Shah Rizal Kasim

Electrophoretic Deposition of Biphasic Calcium Phosphate (BCP) Coatings on 316L Stainless Steel at Room Temperature

Electrophoretically deposition of Biphasic calcium phosphate on 25 × 10 × 1.2 mm (length, width, and thickness) 316L stainless steel plates using ethanol as dispersing medium; It was achieved on the cathode with constant voltages 20, 30, 50, and 100 V during 20, 30, 60, 90 and 120 seconds, respectively. After deposition, the samples were dried at room temperature for 24 hours and deposition weight and thickness of the coatings were measured. The coated samples were sintered in a tube furnace at 800 °C for 1 h in an argon atmosphere. After the sintering, the surface morphology and structure and phase composition of the samples were studied by a scanning electron microscope (SEM), energy dispersive spectrometry (EDX) and phase purity of the coating material by X-ray diffraction.

Effect of Temperature on BCP Ceramics Coating on 316L Stainless Steel Using Electrophoretic Technique

Biphasic calcium phosphate (BCP) coatings on a medical grade 316L stainless steel substrate were prepared by electrophoretic deposition (EPD) using ethanol as a dispersive medium. The deposition voltage of 30V was applied for 1 min at 25, 40 and 60 °C, respectively. The coated substrates were sintered in a vacuum furnace at 800 °C for 1 h. The surface morphology, structure and phase composition of the coatings was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that by increasing deposition conditions of voltage and temperature, crack occurrence and morphological changes increased in the produced coatings. The optimum condition for crack-free surface was at 30 V at 25 °C.

Preparation and Characterization of Biphasic Calcium Phosphate Coatings on 316L Stainless Steel Fabricated by Electrophoretic Deposition

Biphasic calcium phosphate (BCP) ceramic is a synthetic biomaterial exhibiting a chemical composition similar to that of tooth mineral. Therefore, it is viably used in coating metallic implants manufactured from metals and alloys, such as titanium and stainless steel. In the present study, electrophoretic deposition (EPD) has been attempted for depositing BCP coatings on 316L Stainless Steel substrate followed by vacuum sintering at 800 °C for 1 h. The surface morphology, thickness, compositions and microstructure of the BCP coated 316L SS was investigated by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and the bond strength of the coating was measured.

Effects of Different Gloss Firing Temperature on the Crystallization of Zinc-Based Crystal Glaze

Ceramic products with crystalline structure on its body give an artistic effect. The usage of zinc oxide which acts as a flux material has a beneficial effect in many colored glazes amongst which is crystalline glaze. Samples are fired at different gloss firing temperature of 1200oC to 1250oC for half an hour and hold for five hours at crystal growth temperature. After firing, the morphology of crystalline structure on the ceramic substrate body was identified using visual observation. The result show crystals start to develop at 1230oC of gloss firing temperature. Scanning Electron Microscope (SEM) analysis shows that these crystals are made of acicular needle shape crystals. X-ray Diffraction (XRD) and Energy Dispersive X-ray Spectrometer (EDX) analysis of the phases identified these crystals as willemite, Zn2SiO4 which formed spherulites. The results also show obvious growth and distance distribution between each of spherulites as the gloss firing temperatures increase to 1250oC.

Effect of Co-Dopant on the Phase Structure and Photoluminescence Properties of Sr2mgsi2O7: En2+ Phosphors

The role of co-dopants, i.e. Dy, Ce, Tb or Y in SMS : Eu, RE3+ phosphor sintered using solid state reaction method at 1250°C under forming gas was studied. All SMS phosphors exhibited tetragonal Sr2MgSi2O7 as the domain phase and monoclinic SrSiO3 as the minor phase based on XRD analysis. It is noted that only single blue emission (469nm) contributed by Eu2+ ions was detected in RTPL measurement regardless types of co-dopants introduced during the sintering process. This result indicates that the co-dopants did not act as luminance centres in the SMS phosphor. The time-decay PL and temperature dependent PL analysis suggest that Ce3+ ions acted as sensitizer which improved the luminescence intensity and afterglow property of SMS phosphor. The present of Dy3+ ions pro-longed the afterglow property by introducing more traps density in the SMS phosphor structure. The co-doping of Tb or Y into the SMS phosphor generated many non-radiative recombination centres which deteriorated the optical performance of SMS: Eu2+, RE3+ phosphor.

