基合金在1000℃、1100℃和1200℃氧化100h的实验,分析了氧化膜的形貌及形成机制。研究表明,高铪Ni3Al基合金直到1100℃仍可达到完全抗氧化级,氧化膜完整致密,氧化增重速率0. 03g/m2·h,氧化皮剥落量0. 52g/m2,较0. 5%Hf的Ni3Al基合金降低一倍;1200℃时,氧化皮剥落量明显增多,抗氧化性能降至次抗氧化级。高铪Ni3Al基合金氧化后,形成了大面积具有保护作用的Hf O2和Al2O3氧化膜,随着氧化温度由1000℃逐渐升高至1100℃,氧化膜由以Hf O2为主,转变为以Al2O3为主;合金氧化过程中Hf O2优先形成,Al2O3以Hf O2为核心形核生长,铪含量的提高促进了Al2O3氧化膜的快速形成,抗氧化性能显著提高。

The oxidation experiments of high-Hf-content(1.5%Hf)Ni3 Al-based alloy at 1000,1100 and 1200℃for 100 h were carried out,and the morphology and formation mechanism of the oxide films were analyzed.The results show that the high-Hf-content Ni3 Al-based alloy can achieve complete oxidation resistance level up to 1100℃with the complete and compact oxide film.The oxidation weight gain rate is 0.03 g/m2·h,and the oxide spallation amount is 0.52 g/m2,both of which are only half of that of Ni3 Al-based alloys with 0.5%Hf.The exfoliation of oxide film increased obviously at 1200℃and the oxidation resistance decreases to the less oxidation resistance level.A large area of protective Hf O2 and Al2 O3 oxide films were formed for oxided high-Hfcontent Ni3 Al-based alloy.Besides,the main type of oxide film changed from Hf O2 to Al2 O3 with the temperature increasing from 1000 to 1100℃.During the oxidation process,Hf O2 formed first,with which as a core Al2 O3 nucleated.The high-Hf content promoted the rapid formation of Al2 O3 oxide film,and remarkably improved oxidation resistance of Ni3 Al-based alloy.