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This study aims to fabricate low-cost foam glass-ceramic using soda-lime-silica (SLS) glass waste and clamshells (CS) as foaming agent in content between 1 and 12 wt.% by conventional powder processing method. The samples were undergoing sintering process between 700 and 1000°C with holding time of 30 minutes and characterized according to the physical and structural properties. Samples containing 3 wt.% CS treated at 800°C show the greatest size of porosity. As the sintering temperature increased, the samples tend to become less dense. However, for the samples sintered at 900 and 1000°C, the trend of the density changes because of the excess CO2 gases generated during the heat treatment process promotes an increase in internal pressure, which results in the rupture of the pore walls. For linear expansion, for samples with a sintering temperature of 800°C and higher, the increment of the temperature will lead to the decrement of linear expansion (%). As the sintering temperature increases from 700 to 800°C, the water absorption (%) increases. However, the percentage of water absorption decreases with the further increment of sintering temperature. The XRD characterization showed the formation of wollastonite phase (CaSiO3) and further revealed the formation of greater peaks of CaSiO3 at the higher sintering temperatures. The results of compressive mechanical strength between 0.15 and 1.50 MPa indicate that the obtained glass-ceramic foams have potential for building material applications.

The effect of sintering temperatures on crystallization and structural of the soda lime silica (SLS) glass was reported. Elemental weight composition of the SLS glass powder was identified through Energy dispersive X-ray fluorescence (EDXRF) analysis while the thermal behavior of the glass was determined using Differential thermal analysis (DTA) technique. Archimedes’ method and direct geometric measurement were respectively used to determine bulk density and linear shrinkage of the glass samples. Crystallisation behavior of the samples was investigated by X-ray diffraction (XRD) analysis and chemical bonds present in the samples were measured using Fourier Transform Infrared (FTIR) spectroscopy. Results showed an increase in the density and linear shrinkage of the samples as a function of the sintering temperature. The XRD analysis revealed the formation of α-quartz (SiO2) and a minor amount of devitrite phases in the samples and these were further verified through the detection of chemical bonds by FTIR after sintering at 800ºC. The properties of the glass-ceramics can be explained on the basis of crystal chemistry which indicated that the alkali ions formed as carriers in the random network structure and can be recommended for the manufacture of glass fiber or toughened glass-ceramic insulators.

In this current study, the behavior of dysprosium oxide (Dy2O3) doped willemite glass‐ceramic (WGC) derived from ZnO‐B2O3‐RHA: Dy2O3 glasses and rice‐husk ash (RHA) works as the active alternative silica has been studied. The fusions of the ternary host system of oxide components doped with rare earth oxide go through the melt‐quench technique followed by solid‐state sintering on the compacted glass frits. The sintered green samples are characterized utilizing the physical, structural, and optical properties to investigate the effect of different sintering temperatures on the samples accordingly. The bulk density of WGC increases together with the increment of sintering temperature from 2.571 to 2.940 g cm–3. Meanwhile, the increment of sintering temperature escalates the crystallization of the main crystalline phase, Zn2SiO4, corroborated by the enlargement of average crystallite size from 161 to 550 nm. Furthermore, the emission activity in the WGC also intensifies on the green emission region (524 nm) accordingly. This fabricated Dy3+:WGC contributes to the nomination as the potential solid‐state lighting material. [ABSTRACT FROM AUTHOR]

