Fundamental Research On Microwave Sintering Of Micron-sized Diamond Copper-bonded Grinding Wheel Segments

The temperature distribution of microwave sintering is uniform from inside to outside among material,which can not only avoid the temperature gradient inside the material caused by traditional heating process,but also improve the heating rate and reduce effectively the sintering temperature.At present,the application of microwave sintering is mainly focused on fabricating of ceramics and powder metallurgy,and it is rarely used for sintering of metal bonded diamond abrasive tools,therefore,the feasibility and sintering mechanism as well as the influence of sintering process parameters on wheels are not understood.The fundamental research on fabrication of metal bonded diamond grinding wheels segments by microwave sintering is carried out in this paper,and the main research works are following:(1)Cu,Sn,Fe and Ni powders are selected as metal bond materials,and their mass ratio is 6:2:1:1,by adding super pure diamond powder as abrasive and NH4HC03 with 2%mass ratio as pore forming material.The weighing,mixing,drying,cold press molding and microwave sintering process are studied for fabricating metal bonded diamond grinding wheel segments.The wheel segment samples are fabricated by controlling the copper powder particle size and concentration of diamond.(2)Through hardness and bending strength measurement,the influence of copper powder particle size and the diamond concentration on hardness and bending strength of metal bonded diamond grinding wheel segments is analyzed.(3)Through density measurement and linear shrinkage rate calculation,the influence of copper powder particle size and the diamond concentration on density and linear shrinkage rate calculation of metal bonded diamond grinding wheel segments is analyzed.(4)Using SEM to observe the binder interface of metal bonded and diamond abrasive and EDS to research the elements on the surface of diamond which demonstrates the combination of metal bonded and diamond abrasive.(5)The grindabiltiy of diamond grinding wheel segments on carbide WC is experimentally investigated.The analysis is focused on the influence of copper powder particle size and W20 diamond concentration to surface roughness of the workpiece and grinding ratio of diamond grinding wheels segments.