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The present study investigated the mechanical and thermal properties of geopolymer composite. The geopolymer composite was prepared by mixing fly ash and wollastonite with the alkaline activator, which was 6 M KOH:K2SiO3 in a mass ratio of 1:1 and a solid:liquid mass ratio of 3:2. The compressive strength at 28 days of geopolymer was 33.3 MPa and possessed the highest strength of 38.3 MPa when 30 wt% wollastonite was added. The flexural strength presented differently whereby it increased from 2.1 MPa to 6.8 MPa. It increased remarkably up to 200% with the addition of 50 wt% wollastonite. The geopolymer composites were exposed to high temperatures at 800℃ to 1100°C for 2 h. Cracks were reduced since 20 wt% wollastonite was added. A high percentage of wollastonite presented excellent thermal stability. The total weight loss of the geopolymer composite at temperatures of 30℃ to 1400°C was minimized. It decreased from 25% to 12% when 50 wt% wollastonite was added, and the dilatometric data resulted in a dimensional change of almost zero. The phase development of the geopolymer composites at high temperatures showed the crystallization of leucite, kalsilite, calcium silicate, calcium aluminium silicate, and calcium aluminium oxide, which were the high temperature stable phases. The results indicated that wollastonite reinforced fly ash-based geopolymer composites are promising for use in high temperature applications.

The massive amount of kaolin processing waste was daily formed. To reduce the amount of their waste deposited in landfills and to increase the value- adding of recyclable waste, this work interested to use as raw materials in the preparation of geopolymer. This paper studied the reaction mechanisms of calcined kaolin processing waste-based geopolymers in the presence of low alkali activator solution by the pressing method. The reaction mechanisms of geopolymer were measured as a function of NaOH concentration by DSC, XRD, and FTIR analysis. Furthermore, the effects of NaOH concentration and curing time on the mechanical properties and microstructure of calcined kaolin processing waste-based geopolymer were investigated. The DSC, XRD, and FTIR results indicated that the geopolymerization reaction increased with higher NaOH concentrations. Forming the geopolymer by the pressing method led to the particles being close together in a compact matrix. Subsequently, their surfaces were dissolved with NaOH solution, inducing the geopolymerization reaction. This reaction and continuous reaction resulted in the compressive strength and microstructure of the geopolymer. The compressive strengths of the geopolymer synthesized with NaOH concentration of 10 M (curing time of 7 days) and a curing time of 28 days were 26.98 MPa and 28.55 MPa, respectively, which were approximately 22.58% and 52.35% higher compared to the geopolymer synthesized with NaOH concentration of 4 M and a curing time of 1 day. The SEM micrographs of the geopolymer samples displayed more geopolymeric gel and denser matrices with increases in NaOH concentration and curing time. The nitrogen adsorption and pore volume decreased with increases in NaOH concentration and curing time. Synthesis of geopolymers using kaolin processing waste as a raw material is a value- adding and environmentally friendly process.

This paper describes a simple and effective process for fabricating geopolymer-polymer composite fiber. The fiber is synthesized by mixing geopolymer powder with Polyethersulfone (PES) – N-Methyl-2 pyrrolidone (NMP) solution and the slurry was extruded then transformed into a fiber by phase inversion method. The fiber is constructed of PES and fly ash-based geopolymer (FAG) particles with porous structure. Analysis of the pore structure of fiber revealed that BET surface area is 168.30 m2/g. In addition, the adsorption capacity of heavy metal ions on geopolymer composite fiber follows the order of Pb2+ > Cu2+ > Cd2+ > Ni2+. This work provides a convenient, low-cost and environmental friendly adsorbent for removing heavy metal ions from waste water.

This paper observes the fabrication of partial black porcelain by carbon diffusion from wood charcoal as a solid carbon source, and the characterization of body at bottom area. The porcelain cup was created by conventional ceramic technique. For second firing step, the cup was set on the wood charcoal pieces contained in a closed refractory container and fired at 1250°C for 1 h. The traces of carbon compounds at different positions on a cross-section sample were detected by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Graphitic carbon and Si−O−C were discovered. Furthermore, graphite peak was detected by X-ray diffraction (XRD). This work provides a confirmation of solid diffused carbon from wood charcoal into the porcelain body by scientific techniques.

