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文章针对提高硬质合金刀具金刚石涂层结合力问题,提出了一种热处理和酸处理相结合的预处理工艺,详细研究和分析了800~1 000℃范围内,热处理温度变化与硬质合金刀具表面形貌、金刚石涂层质量、涂层与刀具间附着力之间的关系。热处理工艺显著降低了生长过程中钴对金刚石涂层石墨化的催化作用,进一步提高了碳化钨颗粒的比表面积及金刚石二次形核密度,得到的金刚石涂层晶粒尺寸及压应力较小。过高的热处理温度虽然可以细化基体表面,增加基体与金刚石涂层之间的“机械锁合”作用,但预处理过程中残留在基体表面的深坑却不利于金刚石涂层附着力的提高,在外力的作用下容易在深坑附近产生微裂纹。实验结果显示,在氩气气氛中,900℃时热处理的硬质合金基体表面生长的金刚石涂层质量和附着力最佳。
In order to improve the bonding ability of diamond coating on cemented carbide cutting tools, a pretreatment process combining heat treatment and acid treatment is proposed. The effects of heat treatment temperature change and cemented carbide cutting tools Surface morphology, diamond coating quality, coating and the relationship between the cutting tool. The heat treatment process significantly reduces the catalytic effect of cobalt on the graphitization of the diamond coating during growth, further increases the specific surface area of the tungsten carbide particles and the secondary nucleation density of the diamond, and the grain size and the compressive stress of the obtained diamond coating are small. Excessively high heat treatment temperature can refine the surface of the substrate and increase the “mechanical locking” effect between the substrate and the diamond coating. However, the deep pits remaining on the surface of the substrate during pretreatment are not conducive to the adhesion of the diamond coating Of the increase in the role of external forces prone to micro-cracks near the pit. The experimental results show that the quality and adhesion of the diamond coating grown on the surface of the cemented carbide substrate heat-treated at 900 ℃ is best under argon atmosphere.