Effect of Curing Time and Sintering to the Properties of Geopolymer Mortars

In this study, the geopolymer mortars were synthesized with fly ash (FA) and silica powder as aluminosilicate sources and a combination of sodium hydroxide (NaOH) solution, sodium silicate (Na2SiO3) solution and distilled water as alkaline activator. Commercial sago was used as a pore former in the mortars. The percentage of sago used were 10, 20 and 30 wt% of FA. The amount of added water used in each mixture was 5% by weight of FA, NaOH solution and Na2SiO3 solution. The formed geopolymer mortars were cured for 1, 3 and 7 days and sintered at 1000 °C. X-ray fluoresence (XRF) shown that FA contains higher amount of silica (SiO2) and alumina (Al2O3) which is important as aluminosilicate sources. The properties of the geopolymer mortars before and after sintered at 1000 °C have been investigated. The results show that geopolymer mortars with 10% of sago content with curing time of 7 days and sintered at 1000 °C give the highest compressive strength of 13.5 MPa.

Microstructure and Mechanical Properties of Cement Mortar Incorporate with Coated Expanded Polystyrene Beads

Abstract. Coated Expanded polystyrene (CEPS) mortar is a new lightweight building material that demonstrate a good mechanical properties by improving it interfacial bonding properties. By using the field emission scanning electron microscope (FESEM) with high resolution imaging, the mortar morphology at different ages (7, 14 and 28 days) can be observed. The results shows that coated EPS bead provide a good bonding as there is no gap in the interfacial surface at 28 days.

Luminescent Properties of SrAl2O4 Activated Eu2+, Dy3+ for Transparent Glaze Ceramics

Green phosphor strontium aluminate activated by Eu2+ and Dy3+, SrAl2O4:Eu2+, Dy3+ powder was synthesized by solid-state reaction by firing at 1250 °C in a graphite crucible. The glow glaze was produced by a combination of SrAl2O4:Eu2+, Dy3+ powder with transparent glaze. Characteristics of the phosphor powders and the posttreated particles such as crystallinity and luminescent properties were investigated. Observation of the glowing intensity and luminescent properties of the glow glaze showed the dependency on particle size and refiring temperatures. Proper interaction between phosphor/glaze interfaces depends upon the firing process and nature of the SrAl2O4:Eu2+, Dy3+ phosphor powders.

Improvement of Porous Porcelain through Glaze Coating

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.

Effect of Stirring and Aging Time on the Formation of β-Tricalcium Phosphate (β-TCP) Powder

In this research, the effect of stirring and aging time on the formation of β-tricalcium phosphate (β-TCP) powder was studied. β-TCP powder was synthesized using calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) (0.6M) and diammonium hydrogen phosphate (NH4)2HPO4) (0.4M) via wet precipitation method. The mixture was stirred with different duration (1, 3, 5 and 7 hours) then centrifuged before washed with distilled water (twice) and ethanol followed by drying in oven (80°C, 24 hours). The cake was ground to form powder. The as prepared powder was analyzed using thermo-gravimetric (TGA) to determine the suitable calcinations temperature. TGA results show that the proper calcinations temperature was 800°C. The formation of β-TCP was characterized using X-ray Diffraction (XRD) analysis. Sample with optimum formation of β-TCP phase will choose for further study on the effect of aging time (0.5, 1, 20 and 24 hours). XRD analysis confirmed that sample stirred for 7 hours and aging for 24 hours produced β-TCP as major phase. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) proved that β-TCP powder form as agglomerated particles