For the very first time, a study on the crystallization growth of zinc silicate glass and glass-ceramics was done, in which white rice husk ash (WRHA) was used as the silicon source. In this study, zinc silicate glass was fabricated by using melt–quenching methods based on the composition (ZnO)0.55(WRHA)0.45, where zinc oxide (ZnO) and white rice husk ash were used as the raw materials. The control crystallization technique was used in which the sample was sintered at 700–950 °C; then, the physical, structural, and optical properties of the glass and glass-ceramics were investigated by using a densitometer, linear shrinkage, X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR), field-emission scanning electron microscopy (FESEM), and photoluminescence spectroscopy (PL). The density and linear shrinkage increased as the crystallinity increased and the XRD results showed the progression of the crystal formation, in which the sample was still in an amorphous state at 27 °C and 700 °C; the crystalline phase started at 750 °C. Based on the FTIR spectra, all samples showed sharpened absorption bands as the sintering temperature was increased, and the FESEM image showed the progression of crystal growth, indicating the formation of zinc silicate glass-ceramics. Lastly, the PL spectra emitted three emission peaks, at 529, 570, and 682 nm for the green, yellow, and red emission, respectively. [ABSTRACT FROM AUTHOR]

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The effect of different sintering temperatures on structural and optical properties of ZnO-Zn2SiO4 composite was investigated. In this study, a ZnO-Zn2SiO4 composite was prepared by encapsulated zinc nitrate hexahydrate with amorphous silica nanoparticles in deionized water. The amorphous silica nanoparticles were prepared by reacting sodium silicate with ethanol. Zinc nitrate was mixed with the obtained amorphous silica nanoparticles with the ratio of 2:1 and 1.25:1 for Zn:Si and subjected to the different sintering temperatures from 600 to 1000 °C. Field emission scanning electron microscope (FESEM) microstructure showed that samples exhibit spherical morphology up to 700 °C and dumbbell morphology above 800 °C sintering temperature. The formation of Zn2SiO4 crystal phase appears from 700 °C and onwards together with ZnO crystal phase. The gaining of sintering temperature has also raised the amount of Zn2SiO4 phase and band gap values of the ZnO-Zn2SiO4 composite. [ABSTRACT FROM AUTHOR]

Abstract A study on the effect of sintering temperature to the physical and structural of Alumino-Silicate-Fluoride (ASF) glass ceramics fabricated from clam shell (CS) and soda lime silicate (SLS) glass is conducted through conventional melt-quench technique. ASF glass ceramics composition with 25SLS-20CS-20P 2 O 5 -20Al 2 O 3 -15CaF 2 by weight percentage is analysed by using Energy X-ray (EDX), density (ρ), linear shrinkage, X-ray Diffraction (XRD), Fourier Transforms Infrared (FTIR) and Field Emission Scanning Electron Microscopy (FESEM). High content of Ca and Si in CS and SLS glass respectively promote the use of waste materials in production of ASF composition. The density and linear shrinkage of the samples varies with sintering temperature. Besides, XRD results showed that fluorapatite (Ca 5 (PO 4) 3 F) is a main phase existed in all samples meanwhile FTIR confirmed the presence of silica and also the formation of Ca P phase in the composition. FESEM analysis showed the increasing of grain size and formation of needle-like microstructure known as fluorapatite when sintering temperature increase. Overall results promoted the ASF glass ceramics samples produced from waste materials as a high potential candidate for dental application. [ABSTRACT FROM AUTHOR]

Highlights • Nanocrystal Hydroxyapatite (HA) were synthesized from high potential calcium sources which is ark clam shell via wet chemical precipitate. • The formation of biphasic HA and β-tricalcium phosphate ceramic at high sintering temperatures from 200 to 1400 °C. • Physical characteristics, microstructure and mechanical properties were varied according to the temperature applied upon sintered ceramics. Abstract This paper reported the formation of biphasic hydroxyapatite, (HA) and β-tricalcium phosphate, (β-TCP) sintered at various sintering temperature from waste material. The phase stability of HA ceramic was investigated by imposing the high sintering temperature in order to study the transformation of the single phase of HA to biphasic HA/β-TCP ceramic. The evolution microstructure of HA and biphasic HA/β-TCP ceramic was studied at various sintering temperature reach up to 1400 °C. The single phase of HA was observed from 200 to 1200 °C and the secondary phase β-TCP appears due to the decomposition of partial HA at 1300–1400 °C. The optimum temperature for a single phase of HA was identified after sintering at 1200 °C to produce HA with high mechanical hardness about 5.11 GPa. This is clearly related to the phase stability and morphology of HA. The particles size of HA as-synthesized were recorded in nano range scale at ∼9 to 20 nm. However, the average particle sizes become larger and compact between ∼0.21 and ∼3.3 μm from 600 to 1200 °C. Thus, the sintering temperature gives an impact on the phase stability, microstructure and microhardness of HA derived from high potential waste sources. [ABSTRACT FROM AUTHOR]

