Materials Science Forum Vol. 846

Abstract: Achieving tuneable photoluminescence via controlled co-doping of rare earth ions in lithium niobate based glasses are challenging. A series of Er³⁺/ Nd³⁺ co-doped tellurite glasses of composition (70-x-y) TeO₂ – 15 Li₂CO₃ – 15 Nb₂O₅ – (x) Er₂O₃ – (y) Nd₂O₃ with x = 0; 1.0 mol % and 0 ≤ y ≤ 1.0 mol % are prepared using melt quenching technique. The influence of co-dopants on the emission properties is analyzed and discussed using partial energy level diagram of rare earth ions. The dopants concentration dependent physical properties such as refractive index, molar volume, density, polarizability and molar refractions are determined. The down-converted luminescence spectra for ²G_9/2 à⁴I_9/2 transition reveal a strong green emission band centred at 497 nm is attributed to the energy transfer from erbium to neodymium ion. The emission spectra exhibit five prominent peaks centred at 497, 539, 553, 616 and 634 nm corresponding to the transitions from ²H_11/2, ⁴S_3/2 and ⁴F_9/2 excited states to the ground state of Er³⁺ ion and the transitions from ²G_9/2, ²G_7/2, ²H_11/2 and ⁴F_9/2 excited states to ground state of Nd³⁺ ion. The highest intensity is achieved for x = y = 1.0 mol%. The excellent luminescence response suggests that our glasses may be nominated for solid state lasers and other photonic applications.

Abstract: Glass samples of composition 79TeO₂ – 15PbO – 5PbCl₂ – 1Er₂O₃ – (x)AuCl₃ with (0.0 ≤ x ≤ 0.1 mol%) were successfully synthesized by using melt-quenching technique. The impacts of gold nanoparticles (GNPs) concentration in stimulating the ligand field interaction inside the erbium-tellurite glass network were inspected. Amorphous nature of the sample was confirmed through XRD pattern. TEM images display the existence of GNPs with average diameter ~1.24 nm. Optical absorption spectra were recorded in the UV-Visible range. The absorption displays several prominent peaks corresponding to the transitions from the ground state to the excited states of Er³⁺ ion. The compositional dependence of the ligand parameters in terms of crystal field strength and Racah parameter were determined.

Abstract: The zinc oxide based varistor are widely used as circuit protective devices by literally absorbs these dangerous surges and spikes or grounding this unwanted magnitudes. In this research, zinc oxide is added with 0.5 mol % CaMnO₃ as an additive and 0.2 mol % of rare earth doped of lanthanum oxide. Citrate-gel method is used as fabrication method. Complex compound undergoes sintering process which varied at 900 °C, 950 °C and 1000 °C, while, the sintering time are setting at 1 hour and 2 hours. Thermo gravimetric analysis (TGA) shows the forming of CaMnO₃ at 334-1000 °C. Fourier Transform Infrared (FTIR) spectra proved that the functional group present are.-O-H, C-H and C-O. The surface morphology with the grains size below 1μm was observed by Scanning Electron Microscopy (SEM). The α varistor ceramics was calculated from data analysis of I-V characteristics obtained through a Source Measure Unit (Keithley 236). The calculation of α is done by using Origin Pro8.0 software. I-V characteristic shows the value of α in the range of 1.00 to 4.05.

Abstract: This presentation provides a panoramic overview of the recent progress in nanoglass plasmonics, challenges, excitement, applied interests and the future promises. Enhanced optical properties of rare earth (RE) doped glasses for sundry applications are current challenges in materials science and technology. Nanoparticles (NPs) dispersed up-converted (UC) glasses seem to be the ideal candidates in terms of both efficiency and large area coverage provided the absorption cross-section be enhanced. The glasses containing gold NPs (AuNPs) and silver NPs (AgNPs) doped with optimum concentration of RE ions are of particular interest to us. We report the influence of embedded NPs on the luminescence and absorbance characteristics of RE ions doped tellurite glass prepared by melt-quenching method. The absorption and emission spectra displays several prominent peaks corresponding to the transitions from the ground state to the excited states of RE ion. The observed efficient enhancement of up-conversion emissions and absorbance in the entire visible region is attributed to strong localized electric field in vicinity of NPs. Improvements of radiative emissions suggests that the proposed glasses are potential for the development of solid state lasers, color displays and nanophotonic devices.

Abstract: Melt quenching technique (MQT) has been used to prepare the series of 75P₂O₅-17MgO-(3-x)TiO₂-5Li₂O glasses doped Nickel nanoparticles (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0), which was converted into glass-ceramic through heat treatment at 350 °C. In this study, the effects of NiO nanoparticle addition and heat treatment on microstructure were investigated through DTA and XRD. The frequency-dependent electrical data were used to study the conductivity mechanism. Preliminary experimental results from DTA measurement showed that the stability of the glasses are increased when the increment of TiO₂ in the glasses. The XRD results showed the completely amorphous products were prepared by MQT and crystallite structured of glass ceramic were obtained via further heat treatment. Upon the increment of temperature, conductivities increased significantly.