Waste management and water quality are two main problems nowadays. Geopolymer material has efficiency for adsorbing the ions from wastewater. In this research, the metakaolin based geopolymer was studied and used as an adsorbent to remove heavy metal ions. Moreover, the factors which affect adsorption process of heavy metals on geopolymer materials were investigated. The kaolin as used in this research was from Thailand. The metakaolin geopolymer was synthesized by mixed raw materials with an alkaline solution. The metakaolin geopolymer was washed and sieved through 100 mesh. The produced metakaolin geopolymer powder was used as an adsorbent. The XRD results showed a highly amorphous structure in obtained metakaolin geopolymer. Moreover, the BET surface area of metakaolin and geopolymer particles were 9.83 m2/g and 20.36 m2/g, respectively. The parameters of adsorbent amount, initial pH, time of shaking, temperature and initial metal ions concentration on the removal potential of geopolymer were studied. In addition, the multi-and mono-cations solution were demonstrated to compare the efficiency of each heavy metal ions. The results showed that the amount of Pb2+, Cu2+, Cd2+, and Ni2+ions adsorbed onto metakaolin geopolymer increased with an increasing contact time, pH, temperature and amount of geopolymer. It is concluded that Pb2+, Cu2+, Cd2+, and Ni2+ions in aqueous solution are efficiently removed by metakaolin geopolymer which could be applied as a low cost and good alternative for wastewater treatment.

This work aims to evaluate the effectiveness of fly ash based geopolymer powder as an adsorbent for heavy metals in aqueous solution. The structure of synthesized geopolymer was found to be highly amorphous due to the dissolution of fly ash phase. Moreover, the fly ash geopolymer powder has higher surface area compares to original fly ash with specific surface area of 85.01 m²/g and 0.83 m2/g, respectively. For this reason, the geopolymer powder has much higher removal efficiency compared to the original fly ash powder. The removal efficiency was affected by contact time, geopolymer amount, heavy metal initial concentration, pH, and temperature. The four heavy metals were chosen (Pb2+, Cu2+, Ni2+, Cd2+) for adsorption test. The highest heavy metal removal capacity was obtained at pH 5. The geopolymer powder adsorbed metal cations in the order of Pb2+>Cu2+>Cd2+>Ni2+. In addition, Langmuir model is more suitable for fly ash geopolymer powder adsorption of heavy metal ions in aqueous solution than Freundlich model. The results showed that the fly ash geopolymer powder has high efficiency for removal metal which could be employed excellent alternative for wastewater treatment.

Basalt fiber has been used as a reinforced material in cement-based materials because it has higher mechanical strength and cheaper than common silicate based glass-fibers. However, silicate-based glass fibers have low alkali resistance especially in cement matrix composite. In this work, we studied the improvement of alkali resistance by addition of zirconium silicate (ZrSiO4) in original basalt glass composition. The batch of basalt glass with additional ZrSiO4 contents of 0.00, 2.50, 5.00, 7.50 and 10.00 wt% were melted at 1500 °C. The liquidus temperature (TL) is important in for the fiber glass manufacturing. It need to formulate glass composition which requires a lower melting temperature and is crystallization resistant. TL as a function of composition is usually determined experimentally. In this study, glassy phase was determined by X-ray Diffraction (XRD). The glass transition temperature (Tg), the crystallization temperature (Tc) and TL were analyzed by Differential Thermal Analysis (DTA). The results found that the addition of ZrSiO4 in a basalt glass batch increased Tg while Tc of each sample was closed to original basalt fiber. Moreover, the alkali resistance of these glasses increased with an increasing of ZrSiO4 content. However, excessive ZrSiO4 contents (7.50 and 10.00 wt%) resulted in crystallization of ZrO2 which separated from glassy phase.