Lithium hafnium phosphate LiHf2(PO4)3 (LHP) was synthesized via solid-state synthesis technique. The sintering behavior, structure, and phase composition of the as-prepared sample was analyzed using X-ray diffraction (XRD) characterization technique. The XRD-Rietveld refinement analysis showed that after sintering at low temperatures 500 to 1000 °C, it exhibited various secondary phases. However, a single phase was observed as the sintering temperature increases from 1100 to 1200 °C. LHP sintered at 1100 °C produced real features of sodium superionic conductor type (NASICON-type) with hexagonal crystal axis indicating R-3c space group. The electrical properties were studied using impedance spectroscopy technique. Frequency and temperature dependence behavior of conductivity (ac and dc) and dielectric permittivity were studied. The results obtained describes the conduction mechanism in the system. Electric modulus formalism was performed to investigate the relaxation behavior which showed that as measuring temperature increases, the relaxation frequency increases whereas relaxation time decreases. This behavior explains the hopping mechanism of the charge carriers in the system. Likewise, the correlated barrier hopping model elucidates the dominant hopping mechanism. [ABSTRACT FROM AUTHOR]

This work investigates the role of sintering temperature on bioactive glass-ceramics derived from the new composition CaO–P 2 O 5 –Na 2 O–B 2 O 3 –SiO 2 glass system. The sintering behaviour of the samples' physical, structural, and mechanical properties is highlighted in this study. The experimental results indicated that the sintering process improved the crystallization and hardness of the final product. Results from XRD and FTIR showed the existence of carbonate apatite, pseudo-wollastonite, and wollastonite phases. From the results, the bioglass-ceramics sintered at 700 °C obtained the highest densification and optimum mechanical results. It had the value of 5.34 ± 0.21 GPa regarding microhardness and 2.99 ± 0.24 MPa m1/2 concerning fracture toughness, which falls in the range of the human enamel. Also, the sintered samples maintained their bioactivity and biodegradability after being tested in the PBS medium. The bioactivity does not affect but slows down the apatite formation rate. Overall results promoted the novel bioglass-ceramics as a candidate material for dental application. [ABSTRACT FROM AUTHOR]

The Er 3+ doped zinc soda lime silica (ZnO-GSLS) glass system was prepared by the conventional melt-quenching technique using waste green soda lime silica (GSLS) glass, zinc oxide (ZnO) and erbium oxide (Er 2 O 3 ) powder as starting materials. Er 3+ doped willemite based glass-ceramics (Zn 2 SiO 4 :Er 3+ ) were derived from this precursor glass by a controlled sintering process. The effect of sintering temperature on the density and linear shrinkage of the sample was investigated. XRD analysis revealed the presence of thermodynamically stable zinc orthosilicate (α-Zn 2 SiO 4 ) phase at sintering temperatures above 700 °C. FESEM image shows the presence of densely packed grains as the sintering temperature increase. FTIR spectroscopy was used to observe the structural of SiO 4 and ZnO 4 groups in the formation of willemite phase evolution. The UV–Vis absorption spectra reveals four peaks centered at excitation of electron from ground state 4 I 15/2 to 4 G 11/2 (∼363 nm) , 4 F 7/2 (∼488 nm), 2 H 11/2 (∼523 nm), and 4 F 9/2 (∼652 nm). PL spectroscopy measurements were performed at room temperature using 385 nm excitation wavelengths. Enhancement of the Er 3+ luminescence was observed with the progression of sintering temperature. [ABSTRACT FROM AUTHOR]

