超细/纳米晶无黏结相WC硬质合金的研究进展

Research Progress of Ultrafine/Nanocrystalline Binderless WC Cemented Carbides

无黏结相WC硬质合金(Binderless tungsten carbide,BTC)因具有传统硬质合金无可比拟的优异耐磨性、抗腐蚀性、极佳的抛光性和抗氧化性,在耐冲蚀、高耐磨的工具、精细刀具以及石油、页岩气开采等领域有很好的应用前景。超细/纳米晶BTC制备的关键问题之一是如何控制WC晶粒的长大,本文从超细/纳米WC粉末的制备技术、BTC材料成分设计及成型工艺和烧结技术等方面对超细/纳米晶BTC的相关研究成果进行综述,强调了原料WC粒度、第二相化合物添加、先进成型工艺和烧结技术在BTC致密化过程中的关键作用,对比了不同成分体系、不同烧结工艺下超细/纳米晶BTC材料的性能差异;指出超细/纳米晶BTC制备过程中存在的主要问题为致密化和强韧化,可通过已开发的多种先进烧结技术及第二相增强增韧技术来解决,但尚未实现工业化应用;最后,阐明了超细/纳米晶BTC的发展趋势为在低温低压下获得更细的致密烧结体。

Binderless WC cemented carbide(binderless tungsten carbide,BTC)has excellent wear resistance,corrosion resistance,polishing performance,and oxidation resistance,which are unparalleled compared with traditional cemented carbide.It has a good application prospect in erosion-resistant and high wear-resistant tools,fine tools,oil and shale gas exploitation,and other fields.One of the key problems in the preparation of ultrafine/nanocrystalline BTC is to control the growth of WC grains.In this paper,the related research results of ultrafine/nanocrystalline BTC were reviewed from the aspects of preparation technology of ultrafine/nanocrystalline WC powder,material composition design of BTC,and molding process and sintering technology.The key role of raw material WC particle size,addition of second phase compounds,and advanced molding process and sintering technology in the densification process of BTC was emphasized.The performance differences of ultrafine/nanocrystalline BTC materials under different composition systems and different sintering processes were compared.It was pointed out that the main problems in the preparation process of ultrafine/nanocrystalline BTC were densification and strengthening and toughening,which could be solved by various advanced sintering technologies and developed second phase strengthening and toughening technologies,but they have not yet achieved industrial application.Finally,it was clarified that the development trend of ultrafine/nanocrystalline BTC was to obtain finer dense sintered bodies at low temperatures and low pressures.