Class C fly ash is widely used as a geopolymer raw material. It contains high calcium oxide and iron oxide resulting in a fast setting property. The influence of using kaolin and metakaolin replaced class C fly ash in geopolymer processing were investigated in term of compressive strength and setting time. Kaolin and metakaolin which calcined at different temperature of 600°C and 700°C replaced Class C fly ash between 0 to 50 wt. %. The geopolymers were prepared at constant KOH concentration as 6.0 M, K2SiO3/KOH ratio as 1.0, solid/liquid ratio as 1.5 and 7 days of curing. The compressive strength is obviously increased when fly ash was replaced with both kinds of metakaolin, although, it is inclined to decrease when replaced by kaolin. The compressive strength is increased up to 13% and 47% with the replacement by 50 wt. % of metakaolin calcined at 600°C and 700°C, respectively. On the other hand, the replacement by 50 wt. % of kaolin give the initial setting time prolonging from about 6 min to 80 min. However, the initial setting time of metakaolin calcined at 600°C and 700°C replacement is also improved to about 37 min and 20 min, respectively. These results from their difference of amorphous phase and reactivity of the replacement materials. XRD analysis reveals the combination phases of amorphous geopolymer gel that is the broad hump centered at 28 – 30° 2θ, and products from the reaction such as calcium oxide, arcanite, calcium silicate hydrate, quartz and muscovite which the two latter are from unreacted metakaolin. They are confirmed by FT-IT result and microstructure evaluation by SEM. Therefore, the partially replacement of fly ash with kaolin and metakaolin in fly ash-based geopolymer production are affected to the compressive strength and resulted to modify the setting time.

Geopolymer particles from waste coal fly ash were prepared in order to investigate adsorption process of Cadmium ions. The aim of the study is to focus on factors which affect adsorption process of heavy metals on geopolymer materials. The raw fly ash was mixed with sodium hydroxide solution and sodium silicate solution. After that geopolymer was cured at 80 °C for 24 hr. The sample was ground and washed until pH=7. The obtained geopolymer particles were dried at 60 oC. The raw materials and geopolymer were characterized. The XRD results showed a highly amorphous structure in obtained geopolymer. The major components of waste coal fly ash and synthesized geopolymer were SiO2, Al2O3, Fe2O3 and CaO. The BET surface area of fly ash and geopolymer particles were 0.83 m2/g and 85.01 m2/g, respectively. The adsorption conditions (initial concentration from 10-120 mg/L, temperature at 25-45 °C, pH of cadmium ions solution from 1-5, 0.02-0.14 g. of geopolymer and contact time for 5-180 min) were studied. From removal efficiency results, synthesized geopolymer had high removal capacity for cadmium ions (Cd2+). At pH 5 of solution, the highest Cd2+ removal capacity was obtained. In addition, the removal efficiency increases with an increasing geopolymer dosage, contact time and a decreasing of Cd2+ initial concentration. Moreover, both Langmuir and Freundlich models were investigated for studying adsorption isotherm. The result showed Langmuir model is more suitable for geopolymer adsorption of cadmium ion in aqueous solution than Freundlich model.

This project presents how steel recycling by-products employed as decorative ceramic glaze raw materials.Two steelmaking wastes were of interests: electric arc furnace dust and mill scale.EAF dust is collected from off-gas fume during melting.The dust containing zinc ferrite with some heavy metals is concerned as a toxic waste.Mill scale collected from a hot-rolled reheating furnace is iron-rich oxide and non-toxic.The as-received wastes were chemically analyzed.A mid-fired glaze, oil spot tenmoku, were carefully formulated and investigated.The work showed both wastes successfully provided the glaze with lustrous and silvery spotting effect

Objective: To investigate the flexural strength and cytotoxicity of ZCC, a resin modified zinc oxide-calcium carbonate liner prototype, compared with commercial dental liners. Materials and Methods: ZCC, Dycal, Ultra-Blend® plus (UB), and TheraCal LC® (TC) were evaluated for flexural strength. Six samples of each material were incubated in growth medium (10% fetal bovine serum supplemented DMEM) for 24 h. Primary human dental pulp cells were cultured in the conditioned medium from each sample, with growth media used as a control. Cytotoxicity was determined using an MTT assay. Data were analyzed by one-way ANOVA. The value of pppp>0.05). Conclusion: ZCC met the requirements for flexural strength per ISO 9917-2:2010(E). There was no significant difference in viability between the control and ZCC group at 24 and 48 hours.

