Effects of calcination temperature and time on the Ca3Co4O9 purity when synthesized using starch-assisted sol-gel combustion method  

作　　者：M.A.MOHAMMED M.B.UDAY S.IZMAN 

机构地区：[1]School of Mechanical Engineering,Faculty of Engineering,Universiti Teknologi Malaysia(UTM),UTM Skudai 81310,Johor,Malaysia [2]Centre for Advanced Composite Materials(CACM),Institute for Vehicle Systems and Engineering,Universiti Teknologi Malaysia,UTM Skudai 81310,Johor,Malaysia [3]Department of Materials Engineering,College of Engineering,University of Basrah,Basrah,Iraq

出　　处：《Journal of Advanced Ceramics》2020年第2期162-172,共11页先进陶瓷（英文）

基　　金：This research study was supported by the Ministry of Education Malaysia(MOE)for the FRGS Grant(R.J130000.7824.4F723);Universiti Teknologi Malaysia(UTM)research grant(Q.J130000.2524.17H83).

摘　　要：Ca3Co4O9 is a p-type semiconducting material that is well-known for its thermoelectric(TE),magnetic,electronic,and electro-optic properties.In this study,sol–gel autoignition was used to prepare Ca3Co4O9 at different calcination temperatures(773,873,973,and 1073 K)and time(4,6,8,10,12,and 14 h)using starch as a fuel.The phase and microstructure of the prepared Ca3Co4O9 powder were investigated.Thermogravimetry–differential thermal analysis(TGA)confirms that the final weight loss occurred at 1073 K to form Ca3Co4O9 stable powder.The variable-pressure scanning electron microscopy(VP-SEM)images show that the size of powder particles increases from 1.15 to 1.47μm as calcination time increases from 4 to 12 h,and the size remains almost constant thereafter.A similar pattern is also observed on the increment of the crystallite size and percentage of crystallinity with X-ray diffraction(XRD)analysis.The highest crystallinity is found about 92.9%when the powder was calcinated at 1073 K for 12 and 14 h with 458 and 460Åcrystallite size,respectively.Energy dispersive X-ray spectroscopy(EDS)analysis demonstrates that the calcinated powder has a high intensity of Ca,Co,and O with uniform distribution.High-resolution transmission electron microscopy(HRTEM)images prove that there is no distinct lattice distortion defect on the crystal structure.

关 键 词：calcium cobalt oxide SOL-GEL STARCH combustion method crystallite size CRYSTALLINITY 

分 类 号：TB34[一般工业技术—材料科学与工程]