Abu Seman Anasyida

Recycling of Malaysia's electric arc furnace (EAF) slag waste into heavy-duty green ceramic tile.

Recently, various solid wastes from industry such as glass waste, fly ash, sewage sludge and slag have been recycled into various value-added products such as ceramic tile. The conventional solutions of dumping the wastes in landfills or incineration, including in Malaysia are getting obsolete as the annual huge amount of the solid wastes would boost-up disposal cost and may cause permanent damage to the flora and fauna. This recent waste recycling approach is much better and greener as it can resolve problems associated with over-limit storage of industrial wastes and reduce exploration of natural resources for ceramic tile to continuously sustain the nature. Therefore, in this project, an attempt was made to recycle electric arc furnace (EAF) slag waste, obtained from Malaysias steel making industry, into ceramic tile via conventional powder compaction method. The research work was divided into two stages. The first stage was to evaluate the suitability of EAF slag in ceramic tile by varying weight percentage of EAF slag (40 wt.%, 50 wt.% and 60 wt.%) and ball clay (40 wt.%, 50 wt.% and 60 wt.%), with no addition of silica and potash feldspar. In the second stage, the weight percentage of EAF slag was fixed at 40 wt.% and the percentage of ball clay (30 wt.% and 40 wt.%), feldspar (10 wt.% and 20 wt.%) and silica (10 wt.% and 20 wt.%) added was varied accordingly. Results obtained show that as weight percentage of EAF slag increased up to 60 wt.%, the percentage of apparent porosity and water absorption also rose, with a reduction in tile flexural strength and increased porosity. On the other hand, limiting the weight percentage of EAF slag to 40 wt.% while increasing the weight percentage of ball clay led to a higher total percentage of anorthite and wollastonite minerals, resulting in higher flexural strength. It was found that introduction of silica and feldspar further improved the flexural strength due to optimization of densification process. The highest flexural strength, lowest apparent porosity and water absorption of EAF slag based tile was attained at the composition of 40 wt.% EAF slag--30 wt.% ball clay--10 wt.% feldspar--20 wt.% silica. The properties of ceramic tile made with EAF slag waste (up to 40 wt.%), especially flexural strength are comparable to those of commercial ceramic tile and are, therefore, suitable as high flexural strength and heavy-duty green ceramic floor tile. Continuous development is currently underway to improve the properties of tile so that this recycling approach could be one of the potential effective, efficient and sustainable solutions in sustaining our nature.

Microstructure Evolution of Conventional and Semi-Solid Cast of A356 Aluminium Alloy with Addition of Inoculant

This paper investigated the effect of inoculant, Al-5Ti-1B in conventional and semi-solid casting A356 aluminium alloy. A356 aluminium alloy was melted at 850 oC and poured at 680 °C directly into the steel mould and on the inclined slope into steel mould. Inoculant was added in various percentages of 1 wt.%, 2 wt.%, 3 wt.% and 3.5 wt.% in A356 aluminium alloy melt. Microstructure and microhardness were characterized using optical microscope and Vicker’s microhardness tester. The addition of master alloy up 3.5 wt.% Al-5Ti-1B in conventional casting refined dendritic structure with average grain size of 33.41 μm. The microstructures of semi-solid A356 aluminium alloy with addition of Al-5Ti-1B consist of equiaxed structure of α-Al. Further addition of Al-5Ti-1B refined the globular structure of α-Al. The higher hardness was achieved for A356 alloy prepared using semi-solid with addition of 3.5 wt.% of Al-5Ti-1B.

Effect of Complexing Agent in Ni-P Coating on Cu Substrate

Complexing agent in the electroless nickel coating (Ni-P) solution plays an important role to maintain the coating deposition rate during the coating process. This paper studies the effect of two complexing agent; sodium citrate and sodium acetate in Ni-P coating. Ni-P coating was prepared in bath containing: NiSO4·6H2O, NaPO2H2·H2O, C2H5NO2, and Pb (NO3)2. Ni-P coating was coated on polished Cu substrate. Morphology, thickness and surface roughness of Ni-P coating were characterized using scanning electron microscope (SEM)/electron dispersive x-ray (EDX), optical microscope (OM), and atomic force microscopy (AFM). The result showed that sodium acetate have higher deposition rate up to 12 μm/h, whereas sodium citrate provided better surface morphology with lower surface roughness.

Ageing Characteristics of Equal Channel Angular Pressed Al-Mg-Si Alloy

This study investigated the effect of severe plastic deformation (SPD) and artificial ageing treatment on mechanical properties of cast Al-Mg-Si alloy. 6061-T6 aluminum alloy was remelted and casted into a rod of 13mm in diameter and 60mm in length. The rod samples were then subjected to equal channel angular pressing (ECAP) for SPD process, up to 2 passes, through Bc route. Cast and ECAPed samples were solution heat treated at 530 °C, quenched in water and held at 180 °C at various ageing time to determine the effect of artificial ageing. Cast alloy consisted of α phase grains that were surrounded by Mg2Si particles locating at the grain boundaries. The hardness increased with accumulative applied strain by 2-pass ECAP process with the value of 99.4 Hv. For heat treated samples, maximum hardness was achieved after 5-hour ageing.