Solid oxide fuel cell (SOFC) is an electrochemical energy conversion device which is considered as clean energy source generator with reliability and relatively inexpensive production cost. One of the most important components for planar design SOFC is the hermetic seal that prevents fuel from leaking out of between the stack of fuel cells. Glass-ceramics are attractive materials as sealing materials for this device. The expected coefficient of thermal expansion (CTE) of the glass-ceramic sealants should be between 9 and 12 x 10−6 K−1. Glass – ceramics based on åkermanite (Ca2MgSi2O7) crystalline phase were reported their high CTE value from about 10 to 11.3 x 10−6 K−1. In this study, glass compositions in the CaO-MgO-B2O3-Al2O3-SiO2 system with varying amounts of Bi2O3 from 0 to 10 wt. % were prepared by conventional melting and investigated their properties. The selected compositions were derived from ternary åkermanite–forsterite–anorthite phase diagram. Phase composition and quantitative phase analysis of glass–ceramics were examined by X-ray diffractometer. The onset of crystallization (Tx) and crystallization temperature (Tc) were measured by DTA. The thermal properties of bulk glass samples and heat treated samples at 900 oC for 2 h which were glass transition temperature (Tg), dilatometric softening temperature (Ts), and coefficient of thermal expansion (CTE) were determined by dilatometer. Furthermore, the long-term stability of their CTE was investigated. The samples were continued to soak at 800 °C for 100 h and observed their change in CTE value. The results found that the åkermanite phase tended to increase with increasing amount of Bi2O3 content.

Microwave synthesis of porous fly ash geopolymers was achieved using a household microwave oven. Fly ash paste containing SiO 2 and Al 2 O 3 component was mixed with sodium silicate (Na 2 SiO 3 ) solutions at different concentrations of sodium hydroxide (NaOH) of 2, 5, 10, and 15 M, which were used as NaOH activators of geopolymerization. The mass ratio of Na 2 SiO 3 /NaOH was fixed at 2.5 with SiO 2 /Al 2 O 3 at 2.69. After the fly ash and alkali activators were mixed for 1 min until homogeneous, the geopolymer paste was cured for 1 min using household microwave oven at different output powers of 200, 500, 700, and 850 W. Porous geopolymers were formed immediately. Micro X-ray CT and SEM results showed that the porous structure of the geopolymers was developed at higher NaOH concentrations when using 850 W power of the microwave oven. These results derive from the immediate increase of the temperature in the geopolymer paste at higher NaOH concentrations, meaning that aluminosilicate bonds formed easily in the geopolymers within 1 min.

Electric Arc Furnace (EAF) is commonly used in steel recycling industries. Apart from steel metal product, a waste in the form of dust is also produced and so called EAF dust. The fine particulates mainly contain zinc-iron oxides along with a small amount of heavy metals like chromium and lead, and have been categorized as a toxic waste. Proper treatments can be crucially required in order to recover crude zinc oxide and iron oxide from the dust; however, no practical recycling plants have been now readily operated in Thailand. To reduce its toxicity, EAF dust could be mixed with silica-based materials and vitrified into glass. Therefore, EAF dust can possibly be employed as a ceramic glaze raw material. This work pointed out how to make decorative “oil spot” ceramic glaze by substitution of EAF dust for a conventional iron oxide. The prepared glaze mixtures were applied over the ceramic bodies and fired at 1250 °C in oxidation atmosphere. The as-fired glaze appearances with tiny and silvery crystals floating over dark brown based-glaze were exhibited. Phase content and characteristics of the obtained glaze were analyzed. The roles of zinc oxide to iron oxide ratios on oil spot and crystal generation was concerned. A comparison of oil spot effects due to different iron oxide sources was presented and discussed. Oil spot glaze made from a combination of EAF dust and iron oxide powder was also proposed.

Hydroxyapatite (HA) nanoparticles were synthesized using a wet mechanochemical method without a calcination process. Dicalcium phosphate dihydrate (CaHPO4 ·2H2 O) and calcium carbonate (CaCO3 ) were mixed and milled in a planary mill using ethanol or water as liquid media in the two different synthesized routes. Effects of rotation speed and milling time on the final products formed have been studied. Experimental results showed that HA phase having a characteristic of low crystallinity could be formed under the synthesis route using water. The original phases of both starting chemicals were remained without HA formation in the synthesis route using ethanol. Particle size and morphology of HA nanoparticles were obviously depended on optimum conditions of rotation speed and milling time. Differences on phase formation in both synthesized routes have been considered and discussed based on occurring chemical reaction possibilities. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 679-688, 2017.

