不同湿度环境下镀钛金刚石烧结聚晶金刚石的摩擦学性能  

Tribological Behaviors of Polycrystalline Diamond Sintered by Titanium-coated Diamond Particles under Humid Condition

作　　者：沙小花 李金彦[1] 周波 岳文[2,3] SHA Xiaohua;LI Jinyan;ZHOU Bo;YUE Wen(School of Electronoics and Control Engineering,Ningxia Vocational Technical College of Industry and Commerce,Yinchuan 750021,China;School of Engineering and Technology,China University of Geosciences(Beijing),Beijing 100083,China;Zhengzhou Research Institute,China University of Geosciences(Beijing),Zhengzhou 450001,China)

机构地区：[1]宁夏工商职业技术学院电气与控制工程学院,银川750021 [2]中国地质大学(北京)工程技术学院,北京100083 [3]中国地质大学(北京)郑州研究院,郑州450001

出　　处：《中国表面工程》2023年第6期79-89,共11页China Surface Engineering

基　　金：国家自然科学基金(51875537);宁夏重点研发计划(引才专项)(2021BEB04028);宁夏教育厅高等学校科学研究(NYC2028344);第六批宁夏青年科技人才托举工程资助项目。

摘　　要：聚晶金刚石(Polycrystalline diamond,PCD)机具在钻探破岩与切削过程中服役于边界润滑环境,湿度条件是影响其摩擦磨损性能及切削钻进效率的重要因素。采用磁控溅射技术在金刚石微粉表面沉积厚度为~500 nm的钛薄膜,并选用镀钛金刚石微粉为原料烧结聚晶金刚石(Ti-polycrystalline diamond,Ti-PCD)。研究了Ti-PCD在5%~50%相对湿度(Relative humidity,RH)条件下对磨氮化硅的摩擦磨损性能,利用SEM、XRD、AES等表征镀钛金刚石微粉和Ti-PCD的微观组织、表面形貌及相结构。采用光学显微镜、白光三维形貌仪、拉曼光谱仪分析Ti-PCD和氮化硅球的磨损形貌。结果表明,Ti-PCD中金刚石晶粒与粘结剂钴界面处形成碳化钛过渡层。在相对湿度为5%~50%RH条件下,氮化硅磨斑处的碳质转移膜是影响Ti-PCD稳态摩擦因数的主要原因。5%RH干燥环境下,摩擦滑移过程中碳原子重杂化过程形成连续均匀的碳质转移膜,获得超低的稳态摩擦因数0.034。Ti-PCD表面相对较疏水,水分子钝化作用减弱,有助于形成具有减摩作用的碳质转移膜,致使湿度环境下的稳态摩擦因数比传统PCD降低~30%。Ti-PCD磨损在5%~50%RH湿度范围内逐渐减轻。Ti-PCD中的碳化钛相发挥结合桥作用,利用界面效应强化粘结剂钴和金刚石的界面结合,抑制摩擦滑移过程中的金刚石颗粒剥落,提高Ti-PCD的耐磨性。应用金刚石微粉表面涂层技术制备减摩Ti-PCD,从界面结合和补强增韧方面强化金刚石与粘结剂钴的界面状态,对设计制造高效长寿钻探机具有重要的研究意义。The polycrystalline diamond(PCD),sintered at a high temperature(1 460-1 500 ℃) and pressure(5-5.5 GPa),consists diamond particles and a cobalt binder.PCDs are widely used in geological and petroleum drilling systems,such as thrust bearings and drill bits,owing to their high hardness,toughness,thermal conductivity,and wear resistance.In geological drilling,PCD tools are used in a complex boundary lubrication environment in which the relative humidity(RH) significantly affects the tribological behavior and drilling efficiency.Coating diamond particles with strong carbide-forming elements has been proposed to strengthen the interfacial bonding between the diamond and cobalt binder in PCDs,which influences the tribological behavior.However,the tribological behavior of a PCD sintered by coated diamond particles at different RH levels,and the corresponding mechanisms,have yet to be studied in detail.A titanium(Ti) coating with a thickness of ~500 nm was deposited onto diamond particles via magnetron sputtering.The Ti-coated diamond particles were then sintered at high temperature and pressure to synthesize the Ti-PCD.The tribological properties of the Ti-PCD were studied at 5%-50% RH.The Ti-coated diamond particles and Ti-PCD were analyzed by scanning electron microscopy,X-ray diffraction,Auger electron spectroscopy,impact tests,and tribological tests.The wear morphology of the samples was analyzed by an optical microscope,a Nano Map-D three-dimensional white-light interferometer,and Raman spectroscopy.The results showed the formation of a titanium carbide transition layer between the diamond grain and cobalt binder in the Ti-PCD.The as-obtained titanium carbide phase promoted the tribological behavior of the Ti-PCD under humid conditions,including the reduction of the friction factor and enhancement of the wear resistance.The friction factor of the Ti-PCD tested at different RH levels had a run-in period and steady state.The friction factor significantly fluctuated during the run-in period and stabilized after ~8 mi

关 键 词：镀钛金刚石微粉 聚晶金刚石 摩擦学性能 碳质转移膜 界面结合 

分 类 号：TG156[金属学及工艺—热处理] TB114[金属学及工艺—金属学]