00Cr25Ni22Mo2N奥氏体不锈钢的高温氧化行为

Oxidation behavior of 00Cr25Ni22Mo2N austenitic stainless steel at high temperature

采用静态增重法研究了00Cr25Ni22Mo2N奥氏体不锈钢在不同温度下的循环氧化动力学曲线。结果表明,00Cr25Ni22Mo2N不锈钢在700℃时的氧化动力学曲线是一条平行于时间轴的直线,这说明其在该温度下氧化反应非常微弱;在800和900℃时的氧化动力学曲线遵循抛物线氧化规律,具有良好的抗氧化性能。利用扫描电镜、能谱分析和X射线衍射对氧化膜的表面形貌、截面形貌和相组成进行研究,发现该钢在3个温度下都生成了致密和黏附性好的保护性氧化膜,700℃生成的氧化膜主要由Cr_2O_3和Fe_2O_3组成,氧化膜很薄;800℃生成的氧化膜由Cr_2O_3、Fe_2O_3和少量的Ni Cr_2O_4、FeCr_2O_4组成,氧化膜厚度增加;900℃生成的氧化膜由Cr_2O_3、Fe_2O_3和NiCr_2O_4组成,氧化膜厚度进一步增加。认为氧化膜组成和结构是00Cr25Ni22Mo2N不锈钢具有良好抗高温氧化性能的重要原因。

The oxidation kinetics of 00Cr25Ni22Mo2N austenitic stainless steel at different temperatures was studied by thermal gravity analysis （TGA） method. The results showed that the linear isothermal oxidation kinetic curve at 700 ℃ paralleled to the time axis, indicating that the oxidation hardly occurred. While, the oxidation kinetic curves followed a parabolic rate law at 800 and 900 ℃, suggesting that the 00Cr25Ni22Mo2N stainless steel possessed superior high tem- perature oxidation resistance. The surface and cross section morphologies and the phase composition of the oxide film on the steel at different temperatures were examined by SEM, EDS, and XRD. The results showed that sticking and compact oxide films were formed on the surface of 00Cr25Ni22Mo2N stainless steel. The oxide film was thin and composed of Cr203 and Fe203 at 700 ℃. While a thicker oxide film was formed at 800 ℃, which consisted of Cr203, Fe203 and small amount of NiCr204, FeCr204. As the temperature increased to 900 ℃, the oxide film also consisted of Cr203, FezO3 and NiCr204, and the thickness of the oxide film was further increased. It is suggested that the composition and structure of the oxide film contributed to the excellent high temperature oxidation resistant performance of 00Cr25Ni22Mo2N austenitic stainless steel.