Porous geopolymer could be synthesized by using metakaolin and silica fume as foaming agent. The foam morphology was estimated in the function of water, silica fume content, and curing temperatures. Raw materials were mixed by Hobart mixer for 5 minutes and then poured in to cylinder mold after that cured at 70 degree celsius for 24 hours. During the synthesis process, the complex reaction would occur such as polycondensation and oxidation. These reactions affect to chemical and physical properties of porous sample. The parameters that mention above affect to density, physical, and chemical properties. The thermal conductivity of porous geopolymer that contained with 14 molal NaOH concentration yield the lowest values of 0.5101 W/mK and pore size distribution of 0.01-0.8 mm.Keywords: Porous geopolymer, thermal conductivity, metakaolin

Calcium phosphate cement has been widely used as a bone substitute because of its chemical similarity to natural bone. In this study, calcium phosphate cement was prepared using dicalcium phosphate dihydrate (CaHPO4.2H2O) and calcium carbonate (CaCO3) as starting raw materials. The cement pastes were mixed and the chemistry adjusted with two different aqueous solutions of sodium hydroxide (NaOH) and disodium hydrogen phosphate (Na2HPO4). Concentrations of the solution were varied in the range 0.5 to 5.0 mol/L with the ratio of solid/liquid = 2 g/ml. The cement paste was then poured into a silicone mold having a diameter of 10 mm and a height 15 mm. Setting times for the cement were measured using a Vicat apparatus. XRD, FT-IR, and SEM techniques were used to characterize properties and microstructure of the cement. From the experimental results, it is clear that different concentrations of Na2HPO4 and NaOH have affected the setting times of the cement. The relationship between concentration of NaOH and Na2HPO4 and setting time, including final properties of the cement, is discussed.

Geopolymeris an alumino-silicate material with three dimensional amorphous structures. The main compositions are silica and alumina which were decomposed by alkaline solution. Geopolymer materials not only have comparable or superior properties to portland cement, but also have lower greenhouse emission. In this study, Preparation and characterization of geopolymer were investigated. The main composition of fly ash from Mae Moh power plant is SiO2 and Al2O3. The major composition of Aluminium waste from aluminium frame industry is Al2O3.The geopolymer pastes were mixed at various proportions of FA:Al-waste of 100:0 80:20 60:40 and 40:60 by weight. Sodium hydroxide and sodium silicate were used as alkali activators.A mass ratio of 2.5 Na2SiO3/NaOH and three concentrations of NaOH (5 10 15 M) were used. Geopolymer were cured at ambient temperature for 7days. Properties of geopolymer specimens were measured for example compressive strength, bending strength, phase by XRD, and bonding by FT-IR.

Nanoporous alumina membrane and continuous zeolite L membrane were fabricated on the inner surface of microporous alumina tubes. In the former case, an electrophoretic deposition (EPD) technique was used for the deposition of bimodal alumina particles for the subsequent low temperature sintering. In the latter case, the EPD was used for the seeding process of zeolite L particles for the subsequent hydrothermal synthesis. A thin layer of polypyrrole was synthesised on the inside wall of the porous tubes by the chemical polymerisation of pyrrole to give the wall electric conduction for the EPD electrode. The thickness of the coating layers was controlled by altering the applied voltage and deposition time. The interfacial connection of the alumina or zeolite coated layer and the substrate was evaluated by SEM observations before and after the thermal treatment. The nanoporous structure of the alumina membrane was also characterised by a pore size analyser.

The nano-porous Al2O3 layer was performed onto inner surface of micro- porous Al2O3 tube by using electrophoretic deposition (EPD). Initially, Polypyrrole (Ppy) was applied on inner wall of tube to make conductive surface. The Al2O3 deposition was carried out in Al2O3 suspension with 5 wt % solid content in ethanol medium system using various applied voltages. Thickness of the deposited layer depends on applied voltages, after sintering at 1400oC the morphology of the deposited layer was investigated by FE-SEM. The good deposited surface without cracks and peeling has been prepared under applied voltage condition of 10 V.

