(華北水利水電大學(xué) 機(jī)械學(xué)院，鄭州 450011)
摘 要: 采用新型電火花沉積設(shè)備，將亞微米WC-4Co陶瓷硬質(zhì)合金材料沉積在鑄鋼材料上，制備電火花沉積合金涂層，利用SEM和XRD等技術(shù)研究沉積層與基體間的界面行為，分析沉積層的表面潤濕性、物相形成機(jī)理、微觀組織結(jié)構(gòu)、界面元素分布、界面結(jié)合機(jī)理和顯微硬度變化等。結(jié)果表明：電火花沉積技術(shù)可以在金屬基體表面制造出微納米非晶高熔點(diǎn)強(qiáng)化層。鑄鋼表面沉積層主要由Fe3W3C、Co3W3C、Si2W和Fe2C 等相組成；沉積層與基體呈冶金結(jié)合，過渡層中出現(xiàn)一些柱狀晶和等軸晶的組織結(jié)構(gòu)，沉積層中細(xì)小的Fe2C和Si2W等硬質(zhì)相顆粒彌散分布于Fe3W3C和Co3W3C沉積層上。沉積層的厚度大于20 μm，沉積層的平均顯微硬度為1803.2 HV，細(xì)小彌散分布的硬質(zhì)相是沉積層硬度提高的主要因素。
關(guān)鍵字: WC-Co硬質(zhì)合金；電火花沉積；組織結(jié)構(gòu)；界面行為
（School of Mechanical Engineering, North China University of Water Conservancy and Electric Power,
Zhengzhou 450011, China）
Abstract:Submicron WC-4Co cemented carbide material was deposited on the surface of cast steel by electro-spark deposition (ESD), the electro-spark deposition coating was prepared. The behavior of interface between the coating and the substrate was studied by SEM and XRD. The surface wettability, the forming mechanism of phase, microstructure, element distribution of deposition, bonding mechanism of interface and microhardness of the coating were investigated. The results show that micro/nano and amorphous coating with high melting-point is produced on the surface of cast steel by ESD. The coating consists of Fe3W3C, Co3W3C，Si2W and Fe2C phases. The coating is well metallurgical bonded with the cast steel roll substrate. The microstructure of the transition layer is a structure of fine columnar crystals and equiaxed crystals. The extra-fine structure hard Si2W and Fe2C phases distribute dispersedly in Fe3W3C and Co3W3C deposition. The coating is usually more than 20 μm thick. The average microhardness of the coating is 1803. 2 HV. These fine and dispersed hard phases can greatly improve the hardness of coating.
Key words: WC-Co cemented carbides; electro-spark deposition; microstructure; interface behavior
