ORALS

SESSION: CompositeMonPM1-R8	6th Intl. Symp. on Composite, Ceramic and Nano Materials Processing, Characterization and Applications
Mon Nov, 5 2018 / Room: Grego (50/3rd)
Session Chairs: Raman Singh; Gabor Patonay; Session Monitor: TBA

14:25: [CompositeMonPM106]
Effects of Various Additives and Sintering Temperature on Phase Evolution and Properties of Carbon-Clay Ceramic Composites
Fatai Olufemi Aramide¹ ; Olusola Dayo Adepoju² ; Patricia Abimbola Popoola³ ; ¹Department of Metallurgical and Materials Engineering, Federal University of Technology, Akure, Nigeria; ²Metallurgical and Materials Engineering, Federal University of Technology, Akure, Nigeria; ³Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria, South Africa;
Paper Id: 89 [Abstract]

Effects of Ifon clay, various additives, and sintering temperature on the phase development and physico-mechanical properties of mullite-carbon ceramic composite were investigated. Powders of Ifon clay, kaolin from Okpella, and graphite of known mineralogical composition were thoroughly blended in a ball mill for 3 hours at a speed of 60 rev/min using a predetermined ratio. From the blended powders, standard samples were produced by uniaxial compression. This was followed by sintering in an electric furnace at 1400°C, 1500°C and 1600°C for one hour. The sintered samples were characterized for various physical and mechanical properties. The phases developed in the sample during sintering were also investigated using X-ray diffractometer (XRD). Morphology and microanalysis of the sintered ceramic composite samples were determined using ultrahigh resolution field emission scanning electron microscope (UHR-FESEM) equipped with energy dispersive spectroscopy (EDS). It was observed that the Ifon clay addition to the sample favours the formation of microcline over mullite at temperatures between 1400°C and 1500°C in sample A. As the sintering temperature increases to 1600°C, there is the formation of mullite phase and pores in sample A [1]. For sample B, 10% SiC served as nucleating point for SiC around 1400°C [2, 3]. 10% TiO₂ led to the development of 2.5% TiC at 1500°C which increased to 6.8% at 1600°C. Ifon clay in the sample led to the development of anorthite and microcline in the samples. 10% TiO₂ is effective as anti-oxidant for graphite up to 1500°C in sample C [3]. For sample D, the addition of TiO₂ and SiC in the sample led to the formation of TiC in the sample at 1400°C and 1600°C. This takes place through high temperature solid state reaction (reaction sintering) of TiO₂ and SiC. This also contributes to the reduction in the apparent porosity of the sample with increased sintering temperature [4, 5]. The presence of titania in the sample does not favour the stability of anorthite beyond 1400°C. The formation of 50.6 % mullite in the sample at 1500°C gave it the highest cold crushing strength and absorbed energy. The sample D sintered at 1500°C is considered optimal.

References:
[1] F. O. Aramide, Effects of sintering temperature on the phase developments and mechanical
properties Ifon clay, Leonardo J. of Sc., 14, 26, (2015), 67-82.
[2] Forrest, C. W.; Kennedy, P.; Shennan, J. V. Special Ceramics. 5 (1972) 99.
[3] Kennedy, P. Non-Oxide Technical and Engineering Ceramics; Hampshire, S. Ed.; Elsevier: New York, (1986) 301-317.
[4] Sawyer, G. R.; Page, T. F. J. Mater. Sci. 13 (1978) 885.
[5] Ness, J. N.; Page, T. F. J. Mater. Sci. 21 (1986) 1377.