Papers by Keyword: Glaze

Abstract: In the present scenario aluminium is an useful metal due its admirable properties such as light weight, low cost and excellent thermal conductivity.In order to take advantages of these properties aluminium is being used to make the metal matrix composites for tribological application, In this present investigation effort has been made to assess the wear properties of Al–B₄C–Gr metal matrix composite at various temperatures such as 323° K, 373° K and 423° K. Al–B₄C–Gr Hybrid metal matrix composites were fabricated by stir casting technique. The influence of parameters like load, speed, distance and temperature on the wear rate was investigated. A plan of experiments, based on Taguchi model with L27 orthogonal array and analysis of variance was employed to investigate the influence of process parameters on the wear behaviour of these hybrid metal matrix composites. The wear resistance increased with increasing temperature, but wear resistance decreased at higher loads. It was observed that the abrasive wear is dominates while sliding as observed by SEM analysis of worn out specimens.

Abstract: This study examined the chemical stability of malayaite pigments in ceramic glazes containing high amounts of zinc oxide (ZnO). The calcined pigments were embedded in a molten glaze which is basically corrosive glass. Within the glaze, ZnO has been known among potters to be undesirable as some pigments are not stable in glazes containing ZnO. The synthesized pigments’ particle size ranges from 4 to 18 μm without dominant preferential orientation. Their colors were in the red and yellow tones. Chemical stability between the pigments and glazes was tested using X-ray Diffraction (XRD). Slight changes were observed. Increasing amounts of ZnO resulted in an interfacial layer of approximately 50 μm between the crystalline pigment and surrounding amorphous glaze. The a color parameters gradually decreased while the b parameters switched to a negative value. The resulting glazes evolved from maroon to pale violet. The correlation between color and microstructural alterations was discussed.

Abstract: Spinel-based ceramic color pigments were successfully synthesized from utilization of aluminum dross waste and relevant oxide precursors by solid-state processing. Cobalt ions were selected as a chromophore to produce blue pigments. The conventional oxide route was also carried out for comparison purposes. The spinel phase readily formed when fired at 1100 °C; longer duration yielded a higher degree of purity. No preferential orientation of XRD reflection was observed, indicating random crystallographic arrangement. Phase formation was also confirmed by Fourier Transformed Infrared Spectroscopy (FTIR) which displayed both Co-O tetrahedral and Al-O octahedral which are the main framework for a spinel crystal. Slightly sharper FTIR peaks for the dross route compared to those from the oxide route suggest a difference in crystallinity between the two with different precursors. The particle size distribution was relatively wide (5 – 30 micron), possibly due to a crude nature of the dross precursor. The UV-vis spectra showed absorption in the range of 450-550 nm which is associated with the blue color caused by a shift of the 3d⁷ electrons of Co2+. The obtained dross-route pigments possessed both a and b color parameters (a = -2.3 to-2.6; b = -3.4 to-4.0) in the negative territory, implying greenness and blueness respectively. The L values were in the 20-30 range. When incorporating into practical glazes, the b parameters unexpectedly became more negative, indicating an even deeper blue tone. This result suggested a high potential for utilization of this dross waste as an alternative precursor source for sustainable production of spinel ceramic pigments.

Abstract: The objective of this work was to produce red ceramic glazed with dimension stone waste. The clay and residue were characterized for crystalline phases (XRD), chemical analysis (XRF) and particle size. Additives were added to the residue in order to reduce the melting point of 1280 oC to 980 °C, because 1100 °C is the temperature typically used in industrial sintering of coating ceramics. It was studied different compositions of glaze and analyzed its viscosity. The engobe and the glaze were applied on the red ceramic, previously pressed with 100x100x5 mm³ size, and sintered at 1100 oC for 1 h, in order to obtain the ceramic coating. These ceramics were analyzed for abrasion resistance, water absorption and chemical attack, according to NBR 13.818/1997, being classified as PEI 1, indicate for use in residential bathrooms and bedrooms without doors outwards, showing the potential use of dimension stone waste for flooring ceramics, mitigating environmental impacts in mineral industry.

Abstract: The dimension stone industry produces large amount of residue. An alternative to reduce this environmental liability is to apply as glaze in coating ceramic. This research is about the wettability between glaze and red ceramic, applying the sessile drop method. The waste and additives were mixed, pressed, and put over red ceramic plate previously sintered. The system was heated until the melting point of the glaze and the contact angle decreasing was measured in function of the temperature, and in a function of the time at 750 °C and 800 °C. The minimum contact angle value was near 6 ° at 994 °C in the testing changing the temperature, and presents 19 ° and 10 °, respectively, at 750 °C and 800 °C, when the time was varied. The longitudinal section of the samples was analyzed using optical microscopy, showing physical wettability in all testing. This glaze presents good wettability on red ceramic with potential as coating ceramic.

