论文部分内容阅读
采用动态高压釜实验研究了Zr-2.5Nb合金在500℃,25 MPa的超临界水中的腐蚀行为。通过SEM,EDS,XRD等对腐蚀实验后的试样进行了分析。结果表明,在超临界水中Zr-2.5Nb合金的腐蚀速率较快,初期表面生成黑色光亮的氧化膜,主要由四方相ZrO2构成,随着腐蚀时间增长,表面逐渐转变为灰白色的单斜相ZrO2且产生了大量裂纹;原本表面已覆盖ZrO2涂层的试样腐蚀后发生涂层剥落的现象,且腐蚀速率无明显减缓。四方相ZrO2的存在对Zr-2.5Nb合金的抗氧化性能有积极的作用,随着腐蚀时间延长,逐渐出现的单斜相会破坏表面氧化膜的保护性,从而恶化材料的耐蚀性能。
The dynamic behavior of autoclave in Zr-2.5Nb alloy at 500 ℃ and 25 MPa in supercritical water was studied. The samples after corrosion test were analyzed by SEM, EDS and XRD. The results show that the corrosion rate of Zr-2.5Nb alloy in supercritical water is high, and the black oxide film is formed on the initial surface mainly composed of tetragonal ZrO2. With the increase of the etching time, the surface gradually turns into the gray-white monoclinic ZrO2 And produced a large number of cracks; the original surface has been coated with ZrO2 coating sample after the occurrence of corrosion coating peeling phenomenon, and no significant slowdown in corrosion rate. The existence of tetragonal ZrO2 has a positive effect on the oxidation resistance of the Zr-2.5Nb alloy. With the prolongation of the etching time, the monoclinic phase gradually destroys the protective properties of the surface oxide film and deteriorates the corrosion resistance of the material.