摘要
采用盐浴镀覆法对金刚石表面进行双金属层改性处理,以实现金刚石/金属界面结合力的提升。通过对Ti-Ni、Ti-Mo、Ti-W、Ti-Co 4种双金属层改性金刚石的物相组成、微观形貌、镀层厚度、表面粗糙度等进行测试及分析,探究金属组合差异对金刚石镀层性能的影响。结果表明:金属化合物的热力学稳定性、界面相容性以及金属间晶格失配度影响镀层质量;Ti-W改性的金刚石表面因TixW1−x化合物的高稳定性、W的低扩散速率及Ti-W的高效还原性,其镀层厚度最大为3.4μm,较界面亲和度较弱且晶格失配度较大的Ti-Co样品的镀层厚度提高了161.54%;Ti-Mo与Ti-W改性的金刚石表面因晶格失配度低,在金刚石(111)晶面表现出优异的表面平整性,其表面粗糙度Ra较Ti-Ni样品的分别降低了12.41%、21.05%,较Ti-Co样品的分别降低了57.16%、61.39%。
Objectives:With the increasing demand for superhard tool performance in precision machining,the problems of weak bonding between diamond and metal interface,and high cost of controlling coating thickness urgently need to be solved.In this study,the molten salt plating process is adopted.The diamond surface is subjected to bimetallic synergistic modification treatment through the combination of four different metals,namely Ti-Ni,Ti-Mo,Ti-W and Ti-Co,in order to enhance the bonding force at the diamond/metal interface.Meanwhile,the influences of the differences in metal combinations on the coating are explored.Methods:Four kinds of bimetallic modified diamond samples are prepared by the same molten salt plating process.The phase composition,the microscopic morphology,coating thickness and roughness of the samples are tested and analyzed to explore the influences of metal composition differences on the performance of diamond coatings.Taking the Ti-Ni plated sample as an example,its preparation process is as follows:(1)Under the conditions of NaCl mass fraction of 20.31%,KCl mass fraction of 25.84%,diamond mass fraction of 23.08%,titanium mass fraction of 7.69%,and nickel mass fraction of 23.08%,the masses of each raw material are weighed,and the mixture with a total mass of 3 g is placed in a burning boat.(2)The mixture is subjected to metallization plating treatment in a tubular furnace fully protected by argon gas.The plating temperature is 1000℃ ,the holding time is 60 min,and the argon gas flow rate is 0.2 L/min.(3)After plating,the product is ultrasonically cleaned at 40 kHz for 30 minutes to remove the residual salt and the metal particles on its surface.Then,it is dried under vacuum at 60℃ ,ground and sieved to obtain the coated sample.Results:(1)The thermodynamic stability and the interfacial compatibility of metal compounds affect the coating thickness.For the Ti-W modified diamond sample,due to the high stability of the TixW1−x compound,the low diffusion rate of W and the efficient reducing property of Ti-W,the maximum coating thickness is 3.4μm.Due to the weak affinity of Ti-Co,the thinnest coating of the Ti-Co modified sample is 1.3μm.Therefore,the coating thickness of the Ti-W sample is increased by 161.54%compared with that of the Ti-Co sample.Moreover,in the same sample,the thickness of the Ti-C layer formed by chemical bonding and the intermetallic compound layer varies greatly.The thickness difference between the Ti-C layer formed by chemical bonding and the intermetallic compound layer in the same sample is significant,with the former accounting for more than 79%of the thickness,while the physically deposited elemental metal layer is thinner.Therefore,the synergistic effect of the Ti-C covalent bond dominated by chemical bonding and the intermetallic compound interface structure with the metal layer assisted by physical deposition can effectively coordinate the interfacial stress and improve the bonding stability of the coating.(2)The lattice mismatch between metals affects the surface roughness Ra of bimetallic modified diamond.Low mismatch Ti-Mo(with mismatch degree of 0.0646)and Ti-W(with mismatch degree of 0.0707)bimetallic modified diamonds exhibit better surface quality on the(111)crystal plane,with Ra values of 17.021 and 15.341 nm,respectively,which are 12.41% and 21.05% lower than those of Ti-Ni(with mismatch degree of 0.1938)bimetallic modified diamond,and 57.16%and 61.39%lower than those of Ti-Co(with mismatch degree of 0.1518)bimetallic modified diamond,respectively.This is due to the regulatory effect of lattice compatibility on the interfacial bonding strength,which in turn affects the surface morphology of the coating.The mismatch degree between Ti-Co is lower than that between Ti-Ni,but its roughness is actually higher,which is related to the surface protrusions on the coating surface caused by the accumulation of cobalt elements during the deposition process.Conclusions:The use of the molten salt method for bimetallic modification of diamond successfully triggers the interfacial chemical reaction between diamond and metal,transforming the bonding mode from single physical coating to a comprehensive combination of chemical bonding and physical coating.This significantly enhances the interfacial bonding strength of diamond/metal,providing a reference for the experimental optimization of high-performance diamond tools.
作者
陈蕾莹
陈雷明
刘雪婷
王旭磊
程绍坤
朱子怡
陈博宇
鞠恒冬
潘晓宇
姚梦媛
CHEN Leiying;CHEN Leiming;LIU Xueting;WANG Xulei;CHENG Shaokun;ZHU Ziyi;CHEN Boyu;JU Hengdong;PAN Xiaoyu;YAO Mengyuan(School of Materials Science and Engineering,Zhengzhou University of Aeronautics,Zhengzhou 450046,China;Henan Key Laboratory of Aeronautical Material and Application Technology,Zhengzhou,450046,China)
出处
《金刚石与磨料磨具工程》
北大核心
2025年第4期458-469,共12页
Diamond & Abrasives Engineering
基金
河南省科技攻关项目(202102210216,232102231005)。
关键词
盐浴镀
金刚石
碳化物
双金属镀层
salt bath plating
diamond
carbide
bimetallic coating
