烧结合成Mg-β″-Al2O3的组成和形貌  

Composition and morphology of Mg-β″-Al2O3 synthesized by sintering

作　　者：高振昕[1,2] 刘百宽 傅秋华 王米娜 Gao Zhenxin;Liu Baikuan;Fu Qiu-hua;Wang Mina

机构地区：[1]中钢集团洛阳耐火材料研究院有限公司,河南洛阳471039 [2]濮耐高温材料(集团)股份公司北京研发中心,北京101318

出　　处：《耐火材料》2020年第1期1-4,共4页Refractories

摘　　要：为了表征Na 2O-MgO-Al2O3系中β″-Al2O3的组成和结晶形貌,以化学纯氧化铝、分析纯氧化镁和400℃灼烧的分析纯碳酸氢钠为原料,按Na 2O、MgO、Al2O3的质量分数依次为5%、10%和85%配料,成型后于1650℃保温3 h烧结合成了Mg 2+稳定的β″-Al2O3(即Mg-β″-Al2O3)。XRF检测的合成产物实际组成(w)为:Al2O385.58%、MgO 9.48%、Na 2O 4.80%,与原始配料组成有少许偏差。XRD分析表明,烧结试样中Mg-β″-Al2O3晶体的特征线d值为1.5983、0.7968、0.5322 nm。在场发射扫描电镜下以20000和40000的倍率观察发现:自形晶呈典型的六方片状,单晶面的较大尺寸为5~10μm,厚度为0.5~1μm;部分晶体呈平行连生,沿[0001]方向叠加。借EDS测得晶体的组成(w)为:Na 2O 4.0%~4.7%,MgO 9.3%~9.8%,Al2O385.7%~86.3%,该组成范围与原始配料组成相近,也与理论组成相当;这意味着本合成反应相当完全,获得了Na 2O-MgO-Al2O3系中β″-Al2O3完整单晶的真实化学组成。The purpose of this study was to characterize the composition and morphology ofβ″-Al 2O 3 in Na 2O-MgO-Al 2O 3 system.Chemically pure Al 2O 3,analytically pure MgO,and analytically pure NaHCO 3 which was fired at 400℃were mixed at the mass ratio of Na 2O MgO Al 2O 3=51085.After shaping,the green body was fired at 1650℃for 3 h to get Mg 2+stabilizedβ″-Al 2O 3(namely Mg-β″-Al 2O 3).The XRF result shows that the actual composition of the synthetic material is 85.58%Al 2O 3,9.48%MgO,and 4.80%Na 2O,by mass,which has small deviations from the initial composition.The XRD analysis shows that the characteristic d values of Mg-β″-Al 2O 3 crystals in the sintered sample are 1.5983,0.7968,and 0.5322 nm.The FESEM images at magnifications of 20000 and 40000 show that the euhedral crystals present typical hexagonal plate shapes,the large crystals have size of 5-10μm and thickness of 0.5-1μm.Some crystals appear as parallel group growth along[0001]orientation.The EDS results show that the crystal composition is 4.0%-4.7%Na 2O,9.3%-9.8%MgO,and 85.7%-86.3%Al 2O 3,by mass,which is close to the initial composition and also corresponds to the theoretical values.These mean that the synthetic reaction is quite complete,and the real chemical composition ofβ″-Al 2O 3 complete monocrystals in Na 2O-MgO-Al 2O 3 system is obtained.

关 键 词：Mg-β″-Al2O3 Na2O-MgO-Al2O3系 六方片状晶体 烧结合成 

分 类 号：TQ175[化学工程—硅酸盐工业]