Research On Preparation Process Of Aqueous Alumina Paste

Along with the development of modern science technology and high-performance structure ceramic material widely used in various sectors ,the reliability and controlling of ceramic put forward higher requirements,which posed a challenge to the existing ceramic forming. It can be show that the hotspots research of ceramics has gone from sinter to powder and now to the forming process in the history of the development of ceramics in recent half century. The ceramic paste extrusion is one of the rapid prototyping manufacturing technology, but the high solid content and good rheological paste must be made before the shaping method. So this topic through with the factors influencing of the dispersion alumina slurry and paste rheological to study, so as to the application of alumina paste provide theory basis and the data support. The main text as follows:1) The dispersion of slurry with the different solid content, dispersant types and addition amount(KH, NH4-citrate, PAM), pH and the ball milling time to the fluidity were discussed in the thesis. The study showed that the viscosity of slurry adds with the solid content increase, the viscosity of slurry increases exponentially when the solid content is more than 51vol%; it increases and then decreases with the increase of pH; it decreases and then increases with the increase of dispersant and ball milling time. The alumina slurry with low viscosity and good dispersion was obtained with the 50vol% of high solid content, pH=9, the KH or NH4-citrate in 0.4vol% or in 0.5vol% and 12h ball milling time.2) The alumina paste extrusion was prepared by adjusting the pH value of slurry. The paste rheology is the Bingham fluid performance with the different solid content, pH and KH by adding the amount of cases. The effect of the paste fluidity with different solid content, dispersant types and addition amount(KH, NH4-citrate, PAM) and pH was discussed in the present thesis. The study showed that the viscosity of paste increases with the solid content increase;it increases and then decreases with the growth of pH; it decreases and then increases with the addition of increasing KH. The good dispersion and rheological alumina ceramic paste, which it contains 50vol% in solid content and 0.4vol% KH and pH=7(or 0.5vol% NH4-citrate,pH=5), was prepared.3) The effect of solid content to the relative density,linear shrinkage, three-point bending strenth and fracture toughness was discussed. The fine properties green body with 82.7% relative density, 2.3% linear shrinkage, 20MPa three-point bending strenth are pepared. In the paper, microstructure analysis of green body formed by ceramic paste extrusion of alumina is discussed. The results showed that it is particles disperse uniformly, relatively small gap and properties of microstructure, and reduces the number of pore and improves rhe dispersity of micropore.