Silver film was fabricated on a glass substrate by electroless plating technique. Plating solution, which also known as Tollen’s reagent, consisted of three main solutions: silver nitrate solution as a silver source, ammonia and sodium hydroxide as pH controllers and D-glucose as a reducing agent. Glass surface was treated by three different methods: HF etching, SnCl2activation and SiC paper grinding. After that, a glass slide was immersed in plating solution for 90 minutes at a room temperature. The purpose of this work was to study the effects of different surface treatments on adhesion between substrate and film. X-ray diffraction (XRD) pattern confirmed that the obtained film was a silver phase. Surface morphology of glass slides, before and after plating was investigated by scanning electron microscope (SEM). Moreover, the adhesion of silver film to glass substrate was performed by crosscut test and it was indicated that combined treatment by SiC paper grinding and HF etching was the best surface treatment which provided a good adhesion of film to substrate.

The planar solid oxide fuel cell (p-SOFC) is a promising configuration of a high-T fuel cell. Barium alumosilicate glass ceramics are suggested to use as sealants by many authors since these materials seem to meet the requirements to establish a hermetic and electrically insulating seal between the steel components of the SOFC. However, in long-term application, the formation of BaCrO4 may degrade the interfacial strength between glass-ceramics and metallic interconnect and disrupt the cell components. In this work, a series of barium-free glass-ceramics in the system of CaO-MgO-B2O3-Al2O3-SiO2 were prepared. The selected compositions were located within the constitutional range of åkermanite – forsterite –anorthite. The thermal properties including glass transition temperature (Tg) and crystallization temperature (Tc) of the produced glasses were measured. The effect of boron oxide additions was studied in order to optimize the softening and flow behavior. For the experiments, a hot – stage microscope was used. Some glass compositions were mixed with high – CTE akermanite powder in order to increase their CTE after sintering. The CTE of the investigated materials after sintering at 900 °C, 2 h, ranged from 10.5 to 11.8 10−6 K−1.

In the present study, nanocrystalline χ-Al 2 O 3 were prepared by thermal decomposition of fine gibbsite (χ-GB) and solvothermal method (χ-SV) and employed as supports for preparation of 20 wt% Co/Al 2 O 3 catalysts. As compared to the use of γ-Al 2 O 3 with similar BET surface area, Co dispersion and CO hydrogenation activity were higher on the nanocrystalline χ-Al 2 O 3 supported Co catalysts. The transmission electron microscopy (TEM) results revealed that the wrinkled sheets-like structure of γ-Al 2 O 3 was completely destroyed after CO hydrogenation for 6 h whereas the spherical particles of χ-SV and plate-like structure of χ-GB were maintained. The H 2 -temperature program reduction (H 2 -TPR) also revealed a stronger interaction between cobalt and alumina supports for the Co/χ-Al 2 O 3 catalysts.

Gibbsite (FG) with mean particle diameter (d50=13 μm) was milled in an attrition mill for 12 and 24 h using alumina balls as grinding media and calcined at different temperatures in the range of 350°–600°C. The properties of the alumina obtained were determined by X-ray diffraction, N2 physisorption, thermogravimetric/differential thermal analyses, and transmission electron microscopy. Without milling, the alumina obtained normally contained the mixed phases between γ- and χ-phase alumina. On the other hand, high purity of nanocrystalline χ-phase alumina (100 wt%) can be produced by calcination of the 24-h milled FG at 600°C. The isothermal kinetics measurements revealed that the rate constant (k) for phase transformation increased as the particle size of gibbsite decreased and the calculated activation energy for transformation from FG to alumina decreased from 20.6 to 14.7 and 6.8 kJ/mol after milling for 12 and 24 h, respectively. The physical properties of nanocrystalline χ-alumina obtained by the calcination of milled FG were comparable to those produced by the solvothermal method. The present results offer a simple way to prepare a large amount of pure χ-phase alumina for particular industrial applications.

