Almaslow A.,National University of Malaysia |
Ratnam C.T.,Malaysian Nuclear Agency |
Ghazali M.J.,National University of Malaysia |
Talib R.J.,AMREC |
Azhari C.H.,National University of Malaysia
Composites Part B: Engineering | Year: 2013
Semimetallic friction composites (SMFCs) consisting of epoxidized natural rubber (50 mol% epoxidation, ENR 50), alumina nanoparticles, steel wool, graphite, and benzoxazine were prepared via melt mixing using a Haake internal mixer at 90 C and 60 rpm rotor speed. The composites were vulcanized using sulfur and electron-beam (EB) crosslinking systems. The SMFC samples were then subjected to friction, hardness, porosity, and density tests to determine their friction and wear properties. The morphological changes in the samples were also observed under a scanning electron microscope. The friction and wear properties of SMFCs crosslinked via the EB irradiation and sulfur vulcanization systems were compared. The friction coefficients in normal and hot conditions, as well as the hardness and density of the irradiated SMFC, were higher than those of the sulfur-vulcanized samples at all applied doses. The porosity of the irradiated SMFC at 50, 100, and 150 kGy was higher than that of the sulfur-vulcanized samples; however, the irradiated SMFC exhibited a descending trend at 200 kGy. On the other hand, the specific wear rates of the irradiated samples were lower than those of the sulfur-vulcanized samples at all applied doses. The sample crosslinked via EB irradiation at 150 kGy exhibited the greater tribological property compared with the sulfur-vulcanized SMFC, as indicated by the higher friction coefficient (approximately 0.461) and lower wear rate achieved at 150 kGy irradiation. © 2013 Elsevier Ltd. All rights reserved.
AIP Conference Proceedings | Year: 2010
Tin oxide anode materials used in lithium-ion cells experience large volume changes during charging and discharging which cause substantial losses in capacity. In this work, the tin oxide-graphite composite is proposed as an alternative anode material to overcome this problem. The composite was synthesised from a solution of tin chloride dihydrate and graphite powders with citric acid as the chelating agent. In this sol-gel method, a solid phase is formed through a chemical reaction in a liquid phase at moderate temperature. The technique offers several advantages compared to the solid state synthesis technique such as the ability to maintain the homogeneous mixture of precursors during synthesis and to produce small particles. The electrochemical behaviour of the anode material was investigated by means of galvanostatic charge discharge technique. An initial reversible capacity of 748 mAh/g is obtained and nearly 600 mAh/g was retained upon the reaching the fifth cycle. This study shows that the presence of graphite is able to minimise the agglomeration of tin particles that causes large volume changes during cycling, thereby improving cyclability of the anode material. © 2010 American Institute of Physics.
Aiza Jaafar C.N.,Universiti Sains Malaysia |
Malaysian Journal of Microscopy | Year: 2011
In this study the effect of composition on the ageing behaviour and microstructure of over-aged alloys AA6061 and AA6070 are described. The alloys were contained different levels silicon (Si) and copper (Cu) but similar magnesium (Mg) content. The effects of artificial ageing (T6) were studied on the two alloys. The ageing response of alloys was followed by hardness measurements using the Vickers hardness test. The morphology, distribution and crystal structures of the precipitates formed during over-ageing were characterised by transmission electron microscopy (TEM). The results showed a correlation between the Si contents and the hardness of the alloys as well as indicated changes in the precipitation hardening behaviour. The results also suggest that excess Si (ExSi) is more effective than Cu in improving the hardness value. The precipitates formed during over-ageing were β' or lath-shaped with their major axes parallel to  directions of the matrix.
Sahab A.R.M.,AMREC |
Saad N.H.,University of Selangor |
Kasolang S.,University of Selangor |
Saedon J.,University of Selangor
Procedia Engineering | Year: 2012
Alumina-titania coatings produced by plasma spray processes are being developed for a wide variety of applications that require resistance to wear, erosion, cracking and spallation. Consideration of parameters setting will develop reliable coatings with high performance properties for demanding coating application. Al2O3 3%wt TiO2 coating was produced onto metal substrate using Praxair Plasma Spray System with SG-100 Gun. This paper discusses the experimental and testing performance analysis of the coating which prepared based on three varied process parameters (current, powder flow rate and stand-off-distance). With the varied coating parameters, test results showed that increasing current from 550A to 650A and powder flow rate from 22.5g/min to 26 g/min increased the performance of mechanical properties of coating (adhesion strength & hardness) and gave the lowest friction coefficient value (i.e. best wear resistance) of coating. Increasing stand-off-distance from 75mm to 90mm also increased hardness performance and provided the lowest friction coefficient value of coating. However increasing stand-off-distance has decreased adhesion strength at setting powder flow rate of 26g/min and 650A current. The behavior of such parameters setting significantly influenced the production of optimum Al2O3 3%wt TiO2 coating onto metal substrate. © 2012 The Authors.
Azmi B.M.,Petronas University of Technology |
Hasanaly S.M.,AMREC |
Zakaria M.,Petronas University of Technology
Advanced Materials Research | Year: 2012
Mesoporous SnP 2O 7 was synthesized via a surfactant templating method where an anionic surfactant, sodium dodecyl sulfate was used. X-ray diffraction (XRD) analysis indicates presence of mesostructure when the precursors were calcined at 200, 300 and 400°C. Cyclic voltammetry tests carried out within 0-2.0 V (vs. Li/Li +) indicated that irreversible reduction of tin phosphate to form lithium phosphate phases and metallic tin occurred around 1.10 V and 0.69 V whereas the reversible alloying and de-alloying reaction involving lithium with tin occurred at 0.19 V and 0.52 V, respectively. Galvanostatic charge-discharge cycling tests carried out within 0-1.2V (vs. Li/Li +) showed that the mesoporous tin phosphate calcined at 400°C exhibited a reversible discharge capacity of 738 mAh/g in the second cycle and upon reaching the tenth cycle, it retained a discharge capacity of 461 mAh/g. The relatively high capacity obtained for this anode was attributed to the mesoporous framework which provided larger surface area for reaction with lithium and minimized effect of volume changes experienced by the anode during repeated charging and discharging cycling. © (2012) Trans Tech Publications, Switzerland.