Parinya Chakartnarodom

Foam Glass Development Using Glass Cullet and Fly Ash or Rice Husk Ash as the Raw Materials

The aim of this work is to study the recycling of glass cullet (waste glass), fly ash, and rice husk ash as the foam glass, a porous construction material having high compressive strength but low density, which are similar to the light weight brick. The foam glasses were prepared by mixing the ground glass cullet/ash mixtures with calcium carbonate (foaming agent) at 1 wt% and sodium silicate solution (binder) at 10 wt%, and then compacted into the rectangle shapes (30 cm × 30 cm × 7cm) which were fired at 650 °C for 30 min, and then for 1 hour at 750, 800, 850, or 900 °C. The sources of glass cullet were art glass factory and glass window industry. The percentages of ash in the ground glass cullet/ash (fly ash or rice husk ash) mixtures were 20, 40, and 60 wt%. The results showed that the foam glass that was made from 80wt% window glass/ 20wt% fly ash and fired at 750 °C had the most suitable properties for being produced commercially because it had good alkaline resistant, and the compressive strength and degree of water absorption better than the light weight brick (G2-type and G4-type autoclaved aerated concrete) while the density was similar to G2-type but lower than G4-type. The compressive strength, density, and degree of water absorption of this foam glass were 59.9 kg/cm2, 421 kg/m3, and 2.1 % respectively. Furthermore, as of September 2013, the total production cost (materials, labor, energy, etc.) of this foam glass is about 16 baht per piece (20 cm × 60 cm × 7.5 cm) which is 12.5 to 43.75% lower than the wholesale price of a light weight brick (18-23 baht per piece for G2-type and G4-type autoclaved aerated concrete).

Fabrication of Injection Moulded 304L Stainless Steels Reinforced with Tungsten Carbide Particles

Powder injection moulding of 304L stainless steel - tungsten carbide (WC) composites were carried out in the present work. Two different WC particle i.e. WC having average size of 4.8 µm and 1.6 µm were used. Feedstock of powder loading up to 55 vol% were successfully prepared using binder composed mainly of polyethylene glycol (PEG) and a minor constituent of polymethylmethacrylate (PMMA). The mouldings were leached in water at temperatures of 40 °C and 60 °C from 30 minutes to 24 hours in order to study the effect of leaching conditions on the removal of the PEG. The remaining binder, PMMA, provided strength to the mouldings after leaching of the PEG and it could be removed by pyrolysis during ramping up to the sintering temperature. Specimens were sintered under hydrogen atmosphere at 1250 °C for 1 hour. Sintered components were subjected to testing and characterisation. Scanning electron microscope was used to observe microstructure of specimens after moulding, leaching and sintering. It was found that the hardness of the sintered specimens increased with either increasing the amount of the powder loading in the feedstock or reducing the average size of WC in the powder mixture. In addition, the water leaching of the PEG linearly correlates with the natural log of time and the equation predicts that PEG will be removed completely in 11.24 ± 1.31 hours which corresponds with the experiment result that PEG completely removed in 12 hours.

Application of Numerical Method and Statistical Analysis in the Integrated Intensity Calculation of the Peaks from the X-Ray Diffraction (XRD) Pattern of α-Iron

The aim of this work is to analyze the error of the calculated integrated intensity of the x-ray peaks of a-iron (BCC-Fe) powder from x-ray diffraction (XRD) pattern by using the numerical method and the statistical analysis. The a-Fe powder was characterized by the x-ray diffractometer using step scan mode, step sizes 0.03o 2q and 0.05o 2q, and preset times from 0.1 to 3.5 s. The integrated intensity () of an x-ray peak and its error () were calculated using numerical method. The correlation between the relative error () and the preset time or step size were analyzed by the statistical analysis methods which are linear regression and statistical hypothesis testing. The results from the statistical analysis at significance level of 0.05 show that the relative error () correlate with x = preset time or integrated intensity by when a1 and a2 are the positive constants. From the mathematical model, for this work, the step size does not affect the relative error. However, the increasing of preset time reduces relative error on integrated intensity calculation. To minimize the error on XRD analysis, the preset time should be greater than one second. Moreover, on a XRD pattern, the lower integrated intensity peak has the higher relative error.

Feasibility Study of Using Basalt Fibers as the Reinforcement Phase in Fiber-Cement Products

The aim of this work was to study the feasibility of using basalt fibers as the reinforcement phase in fiber-cement products which was the fiber-reinforced construction materials used for roof, wall, ceiling, and floor applications. The feasibility study included (1) the alkaline resistant test of the basalt fibers by soaking the basalt fibers in 1 N Ca(OH)2 up to 28 days, and (2) the mechanical test based on ASTM C1185 standard on the fiber-cement board that used basalt fibers as a reinforcement phase. Scanning electron microscope (SEM) and x-ray diffractometer (XRD) were used to characterize the basalt fibers after alkaline resistant test. The basalt-fiber reinforced cement board was produced on the industrial level by using Hatschek process.From the alkaline resistant test, basalt fibers had well alkaline resistant. From the mechanical test, the modulus of rupture (MOR) of basalt-fiber reinforced cement boards passed the requirement of TIS 1427-2540 and ASTM C1186 standard. Therefore, basalt fibers could be considered as a good candidate for using as a reinforcement phase in the fiber-cement products.

