(中國(guó)科學(xué)院 半導(dǎo)體研究所 全固態(tài)光源實(shí)驗(yàn)室，北京 100083)
摘 要: 在304不銹鋼(304SS)和Q235碳鋼上分別熔覆Ni60A及Ni60A-WC金屬粉末，以及添加Cr和Cr3C2的涂層，利用光學(xué)顯微鏡(OM)、掃描電鏡(SEM)、能譜儀(EDS)分析涂層的宏觀形貌、微觀組織和元素分布，用顯微硬度計(jì)對(duì)涂層的硬度進(jìn)行測(cè)試分析。結(jié)果表明：基材中元素成分的不同會(huì)導(dǎo)致涂層氣孔和裂紋的差異，Ni、Cr元素含量高的304SS上的涂層氣孔和裂紋數(shù)明顯比Q235碳鋼上的少；基材的導(dǎo)熱性能對(duì)涂層的稀釋率與性能具有明顯影響，導(dǎo)熱性能差的304SS稀釋率大，WC顆粒分解多，涂層組織粗大；由于Q235導(dǎo)熱性能好，冷卻速率高，導(dǎo)致涂層硬度高，Ni60A+40%WC涂層平均硬度高達(dá)1000HV0.2。此外，Cr和Cr3C2的加入能有效防止涂層氣孔的產(chǎn)生。
關(guān)鍵字: WC涂層；激光熔覆；顯微組織；顯微硬度
（Laboratory of All-Solid-State Laser Sources, Institude of Semiconductors,
Chinese Academy of Scienses, Beijing 100083, China）
Abstract:Ni60A and Ni60A-WC laser cladding coatings were prepared on 304 stainless steel and Q235 carbon steel, respectively, as well as adding Cr and Cr3C2 coatings. The macroscopic morphology, microstructure and elemental distribution of the coatings were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The microhardness of the coatings were tested with microhardness tester. The results show that the element composition on the substrate can cause the differences of pores and cracks. The pores and cracks of the coatings on 304 stainless steel (with high contents of Ni and Cr elements) are significantly less than those of the the coatings on Q235 carbon steel. The thermal conductivity of the substrates have a significant impact on the dilution rate and performance of the coatings. Because of poor thermal conductivity, the coatings on 304 stainless steel have high dilution rate, more WC particles decompose and then coarsen the microstructure. The average hardness of Ni60A +40%WC coating on Q235 substrate up to 1000HV0.2 attributes to its good thermal conductivity and high cooling rate. Furthermore, pore free coatings adding with Cr and Cr3C2 are obtained.
Key words: WC coating; laser cladding; microstructure; microhardness
