基于原料选控的氧化铝水基凝胶成型工艺分析

Water based Gel Forming Process of Alumina by Raw Material Controling

随着结构陶瓷各种新型胶态成型工艺的发展,精密复杂陶瓷件的制备对其原料粉体提出了越来越高的要求。国际高纯氧化铝原料市场主要由日、法两国占有,国内生产厂家良莠不齐。本文首先通过干压成型烧结试验,从12个批次的国产氧化铝粉体中筛选了烧结活性较高的原料。选用异丁烯/马来酸酐共聚物(Isobam)作为粘结剂,通过调整浆料分散剂体系,控制固含量和粘度,筛选出4种适用于凝胶注模的原料粉体。比较了凝胶注模样品与干压样品的性能差异。配置出了固含量达到50vol%的低粘度凝胶注模浆料,并在1650℃烧结3 h的条件下,得到了致密度97.3%、弯曲强度236 MPa的氧化铝异型陶瓷。

With the development of novel colloidal forming techniques for structural ceramics,the preparation of complex shape ceramic parts puts forward higher and higher requirements for raw material powders.High purity alumina raw material market is mainly occupied by Japan and France while domestic manufacturers are of varying quality.In this paper,several raw materials with higher sintering activity were selected from eleven kinds of domestic alumina powders through dry pressing and sintering experiments.A water-soluble copolymer of isobutylene and maleic anhydride,commercially called Isobam,was used as the binder to prepare alumina slurry.Four kinds of alumina powders suitable for gel casting were chosen according to solid content and viscosity of the slurry by adjusting the dispersant system.The difference in performance between the gel cast and dry pressed samples was compared.Low viscosity gel casting slurry with a solid content of 50 vol%was successfully prepared.The results showed that alumina ceramics with relative density of 97.3%and flexural strength of 236 MPa can be obtained after sintering at 1650℃for 3 hours.