X-Ray Diffraction Analysis of ZnO Particles Prepared by Microwave Plasma

The aim of this work is to use x-ray diffraction (XRD) technique to analyze ZnO particles prepared by the reaction between the zinc vapor and oxygen within microwave plasma. The microwave plasma was created by the interaction between the 1200-W 2.45-GHz microwave, the conductive material, and the argon-oxygen gas mixture. Due to the high effective temperature of the plasma, it was thermodynamically and kinetically possible to generate zinc vapor from the solid zinc and then reacted with the oxygen in the gas mixture to form ZnO particles. The synthesis of ZnO in the microwave plasma has been done for 10 to 15 minutes. The XRD results show that the synthesized ZnO samples have wurtzite structure. Moreover, the increasing of synthesis time from 10 to 15 minutes affects the lattice constants, the crystallite size, and the magnitude of strain in ZnO crystals.

Influence of Scanning Parameters on X-Ray Diffraction Peaks of Copper

The aim of this work is to study the influence of x-ray diffractometer scanning parameters on the integrated intensity and full-width at half maximum (FWHM) of copper powder x-ray diffraction peaks by using statistical analysis methods. X-ray diffraction (XRD) analysis of the copper powder was accomplished using step scan mode with step sizes of 0.03o and 0.05o 2q, and preset time changes from 0.1-3.5 s. Integrated intensity of an x-ray peak was calculated by the numerical method. FWHM was measured as the width of Pearson VII model of the x-ray peak at the half-maximum intensity. The statistical analysis methods including linear regression and statistical hypothesis test were used to analyze the correlation between the preset time and the error on integrated intensity calculation, and the FWHM of a peak on the XRD pattern. The results from statistical analysis show that increasing the preset time from 0.1 s to 3.5 s does not affect the FWHM of an x-ray peak, but it reduces the relative error in integrated intensity calculation. Moreover, using the preset time greater than 1 s will minimize the relative error in integrated intensity calculation of an x-ray peak. While step size did not affect both the relative error in integrated intensity calculation or FWHM, the smaller step size would provide more data points for better accurate model of an x-ray peak.

Powder Injection Molding of Mullite: The Study of Binder Dissolution Behavior during Debinding Step Using Statistical Methods

The purpose of this work is to use the statistical methods including linear regression and statistical hypothesis test to study the dissolution behavior of polyethylene glycol (PEG), a water-soluble binder, during debinding step of the green specimens of mullite formed by powder injection molding (PIM). Two systems of composite binders were investigated including (A) 80 wt% polyethylene glycol (PEG) and 20 wt% polyvinyl butyral (PVB) and (B) 78 wt% PEG, 20 wt% PVB, and 2 wt% steric acid (SA)The lab-scale plunger type PIM machine was used to prepare the green specimens consisting of mullite powder and the composite binder. The possible solid loadings of the green specimens that could be prepared by this machine were 50, 52, and 54 vol% mullite (50, 48, and 46 vol% binder). The debinding was done by soaking the green specimens in the warm water at 40 or 60 oC to remove PEG. At level of significance 0.05 for statistical analysis, the dissolution behavior of PEG can be fitted with Avarami equation. In addition, from the Avarami equation obtained from each experimental condition, the dissolution rate of PEG was independent of the parameters used in this study including solid loading in the green specimens, water temperatures for debinding, and composite binder systems.

The Fabrication of Refractory Cordierite from Aluminium Buff Mixture

The aim of this work is to propose the utilization of aluminium buff from aluminium part manufacturer as a raw material for cordierite batch composition. The powder mixtures were compacted by uniaxial pressing. The green compacts were sintered at temperature in the range 1300-1400°C for 2 hours in air. The physical properties were characterized by Archimedes method, Brazilian test and dilatometry. Phase and microstructural analysis were done by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis showed the major phase was cordierite along with sapphirine as a secondary phase. The fired properties of materials were demonstrated that the optimal properties was achieved from the specimen sintered at 1375 °C.

Powder Injection Molding of Mullite: The Study of Mechanical and Physical Properties of the Sintered Products Using Statistical Methods

The aim of this work is to propose the application of statistical methods (linear regression and statistical hypothesis test) to analyze the effect of parameters used in powder injection molding including sintering temperature and the feedstock composition on the flexural strength, the porosity and the density of the sintered specimens of mullite prepared by powder injection molding (PIM) and using the composite binder consisting of 80 wt% polyethylene glycol (PEG) and 20 wt% polyvinyl butyral (PVB) for molding. The lab-scale plunger type PIM machine was used to prepare the specimens. The feedstock compositions were 50 to 54 vol% mullite, and the sintering temperatures were 1300 and 1400 °C. At level of significance 0.05 for statistical analysis, feedstock composition did not affect flexural strength, porosity, and density of the sintered specimens. For sintering temperature, the specimens sintered at 1400 °C have the greater density and the lower porosity. However, the flexural strength of the specimens sintered at 1300 °C and 1400 °C are statistically similar.

Application of Statistical Analysis in the Powder Injection Molding (PIM) of Mullite

In this work, the statistical analysis methods, including least square method and statistical hypothesis testing, were used to study the flexural strength and density of the specimens formed from mullite powder by powder injection molding (PIM). The feedstock for PIM consist of mullite powder and the composite binder consisting of 78 wt% polyethylene glycol (PEG), 20 wt% polyvinyl butyral (PVB), and 2 wt% stearic acid (SA). The PIM machine used in this work was the lab-scale plunger type. The compositions of the feedstock that could be injection molded by this machine were 50, 52, and 54vol% mullite. After molding, PEG in the green specimens was removed prior to sintering by soaking the specimens in the water at 60 °C for 24 hours while PVB and SA were removed during sintering. The sintering temperatures were 1300 to 1450°C. At significance level of 0.05, the least square method and the statistical hypothesis test showed that both feedstock compositions and sintering temperatures used in this work affected the densities of sintered specimens. However, the increasing of the flexural strength of sintered specimens was mainly by the increasing of the sintering temperature.