Surface Nickel Plating Of Diamond Particles And Its Application In Fixed Abrasive Lapping

Fixed abrasive lapping has the advantages of high machining efficiency, environmentallyfriendly etc. and it has broad application prospects in the field of precision and ultra-precisionmachining. The bonding ability between abrasives and resin deteriorates due to the smooth surfaceand low free energy of diamond abrasives, which reduces the utilization of abrasives and its lappingefficiency.In this paper, diamond abrasives were coated with Ni layer by using electroless plating orelectroplating to improve abrasive retaining performance. Fixed abrasive pads (FAPs) were preparedbased on nickel plated diamonds. Machining performance of FAPs was investigated by lapping testand the marathon experiments. The main work and results are as follows:(1) The electroless plating process of diamonds with Ni-P was explored. The influence ofparameters on Ni covering ratio and coating morphology was analyzed. Control parameters of precisecoating ratio were investigated. Results show that a homogeneous layer of Ni-P is formed on thesurface of diamonds. The morphology of coated diamond abrasives is distinct significantly andparameters formula of accurate coating rate is obtained.(2) Machining performance of FAP with electroless nickel abrasives was optimized. Theinfluence of Ni covering ratio on coefficient of friction, acoustic emission, material removal rate andsurface roughness of work-pieces during the lapping process were investigated. Lapping mechanismunder different coating rate was discussed. Results demonstrate that the grinding mechanism underdifferent covering ratio is disaffinity.The machining performance is the best when FAP embeddedwith diamond abrasives with a Ni covering ratio of50%. Material removal rate increases by2.8timesin contrast with pure diamonds after sustainable process for50minutes.(3) The electroplating process of diamonds with Ni was explored. A new barrel for nickelplating equipment in laboratory was designed. The effect of current density on the morphology ofplated diamonds was analyzed. Results show that uniform coating can be obtained through the nickelplating apparatus developed by our laboratory. The amount of burrs formed on the particle surfaceincrease with the current density.(4) Machining performance of FAP with electroplating nickel abrasives was optimized. Theinfluence of current density on coefficient of friction, acoustic emission, material removal rate andsurface roughness of work-pieces during the lapping process was investigated. The morphology of FAPs after lapping was analyzed. A comparison with electroless nickel abrasives was discussed.Results demonstrate that the increase of current density improves machining performance of FAP withelectroplating nickel abrasives. Material removal rate under1.5A/dm2doubled in contrast with0.5A/dm2, while they are lower than the FAP embedded with the diamond coated by electrolessplating, its stability improves60%compared with electroplating ones.