| Superhard materials refer to materials with high hardness above 40 GPa,mainly including diamond and cubic boron nitride.Superhard materials and resin bond make up superhard resin abrasive,which are widely used in the automotive industry,oil drilling,construction engineering,mechanical processing,instrumentation,electronics industry,aerospace and modern cutting-edge science.Resin bond abrasives are self-sharpening and easy to process and trim.However,the superhard materials in resin abrasive tools are easy to fall off when applied,and the holding force is not large,so that the superhard abrasives cannot fully work.The metal bond has a good holding force during the work process,and when the superhard abrasive was combined with the metal material,added it to the resin abrasive after being prepared as a composite abrasive,which can improve the holding force of the superhard material and make it play a greater application value.This research mainly includes the following:(1)Preparation of hard and brittle metal binder by powder metallurgy,using electrolytic Fe,Cu85Sn15 as the basic formula,adding elements P and B,the effects of different elements,different element addition amounts and different sintering process parameters on the mechanical properties and microstructure of iron-based metal binder materials were studied.When non-metallic elements P and B were added,the impact resistance and bending strength decreased,and the hardness increased,which made the iron-based metal bond hard and brittle.After adding non-metallic elements of P,the optimal sintering temperature was 710?,the optimal volume of addition was 5%,and in this temperature the impact strength and bending strength are reduced from the original 135 k J/m2 and 840 MPa to 111 k J/m2 and 560 MPa,the respectively reduction rates were 82.2%and 33%,the hardness was increased from the original HRB 65 to HRB 91,the increase rate was 40%;What's more The best sintering temperature of B was 730?,and in this temperature,the addition of 3%-11%can meet the requirements of use,and there was no optimal value.(2)Preparation of composite abrasives of Fe-CuSn-P bond and superhard materials,the preparation process of diamond/Fe-CuSn-P composite abrasives,the type of wetting agent(inorganic wetting agent phosphate,organic wetting agent W-120 granulated powder)and volume of addition(0.20 g,0.25 g,0.30 g)on the performance and application of composite abrasives were studied.The research shows that the temperature of the hot pressing sintering preparation process was 720?,and the holding time was 6 min,the optimal sintering process in pressureless sintering temperature was 780? and holding time was 3 h;The hot pressing sintering preparation process was simple,and the surface of the composite abrasive were smooth,what's more,the particle size was 10#?and the finished product rate as high as 70%.The composite abrasive prepared by the pressureless sintering preparation process has a rough surface and a toothed structure,it has wide range of abrasive particle size that with a particle size of 18#has a finished product rate of 55%,and single particle average strength 200 N.The finished rate of composite abrasive with a particle size of 10#was about 25%and a single particle average strength of 400 N;When the superhard material and the metal directly added to the resin abrasive tool,the wear ratio was 1.52,when the composite abrasive was added to the resin abrasive tool the wear ratio was 20.7,which improved the holding force of the superhard abrasive and the wear ratio of the resin abrasive tool by nearly 20 times,also reduced the burn of the workpiece and improved the surface quality of the polished workpiece. |
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