摘要
用粉末包埋法在316L不锈钢样品和钢管内表面制备Fe-Al涂层,使用扫描电镜(SEM)、能谱分析(EDS)和X射线衍射仪(XRD)等手段表征其组织形貌、成分分布和物相组成并比较316L不锈钢平面涂层和管内壁涂层生长的差异,研究了渗铝剂配比、渗铝温度和渗铝时间对其组织结构和物相成分的影响。结果表明,在700~800℃保温渗铝6 h、Fe-Al粉质量分数为75%的涂层其生长效率最高,制备出的涂层均匀平整,致密性良好。在此温度区间,渗铝温度对涂层的物相组成影响不大。这种Fe-Al涂层具有双层结构,外层富铝层主要由FeAl韧性相组成,内层元素扩散层由Fe_(3)Al相组成。随着渗铝时间的增加元素扩散增强,使涂层表面的致密性提高并在富Al层与扩散层界面区域出现尺寸约1~2μm的孔洞。渗铝时间越长,孔洞数量越多。在700~800℃渗铝,在316L不锈钢管内壁制备的Fe-Al涂层与316L不锈钢基体界面结合紧密且没有孔洞。在曲面上涂层晶核的体积比在平面上的涂层小,在曲面上形核的几率高、形核更快。在渗铝工艺参数相同的条件下,在不锈钢管内壁生长的涂层厚度约为在不锈钢平面生长的涂层厚度的1.1~2.1倍。
The Fe-Al coatings were prepared on the surface of 316L stainless steel plate and the in-ner surface of 316L tubes by pack cementation method.The effect of aluminizing agent ratio,tempera-ture and time on the microstructure and phase composition of the Fe-Al coatings were investigated by Scanning electron microscopy(SEM),energy spectrum analysis(EDS)and X-ray diffractometer(XRD).The growth rate of coatings was measured for the planar samples and the inner wall of the tubes.The re-sults showed that uniform Fe-Al coatings with good coherence to the substrate were obtained after alumi-nizing at 700~800℃ for 6 h.The higher growth rate of coating was achieved in the aluminizing agent with Fe-Al powder content of 75%.The aluminizing temperature has little effect on the phase compositions of the coatings obtained in the range of 700~800℃.The prepared Fe-Al coating show double-layered struc-ture,with the outer Al-rich layer mainly composed of FeAl toughness phase,and the inner elemental diffu-sion layer mainly composed of Fe_(3)Al phase.With the increasing time,the element diffusion is enhanced in the coating,which leads to dense and smooth coating surface.On the other hand,due to the en-hanced element diffusion,some pores with 1-2μm diameter appears in the region near the interface be-tween Al-rich layer and diffusion layer and the number of pores is increasing with time.The Fe-Al coating without pores at the interface of the 316L substrate was prepared on inner surface of 316L stainless steel tubes in the temperature range of 700~800℃.After the same aluminizing process,the thickness of the coating grown on the inner tube surface is about 1.1~2.1 times of that on the plate surface.It can be ex-plained by the smaller nuclei volume of coating nucleated on a curved surface than that on a flat surface,which result in the higher nucleation efficiency and faster growth rate of coating on the inner surface of tubes.
作者
陈继弘
王永利
熊良银
宋立新
CHEN Jihong;WANG Yongli;XIONG Liangyin;SONG Lixin(College of Materials Science and Engineering,Shenyang University of Chemical Technology,Shenyang 110142,China;Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;CAS Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2024年第11期801-810,共10页
Chinese Journal of Materials Research
基金
中核集团领创科研项目。
关键词
材料表面与界面
Fe-Al涂层
粉末包埋法
316L钢
形核效能
管内壁涂层
surface and interface in the materials
Fe-Al coating
pack cementation method
316L steel
nucleation efficiency
pipe wall coating
