铝酸盐水泥提高陶瓷模具石膏性能及机理  

Performance improvement and mechanism of model-gypsum by aluminate cement

作　　者：赵敏[1] 彭家惠[1,2] 张明涛[1] 李志新[1] 朱登玲[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400030 [2]重庆建大建材有限公司,重庆400030

出　　处：《东南大学学报（自然科学版）》2014年第5期1030-1036,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(50872160)

摘　　要：为提高陶瓷模具石膏使用性能,研究了铝酸盐水泥(AC)对模具石膏凝结硬化、强度、耐水及耐溶蚀性能的影响.采用X射线衍射、扫描电镜和差热分析研究了AC作用机理.结果表明:掺入AC可减少拌合水用量,从而延缓了石膏凝结硬化速率;AC掺入使石膏3 d干抗折强度显著增强,且无后期强度倒缩现象;硬化体耐水、耐溶蚀及耐磨损性能大幅提高,吸水率略有下降,6%为最佳AC掺量.机理分析表明:石膏、铝酸盐水泥复合水化形成由针棒状二水石膏、钙矾石晶体及无定形铝胶构成的网状结构,细针状钙矾石穿插于石膏晶隙间,增强了晶间桥接作用及网状结构稳定性,铝胶紧密填充于晶隙内形成密实的晶胶结构,同时覆盖在石膏表面减少了结晶接触点,使结晶稳定性增强,有效提高了模具石膏综合性能;稳定的水化产物及密实的晶胶结构进一步增强了石膏热稳定性能.The effects of alumiate cement （AC ）on the setting and hardening characteristics,mechanical strength,water resistance and corrosion resistance of modeling gypsum were investigated to improve the performances of gypsum models.The mechanisms were analyzed by measurements of XRD（X-ray diffraction ）,SEM-EDS （scanning electron microscope-energy dispersive spectrometer）and DSC-TG（differential scanning calorimetry-thermogravimetric ）.The result shows that less water is needed to reach the equal fluidity compounding with AC.The setting and hardening rate are prolonged.The flexural strength is strengthened greatly after 3 d of hydration with the addition of AC.There is no strength decreasing at later stage.The water-resistance,corrosion-resistance and arasion-resistance properties are all remarkably enhanced.Water absorption is reduced slightly.The optimum amount of AC is 6%.The mechanism analysis show that AFt and AH3 is produced by the hydration of gypsum and AC.A net-structure is produced by the crystal of needle,clavuligerus gypsum interconnected with acicular AFt.The pore space is filled with AH3 and the contact points of crystallization are reduced.A more compacted microstructure is obtained to make the structure stability improved.The thermal stability of gypsum is also improved.

关 键 词：陶瓷模具石膏 铝酸盐水泥 宏观性能 微观机理 

分 类 号：TQ177.3[化学工程—硅酸盐工业]