T92钢料浆低温渗铝层生长方式研究  

Study on Growth Mode of Low Temperature Aluminized Layer of T92 Steel Slurry

作　　者：安春香 龚兵兵 刘光明[2] AN Chunxiang;GONG Bingbing;LIU Guangming(Shanghai Electric Power Plant Equipment Co.,Ltd.Turbine Plant,Shanghai 200240,China;School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]上海电气电站设备有限公司汽轮机厂,上海200240 [2]南昌航空大学材料科学与工程学院,南昌330063

出　　处：《热力透平》2022年第4期278-284,共7页Thermal Turbine

摘　　要：通过调节渗铝温度、料浆层厚度对渗铝层生长行为进行了研究。试验发现,渗铝温度、料浆层厚度对渗铝层形貌和厚度均有明显影响。在渗铝温度700℃、料浆层厚度80μm左右、保温10 h条件下,能获得厚度约56μm的渗铝层。扫描电镜(SEM)和能谱仪(EDS)分析发现,渗铝过程中活性Al原子([Al])内扩散形成FeAl(B2)内层相、Fe2Al5(η)中间层相。待原始界面有[Al]积累时,Fe向外扩散,形成较厚的FeAl3(θ)和Fe2Al5(η)混合相外层。采用显微硬度计测量了渗铝层截面硬度,渗铝层硬度随渗层中Fe-Al金属间化合物Al含量的降低而降低,渗铝能显著提高基体的硬度。从热力学的角度探讨了Fe-Al金属间化合物生成驱动力的大小。研究成果可为提高马氏体耐热钢的抗氧化性能提供参考,使马氏体耐热钢用于更高的温度环境。The growth behavior of the aluminized layer is studied by adjusting the aluminizing temperature and the thickness of the slurry layer.Experiments show that the aluminizing temperature and the thickness of the slurry layer have obvious effects on the morphology and thickness of the aluminizing layer.An aluminizing layer with a thickness of about 56μm can be obtained at the aluminizing temperature of 700℃keeping 10 hours and in the slurry layer thickness of about 80μm.Using scanning electron microscope(SEM)and energy dispersive spectrometer(EDS),analysis shows that FeAl(B2)inner layer phase and Fe2Al5(η)interlayer phase are formed in internal diffusion of active Al atoms([Al])during aluminizing process.When[Al]accumulates at the original interface,Fe diffuses out to form a thick outer layer of FeAl3(θ)and Fe2Al5(η)mixed phases.The hardness of the aluminized layer is measured by micro hardness tester,and the result shows that the hardness of the aluminized layer decreases with the decrease of the Al content in the Fe-Al intermetallic compound in the aluminized layer,so it can be concluded that the aluminized layer can significantly improve the hardness of the substrate.From the perspective of thermodynamics,the driving force for the formation of Fe-Al intermetallic compounds is discussed.The research result can provide reference for the improvement of oxidation resistance of Martensitic heat resistant steel,so that the steel can be applied in circumstance with higher temperature.

关 键 词：T92钢 低温料浆渗铝 渗铝层 热膨胀系数(CTE) 

分 类 号：TG174.4[金属学及工艺—金属表面处理]