Abstract: Palm fiber ashes are the industrial waste which is abundantly available in Malaysia. In this study, palm fiber ash were used to produce decorative ceramic glaze. The content of minerals in the palm fiber ash were analyzed by using X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF), respectively. The formulations of glaze with different composition of raw materials were studied by adding different amount of calcium carbonate and feldspar. The glaze slurries then coated on ball clay body bisque which was obtained from Kg. Dengir and sintered at 1200 ° C for two hours.The glaze was characterized in term of its physical appearance such as type of glaze and colour. Both glossy and matte glaze produced by using different composition of glaze formulation. The presence of silica minerals (79 %) contributed to glossy surface to the glaze. It is clearly seen that the glossiness of glaze improved by increasing amount of feldspar. Feldspar acts as fluxing agent which form a glassy phase at lower temperature. In addition, the presence of small amount of iron oxide (2.2 wt.%) contributed to brown colour of glaze. An addition of calcium carbonate give effect to the colour of glaze, which change from brown to yellow colour as amount of CaCO3 increased. As a conclusion, the palm fibre ashes were highly suitable to supply abundant and cheap raw materials to produce decorative ceramic glaze.

Abstract: The feasibility of developing glass-ceramic glaze in the system KNaO-CaO-MgO-ZnO with a variation in the composition of SiO₂, TiO₂, and B₂O₃ was studied. The SiO₂, TiO₂, and B₂O₃ were varied in the amount of 2.25-1.50, 0.001-0.10, and 0-0.1 molar equivalents respectively. The samples were one fired at 1180°C or double fired by reheat at the crystallization temperature for 10 minutes. The gloss, sintering behavior, phase, microstucture, and hardness, and were examined by glossmeter, side-view hot stage microscope, X-ray diffraction, SEM, and Vickers hardness respectively. The results showed the importance effect of SiO₂, TiO₂, and B₂O₃ on the glaze crystallization ability and its properties. At the fix value of Al₂O₃ at 0.24 molar equivalents and with the 0.001-0.10 molar equivalents of TiO₂, lower the SiO₂ content to 1.50 molar equivalents increased the glaze crystallization potential. An increase in the B₂O₃ to 0.1 molar equivalents suppressed the potential of glaze crystallization. The phases of samples were amorphous or composed of silicon dioxide and diopside as the main phases depending on the glaze composition and the firing history. In this study, the glaze appearances transparent to opaque and varied from gloss to matte with the specular gloss values between 23-100 GU. All samples appeared to have high Vickers hardness value in the range of 553-644. The crystallization decreased the gloss but increased the hardness value for the 2.25 molar equivalents SiO₂ glaze. Finally, a composition with high hardness and high gloss was identified and its properties was also presented. These results suggested the limitation and the potential for applying this glass-ceramic glaze system to industry applications.

Abstract: The dip coating procedure led to accumulation of coating particles at the coating solution and substrate interface. After sintered, frit dissolution implied an occurrence of liquid phase sintering. Simultaneous improvement of surface morphology and bulk density was evident. The significant appearance of cracks and roughed surface of plain porcelain was revolved into crack free and smoother exterior following the dip-coating and sintering process. The surface was properly glazed. This led to enhanced body densification, and sealing of apparent micropores. At the same time, the deposited coating reduced the amounts of open cells and surface defects, which caused reduction in porosity and increment of bulk density.

Abstract: Titania (TiO₂) is one of a common and favorable material use in the manufacturing industry due to its uniqueness and functional performances to human and environment. The study was focused on the performance of glaze added TiO₂ (anatase phase) in the application of porcelain tiles. Anatase powder in micro size was used (varies at 5 wt%, 10 wt % and 15 wt%) to observe their performance as antibacterial materials. The anatase powders were mix into the glaze composition and apply to the porcelain tile through dip coating. The viscosity of each composition was observed to study their effect. Characterization used to observe the properties of anatase mixed glazed porcelain tile were X-ray diffraction (XRD), Scanning electron microscopy (SEM) and antibacterial test. The results shown that higher composition of anatase powder, viscosity of the mixed glaze is higher and a rougher surface of glazed tiles was formed. XRD result shows that the higher the composition is more the intensity of TiO₂ on the glaze coating surface, supported by SEM results. Antibacterial testing towards E.Coli was observed by counting the colonies of bacterial growth in 0 hr, 2 hrs, 4 hrs and 8hrs. The antibacterial properties increase when the composition of anatase increases.

Abstract: Glazes is a layer of vitreous substance, which is combined to ceramic object through a firing process. The aim of this study is to evaluate the potential of Ibai River sediment as raw material for producing ceramic glazes. Minerals and heavy metal in sediment have been characterized using Atomic Absorption Spectroscopy (AAS) and X-Ray Fluorescence (XRF). Glazes formulation has been studied by adding CaCO₃ and stoneware into the sediment at different compositions. Glazes sample was tested for chemical resistance and thermal shock resistance. The AAS results show that sediment contains high Fe content of 65.5000 ppm while amount of Cr, Co and Pb are less than 0.4850 ppm. XRF analysis shows that the presence of important minerals in sediment, which is commonly found in commercial glazes formulation and contributes to formation of good glazes. Matte glazes can be obtained by using only sediment while shiny glaze can be obtained by adding CaCO₃ to the sediment as fluxs. High concentration of iron in sediments contributed to brown or reddish brown in color of glazes products. The results show that the glazes produced has chemical resistance towards acids and high thermal shock resistance. As a conclusion, the Ibai River sediment is highly suitable to supply abundant and cheap raw materials for producing decorative ceramic glaze for small-scale ceramic industry in Terengganu, which generate new economic source for local community.