Papers by Keyword: Lithium Oxide

Abstract: The effect of lithium Oxide content on the characteristics and mechanical property of willemite (2ZnO.SiO₂) under a heating condition in Na₂O-K₂O-Li₂O-CaO-(ZnO)-Al₂O₃-SiO₂ glazing system used in stoneware, sintered at a maximum at temperature 1250 °C by a heating rate of 2.6 °C/min for 8 hours is the firing process of the glazes and clay to melt. After 15 minutes, the temperature dropped to 1100 °C for 40 minutes was stimulated crystallization and soaked in kiln at 1100 °C for 4 hours. This result was consistent with the chemical compositions from the XRF technique indicated that the glaze comprised ZnO and SiO₂ were the main compositions and compared to the mineral composition after sintering of the glazed crystal which revealed 2ZnO.SiO₂ as the main component and the result from the XRD technique. The microstructure of the glazed crystals after sintering was needle shaped and had spherical growth. The analytical results from Vickers hardness technique showed that microhardness by adding 3-5 % of Li₂O of the glazes S1, S2, S3, S4 and S5 as 105.96 ± 4.58, 112.30 ± 9.95, 153.90 ± 7.29, 244.80 ± 5.42 and 382.62 ± 9.20, respectively. More willemite crystals in the glaze results in more strength of the glaze as well.

Abstract: Tin oxide is the most promising material for thin film anodes of Li-ion batteries due to its cycling performance and high theoretical capacity. It is assumed that lithium-tin oxide can demonstrate even higher performance. Lithium-silicon-tin oxide nanofilms were prepared by atomic layer deposition (ALD), using the lithium bis (trimethylsilyl) amide (LiHMDS), tetraethyltin (TET) as a metal containing reagents and ozone or water or oxygen plasma as counter-reactants. Monocrystalline silicon (100) and stainless steel (316SS) were used as supports. The thicknesses of the nanofilms were measured by spectral ellipsometry (SE) and scanning electron microscopy (SEM). It was found that oxygen plasma is the most optimal ALD counter-reactant. The composition and structure were studied by Time-of-Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD). The nanofilms contain silicon as impurity, whose source is the ALD precursor (LiHMDS). The nanofilms deposited on stainless steel have shown the high Coulombic efficiency (99.1-99.8%) and cycling performance at a relatively high voltage (0.01 to 2.0V).

Abstract: Lithium-oxygen thin films were deposited by atomic layer deposition (ALD) on the surface of silicon and stainless-steel using lithium bis (trimethylsilyl) amide (LiHMDS) and different counter-reagents (water, ozone, oxygen plasma). The deposited films were non-stable at storage in the air atmosphere. Results of scanning electron microscopy showed that films show a tendency to crystallization and peeling from the substrate surface. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy revealed that films mainly consist of LiOH/Li₂CO₃. Coating the surface of lithium-oxygen films with an aluminum oxide layer using the ALD trimethylaluminum (TMA) and water as precursors did not lead to a significant improvement in stability. Nevertheless, the stable films can be obtained using ALD supercycles consisting of sequential pulsing of LiHMDS-water-TMA-water at 250°C.

Abstract: This investigation promotes the design of emulsion explosives and the development of detonation theory on a microscale. As the total composition of oxidizing and reducing elements of the reactants leave related to the thermochemistry of the system, the computational details of predicting the temperatures of detonation were introduced. It was found that a significant improvement was achieved in the emulsion explosives with an aquiferous system. An improvement in the detonation synthesis of nanolithium and zinc oxides is due to the formation of an activated matrix of the metal nitrates’ oxidizer with the corresponding fuel. Temperatures of detonation of emulsion explosives and explosive formulations are predicted using thermochemistry information. The methodology assumes that the heat of detonation of an explosive compound of composition C_aH_bN_cO_dLi_eZn_f can be approximated as the difference between the heats of formation of the detonation products and that of the explosive, divided by the formula weight of the explosive. For the calculations in which the first set of decomposition products is assumed, predicted temperatures of detonation of emulsion explosives with the product H₂O in the gas phase have a deviation of 413.66 K from results with the product H₂O in the liquid state. Fine-particle lithium and zinc oxides have been prepared by the detonation of emulsion explosives of the metal nitrates, M (NO₃) _x (M = Li, Zn) as oxidizers and paraffine as fuels, at high temperature and short reaction time. The detonation products were identified from X-ray powder diffraction (XRD) patterns, and transmission electron microscopy (TEM) measurements. XRD analysis shows that nanoparticles of lithium and zinc oxides can be produced from detonation of emulsion explosives due to fast quenching as well as appropriate detonation velocity and temperature.

Abstract: Four formulas of the stoneware bodies were formulated with and without an increasing amount of lithium oxide. The bodies were designed to vitrify at the temperature lower than 1150°C. A comparison on the physical properties and the phase formation of the bodies after firing at the temperature of 1100°C, 1150°C, and 1200°C was studied. The experiment results showed that the bodies containing lithium oxide vitrified at lower temperature and showed less variation in water absorption, density, and shrinkage values in the firing range 1100-1200°C. The XRD results showed that, at 1100°C, all the bodies composed of mullite, albite, and quartz. A reduction in the amount of albite and quartz associated with mullite formation was observed when increasing the amount of lithium oxide or the temperature. Furthermore, the body with lithium oxide tended to have higher value of the Modulus of Rupture.

Abstract: Recently alkali oxide materials, such as sodium - potassium niobate have drawn much attention due to their ultrasonic applicability and are also considered as promising candidates for a piezoelectric lead-free system. However, it is difficult to sinter such NKN-based materials via conventional sintering process. Therefore, in this study, dense 0.95(Na0.5K0.5)NbO3-0.05LiTaO3 (NKN-5LT) ceramics were developed by conventional sintering process. Sintering temperature was lowered by adding Li2O as a sintering aid. The electrical properties of NKN-5LT ceramics were investigated as a function of Li2O concentration. At the addition of 1 mol% Li2O, electromechanical coupling factor (kP) and piezoelectric coefficient (d33) of NKN-5LT ceramics were found to reach the highest values of 0.37 and 250 pC/N, respectively.

Abstract: In this study, hydroxyapatite (HA) material, obtained from calcinated bovine bone (BHA), was mixed with 0.25, 0.50, 1.00, and 2.00 wt% Li2CO3. The pressed pellets were sintered at various sintering temperatures between 900°C and 1300°C. Measurements of compression strength, microhardness, and density, along with SEM observation and X-ray diffraction analysis were performed. The experimental results showed that the samples with 0.25 and 0.50% Li2CO3 reached a maximum of densification and the highest values of compression strength and microhardness were achieved after sintering at 1300°C. The wetting effect of a Li2O-associated glassy phase was observed even from 900°C.