细晶粒硬质合金预处理工艺优化及金刚石涂层性能研究

Optimization of pretreatment process of fine grained cemented carbide and study on properties of diamond coating

摘要:

为了进一步拓展金刚石涂层刀具的产业化应用,提升金刚石涂层刀具的结合力性能,本文开展了细晶粒钨钴类硬质合金的化学预处理研究,考察了三步法预处理工艺对不同晶粒度基体形貌和成分的影响,实现了金刚石涂层与基体的高结合强度。利用扫描电子显微镜和EDS能谱仪对预处理后基体的表面形貌和钴含量以及涂层形貌进行分析,采用拉曼光谱、X 射线衍射光谱对涂层物相结构进行分析表征,并利用固体颗粒冲刷评价金刚石涂层的抗冲刷性能。结果表明:酸处理对Co的去除起着重要作用,WC晶粒越小所需酸处理的时间越长,碱处理对WC的刻蚀能力表现出先增大后减小的趋势,在3min时达到最大Co暴露量。由此分别确定了WC-6%Co(0.2,0.4,1.0 μm)基体三步法最佳工艺,三步法预处理后的基体均获得均匀致密,晶粒取向为(111)面,抗冲刷性能优异,膜基结合性能好的金刚石涂层。

Abstract:

In order to expand the industrial application of diamond coating tool and improve the adhesive strength of diamond coating tool. In this paper, the “Acid-Murakami-Acid” (AMA) three-step pretreatment process for cemented carbide with different WC grain size of 0.2, 0.4, 1.0μm was systematically studied. The surface morphology of the pretreated substrate, cobalt content and coating morphology were analyzed by scanning electron microscope and EDS spectrometer. The phase structure of the coating was analyzed and characterized by Raman spectroscopy and X-ray diffraction spectroscopy. The scour resistance of the diamond coating was tested by dynamic impact experiments. These results showed that the acid treatment played an important role in removing Co. The smaller the grain size of WC, the longer the acid treatment time was required. The etching capacity of WC by Murakami treatment increased at first and then decreased, and the maximum Co exposure was reached at 3min. Therefore, the best pretreatment process of WC-6%Co (0.2, 0.4, 1.0μm) substates were determined. After the three-step method, the substates obtained uniform and compact diamond coatings with grain orientation of (111), excellent scouring resistance and great adhesion strength.