Influence of Semi-Solid Casting and Equal Channel Pressing on Microstructure of a Hypoeutectic Al-Si Alloy

The aim of this work was to develop understanding of microstructural evolution of the alloy casted in semi-solid condition using a cooling slope and conventional casting followed by ECAP in a 120o die. Feed materials were prepared by cooling slope casting and conventional casting for ECAP process. The microstructures and Vickers hardness of the worked materials extruded by two routes (A and BC) were evaluated. The primary α-Al phase tends to be elongated after processing by route A. However, its morphology was similar in nature to the microstructure of the as-cast sample after processing by route BC. The Si particles become fragmented during ECAP processing and are more nearly globular in shape and uniform in size than in the as-cast sample. The microstructure of the semi-solid cast ECAPed samples was more homogenous than that of the conventional cast ECAPed sample followed by ECAP for both routes. The hardness of semi-solid cast ECAP samples was also higher than that of conventional cast ECAPed samples for both routes.

Sic-Reinforced Aluminum-Silicon Composite via Pressureless Infiltration Using Polystyrene as External Binder for Electronic Assemblies

SiC-reinforced aluminum composite was developed by pressureless infiltration technique using polystyrene as external binder. The metal matrix composites obtained were characterized for phase composition, microstructure, density, porosity, hardness and thermal expansion. The SiC particles were uniformly distributed within the Al-Si matrix with the help of polystyrene as external binder. The variation in the density of the composites was found to be linear with volume percent of SiC. The hardness increased with increasing SiC content and highest hardness was 64.52 HV achieved with addition of 20 vol.% SiC. Thermal conductivity of the composites increased with increasing of SiC volume fraction up to 27.34 W/mK.

Microstructural Study of Sn-3.0Ag0.5Cu Alloy on Cu/NiP-Coated Substrate by Addition of Fe, Sb and Ce

In this study, the effects of alloying elements Fe (0.2 wt.%), Sb (0.5 wt.%) and Ce (0.5 wt.%) on the Sn-3.0Ag-0.5Cu lead-free solder system were investigated. The solder alloy was reflowed on electroless Cu/NiP-coated substrates and their behavior such as microstructure, wetting angle and intermetallic compound (IMC) formation were analyzed. The results showed that the presence of Fe, Ce and Sb reduced the grain size of β-Sn as compared to solder without addition of alloying element. The addition of Fe and Ce was the most significantly refined the microstructure of Sn-3.0Ag-0.5Cu solder alloys. Sn3.0Ag0.5Cu0.2Fe0.5Ce solder was revealed better spreading behavior on Cu/NiP coated substrates which have the lowest IMC thickness of 0.558 μm.

Microstructural Study of Hypereutectic Al-15%Si Containing Ce

In this study the effect of cerium addition on the microstructure of hypereutectic Al-15Si alloy was investigated. Experiments have been conducted on Al15Si alloys with Ce content in the alloy varied from 0 to 2.51 wt.%. The alloys were produced by casting in a permanent mould. Optical microscopy, X-Ray Diffraction (XRD) and Vickers microhardness were used in this investigation. The results showed that the addition of 0 to 2.5 wt.% of cerium led to the formation of precipitation of rod-like Al3Ce phase in the Al-matrix. The microhardness of the alloys increases with the increase in cerium content as a result of the Al3Ce precipitation.

Characterisation of Phases and Lattice Parameter in Eutectic and Hypoeutectic Al-Si-Mg-Ce Cast Alloy

The purpose of this work is to understand the phases formation and lattice parameter changes with addition 0.6 to 2.7 wt.% in Al-Si-Mg-Ce cast alloy. Al-Si-Mg-Ce eutectic and hypoeutectic cast alloy were prepared by conventional casting technique. The alloys were investigated by using optical microscope, Scanning electron microscope (SEM) and X-Ray diffractometry (XRD). The addition of Ce resulted in precipitation of Al4Ce in eutectic cast alloy and CeMg2Si2 in hypoeutectic cast alloy. The lattice parameter of Al increases with increase in Ce content wheareas lattice parameter of Si phase decreases as the Ce content increases.

The Influence of Temperature on the Oxide Layer Formation of Aluminized Carbon Steel

The growth of thin oxide layer due to the variation in temperature on the surface of aluminized carbon steel was investigated. Hot dip aluminizing of low carbon steel was carried out at 750 °C in a molten pure aluminum for 5 minutes. Aluminized samples were heat treated at 600 °C, 700 °C, 800 °C, and 900 °C for 1 hour. The formation of aluminum oxide layer was investigated in this study. Optical microscopy, Atomic Force Microscopy (AFM), SEM and EDAX were used in investigation. From the observation, the appearance of aluminum oxide layer increased with the increase in temperature. The result of EDAX analysis revealed the existence alumina phase. Surface roughness measurement showed increment with the increase in oxidation heat treatment temperature.