In this study, an investigation was conducted to explore and synthesize silicate (SiO 2 ) glass from waste rice husk ash (RHA). MnO 2 doped zinc silicate glasses with chemical formula [(ZnO) 55 + (WRHA) 45 ] 100-X [MnO 2 ] X , (where X = 0, 1, 3 and 5 wt%) was prepared by conventional melt quenching technique. The glass samples were characterized using energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–Vis) spectroscopy. The results revealed that by increasing the concentration of MnO 2 , the color of glass samples changed from colorless to brown and the density of glass increased. XRD results showed that a broad halo peak which centered on the low angle (2θ = 30°) indicated the amorphous nature of the glass. FTIR results showed basic structural units of Si-O-Si in non-bridging oxygen, Si-O and Mn-O in the glass network. FESEM result showed a decreasing porosity with an increasing MnO 2 content, which was attributed to the Mn ions resort to occupy interstitial sites inside the pores of glass. Besides, the absorption intensity of glass increased and the band gap value decreased with increasing the MnO 2 percentage. In this synthesized glass system of MnO 2 doped zinc silicate glasses using RHA as a source of silica, the MnO 2 affect most of the properties of the glass system under investigation. [ABSTRACT FROM AUTHOR]

The impact of different sintering temperatures on physical, optical and structural properties of wollastonite (CaSiO 3 ) based glass-ceramics were investigated for its potential application as a building material. Wollastonite based glass-ceramics was provided by a conventional melt-quenching method and followed by a controlled sintering process. In this work, soda lime silica glass waste was utilized as a source of silicon. The chemical composition and physical properties of glass were characterized by using Energy Dispersive X-ray Fluorescence (EDXRF) and Archimedes principle. The Archimedes measurement results show that the density increased with the increasing of sintering temperature. The generation of CaSiO 3, morphology, size and crystal phase with increasing the heat-treatment temperature were examined by field emission scanning electron microscopy (FESEM), Fourier transforms infrared reflection spectroscopy (FTIR), and X-ray diffraction (XRD). The average calculated crystal size gained from XRD was found to be in the range 60 nm. The FESEM results show a uniform distribution of particles and the morphology of the wollastonite crystal is in relict shapes. The appearance of CaO, SiO 2, and Ca-O-Si bands disclosed from FTIR which showed the formation of CaSiO 3 crystal phase. In addition to the calculation of the energy band gap which found to be increased with increasing sintering temperature. [ABSTRACT FROM AUTHOR]

This paper reported the uses of ark clam shell calcium precursor in order to form hydroxyapatite (HA) via the wet chemical precipitation method. The main objective of this research is to acquire better understanding regarding the effect of sintering temperature in the fabrication of HA. Throughout experiment, the ratio of Ca:P were constantly controlled, between 1.67 and 2.00. The formation of HA at these ratio was confirmed by means of energy-dispersive X-ray spectroscopy analysis. In addition, the effect of sintering temperature on the formation of HA was observed using X-ray diffraction analysis, while the structural and morphology was determined by means of field emission scanning electron microscopy. The formation of HA nanoparticle was recorded (~35-69 nm) in the form of as-synthesize HA powder. The bonding compound appeared in the formation of HA was carried out using Fourier transform infrared spectroscopy such as biomaterials that are expected to find potential applications in orthopedic and biomedical industries . [ABSTRACT FROM AUTHOR]

