【作者】 郑安；

【导师】 朱教群；

【作者基本信息】 武汉理工大学 ， 材料加工工程， 2004， 硕士

【摘要】 聚晶金刚石复合片(Polycrystalline Diamond Compact)已广泛应用于地质钻探、非铁金属及合金、硬质合金、石墨、塑料、橡胶、陶瓷、木材等材料的切削加工等用途中。它的表层为金刚石粉末烧结而成的多晶金刚石，具有极高硬度、耐磨性和工作寿命；底层一般为钨钴类硬质合金，它具有较好的韧性，为表层聚晶金刚石提供良好的支撑，且容易通过钎焊焊接到各种工具上。目前国内外一般都采用超高压高温烧结的方法制造聚晶金刚石-硬质合金复合片。国内聚晶金刚石复合片的性能与国外先进产品有较大差距，主要表现在抗冲击性能较低、易分层、崩刃、破裂等方面。 本课题采用扫描电镜、拉曼光谱、光电子能谱、X-射线衍射分析、电子探针等方法分析了国内外聚晶金刚石-硬质合金复合片在微观组织结构、元素成分分布方面的差异，结合对现有烧结工艺的分析，研讨了造成这些差异的机理；采用扫描电子显微镜、激光粒度分析、原子发射光谱、等离子发射光谱等方法对关键原材料-金刚石微粉的晶形、杂质含量进行了比较分析测试。根据这些工作提出了一些改进国内聚晶金刚石-硬质合金复合片性能的设想。 研究结果表明，国内外复合片具有如下差异和改进方向：Ⅰ．国内聚晶金刚石-硬质合金复合片杂质含量偏高，含有Mo、Fe、Cr等杂质，需要采取综合措施降低杂质含量，包括1．提高金刚石微粉原材料的纯度；2．改善操作环境；3．改进烧结时屏蔽层金属杯的材料；4．改进烧结前的处理和储存，采取真空处理和真空储存以排除金刚石吸附的各种杂质。5．建立金刚石微粉杂质检测方法和标准。Ⅱ．国内聚晶金刚石层中晶粒之间直接连接的共价健(C-C健)比例少，催化剂金属含量过高，导致宏观强度低，应采取如下措施：1．提高金刚石微粉堆积密度以提高烧结时高压传递的有效性和减小晶粒之间的距离；2．减少催化剂金属加入量以避免其隔断金刚石晶粒之间的直接健合，同时提高聚晶的热稳定性。Ⅲ．采取措施防止金刚石微粉在投料时出现粒度偏析。Ⅳ．采取措施降低PDC内部的残余应力。改进金刚石-硬质合金界面结构。Ⅴ．改进硬质合金基体的材料，使其与聚晶层的硬度和热膨胀系数具有更好的适配性。更多还原

【Abstract】 Polycrystalline Diamond Compact (PDC) has been widely used in earth drilling, cutting of various materials such as non-ferrous metal and their alloy, hard metal alloy, graphite, plastics, rubber, ceramics. It’s faced with polycrystalline diamond sintered from diamond powder. It has extremely high hardness, abrasion resistance and serving life. It’s usually supported by tungsten carbide that has good toughness. The substrate provides good support for polycrystalline diamond and can be easily brazed to various tools. Presently PDCs are usually manufactured by HP-HT means. Domestic PDCs are inferior to foreign products. Domestic PDCs exhibit lower impact resistance, are more susceptible to delaminating, chipping and breakage.In the present research, scanning electron microscope (SEM), laser raman spectroscopy (LRS), X-ray photoelectron spectroscopy (XRS), X-ray diffraction (XRD) and electron probe micro analysis (EPMA) were utilized to investigate the difference in micro-structure and elements distribution between domestic and foreign PDCs. Combined with analysis on current manufacturing process, the mechanism for the difference was discussed. Scanning electron microscope (SEM), laser granularity analysis, atom emission spectroscopy (AES) and plasma emission spectroscopy (ICPAES) are also utilized to investigate the grain shape and impurities of key material-diamond power. Based on these work, some suggestions are presented to improve the performance of domestic PDCs.The present work suggests that our PDCs have following difference and could be improved by:I . Domestic PDCs contain more impurities such as Mo, Fe and Cr. They should be controlled by: 1. Improve the purification of diamond powder. 2. Improve the processing environment. 3. Change the material of shielding cup during sintering. 4. Improve the handling process and storage of diamond before sintering. Vacuum heat-treating and vacuum storage are recommended to eliminate impurities absorbed by diamond powder. 5. Standard for testing theimpurity content of diamond powder should be established.II. The direct diamond-diamond bonding between granules in domestic PDCs are poor. Accordingly more catalyst metal are left over, this weaken the strength of the whole PDC. Thus following measures should be adopted: 1 .Increase the pack density of micron diamond power to improve the pressure transmitting between diamond granules and decrease the distance between them. 2. Reduce the content of catalyst metal to prevent it from blocking the direct bonding of diamond granules and improve the thermal stability of PDCs.III. Measures should be taken to prevent uneven distribution of grain size in diamond blending.IV .Measures should be taken to lower the residual stress in PDCs by improving the structure of the interface between diamond and substrate.V .Improve the material of substrate to improve its adaptability to polycrystalline diamond.更多还原