Research On Fabricating Alumina Ceramics Through Stereolithography Technology

Alumina Ceramic,as the most widely used ceramic material,possesses many advantages.However it is difficult to process it in precision because of its hardness and brittleness.Fabricating alumina ceramics through stereolithography?SLA?method can not only shorten the manufacturing cycle but also reduce manufacturing costs.The ceramic suspensions used in SLA method must fulfill some certain requirements,such as low viscosity,high stability and moderate curable parameters.Preparing alumina suspensions is the key issue of fabricating alumina ceramics through SLA method.In this paper,alumina powder was modified by various dispersants to improve its affinity with resin monomers.The effects of various dispersants were also investigated.We also did some optimization to suspensions through adding new resin monomers and additives.The properties of new suspensions were also investigated.?1?OA shows the best performance among all the dispersants and its optimal dosage is 0.1 wt%.40 vol%alumina suspensions with a viscosity?3 Pa·s at 30 s^-1shear rate were successfully formulated with OA.?2?The cure depth?C_d?and the excess width(w_ex)of suspension containing SA-modified alumina are the largest and those of suspension containing OA-modified alumina are the smallest.This phenomenon can be explained by the structural differences between the dispersants as well as the particle size distribution of suspensions containing various dispersants modified alumina.?3?HDDA-HEA-TMPTA?6:3:1?suspensions possess better curability and affinity with the substrate than pure HDDA suspensions.However the viscosities of HDDA-HEA-TMPTA?6:3:1?suspensions are higher than pure HDDA suspensions.?4?Adding 3 wt%PM1590 could not only improve the affinity with the substrate,but also decrease the viscosity of suspensions.However PM1590 would produce some adverse effects on sintering.?5?If a slight reduce on the performance of suspensions is acceptable,we could choose HDDA-HEMA-EOTMPTA?6:3:1?suspensions to reduced the toxicity of monomers.?6?Alumina parts with a density of 3.778 g/cm³,approximately 95%of theoretical density were fabricated from 40 vol%alumina suspensions.