Study On Preparation Technology And Properties Of Coated Magnetic Abrasive Particles

In recent years,since the present preparation process is not ideal,many scholars have been working to improve or study the preparation technology of new magnetic abrasive particles,so as to improve the performance of magnetic abrasive particles,increase production efficiency and reduce production costs.However,some of these processes require highly demanding equipment,some of which are complex process routes,and some are low in fragmentation.These processes can not prepare magnetic abrasive grains which are simple and easy to obtain,and at the same time have good performances.In recent years,there has been a growing increase in the research of Fe₃O₄ and a compound of it,but there is not much research of them on the application of mechanical magnetic abrasive particles.Fe₃O₄ has good magnetic properties.And after chemical or physical modification,it can be better compatible with other organic or inorganic substances.In order to solve the above problems,a kind of coated magnetic abrasive particles,which is simple and without adhesion and breakage,is prepared by chemical method,using iron oxide as the magnetic medium and silica as the abrasive phase.Then,the technological parameters,magnetic properties and processability of the abrasive are studied and analyzed.The main contents of this paper are as follows:1.The preparation methods of Fe₃O₄ and SiO₂ are compared and analyzed.The preparation process of coated magnetic abrasive particles with iron oxide as core and silica as shell is made.The structure,composition,magnetic properties and particle size analysis of the coated magnetic abrasive particles have been carried out.The results show that the SiO₂ of the magnetic abrasive particles prepared by the process are successfully coated with on the surface of Fe₃O₄ and the magnetic abrasive particles have good magnetic properties.2.The influence of the main technological parameters such as the titration rate of ammonia water,the amount of ethyl orthosilicate and temperature on the magnetic abrasive particles in the coating process are analyzed.The whole factor experiment is designed by using Minitab software.The three main parameters are the influence factors and the particle size is the response,and the particle size of the coated magnetic abrasive particles is analyzed.The mathematical relation model between process parameters and granularity is obtained.The whole factor experiment was designed by using Minitab software.With the three main parameters as the influence factor and the particle size as the response,the influence of the process parameters on the size of the coated magnetic abrasive particles is analyzed,and the mathematical relationship model between the process parameters and the particle size is obtained:Particle size=0.0929A+0.97523B-0.051066C-0.01298A*B+0.0000639A*C.3.The model of magnetic loop test device is built according to the ratio of1:1.The model of abrasive grain is established by the ratio of total iron oxide to total particle volume.Maxwell software is used to simulate the magnetic induction intensity of magnetic abrasive particles with different coating thickness under different currents,and the magnetic testing device is used to test the magnetic properties of the magnetic abrasive particles.The simulation results and the measured results show that the magnetic properties of the coated magnetic abrasive particles are decreasing with the increase of the coating thickness.4.The abrasive properties of coated magnetic abrasive particles were verified by processing silicon wafer.The influence of different coating thickness and different grinding fluid on the surface roughness of silicon wafer was explored through experiments.The results show that when the dosage of silicon source is 3 ml,the processing of silicon wafers is better.When NaOH is used as grinding fluid,silicon wafers can be well processed.