Preparation And Properties Of Ceramics Based On In-situ Coagulation Of Ceramic Suspensions Via Dispersant Removal

Ceramic forming process is one of the key processes for obtaining high performance,high reliability ceramics and composite materials.Novel in-situ coagulayion casting of ceramic suspensions via dispersant removal is a new forming method for in-situ coagulation of ceramic suspension by controlled removal of dispersant.Aiming at the problems of easy hydrolysis of aluminum nitride powder and the cumbersome dispersion process of carbon nanotube-alumina mixed suspension,this paper based on the staililzation mechanism of ceramic suspension,selected the corresponding dispersant,and prepared high solid content and low.viscosity non-aqueous aluminum nitride ceramic suspension and carbon nanotube-alumina mixed ceramic suspension;Using ceramic dispersant removal process principle,in-situ solidification of non-aqueous aluminum nitride suspension and carbon nanotube-alumina mixed suspensionwas achieved;And combined with the sintering process,a good performance of aluminum nitride ceramics and carbon nanotube-alumina composite ceramic materials were obtained.the main research contenes are as follows:(1)Dispersion stabilization mechanism based on dispersant,stable dispersion of aluminum nitride powder in organic solvent is achieved by using oleic acid as dispersant and n-octane as solvent.The effects of dispersant addition and solid loading on the rheological behavior of the suspension were studied.The semisteric stability non-aqueous aluminum nitride suspension with good dispersibility was prepared by controlling the amount of oleic acid and selecting the solid loading..(2)In-situ coagulation forming process by low temperature induced dispersant removal,oleic acid separates from the solvent at low temperature,achieving in-situ coagulation of the semisteric stability aluminum nitride suspension.The effects of temperature and solid loading on the gel behavior of aluminum nitride suspension and the properties of aluminum nitride ceramics green and sintered bodies were investigated.(3)Polyisobutylene and maleic anhydride copolymer Isobam as dispersant,carbon nanotube suspension and alumina ceramic suspension with good dispersibility can be prepared,electrostatic stability carbon nanotube-alumina mixed suspension was prepared by controlling the amount of Isobam and adjusting the pH.The dispersant addition amount,pH value of carbon nanotube suspension and alumina suspension dispersion were studied.Impact(4)Using the characteristics of Isobam self-gel,Isobam crosslink or bridges in suspension at high temperature to achieve in-situ coagulation of carbon nanotube-alumina hybrid suspension;The effects of temperature and carbon nanotube addition on the rheological properties of mixed suspensions,composite ceramic green and properties of sintered bodies were investigated.The carbon nanotube-alumina composite ceramic can be prepared by crosslinking the polymer electrolyte dispersant Isobam,so that the carbon nanotubes are uniformly distributed in the alumina matrix,which effectively improves the mechanical properties of the alumina ceramic material.