Transactions of the Indian Ceramic Society ( IF 1.2 ) Pub Date : 2021-08-18 , DOI: 10.1080/0371750x.2021.1915873 Theerthagiri Viswanathan 1 , Soumen Pal 1 , Ariful Rahaman 1 , Panchu Gopal Pal 2
Nanocrystalline spinel forming precursor spinel hydrate (PSH), prepared by co-precipitation technique with controlled concentration of mixed salt, pH, temperature and time, was used as additive in calcined alumina-dead burnt magnesia (DBM) admixture to develop spinel (MgAl2O4) aggregates. Powder granulometry, mixing and dispersion of additive PSH were controlled during milling. Three batches of varying particle size distribution with same proportion of additive were used for body making. Firing was conducted in 1500°-1650°C temperature range. True specific gravity (TSG) of alumina, DBM, spinel and individual fired pellets were used to estimate wt% spinel formation based on the derived mass balance equation and subsequently verified by X-ray diffraction (XRD) analysis. Fired properties, i.e. bulk density, apparent porosity, closed porosity, %linear shrinkage and densification rate were measured. XRD was conducted for phase analysis. SEM and HR-TEM were performed to study the grain/ pore morphology and elemental analysis was done to calculate the spinel stoichiometry. PSH was found to have positive effect both in spinellization and densification; the effect gradually decreased with finer particle size distribution and increasing firing temperatures. The maximum fired density achieved for three batches were 89.21, 92.84 and 96.2% ρth, respectively. Based on the requirements of specific powder granulometry, addition of PSH and firing schedule can be used for bulk production of spinel aggregates.
中文翻译:
纳米晶铝酸镁前驱体和粉体粒度测定对尖晶石化和致密化发展铝酸镁尖晶石聚集体的影响
纳米晶尖晶石形成前体尖晶石水合物 (PSH),通过共沉淀技术制备,控制混合盐浓度、pH、温度和时间,用作煅烧氧化铝-重烧氧化镁 (DBM) 混合物的添加剂,以开发尖晶石 (MgAl 2氧4) 聚合。在研磨过程中控制粉末粒度、添加剂 PSH 的混合和分散。将三批不同粒度分布且添加剂比例相同的批次用于车身制造。烧制在1500°-1650°C的温度范围内进行。氧化铝、DBM、尖晶石和单个烧制球团的真比重 (TSG) 用于根据导出的质量平衡方程估算尖晶石的重量百分比形成,随后通过 X 射线衍射 (XRD) 分析进行验证。测量烧制性能,即堆积密度、表观孔隙率、闭合孔隙率、线性收缩率和致密化率。进行XRD相分析。进行 SEM 和 HR-TEM 以研究晶粒/孔隙形态,并进行元素分析以计算尖晶石的化学计量。发现 PSH 在尖晶石化和致密化方面都具有积极作用;随着粒度分布的细化和焙烧温度的升高,这种影响逐渐减弱。三批达到的最大烧成密度分别为 89.21、92.84 和 96.2% ρth,分别。根据特定粉末粒度的要求,可添加 PSH 和烧成时间表,用于批量生产尖晶石骨料。