The Investigation Of Mechanism And Thermal Phenomena On Advanced Ceramics

Engineering ceramic materials is highly evaluated by high hardness,high strength,high chemical stability,high wear resistance and high heat resistance.These characteristics make it widely used in machinery,metallurgy,chemical and other fields.However,it is difficult to process for excellent chemical and physical properties of engineering ceramics and traditional metal processing methods are no longer applicable.At present,the processing methods of engineering ceramic materials is mainly mechanical processing except for special processing methods and grinding with a diamond wheel is a very effective method.The subject is aim to research two kinds of zirconia and silicon nitride engineering ceramics for grinding.The research of engineering ceramics grinding mechanism and the phenomenon of heat was carried out to provide an effective program,experimental basis and theoretical basis for the actual production and processing,the main research work is as follows:The surface roughness measurement experiment of ceramic material surface grinding was carried out to study the influence factors of surface roughness,including grinding parameters,material properties,cooling conditions.The surface roughness value decreased as the grinding wheel linear velocity increased,the grinding depth increased,and the workpiece feed rate decreased.Material properties of the greater impact on the surface roughness,zirconia ceramic surface roughness was better than silicon nitride ceramics.In the experimental conditions selected grinding parameters,silicon nitride ceramic was suitable for dry grinding and zirconia ceramic was suitable for wet grinding.On dry grinding,the zirconia ceramic surface would produce micro-cracks,and it was easy to have a surface burn.Scanning electron microscopy observation of the planar ground surface of ceramic material showed that the surface of the ground surface of the zirconium oxide ceramic and the silicon nitride ceramic generally has plastic deformation and brittle fracture,and was the main two forms of material removal.The forming process of grinding surface and the type of wear scar were analyzed theoretically.The brittleness removal of the material caused by the transverse crack propagation was caused.The radial crack has a great influence on the strength of the workpiece.The plane grinding force measurement experiment of ceramic material was carried out to study the influencing factors of plane grinding force,including material properties,dry/wet and grinding parameters.The linear velocity of diamond grinding wheel was the factor that has the most influence on the tangential grinding force.The grinding depth was the most influential factor on the normal grinding force.The workpiece feed speed was the least influencing factor on the grinding force.As the grinding wheel linear velocity increased,the tangential grinding force and the normal grinding force decreased,and the tangential grinding force and normal grinding force increased with the increase of grinding depth and workpiece feeding speed.The influencing factors of grinding force of single abrasive grains were discussed.With the increase of grinding wheel linear velocity,the normal grinding force of single abrasive grinding decreased and with the increase of workpiece feed speed and grinding depth,normal grinding force increased.Based on ABAQUS established diamond single abrasive grinding engineering ceramic model can predict the size of grinding force,and the experimental results were basically the same.The engineering ceramic surface grinding experiments were conducted to explore the effects of grinding parameters,material properties and dry/wet grinding on grinding temperature and heat distribution ratio.Grinding the ceramic surface would form a local high temperature.It was found that the influence of grinding parameters is greater in the variation of grinding temperature and grinding heat distribution ratio.The most important factor was the workpiece feed speed and grinding depth,but the influence of diamond grinding wheel speed was small,so the actual grinding process can make diamond wheel line speed appropriate increase.The grinding temperature and grinding heat distribution ratio both increased with the increase of workpiece feed rate and grinding depth.The linear velocity of diamond grinding wheel increased,grinding temperature and grinding heat distribution ratio also increased gradually,and the growth trend gradually was slow.Based on ABAQUS single diamond abrasive grinding ceramic simulation model,can be drawn grinding parameters on the grinding temperature.The results obtained by the simulation model were not much different from those obtained by the experiment and can he used to predict the grinding temperature in the surface grinding.In summary,this thesis explored the influencing factors of engineering ceramics grinding mechanism,surface morphology,grinding force and grinding temperature and established the reasonable grinding process parameters of engineering ceramics through the grinding experimental study and theoretical analysis on zirconium oxide and silicon nitride ceramic.A finite element simulation model of single abrasive grinding ceramic was established to predict the grinding force and grinding temperature.The results were verified by plane grinding experiments.The above results have certain scientific significance and engineering application value for the development of high-quality,high-efficiency new processing technology of ceramic materials.