Alumina ceramics are divided into high purity type and ordinary type two. High purity alumina ceramics department of Al2O3 content in more than 99.9% of the ceramic material, due to its high sintering temperature of 1650 - 1990 DEG C, the transmission wavelength of 1 6 ~ m, generally made of molten glass to replace platinum crucible: using its light transmittance and alkali metal corrosion for sodium lamp; in the electronic industry can be used as the integrated circuit substrate and the insulating materials. Common type of alumina ceramic by different Al2O3 content is divided into 99 porcelain, 95 porcelain, 90 porcelain, 85 porcelain and other varieties, sometimes Al2O3 content in 80% or 75% are classified as ordinary alumina ceramic series. One of 99 alumina ceramic material used for the production of high temperature crucible, refractory furnace tube and the special wear-resistant material, such as ceramic bearings, ceramic seals and valve piece; 95 alumina ceramics is mainly used for corrosion resistance, wear-resistant parts; 85 porcelain occurs frequently in doped portion of talc, and improving the electrical performance and mechanical strength, and molybdenum, can be niobium, tantalum metal sealing, some used as electric vacuum device. Its production process is as follows:A powder preparation:The factory of alumina powder according to the different requirements of products with different forming processes is prepared into powder material. Powder particle size in 1 u m? M? The following, if manufacturing high pure alumina ceramic products in addition to alumina purity in the 99.99%, still need to superfine grinding and make its particle size distribution. By extrusion or injection molding, powder binder and plasticizer is introduced,? Generally with the weight ratio of 10 - 30% of thermoplastic plastic or resin? Organic binder and alumina powder in 150 - 200 DEG C to facilitate mixing, molding operation. The use of hot forming process of powder raw materials without binder. If using a semi-automatic or fully automatic dry pressing, the powder has the special requirements of the process, needs to use the spray granulation method for powder processing, make its present shape of a ball, which is beneficial to improve the fluidity of the powder for molding automatic filling and die wall. In addition, in order to reduce powder and die wall friction, also need to add 1 ~ 2% lubricant? Such as stearic acid and binder PVA?.To dry pressing need for powder spray granulation, which introduce a polyvinyl alcohol as a binder. In recent years, a research institute in Shanghai, the development of a water soluble wax used for Al2O3 spray granulation binder, heated in a case with good fluidity. Spray granulation powder after must have good fluidity, loose density, flow angle of friction temperature less than 30 DEG c.. Particle size ratio ideal conditions, to achieve a large biscuit density.Two forming method:Alumina ceramic products forming method with stem pressure, grouting, extrusion, cold isostatic pressing, hot pressing and casting, injection, hot isostatic pressing forming methods. In recent years at home and abroad and the development of press forming, direct coagulation casting, gel injection molding, centrifugal casting and solid freeform fabrication and molding method. Products of different shape, size, complex shape and precision products require different forming methods. Abstract the common shaping introduction:1 pressing: alumina ceramic dry press forming technology is limited to the shape of herpes and the inner wall thickness to exceed 1mm, the length and diameter ratio greater than 4 : 1. Method of forming a uniaxial or biaxial. Compressor having hydraulic, mechanical type two, a semi-automatic or fully automatic molding method. Compressor maximum pressure for 200Mpa. The yield can reach 15 to 50 pieces per minute. As the hydraulic press stroke uniform pressure, so the powder filling there are differences when pressing different height. Mechanical press for powder filling pressure size and how much change, easily lead to sintering shrinkage difference, affect the quality of the product. So dry pressing process of powder particles are evenly distributed on the mold filling is very important. Filling amount is accurate or not for the manufacture of alumina ceramic parts size precision control influence. The powder particles with a greater than 60 m, ranging from 60 to 200 between the head may be the biggest free flow effect, to achieve the best effect of forming pressure.2 casting method: Casting alumina ceramic using earliest forming method. Due to the adoption of the gypsum mold, low cost and easy forming of large size, the shape of complex parts. Injection molding is the key of alumina slurry preparation. Usually in water flux as medium, adding solution of glue and adhesive after grinding, fully exhaust, then pour into the gypsum mould. As a result of plaster mold capillary on moisture sorption, slurry and solidification in mould. Hollow grouting, in the mold wall adsorption slurry of required thickness, also needs to be poured out excess slurry. In order to reduce body shrinkage, should try to use a high concentration slurry.Alumina ceramic slurry is needed in the organic additives added to make the slurry particles formed on the surface of electrical double layer so that the slurry stable suspension of precipitation. In addition to adding vinyl alcohol, methyl cellulose, alginate amines such as binder and polypropylene amine, Arabia gum as dispersing agent, goal is to make the slurry for grouting forming operation.Three burning technology:Granular ceramic densification and the formation of solid materials technology method called sintering. Sintering is inner particles in hollow out, a small amount of gas and impurity removal so that the particles of organic matter, combined with mutual growth, formation of new material for.Burning heating device used most widely used in electric furnace. In addition to normal pressure sintering? I.e. pressureless sintering?, and hot pressing sintering and hot isostatic pressing sintering. Continuous Hot-pressing Sintering while improving yield, but the equipment and tooling costs are too high, moreover because of the axial heat, products length is restricted. Hot isostatic pressing sintering with high temperature and high pressure gas as pressure transfer medium, has the advantages of uniform heating, very suitable for the shape of complex products sintering. Due to the structure of uniform, material properties than cold pressing sinter is improved about 30 ~ 50%. Than the average increase 10 ~ 15% sintering. Therefore, the high additional value of alumina ceramic products or national defense needs of special parts, such as ceramic bearing, mirror, nuclear fuel and the barrel and other products, field using a hot isostatic pressing sintering method.In addition, microwave sintering, arc plasma sintering method, since the spread node technique is also in development studies.Four fine processing and packaging process:Some alumina ceramic material in sintering, still need to undertake finishing. If used as artificial bone products requirements have high surface smoothness, such as a mirror, to increase the lubricity. As a result of alumina ceramic materials with high hardness, needs to be more hard abrasive polishing brick material for finishing. Such as SiC, B4C or diamond. Usually a coarse to fine abrasive level grinding, the end surface polishing. The general use of < 1 u m? M? Al2O3 powder or diamond abrasive polishing paste. In addition to laser processing and ultrasonic grinding and polishing method can also be used.Some alumina ceramic parts and other materials for packaging processing.