Refractory Alumina Ceramic Tube
Alumina ceramic production process is as follows:
Powder preparation: alumina ceramic powder is prepared according to different product requirements and different molding processes.When using extrusion molding or injection molding, the binder and plasticizing agent shall be introduced into the powder. Generally, the thermoplastic or resin organic binder with a weight ratio of 10-30% shall be mixed evenly with the alumina powder at a temperature of 150-200 ℃ to facilitate the forming operation.There is no need to add binder for powder material formed by hot pressing process.If semi-automatic or full-automatic dry pressing is adopted, it has special technological requirements for the powder. Spray granulation method is needed to treat the powder and make it appear spherical, so as to improve the fluidity of the powder and facilitate the automatic filling of the mold wall during the molding.In addition, in order to reduce the friction between powder and mold wall, 1 ~ 2% lubricant such as stearic acid and binder PVA should be added.
Two forming methods: Alumina ceramic products forming methods include dry pressing, grouting, extrusion, cold isostatic pressing, injection, flow casting, hot pressing and hot isostatic pressing, etc.In recent years, some molding technologies have been developed, such as filter press molding, direct solidification injection molding, gel injection molding, centrifugal grouting molding and free solid molding.
Tri-firing technique: The technique of densifying a granular ceramic body to form a solid material is called sintering.Sintering is to remove the cavity between the particles in the billet, remove a small amount of gas and impurities and organic matter, so that the particles grow and combine with each other, forming a new material method.The most widely used heating device for firing is the electric furnace.In addition to atmospheric sintering, there are also hot pressing sintering and hot isostatic sintering, microwave sintering, arc plasma sintering, self-propagating sintering technology.
