• RITWIK SARKAR

Articles written in Bulletin of Materials Science

• Utilization of steel melting electric arc furnace slag for development of vitreous ceramic tiles

Steel melting through electric arc furnace route is gaining popularity due to its many advantages, but generates a new waste, electric arc furnace slag, which is getting accumulated and land/mine filling and road construction are the only utilization. This slag has been tried to be value added and utilized to develop vitreous ceramic tiles. Slag, to the extent of 30–40 wt% with other conventional raw materials, were used for the development in the temperature range 1100–1150°C. The fired products showed relatively higher density with shorter firing range and good strength properties. Microstructural and EDAX studies were also done to evaluate the developed products.

• Reactive alumina–LaPO4 composite as machinable bioceramics

Sintered Al2O3–LaPO4 composites were prepared using commercially available reactive alumina and phase pure lanthanum phosphate (LP), prepared by the reaction synthesis technique. LP content was varied between 10 and 50 wt% and sintering was carried out between 1400 and 1600°C. Sintered composites were characterized for phase analysis, densification, strength, machinability, microstructure and bioactivity (in SBF solution) and biocompatibility (MTT assay protocol) studies. Composite nature was confirmed by phase analysis and LP was found to reduce the densification and strength values but imparted machinability. Again positive bioactivity and biocompatibility character were observed for all the compositions.

• Sintering of magnesia: effect of additives

Effect of different additives, namely Cr2O3, Fe2O3 and TiO2, up to 2 wt% was studied on the sintering and microstructural developments of the chemically pure magnesia using the pressureless sintering technique between 1500 and 1600° C. Sintering was evaluated by per cent densification and microstructural developments were studied by electron microscopy and elemental distribution of the additives in the sintered products was also investigated for their distribution in the matrix. Cr2O3 and TiO2 were found to deteriorate the densification associated with grain growth. Fe2O3 was found to improve the densification and well-compacted grain distribution was observed in the microstructure.

• Formation of Mg$_2$C$_3$ phase in N220 nanocarbon containing low carbon MgO-C composition

This paper reports a non-conventional microstructurewith sequicarbide (Mg$_2$C$_3$) formation in N220 nanocarboncontaining low carbon magnesia carbon composition having magnesium metal powder as antioxidant. 5 wt% graphitecontaining MgO-C refractory with and without 1 wt% N220 nanocarbon is studied and 2 wt% magnesium metal powder isused as the lone antioxidant. The compositions were mixed with powder and liquid resin binder, pressed uniaxially at 150MPa and cured at 220$^{\circ}$C. Cured samples were coked at 1000$^{\circ}$C for 2 h. Matrix of the coked samples was studied in detail for microstructural analysis phase content and formation of nail-shaped sequicarbide was found in the nanocarbon containing compositions. The in-situ sequicarbide formation has resulted in the strength of the batch.

• Formation and densification of mullite through solid-oxide reaction technique using commercial-grade raw materials

Two different commercially available sources of alumina and silica were used to study the formation and densificationbehaviour of mullite prepared by solid-oxide reaction technique in a single firing. Phase analysis and densificationstudies were carried out on the samples sintered between 1200 and 1600$^{\circ}$C. Effect of addition of 1–6 wt% MgO on thesintered mullite ceramics was also studied.MgO was found to improve the density values for all the compositions till 4 wt%and with higher addition it deteriorated, mainly due to higher extent of liquid phase formation. Mullite formation was foundto start below 1200$^{\circ}$C and constituent oxides were found even at 1600$^{\circ}$C; however, addition of 4 wt% MgO was found to complete the mullite formation at 1600$^{\circ}$C for all the compositions. Microstructural studies showed grain growth in the compositions containing MgO and higher impurities due to formation of greater extent of liquid phase.

• # Bulletin of Materials Science

Current Issue
Volume 42 | Issue 3
June 2019