化学前处理对硬质合金基材及金刚石涂层性能的影响

Effects of Chemical Pretreatment on Properties of Cemented Carbide Substrates and Diamond Coatings

摘要:

为提高金刚石涂层与硬质合金基体的适配性，采用热丝化学气相沉积技术在YG6硬质合金表面制备金刚石涂层，利用扫描电镜、能谱仪、原子力显微镜和固体颗粒冲蚀试验仪分析检测了试样的表截面形貌、成分深度分布、表面粗糙度、抗砂粒冲蚀性能等，研究了不同化学前处理对基材和涂层性能的影响。结果表明：两步法前处理去除钴的深度约4—5 μm，并且形成了厚约1—2 μm的脱钴脆性层；三步法前处理去除钴的深度约14—15 μm，没有出现脱钴脆性层；三步法化学前处理后沉积的金刚石涂层抗砂粒冲蚀时间为两步法化学前处理的4倍以上，并且涂层脱落区宽度仅为两步法化学前处理的1/8，说明三步法化学前处理后所沉积的金刚石涂层的性能比两步法的更优越。

Abstract:

To improve the suitability of diamond coating tocemented carbide substrates， diamond coatings were prepared on YG6 cemented carbide by hot filament chemical vapor deposition. Scanning electron microscopy， energy dispersive spectroscopy， atomic force microscopy and solid particle erosion tester were used to analyze the surface morphology， composition depth distribution， surface roughness and sand erosion resistance of the samples. The effects of different chemical pretreatment on the substrate and coating properties were studied. The results show that the depth of cobalt removed by the two-step pretreatment is about 4—5 μm， and a brittle layer of about 1—2 μm is formed. By comparison， the depth of cobalt removed by three-step pretreatment is about 14—15 μm， and no cobalt-depleted brittle layer is formed. The sand erosion resistance time of the diamond coating deposited after three-step chemical pretreatment is more than 4 times that of the two-step chemical pretreatment， and the width of the coating shedding area deposited after three-step chemical pretreatment is only 1/8 of that of the two-step chemical pretreatment. The diamond coating deposited by three-step chemical pretreatment shows better performance than that by two-step chemical pretreatment.