Kinetics of V(N,C) and Nb(N,C) coatings produced by V-Nb-RE deposition technique

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• 作者：Z.J. Shan ; ^{12371858@qq.com} ; Z.G. Pang ; F.Q. Luo ; F.D. Wei
• 关键词：V(N ; C) and Nb(N ; C) coatings ; V&ndash ; Nb&ndash ; RE deposition ; TRD ; Kinetics
• 刊名：Surface and Coatings Technology
• 出版年：2012
• 期刊代码：106_02578972
• 类别：ms
• 出版时间：25 May, 2012
• 卷：206
• 期：19-20
• 页码：4322-4327
• 文件大小：948 K

摘要

A duplex surface treatment on AISI H13 steel has been developed involving nitrocarburizing and followed by vanadium niobium and rare earths (V-Nb-RE) thermo-reactive deposition (TRD) techniques. The TRD process was performed in molten borax salt bath at 1223, 1283 and 1343 K for 1-4 h, respectively. The process formed a thickness of 6 to 35 渭m of vanadium carbonitride and niobium carbonitride coatings on a hardened diffusion zone. Characterization of the coatings by means of scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) indicates that the compact and dense coatings mainly consist of Vb>8b>Cb>7b>, NbC, NbN and VN phases. The value of Vickers hardness of the coatings was up to 1350 HVb>0.1b> after tempering at 848 K for 2 h. All the growth processes of the vanadium carbonitride and niobium carbonitride coatings obtained by V-Nb-RE deposition technique followed a parabolic kinetics. Activation energy (Q) for the process was estimated to be 215.68 kJ/mol of vanadium carbonitride coating, and 134.32 kJ/mol of niobium carbonitride coating. Under certain conditions, the values of Q were greater than single vanadizing and deposition niobium. However, growth rate constant (K) was very similar among pairs of them.