Transparent glass-ceramic is a new kind of functional material with homogenous and dense structure composed of fine crystal particles.Its preparation technique,species and properties were reviewed,and the development direction was discussed in the paper.

Transparent Glass-ceramics

Spectroscopic and photoluminescence characteristics of Sm3+ doped calcium aluminozincate phosphor for applications in w-LED

Spectroscopic studies of Dy3+ doped borate glasses for cool white light generation

The precursor glass in the ZnO–Al2O3–B2O3–SiO2 (ZABS) system doped with Eu2O3 was prepared by the melt-quench technique. The transparent willemite, Zn2SiO4 (ZS) glass–ceramic nanocomposites were derived from this precursor glass by a controlled crystallization process. The formation of willemite crystal phase, size, and morphology with increase in heat-treatment time was examined by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) techniques. The average calculated crystallite size obtained from XRD is found to be in the range 18–70 nm whereas the grain size observed in FESEM is 50–250 nm. The refractive index value is decreased with increase in heat-treatment time which is caused by the partial replacement of ZnO4 units of ZS nanocrystals by AlO4 units due to generation of vacancies. Fourier transform infrared (FTIR) reflection spectroscopy was used to evaluate its structural evolution. Vickers hardness study indicates marked improvement of hardness in the resultant glass-ceramics compared with its precursor glass. The photoluminescence spectra of Eu3+ ions exhibit emission transitions of 5D0→7Fj (j = 0, 1, 2, 3, and 4) and its excitation spectra show an intense absorption band at 395 nm. These spectra reveal that the luminescence performance of the glass–ceramic nanocomposites is enhanced up to 17-fold with the process of heat treatment. This enhancement is caused by partitioning of Eu3+ ions into glassy phase instead of into the willemite crystals with progress of heat treatment. Such luminescent glass–ceramic nanocomposites are expected to find potential applications in solid-state red lasers, phosphors, and optical display systems.

Thermal, Structural, and Enhanced Photoluminescence Properties of Eu3+-doped Transparent Willemite Glass–Ceramic Nanocomposites

Fabrication and enhanced photoluminescence properties of Sm3+-doped ZnO–Al2O3–B2O3–SiO2 glass derived willemite glass–ceramic nanocomposites

Effect of Yb2O3 and TiO2 on reaction sintering and properties of magnesium aluminate spinel

The influence of surface-modified graphites on the rheological pattern of alumina-carbon cementitious refractory castable matrix

This investigation entails our continued research on calcium aluminate coated graphite for application in alumina-carbon monolithic refractories. Surface treatment of graphite flakes by a scalable sol-gel route has been utilized to develop stable bonds between ceramic phases with the functionalized graphite sheets. This study has been primarily conducted to differentiate between the coating evolution pattern at green and calcined conditions. In this regard, C-H-N analysis, differential scanning calorimetry (DSC), transmission electron microscopy (TEM), x-ray diffraction (XRD) with Rietveld analysis, Fourier transformed infrared spectroscopy (FTIR) and zeta potential studies of three kinds of graphites had been compared and critically estimated. These results were supplemented with thermogravimetry (TG), pore size distribution, oxidation resistance and scanning electron microscopy (SEM) of selected samples. A schematic outline of the work has also been proposed. An appreciable improvement of bulk density, apparent porosity and crushing strength of the respective castable has been correlated with the compatibility of the coating to the reactive matrix constituents of the refractory in wide temperature region (110-1500 degrees C).

Extended studies on surface‐treated graphite vis‐à‐vis its application in high alumina refractory castable

Development of mixed conducting dense nickel/Ca-doped lanthanum zirconate cermet for gas separation application

The performance of alumina- and magnesia-based carbon-containing refractory castables, suitable for different sectors of steel plants, has been compared. Natural flaky graphites have been modified by their surface treatment via sol-gel route. The sustainability of graphite in oxidizing atmosphere was noticeably increased by this method with a synergistic possibility of pollution abatement. The hydrophilic nanocoatings of ceramic oxides derived by inorganic precursors reduced the water demand of the composite batch and simultaneously enhanced its oxidation resistance. The oxide coating compositions together with the precursor chemistry have been varied to substantiate their common beneficial features. Scanning electron microscopy (SEM), Raman spectroscopy, Differential thermal analysis (DTA), Thermogravimetry (TG), X-ray diffraction, thermal conductivity, and zeta-potential studies have been carried out to compare the influence of heat treatment on as-received and surface-modified graphites. The properties of refractory castables, namely, bulk density, apparent porosity, and cold crushing strength have been measured within wide temperature region (110–1500°C), to confirm the positive influence of nanoengineering on graphite surface. The sequence of important phase reactions during sintering of both the composite materials has been discussed. Finally the slag resistance behavior at aggressively fired condition has been investigated to corroborate the improved matrix characteristics due to coated graphites.

Sunanda Mukhopadhyay

Papers

Effect of Yb2O3 and TiO2 on reaction sintering and properties of magnesium aluminate spinel

The influence of surface-modified graphites on the rheological pattern of alumina-carbon cementitious refractory castable matrix

Extended studies on surface‐treated graphite vis‐à‐vis its application in high alumina refractory castable

Development of mixed conducting dense nickel/Ca-doped lanthanum zirconate cermet for gas separation application

Effect of surface‐treated graphites on the properties of carbon‐containing monolithic refractory materials—A comprehensive comparison