Abstract: Glasses of the system {[ (TeO₂)₇₀ (B₂O₃)₃₀]₇₀ (ZnO)₃₀}_100-y (Er₂O₃)_y containing different concentration of Er2O3 (ranging from 0 to 5 mol %) was prepared from melt-quenching technique. The structural changes were studied by XRD analysis and FTIR analysis. The XRD pattern shows the glasses are amorphous. The higher concentration of Er₂O₃, the more unit of TeO₃ would transform to TeO₄ and formation of B-O vibrational groups. The density and molar volume was obtained attribute to non-bridging oxygen (NBO) and are found the density and molar volume of the glass system are increasing. The densities range from 3630 kg/m3 to 3960 kg/m3. The dielectric constant ε’ and dielectric loss factor ε’’ which were characterized in the frequency range 10^-2 – 10⁶ Hz over temperature range 50°C – 200 °C, show a larger value at lower frequency and higher temperature (above 110°C ). The results of dielectric response measurement show that interfacial polarization at low frequency, and orientation polarization at intermediate and high frequency.Keywords: Dielectric properties; Activation Energy; Rare Earth; Polarization; Non-Bridging Oxygen;

Abstract: Significant quantity of solid wastes, especially electric arc furnace (EAF) slag is generated by the growing Malaysia’s steel industries. Recycling them offer a more sustainable solution and also added value to the solid wastes. Therefore, in this project, an attempt was made to recycle the EAF slag waste as one of raw materials in ceramic tile. In our preliminary study of assessing the suitability of the slag in ceramic tile, it was found that at fixed firing temperature of 1150°C, increasing of EAF slag added (wt.%) would deteriorate the properties of tile produced. Meanwhile, introduce an additional silica and feldspar led to better properties of the tile. Optimum composition of the ceramic tile was found to be 40 wt.% EAF slag – 30 wt.% – 20 wt.% silica – 10 wt.% feldspar. Hence, this study aims to further improve the properties of the tile by varying EAF slag’s milling time (15 minutes and 30 minutes) and firing temperature (1075°C, 1100°C, 1125°C and 1150°C). Results obtained show that as milling time was increased from 15 minutes to 30 minutes, average particle size, X₅₀ of the slag was reduced from 53 µm to 3 µm. When the particles size of EAF slag added was smaller, the tile had a higher modulus of rupture (MOR), higher bulk density, lower apparent porosity and water absorption. The improved MOR was due to increase in total anorthite and wollastonite crystalline phases (wt.%) in the tile. The MOR was the highest at firing temperature of 1100°C for 3µm EAF slag particle whereas for larger particle size (53µm), the MOR was highest at 1150°C. This suggests possible improvement in reduction of firing temperature when smaller particles are used.

Abstract: Borate is one of the most popular oxide glass being used in glass research world wide. Due to good reputation, therefore lead sodium borate glasses with compositions (90 - x) B₂O₃ + 10ZnO + xPbO (where = 15, 20, 25, 30 and 35 mol %) have been prepared by using melt-quenching method. In this work, their physical and structural properties with respect to PbO content has been investigated. The densities of these glass samples were increased from 3946.2 kg/m³ to 5107.2 kg/m³ with an increase in PbO concentration. The molar volume are found to vary from 23.78 × 10^-6 m³mol^-1 to 24.39 × 10^-6 m³mol^-1 with respect to PbO content as well. The density and molar volume show inversed result respectively. The FTIR spectral analysis indicates that with the addition of PbO contents in the glass network, structural units of BO₃ are transformed in BO₄. There are no sharp peaks were observed in XRD patterns of the glass samples which confirmed the amorphous nature of the glass. Meanwhile, the micro hardness of these glass samples were also increased from 189 Pa to 355 Pa with increases on PbO content. The results will be discussed and presented in details.

Abstract: Neodymium doped zinc borotellurite glass system were fabricated by using conventional melt-quenching method. The structural properties of the glass system were characterized by using X-ray Diffraction (XRD) method and Fourier Transform analysis (FTIR). The amorphous nature of the glass system was confirmed by using x-ray diffraction method. The transmission band of TeO₃ structural units which indicate the existence of non-bridging oxygen was shown by FTIR analysis. The optical properties of the glass system were determined by using UV-Vis spectrophotometer. Several bands were shown in the absorption spectra which indicate the characteristic of neodymium ions. The obtained values of indirect optical band gap, Eopt lies in the range of 3.151 eV and 3.184 eV.

Abstract: Currently, many researchers interested studying waste materials to recycle them or reuse them in new products. From the sustainable perspective development, it is necessary to implement new technologies to help reduce waste and thus minimize the environmental problems associated with disposal. In this study, the preparation of SiO₂-Na₂O-CaO-P₂O₅ (SNCP) glass-ceramic is composed of Soda Lime Silicate (SLS), Clam Shell (CS), Na₂CO₃ and P₂O₅ in the ratio of 50: 25: 20: 5 respectively. The waste materials that were used for fabricate glass-ceramic are SLS and CS. All the compounds were mixed to fabricate the SNCP glass-ceramic through solid state reaction. The samples were investigated through X-ray diffraction (XRD), field emission microscope (FESEM) and density measurement. The samples were sintered at temperature 550°C, 650°C, 750°C, 850°C until 950°C. The main phase obtained from XRD analysis is Sodium Calcium Silicate, Na₂CaSiO₄ with cubic crystal system at 550°C. The highest intensity phase of the diffraction peak is (220) and at the angle 33.7°. There was new peak presence at right side of the main phase Na₂CaSiO₄, which belong to Silicon Phosphate, SiP₂O₇ at 650°C and 750°C. When heat treatment increased at 850°C - 950°C, the main phase is Combeite, Na₄Ca₄(Si₆O₁₈) at diffraction peak (220) with rhombohedral crystal system which is assigned to high crystallization temperature (T_c). The density of samples increases at 550°C - 750°C and decreases when heat treatment 850°C - 950°C. Sample density decreases at heat treatment 850°C - 950°C due to increases of sample lattice parameter. FESEM analysis showed that the grain size and porosity increased when the heat treatment increased.