The clay-based ceramic was produced by adding with the bottom ash from domestic municipal solid waste incinerator plant in Thailand. The amount of the ash up to 60 wt% was added. The samples were dry pressed and sintered at the temperature range between 1000 and 1125°C. The presence of quartz (SiO2), anorthite sodian (Ca,Na)(Si,Al)4O8, albite (Na(Si3Al)O8) and mullite (Al6Si2O13) was observed in the sample with the addition of the bottom ash. The physical and mechanical properties were also presented. The sintering temperature and the ash addition revealed the effect on the properties of the product.

A novel method for preparation of WO3–SnO2 nanocomposite was described. 0.3–10.0 wt.% WO3 was incorporated into the SnO2 powder by precipitation of hydrated WO3 from ammonium tungstate precursor solution containing SnO2 powder. This preparation method resulted to uniform mixing of ∼35 nm WO3 and ∼100 nm SnO2 nanoparticles as revealed by direct observation using a transmission electron microscope, and by performing elemental dot mapping. Upon calcination to 500 °C, both cassiterite SnO2 and monoclinic WO3 were stable, and no other crystalline phase was observed. To evaluate gas sensing performance, the powders were formed into thick-film sensors using a screen printing technique. It was found that the gas sensitivity of the SnO2 base was enhanced when very small amount of the WO3 (0.3 wt.%) was incorporated. The 0.3 wt.% WO3–SnO2 sensor was very sensitive to 2–8 ppm ethylene at optimum operating temperature of 300 °C. The sensitivity decreased with increasing amount of the WO3.

The effect of glass cullet on physical and mechanical properties of glass-ceramics developed from zinc hydrometallurgy waste and glass cullet was investigated. The glass-ceramics were prepared by mixing zinc hydrometallurgy waste with glass cullet through vitrification process. Two difference types of glass cullet (clear and amber cullet) were used. The parent glasses were ground and pressed into bars and sintered at low temperature (850°C) for 2 hours. The obtained glass-ceramics had low porosity. The glass-ceramics with clear cullet exhibited higher density and strength, comparing with the glass-ceramics with amber cullet. The type and the amount of the glass cullet present in the glass-ceramics have strong effect on their properties.

Hydroxyapatite (HA) nanoparticles were synthesized using a wet mechanochemical method without a calcination process. Dicalcium phosphate dihydrate (CaHPO

The design and reliability of NGK type clay hardness tester, which has been used for measuring the hardness of plastic clay body in order to control and/or check the consistency of the ceramic clay dough in the ceramic production, were investigated. It was found that the hardness values were depended on the design of the hardness tester, and to a larger extent on the human error. The factors affecting the reliability of the hardness values were also discussed.

Inner surface of microporous alumina tube was coated with nanoporous alumina layer using electrophoretic deposition (EPD) process. Polypyrrole (Ppy) film was formed on the inner wall of the porous tube to give electrical conductivity by chemical polymerization of pyrrole (Py). The nanoporous structure was controled using bimodal suspension of alumina powders with 0.6 μm and 30 nm in ethanol. The thickness of the coated layer was controlled by varying the processing parameters such as deposition time and DC applied voltage. After the deposition, the coated substrate was sintered at 1250°C for 2 h to bond the coated layer with the substrate.The microstructure of the substrate and the coated layer was observed by SEM. The results show the good interfacial joining between the substrate and the coated layer; they are not seperatated after the Ppy burnt-out. Crack-free and nanoporous layer on the microporous substrate was successfully fabricated.

The normal firing temperature of ceramic products is around 1200 °C. In order to reduce firing temperature, industrial wastes were utilized in ceramic glaze. Phuket municipal solid waste (MSW), soda lime cullet, and borax were used as raw materials for low firing temperature glazes. The glaze compositions were designed using a triaxial diagram. Stoneware ceramic body was glazed then fired at 1000 and 1150 °C for 15 minutes. Morphology and phase composition of glazes were analyzed by Scanning electron microscopy (SEM-EDS) and X-ray diffraction (XRD). Thermal expansion compatibility of Stoneware body and glazes were investigated using a dilatometer. Melting behaviour of selected glaze was analyzed by heating stage microscopy. Phuket MSW and Soda lime glass cullet can be used in high percentage as major raw materials for low firing temperature ceramic glaze that show good texture and vitrified at lower firing temperature without using any commercial ceramic frits. The firing temperature can be reduced up to 150 °C in this study.