摘要
研究了1Cr18Ni9Ti不锈钢基体上斜入射溅射Ni-7Cr-8Al涂层及其在1000℃空气中形成的氧化膜的组织结构.涂层采用Ni-7Cr-8Al合金靶磁控溅射方法制备.沉积过程中样品静止不动,名义入射角分别为0°和45°.这两种样品在本文中分别称为正入射和斜入射沉积涂层.研究结果表明:两种涂层的晶体结构均为f.c.c.γ-Ni,并且都具有典型的柱状晶组织结构,所不同的是,正入射沉积涂层的柱状晶垂直表面,斜入射涂层的柱状晶与法线间的角度大约为32°,并且后者看起来较疏松.在1000℃空气中50 h内,正入射沉积Ni-7Cr-8Al涂层表面可形成纯α-Al2O3保护性氧化膜,斜入射涂层氧化行为较复杂.氧化10h后的涂层表面为均匀致密的α-Al2O3氧化物;氧化20 h后氧化膜主要为等轴晶形状Fe2O3和NiCrO3,此外还有很多尺寸为几微米的小孔;氧化50 h后,氧化物发生大面积剥落,氧化膜内有大量孔洞,残留的表面氧化物主要由Fe2O3和NiCrO3组成.
The Ni-7Cr-8Al coatings on 1Cr18Ni9Ti stainless steel and the oxide scales thermally grew on the coatings at 1000℃ in air were characterized by SEM and XRD. The oblique angle magnetron sputtering technique was used to deposit the coatings from a target of Ni-7Cr-8Al. The coatings deposited at a flux angle of 45° were referred to as the oblique coatings in this article;while those at a flux angle of 0° were the normal coatings. Both the oblique and normal coatings consisted of f. c. c. γ-Ni with a columnar microstructure. All the columns of the normal coatings were perpendicular to the substrate surface whilst thoses the oblique coatings were at an angle about 32% The oblique coatings were coarser than the normal ones. After oxidation for 50 h at 1000℃ ,unique α-Al2O3 scales formed on the normal coatings. For the oblique coatings, the oxidation behavior was more complex. After 10 h, dense and thin alumina scales were observed, which demonstrated that the oxidation mechanism of the oblique coatings within the first 10 h was the same as that of the normal coatings. After 20 h, however, the growth of equi-axis grains of mixed oxides consisted of Fe2O3 and NiCrO3, predominated. Besides, a great number of cavities with diameter of several microns were observed on the surfaces of the scales. After 50 h ,the oxide scales were mainly Fe2O3 and NiCrO3 ,with a lot of cavities. Severe spallation of the oxide scales occurred.
出处
《腐蚀科学与防护技术》
CAS
CSCD
北大核心
2008年第2期86-90,共5页
Corrosion Science and Protection Technology
