M.Z.M. Zamzuri

Electrodeposited ZnO—Nanowire/Cu2O Photovoltaic Device with Highly Resistive ZnO Intermediate Layer

Cl-doped ZnO-nanowire (Cl:ZnO-nws)/Cu2O photovoltaic devices were prepared by electrodeposition in aqueous solutions, and the effects of the insertion of the highly resistive ZnO (i-ZnO) layer has been demonstrated by an improvement of the photovoltaic performance. The Cl:ZnO-nws and i-ZnO layer were prepared by electrodeposition in a zinc chloride aqueous solution with saturated molecular oxygen and simple zinc nitrate aqueous solution, respectively. The i-ZnO layer was directly deposited on the Cl:ZnO-nws and suppressed the electrodeposition of the Cu2O layer on the Cl:ZnO-nws. The insertion of the i-ZnO layer between the Cl:ZnO-nws and Cu2O layers induced an improvement in the photovoltaic performance from 0.40 to 1.26% with a 0.35 V open circuit voltage, 7.1 mA·cm(-2) short circuit current density, and 0.52 fill factor due to the reduction of the recombination loss.

Effect of heat treatment on microstructure and corrosion behavior of Az91d magnesium alloy

An AZ91D ingot in the as-cast condition was homogenized by heat treatment process. Then, the microstructures produced and corrosion behaviour after heat treatment was studied in detail. As-cast AZ91D was recrystallize by solution treatment at 415°C and then aged at 175°C for various period of time. The corrosion resistance of all the different microstructures was studied in NaCl solution through weight loss measurement in immersion testing. The β phase was found to have a significant influence on the corrosion behaviour. In solution treatment, β phase dissolution decreased the cathode area leading to accelerated corrosion rate. After aging treatment, fine β phase precipitates between grain and microstructure recrystallize causing an increase in the corrosion resistances.

Comparison Study in Consolidation of Yttria Reinforced Iron-Chromium Composites Using Conventional and Microwave Sintering Technique

This research is focused on studying the density and mechanical properties of iron-chromium composites consolidated by innovative rapid microwave sintering technology against conventionally sintered counterparts using slow heating crucible furnace. Another aim of this study is to assess the viability of yttria (Y2O3) ceramic particulates as reinforcement to the iron-chromium composites. Fabrication of iron-chromium-yttria composites consolidated in microwave furnace and conventional crucible furnace was successfully accomplished. Improvement of density is evident in microwave sintered composites. The Y2O3 addition significantly increases the hardness of the composite (118 Hv for microwave specimens as opposed to 110Hv for conventional specimens). The study also successfully established the viability of microwave sintering technique for consolidating iron based powder metallurgy composites by up to 80% reduction of sintering time.

Corrosion resistance by sodium metavanadate for AZ91D magnesium alloy

An oxide film was prepared on AZ91D magnesium alloy by anodizing in solution containing sodium metavanadate (NaVO3). The corrosion resistance of the substrate was investigated at a fixed current density 10 mA/cm2 for 5 mins with different concentration of solution in the range of 0 – 1.0 g/l. The surface morphology, phase structure and corrosion resistance of oxide film were studied by optical microscope, scanning electron microscope (SEM) and energy dispersive spectrometry (EDS) and X-ray diffractometer (XRD), potentiodynamic polarization technique and corrosion test.

Effect of Pressure on the CO2 Absorption into Ladle Furnace Slag

Carbon dioxide (CO2) is one of the greenhouse gases (GHG) and the concentration is much more higher than other GHG gases. Based on the prediction, about 285.73 million tonnes will be emitted in year 2020 with the main contributors are from power generation, manufacturing industries, transportation and residential sector [1]. This research focused to study the effect of pressure on the CO2 absorption with Malaysia steel slag using mechanical stirrer. The steel slag is collected from one of steel industry located in Pasir Gudang Johor Malaysia and characterized to investigated the chemical composition. The reaction between CO2 absorption and the slag was investigated by using different speed and weight. The initial pressure was set at 101.3 kPa which equivalent with 1 atmospheric pressure. The behavior of the reaction between CO2, and ground sample was investigated by measuring the change in the CO2 pressure inside the mechanical stirrer. It was found that the CO2 pressure decreased as soon as the stirrer started and continuously decreased till bout 270 t/min stirring time.