In this studies, 2 wt.% Mn-doped Zn 2 SiO 4 were synthesized from SLS waste glass, ZnO and MnO using conventional solid-state method. Structural and optical properties were examined as functions of sintering temperature. Density and linear shrinkage of samples increased with increasing in sintering temperature. X-Ray Diffraction pattern revealed that sintering temperature play an important role in enhancing crystallization of Zn 2 SiO 4 . It was found that the phase formation changed from amorphous to ȕ- Zn 2 SiO 4 and then to α-Zn 2 SiO 4 with the unsintered to sinter at 600 °C and 700 °C respectively. The morphology under FESEM characterization shows that the samples become more uniform with rectangular shape like as the sintering temperature increased. From UV-Vis spectroscopy, the results obtained showed that the intensive absorption occurred in the UV region, in the range of 250-γλ0 nm. Prominent green emission colours of α-Zn 2 SiO 4 were observed centred at 527 nm while the yellow emission centred at η8η nm resulted from ȕ-Zn 2 SiO at an excitation of 260 nm. However, red emission centred at 600 nm was observed for glass samples. These emissions come from the Mn-dopant and correspond to the 4 T 1 – 6 A 1 transition. [ABSTRACT FROM AUTHOR]

In this paper the effect of sintering temperature on NiZnFeO is examined closely. The evolution of toward magnetically ordered materials was to be tracked with the parallel evolving microstructure subjected to sintering temperatures in an ascending order. The starting powder of NiZnFeO was prepared via mechanical alloying and later molded into toroidal samples. After each sintering, we observed the resulting changes in the materials. The XRD data showed a single phase being formed as early as 600 °C and the peak intensity was increasing with the sintering temperature indicating an increase in the degree of crystallinity. The BH hysteresis loops showed the evolution from paramagnetism to moderate ferromagnetism to strong ferromagnetism with microstructural changes. For lower sintering temperatures, the samples showed paramagnetic behavior dominating the samples. As sintering temperature increased, paramagnetic states decreased and, at 900 °C, a moderately ferromagnetic state appeared. Sintering at 1000 °C produced a strongly ferromagnetic state giving a well-formed sigmoid-shape hysteresis loop. [ABSTRACT FROM AUTHOR]

This paper reports an alternative method for making glass-ceramic from disposal waste water sludge and soda lime silica (SLS) glass. The glass ceramic samples were prepared from a mixture of wastewater sludge and SLS glasses, melted at 1375°C for 3 hours and quenched by pouring into water to obtain a coarse frit. The frit glass was then crushed and sieved to 106μm before it was pressed to a pellet. The sintering process was performed at various temperatures between 700- 1000°C for 2 hours and morphologically characterized with XRD, SEM, and EDX. Overall results showed the crystalline phase of diopside sodian-critobalite glass-ceramic is depending on thermal treatment process and making them attractive to industrial uses such as in construction, tiling, and glass-ceramic applications. [ABSTRACT FROM AUTHOR]

Abstract: Ni0.5Zn0.5Fe2O4 has been synthesized using mechanical alloying method with two variables (milling time and ball-to-powder weight ratio (BPR)) were varied in order to study its effect on the magnetic properties of the material. The effects of these two variables were studied using XRD, SEM, TEM and later by impedance analyzer with the frequency range from 1MHz to 1.8GHz. The results obtained however show that there are no significant trends to relate the milling time and BPR with the permeability and losses of the material studied. After being sintered at 1150°C, all the effects of alloying process seem to diminish. [Copyright &y& Elsevier]

Abstract: The polycrystalline Ni–Zn ferrite powder with the chemical formula Ni0.8Zn0.2Fe2O4 has been synthesized using co-precipitation route. The toroidal and pellet form samples were sintered at various temperatures from 700 to 1300°C/5h in steps of 200°C. The structures of samples were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and the energy dispersive X-ray spectroscopy (EDXS). The magnetic and dielectric measurements were carried out using a vibrating sample magnetometer (VSM) and the impedance analyzer, respectively. The highest density of 4.48gcm−3 was obtained for the sample sintered at 1300°C. It was found that the initial permeability increased from 4 to 17 and the RLF was in the order of 10−3 to 10−4 in the frequency range of 1.0MHz to 1.0GHz. The dielectric constant and dielectric loss were lower compared to the reported values for conventional solid state technique. The electrical resistivity is in the order of 108 Ωcm. Therefore, low relative loss factor and high resistivity make these ferrites particularly useful as inductor and transformer materials for high frequency applications. [Copyright &y& Elsevier]