Tape-Casting Of Transparent Alumina

Transparent alumina was the first to realize the transparent ceramics with high strength,high hardness and high temperature resistant,corrosion resistance,high chemical stability and excellent biocompatibility.Therefore,it was more and more applied in the machinery,military industry,electronics,energy,semiconductor,and in the field of medical high technology.Tapecasting is an important kind of molding technology of the preparation of ceramics,which has been the most important and effective preparation technology of single layer or multilayer ceramic chip as well.This topic,tapecasting was applied to prepare transparent alumina ceramic substrates owning a well topical performance.This paper focusesed on the preparation of transparent alumina ceramics,the controlling the processing parameters of tapecasting and the factors affected on sinering body.The systematic research of preparation and performance of slurry of transparent alumina were carried on in this paper.Ethanol and ethyl ketone which were binary azeotropic system were used as a solvent,and when the volume ratio of 1:1,dissolved PVB best.After sedimentation experiment and the effect on the viscosity of slurry,the results showed that Glycerine trioleate was chosed as a dispersant,the suspension was the most stable,and the optimum dosage was 0.3wt%-lwt%.When Polyethylene glycol(PEG)and dibutyl phalate(DBP)mixed were used as plasticizer,the viscocity of slurry was adjusted,and the best range of the ratio(R)of plasticizer with binder was 1.0?1.3.In this paper,the process was optimized and the mixing material and defoaming were carried on simultaneously,which ensured the solvent maintaining stability through out the preparation of slurry.Each component was dissolved into the solvent well,and the solid content of slurry was further improved.Process parameter was optimized,which ensured the repeatable preparation of high quality substrates.The porosity of body after dumping was minimu,when the volume content of solid phase was at 55%.And the best condition of drying process of the green boy was under the protective atmosphere and the temperature was at 35?.The main factors which influenced in the sintering body were studied in the paper.The effect on the performance of sinered substrate was studied through by heating rate,as a result,it was the best when the heating rate was at l?/min through the dumping process.The tunnel kiln with athydrogen atmosphere was used to sinter the body to prepare the transparent alumina.The effect on he sintering properties,mechanical properties and optical properties were studied through introduction of different amount of sintering aids(mg2+,La3+,Y3+),the results showed that when the substrate was prepared with slurry at the quantity ratio of Mg(NO3)2,Y(NO3)3,La(NO3)3,which were introduced 5%,3%and 3%,the density was best and TFT(max)of sintered body was 73.5%.And the volume cotent of solid phase was at 55%the density was best and TFT(max)of sintered body was 73.5%.