Corrosion Behavior of Porous Mg Alloy in Simulated Body Fluid

Magnesium (Mg) alloy possess a high demand in biomedical applications due to their biocompatibility and biodegradability. However the main limitation for Mg alloy is their fast degradation rates in physiological environment. This paper reports the preparation of porous Mg alloy through powder metallurgy technique by using ammonium bicarbonate (NH4HCO3) as space holder material and hexane as solvent. The corrosion behavior and degradation rate of porous Mg alloy was measured after 24h, 96h and 168h respectively of immersion in simulated body fluid (SBF) with compact Mg alloy as control. The results reported that degradation rate increased with increasing immersion period, yet the compact Mg alloy shows better degradation rate than porous Mg alloy. Moreover, the pH of SBF changed proportional to immersion period and stabilized after 96h of immersion.

Mechanical Properties of Microwave Sintered 60YSZ-Al2O3/10HAP Bioceramics Composites

Microwave heating technology promising shorter processing times and less energy consumption beneficial for economic perspective with improved properties and better microstructural control. This study focussed on microwave sintered bioceramics material of 60YSZ-Al2O3/10HAP mixture fabricated by powder metallurgy route. The study was conducted based on three different sintering temperatures, starting with 900 °C, 1000°C ended with 1100°C. Mechanical properties of materials such as porosity, density, hardness and compressive strength were then determined for each composites. Results showed that lowest porosity was obtained at 1000°C which promoting to higher density, hardness and compressive strength. However, the increasing sintering temperature up to 1100 °C was initiated the decomposition of HAP and constitutes the formation of CaZrO3 determined by X-ray Diffraction (XRD) analysis. Microstructure characterization by Scanning Electron Microscope (SEM) observed the growth of large particles and pores result in excessive grain coarsening. Better sinterability was achieved through an adequate sintering temperature of 1000°C with no reaction reported between HA and ZrO2 during the sintering process facilitate by microwave hybrid heating. The pores was found to be interconnected for each composites via microwave heating expected to be useful for biomedical application which was favorable to osteo-integration.

Characterization of PM Fe-Cr-Y2O3 Composites Prepared by Microwave Sintering Technology

This research is focused on assessing the feasibility of the new and innovative microwave sintering technology for fabricating iron-chromium composites prepared via powder metallurgy route. Accordingly, the microwave sintered iron-chromium compacts was benchmarked against conventional sintered counterparts fabricated in other researches. We also studied the viability of yttria reinforcement to the iron-chromium composites with varying weight fraction from 5 to 20 %. Comparison on the end properties were also being made on the unreinforced iron-chromium matrix (0 wt. % of yttria). The result revealed that the microwave sintered iron-chromium composites possess improved density and micro hardness value. Process evaluation also revealed that microwave assisted sintering can lead to a reduction of 70 % of sintering time when compared to conventional sintering. The micro hardness property of microwave sintered iron-chromium was slightly improved with 5 wt. % addition of yttria, although the density and compressive strength were reduced with increasing content of the ceramic particulates. Most importantly, the study has established the viability of microwave sintering approach used in place of conventional sintering for iron based powder metallurgy composites.

Characteristic and Corrosion Studies of Rare Earth (Ree) Based Anodizing on AZ91D Magnesium Alloy

Oxide coatings on AZ91D magnesium alloy were prepared using anodizing technique with 10mA/cm2 current density for 5 minutes in electrolyte containing La (NO3) and Mg (NO3),with NaVO3 as an additive. The corrosion behaviors of different coatings condition were evaluated by immersion test in 5.0% NaCl electrolyte for 72 hours. The microstructures were analyzed by Optical Microscope (OM) and Scanning Electron Microscope (SEM). It was found that coatings with the addition of NaVO3 produced homogeneous primary α-matrix and bigger β-phase (Mg17Al12) compared to untreated AZ91D magnesium alloy. The oxide film formed by anodizing in electrolyte with NaVO3 enhances the corrosion resistance of the AZ91D magnesium alloy significantly

Characteristic and Corrosion Studies of Rare Earth (REE) Based Anodizing on AZ91D Magnesium Alloy

Oxide coatings on AZ91D magnesium alloy were prepared using anodizing technique with 10mA/cm2 current density for 5 minutes in electrolyte containing Mg (NO3)2 with NaVO3 as an additive. The corrosion behaviors of different coatings condition were evaluated by immersion test in 5.0% NaCl electrolyte for 72 hours. The microstructures were analyzed by Optical Microscope (OM) and Scanning Electron Microscope (SEM). It was found that coatings with the addition of NaVO3 produced homogeneous primary α-matrix and bigger β-phase (Mg17Al12) compared to untreated AZ91D magnesium alloy. The oxide film formed by anodizing in electrolyte with NaVO3 enhances the corrosion resistance of the AZ91D magnesium alloy significantly.