【作者】 熊碧军；

【导师】 杨士勤； 王世兴；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2009， 硕士

【摘要】 硬质合金因具有高熔点、高硬度、化学稳定性好、热膨胀系数低的优点,广泛应用于刀具、模具等方面。为了改善硬质合金的表面性能,本文采用金属蒸汽真空弧离子源(MEVVA)离子注入技术在YG8硬质合金基体表面进行了6种不同的离子注入工艺:离子注入C、V、Cr、C+V、C+Cr、C+V+Cr,并且讨论了不同的注入剂量对试样表面性能的影响。本文利用X射线衍射仪(XRD)对表面物相结构进行了检测;应用X射线光电子能谱仪(XPS)分析了注入层各元素的价态和含量随深度的分布状况;利用拉曼光谱分析仪对类金刚石(DLC)相进行了检测分析;应用维氏硬度计、摩擦系数试验机和电化学腐蚀平台分别对改性层显微硬度、摩擦磨损性能和抗腐蚀性能进行了测试和分析。测试和分析结果表明,用40KV的引出电压对YG8硬质合金进行V离子注入可以达到约800纳米的注入深度;离子注入能提高试样的表面硬度,最大剂量三离子注入样品的维氏显微硬度(HV)可以达到2692,相对于基体增加了约60.8%;离子注入能降低硬质合金表面的摩擦系数,小剂量的多离子注入就能很显著的降低材料表面摩擦系数;拉曼光谱分析结果表明,通过MEVVA源对硬质合金进行大剂量的C离子注入也可以形成类金刚石相,C+V+Cr三离子注入后更容易发现DLC特征;电化学腐蚀测试结果表明,离子注入后腐蚀电位无明显改善,但腐蚀电流和腐蚀速率都有大幅度降低,小剂量的离子注入就能很明显的降低硬质合金的电化学腐蚀速率,其中Cr、C+Cr、C+V+Cr离子注入样品降低腐蚀速率效果较为明显。由此可见,我们可以选用适当的注入元素和注入剂量来得到所需的性能。更多还原

【Abstract】 Due to the high melting point, high hardness, high chemical stability, and low coefficient of heat expansion, hard alloy are widely applied to cuts and moulds. Six experimental procedures (implantation of C, V, Cr, C+V, C+Cr, C+V+Cr ions) are employed to treat the YG8 hard alloys in order to enhance their surface properties by Metal Vapor Vacuum Arc (MEVVA) source implantor. The influence of different implantation dose is discussed.In this thesis, X-ray diffraction (XRD) was used to detect the phase structure of the implanted region. In order to measure the proportion of each element in the surface, X-ray Photoelectron Spectroscopy (XPS) was utilized to study the chemical state and elements depth profile of the modified layer. Raman spectrometer is used to test the formation of DLC. Microhardness, coefficient of friction, and corrosion resistance of the samples surface are measured by Vickers hardness tester, frictionometer, and electrochemical corrosion system, respectively.It was found that the depth of the V ion implanting layer is greater than 800nm with outlet voltage 40KV. Ion implanting can reduce the friction coefficient, even under the condition of using small dose. Results of Raman spectrum show that DLC can be obtained by C ions implanting with large dose, and the DLC feature is more obvious by C+V+Cr ions. The microhardness of the sample surface is increased by ion implanting and the biggest one is HV2692, which is of 60.8% increment compared with the bulk material. The corrosion potential is not changed visibly, but the corrosion current and the corrosion rate are greatly reduced even under the condition of using small dose. The corrosion resistance of Cr, C+Cr, C+V+Cr ions implanted samples are remarkable. In conclusion, we can achieve the predesigned performance by choosing proper species and dose of implanting ions.更多还原