Research On Spherical Corundum Abrasives With Sol-gel Method

Ceramic corundum abrasive prepared by sol-gel method is a new type of abrasive,known as sg. Compared with traditional corundum abrasive, it possesses small grains,self-sharpening, good toughness, high precision, high wear resistance and longservice life. In this paper, sol-gel and spray granulation technique were used toprepare spherical alumina gel powder. And atmospheric pressure sintering technologywas used to prepare spherical corundum abrasives with morphology and particle sizecontrollable. The results are as following:1. Psedo-boehmite sol was prepared by using psedo-boehmite as raw materials.The influences of preparation process on colloidal properties and the changes of itsparticles in sol-gel transition process were discussed. The results showed that: whenthe temperature was70℃, the concentration of acid was10wt%and solid content35wt%, stable performance of the psedo-boehmite sol could be prepared. In theprocess of sol-gel, the system existed aggregation and dissolution reactions, andaggregation played a major role.2. Spherical ceramic corundum abrasive was prepared by spray granudation andcalcination. The influences of spray granudation and sintering process on microscopicand size of spherical ceramic corundum abrasive were discussed. In addition, thechanges of alumina gel phase calcined at different temperatures were analysised byX-ray diffraction. The results showed that: when the spray pressure was0.3MPa,drying temperature was200℃, the firing temperature was1100℃and holding timewas60min,ceramic corundum abrasive that good sphericity, uniform particle sizedistribution was prepared. And the main phase of alumina gel powder was r-Al2O3atthe temperature below900℃, its main phase was θ-Al2O3at the temperature between900℃and1000℃, its main phase was α-Al2O3at the temperature above1100℃.3. Spherical ceramic corundum abrasive was modified by using cationicdispersant, anionic dispersant, non-ionic polymer dispersant and a silane couplingagent. Microscopic morphology and particle dispersion of the modified alumina wereexplored. The results showed that: dispersionof the modified alumina abrasive waspreferably by SDS and PEG. And when the concentration of SDS was2.5mg/L and5mg/L or the concentration of PEG was20mg/L, the dispersion of spherical abrasivewas best. When silane coupling agent accounted for spherical alumina abrasive was 3.5wt%and coupled5.5hours at50℃, dispersion of spherical alumina was better.