CAJ | 학술논문

采用在还原碳化法制备WC粉末前添加稀土氧化物Y2O3或CeO2，以及在WC与Co粉末混合球磨时加入该稀土氧化物两种不同的方式，在 WC-10Co 硬质合金中添加稀土元素，利用金相显微镜和扫描电镜观察稀土硬质合金的组织形貌与显微结构，采用X射线衍射仪(XRD)和电子探针对合金的相成分与微区成分进行分析，并测试合金的硬度、断裂韧性与磁性能，研究稀土及其添加方式对硬质合金结构与性能的影响。结果表明，无论以何种方式添加Y2O3或CeO2，最终制备的硬质合金中稀土元素都与氧共存，并以球形颗粒的形式弥散分布于硬质合金的钴粘结相中。稀土硬质合金中WC晶粒球化趋势明显，WC/WC的邻接度由0.6降低至0.39，断裂韧性由12.8 MPa?m1/2提高至16.7 MPa?m1/2。球形、弥散分布的稀土氧化物颗粒会破坏合金结构的连续性，导致合金强度降低。
채용재환원탄화법제비WC분말전첨가희토양화물Y2O3혹CeO2，이급재WC여Co분말혼합구마시가입해희토양화물량충불동적방식，재 WC-10Co 경질합금중첨가희토원소，이용금상현미경화소묘전경관찰희토경질합금적조직형모여현미결구，채용X사선연사의(XRD)화전자탐침대합금적상성분여미구성분진행분석，병측시합금적경도、단렬인성여자성능，연구희토급기첨가방식대경질합금결구여성능적영향。결과표명，무론이하충방식첨가Y2O3혹CeO2，최종제비적경질합금중희토원소도여양공존，병이구형과립적형식미산분포우경질합금적고점결상중。희토경질합금중WC정립구화추세명현，WC/WC적린접도유0.6강저지0.39，단렬인성유12.8 MPa?m1/2제고지16.7 MPa?m1/2。구형、미산분포적희토양화물과립회파배합금결구적련속성，도치합금강도강저。
The rare earth WC-10Co cenmented carbides were prepared by introducing Y2O3 and CeO2 before preparing tungsten carbide powders or ready-to-press (RTP) mixing powders. The morphology and microstructure of WC-Co cenmented carbide were observed by optical metallographic and scanning electron microscope. Phase compositions were identified by X-ray diffraction and the micro-region composition analyses were carried out on an electron probe micro-analyzer. The hardness, rupture toughness and magnetic properties were tested for investigating the effects of rare earth and their adding ways on microstructures and properties of the cemented carbides. The results show that, for both the two adding ways, rare earths accompany oxygen in the prepared cemented carbides and are dispersed in cobalt binder in the form of spherical particles. WC grains in rare earth cemented carbides show the evidently trend of spheroidization, which can result in the decrease of WC/WC contiguity from 0.6 to 0.39 and lead to the improvement of fracture toughness from 12.8 MPa·m1/2 to 16.7 MPa?m1/2. The strength decreases because that the spherical and dispersed rare earths oxygen particles can destroy the continuity of the cemented carbides structure.