Preparation And Research Of Diamond Ceramic Composite Abrasive Materials For Ultra Precision Grinding

The third generation semiconductor materials,represented by silicon carbide wafers,have become increasingly important in the development of various industries due to their excellent performance.However,due to the high requirements of the working conditions of silicon carbide wafers on their surface quality,and due to the high hardness of silicon carbide,a large amount of grinding heat will be generated during the processing process,which is easy to cause surface burns on the wafer,resulting in a reduction in the surface quality of silicon carbide wafers.The pores of abrasive tools can effectively reduce the grinding heat during the grinding process.Traditional atmospheric hole grinding wheel preparation requires the addition of pore forming agents,but pore forming agents are generally organic and can pollute the environment.Therefore,in this paper,by adjusting the ceramic bond formula,a suitable bond formula for preparing ceramic bond diamond composites capable of machining silicon carbide is found,and then by adjusting the content of the bond and diamond,a honeycomb ceramic bond diamond composite without the need for pore forming agents is prepared.The specific research content is as follows:Using a ternary phase diagram,investigate the effect of changes in the content of Al₂O₃,B₂O₃,and SiO₂in the R₂O-Al₂O₃-B₂O₃-SiO₂system binder on the performance of the binder.The results indicate that the presence of Al₂O₃and SiO₂can improve the fire resistance of the bond,and the influence of Al₂O₃is greater,while the addition of B₂O₃can reduce the fire resistance of the bond.Al₂O₃will reduce the fluidity of the bond,while B₂O₃will increase the fluidity of the bond.When the content of Al₂O₃in the bond is high,the coefficient of thermal expansion of the bond will first decrease and then increase with the increase of B₂O₃content,and the bending strength will first increase and then decrease with the increase of B₂O₃content;When the Al₂O₃content in the bond is low,the coefficient of thermal expansion of the bond will increase with the increase of the B₂O₃content,and the bending strength will decrease with the increase of the B₂O₃content.;When the content of SiO₂is the same,the coefficient of thermal expansion of the bond will increase with the increase of B₂O₃content,and the bending strength will increase with the increase of Al₂O₃content;When the content of B₂O₃is the same,the coefficient of thermal expansion of the bond will increase with the increase of the content of Al₂O₃,and the bending strength will increase with the increase of the content of B₂O₃.The influence of each component in the binder on the microhardness change of the binder is SiO₂>B₂O₃>Al₂O₃.By adjusting the content of SiO2 and B2O3 in the bond,the fire resistance,differential thermal analysis,fluidity,coefficient of thermal expansion,XRD and flexural strength of the bond were tested to explore the influence of different content of SiO2 and B2O3 on the performance of ceramic bond.The results show that when the content of silica is 45.13wt.%,the refractoriness is 630℃,the fluidity is 136%,and the coefficient of thermal expansion is8.85×10-6/℃-1,with a maximum flexural strength of 64.00 MPa and a corresponding sintering temperature of 680℃.Through the comprehensive analysis of the properties of the binder and diamond,the suitable formula of the binder for the preparation of composite materials was selected,and the molding material was designed and configured for the thermal analysis of the molding material,and the sintering temperature of the composite material was determined to be680℃.The shrinkage,relative density,porosity,microstructure,XRD and flexural strength of the prepared composite were analyzed.The results show that:when the binder content is25.00wt.%,the shrinkage of the composite is greater than zero,indicating that the composite shrinks after sintering.When the binder content is 35.00wt.%～55.00wt.%,the shrinkage rate of the composite is less than zero,indicating that the volume of the composite increases after sintering.With the increase of binder content,the relative density of composites decreased and the porosity increased.By XRD analysis of the composite,it is found that the binder is pure glass state,and no new crystal phase is formed.The fracture morphology of the composites was analyzed by optical microscope and scanning electron microscope.When the binder content was 25.00wt.%,the fracture morphology of the composites showed that there were many small pores and relatively dense.When the binder content is 35.00wt.%,the fracture morphology of the composites shows that there are many large pores.When the binder content reached 45.00wt.%,the porosity of the composite was larger and some closed pores appeared.When the binder content is 55.00wt.%,a large number of relatively uniform closed pores are formed in the composite.With the increase of binder content,the flexural strength of the composite decreases.