316L不锈钢表面Fe-Al渗层的制备及其机理  

Preparation and Formation Mechanism of Fe-Al Coating on 316L Stainless Steel by Pack Cementation Aluminizing

作　　者：文锋 张东勋[1] 王韡 滕心跃 楚鑫新[1] WEN Feng;ZHANG Dongxun;WANG Wei;TENG Xinyue;CHU Xinxin(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;College of Chemical and Environmental Engineering,Shanghai Institute of Technology,Shanghai 201400,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]上海应用技术大学化学与环境工程学院,上海201400

出　　处：《材料研究学报》2024年第10期759-767,共9页Chinese Journal of Materials Research

基　　金：国家自然科学基金(11935011)。

摘　　要：使用低含量的NH_(4)Cl活化剂,用粉末包埋法在不同温度对316L不锈钢渗铝不同时间在其表面制备了连续致密的Fe-Al渗层,使用金相显微镜(OM)、X射线衍射(XRD)、扫描电镜(SEM)和能谱分析(EDS)等手段表征了Fe-Al渗层的表面形貌、截面结构以及物相组成,研究了渗铝温度和渗铝时间的影响。结果表明,在不同温度渗铝,渗层主要由Fe_(2)Al_(5)相和FeAl_(3)相组成且呈多层结构,渗层厚度随着渗铝温度的提高而增大;在650~750℃渗铝,渗层呈锯齿状结构嵌入基底,随着渗铝温度的提高齿状形貌特征逐渐消失且渗层表面质量变差。随着渗铝时间的增加,渗层的厚度随之增加但是物相组成不变。结合渗层成分的热力学稳定性,分析了渗层的形成过程。在反应初期已经在基体表面生成了FeAl_(3)相,但是Fe_(2)Al_(5)相一旦开始生成其生长速率就远高于FeAl_(3)相而使其生长受到抑制;而Fe_(3)Al相,只有在温度低于422℃时才开始生成。在动力学基础上建立了渗铝的动力学模型并计算出其扩散激活能。The pack cementation aluminizing method is a common process for preparing tritium barrier coatings.A dense and continuous Fe-Al coating can be prepared on the surface of stainless steels,while the microstructure of the aluminide layer has an important effect on the barrier properties of the top Al2O3 film formed on the coating.Herein,Fe-Al aluminide coating was prepared on 316L stainless steel via pack cementation method with NH_(4)Cl as activator.The surface,cross-sectional morphology,phase composition of the Fe-Al coating was characterized by means of optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy dispersive spectroscopy(EDS).The results show that the aluminized coatings prepared at different temperatures are mainly composed of Fe_(2)Al_(5)and FeAl_(3).The thickness of the aluminized coating increases with the increase of temperature,and shows a multi-layered structure.When the aluminizing temperature is between 650℃and 750℃,the aluminizing coating shows a serrated structure embedded in the substrate.As the temperature increases,the serrated morphology gradually disappears and the surface quality of the aluminizing coating deteriorates;With the increasing aluminizing time,the thickness of the aluminized coating gradually increases,but does not affect its phase structure.In addition,the formation process of the aluminizing coating was analyzed in terms of the thermodynamics stabilities of its structure and conponents.The FeAl_(3)phase was formed on the surface of the substrate at the initial stage of the reaction,however,the growth rate of the Fe_(2)Al_(5)phase was much higher than that of the FeAl_(3)phase,thereby,the former will inhibit the growth of the later once the former emerges at the initial stage,which led to the growth of the FeAl_(3)phase was suppressed.The Fe_(3)Al phase begins to form only when the temperature is lower than 422℃.On the basis of kinetics,a kinetic model of aluminizing process was established and the diffusion activation energy was ca

关 键 词：金属材料 阻氚涂层 包埋渗铝法 Fe-Al渗层 微观结构 

分 类 号：TL341[核科学技术—核技术及应用]