Abstract: The ionic conductivity, super conductivity, ferroelectricity, and magnetic resistance of barium strontium cobalt ferrite (BSCF) make it a good solid cathode material. This study aims to investigate the influence of milling process and calcination temperature on the behaviour of nanocomposite cathode BSCF–samarium-doped ceria (SDC). The BSCF–SDC composite powders were mixed using two milling processes, namely, wet milling and dry milling. The composite cathode powders were mixed through wet milling by high-energy ball milling at 550 rpm for 2 hours. For dry milling, the powders were milled at 150 rpm for 30 minutes. The powders then underwent calcination at 900 °C, 950 °C, 1050 °C, and 1150 °C for 2 hours. The composite cathodes were examined on the basis of phase and microstructure through field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), respectively. In conclusion, the selection of suitable milling process and calcination temperature is important in eliminating secondary phases in BSCF–SDC composite cathodes and in enhancing their properties.
Abstract: The corrosion inhibition efficiency of Rhizophora acipulata(RA) extract was investigated for API 5L Steel corrosion in 3.5% NaCl using weight loss and polarization method. Fourier Transform Infra-Red (FTIR) was used toanalyze the characteristics of extract RA functional groups. The weight loss and polarization result indicated that extract RA inhibited API 5L steel corrosion rate. Based on the polarization result, the inhibition efficiency reached up 97.52% with addition 100ppm of RA extract.
Abstract: The corrosion performance of tinplate (Sn) and aluminum (Al) can as beverage packaging was studied in different acidity of soft drinks available in market. The research objective is to evaluate the acidity of different beverage to corrosion attack. The performance of coating layer provides by manufacturer to enhance corrosion attack was studied as well as corrosion mechanism penetrate on these nonferrous alloy. Electrochemical analysis was used to identify breakdown potential and corrosion damage was analyzed using SEM and energy dispersive spectrometry. Overall, the corrosion rates of stannum are much higher than aluminum for both new and used packaging. From Tafel results, the most corrosion resistant performed by soft drink 1 with pH 2.45 in aluminum packaging followed by manufactured aluminum. Corrosion resistance reduced in tinplate followed by manufactured tinplate. The most corrosion resistance condition was found on the aluminum sheet without manufacturing process that immersed in soft drink A according to its lowest corrosion rate 0.0703mm/yr, followed by manufactured aluminum sheet immersed in soft drink A with second lowest corrosion rate 0.0711mm/yr. All cyclic curves in this test showed that there was no pitting occurred on specimens as the reverse anodic curve was shifted to lower currents and negative hysteresis was produced. From SEM analysis, aluminum was oxidized and oxide film formed on surface to protect the material whereas the tinplate can was corroded and holes produced after electrochemical test. In both corrosion rate measurement and microscope analysis, it was clearly proved that aluminum can had more anti-corrosion properties than tinplate can. There was showed that some leading effect due to can manufacturing to an increasing corrosion rate to the metal beverage cans.
Abstract: Naphthenic acid is a sort of organic acid which present in crude oil and cause severe corrosion in certain circumstances. This type of acid will lead to the corrosion phenomenon known as naphthenic acid corrosion (NAC). Damage mechanism by NAC attack can be analysed using Scanning Electron Microscope (SEM), Electron-dispersive X-ray (EDX) and X-ray Diffraction (XRD). These characterization methods aim to observe the morphology, element content, and crystal structure of the NAC. The objective of this research is to apply failure analysis (FA) on heat exchanger (HE) tube bundle made form stainless steel 410 (SS410). SEM reveals the inter-granular attack initiate to crack propagation. A particular result of interest is that nickel catalytically decomposes naphthenic acids at high temperatures (e.g. 270°C) via a catalytic mechanism. For XRD testing, the corrosion product have been known and the main causes that lead to the corrosion has been detected which there is a formation of chromium carbide continuously along the pipe tube. However there is also formation of iron sulphide and chromium sulphide obtained in the XRD analysis where both are the reaction element that can retard the formation of NAC. Material selection is the most crucial task to resists from corrosion attack especially in high temperature applications. The mechanism of resistance of these elements provides insight into the failure mode of 304 and 400 series stainless steel in NA service.
Abstract: The aim of this research is to investigate the hardness of implant material Stainless Steel (SS) 316L due to ball peening at low temperature. In this paper, SS316L ball peening was conducted in various cryogenic temperature. The steel ball peening mechanism was bombarded on metal surface using peening ball. The shot peening treatment was performed for 10 minutes using steel balls with the size of 5 mm and 6 Bar compressed air flow. The treatment temperatures were carried out at-35°C, -45°C, and-55°C respectively. The results show that the hardness of SS316L after steel ball peening processes increasing as decreasing temperature treatment.
Abstract: The difficulties of machining nickel-titanium alloys are due to their high ductility and super-elasticity, strong strain-hardening, and excellent wear resistance. These characteristics lead to poor chip breakability, high cutting forces, rapid and aggressive tool-wear, as well as excessive burr formation during mechanical machining processes. The present study addresses these issues by evaluating the effects of drilling parameters and drill bit coatings on the growth of tool wear and development of the drilling thrust force. The findings from this research indicate that the TiAlN coated carbide drill was found to significantly improve the wear resistance of the cutting tool. Likewise, the results of thrust force development are consistent with the trends of tool wear growth for all of the tested carbide drills.
Abstract: Drilling is the metal cutting process that are widely used in industrial sector such as in aerospace, automotive and manufacturing to produce a various of durable parts. Stainless steels in general are regarded as difficult to machine materials due to their high tendency to work harden; their toughness and relatively low thermal conductivity. In this research, the experimental setup for the effect of various parameters on drill performance in term of cutting force and surface roughness. Stainless steel 316L used as workpiece and uncoated tungsten carbide drill bit as the tool. From the experimental investigation, the results show that internal coolant with helix angle of 40 and feed rate of 0.1 mm/rev condition is the best drilling condition in term of thrust force and surface roughness. By observation on experiment, MQL coolant condition give highest thrust force while internal coolant is best condition to have most minimum force. For internal coolant, MQL and external supply, the optimum helix angle to obtain low surface roughness is 15° and 40°.
Abstract: Development of lightweight materials becomes essential and has been applied for various structural and functional applications in industrial field since last decade. Porous metal can contribute to lightweight material with great mechanical, thermal and electrical properties. In this study, porous stainless steel was fabricated by using powder metallurgy technique and egg shell as a new potential space holder material. Stainless steel 316L was used as metal matrix powder, egg shells as space holder material, and polyethylene glycol (PEG) as binder to increase the green density of the preforms. The material was mixed using roller mill before the mixtures are ready to the next process of compaction by using uniaxial pressing machine. The samples were sintered to two-stage sintering at temperature 1000°C in a tube furnace. Physical properties of porous stainless steel were studies by performing density and porosity test. Scanning Electron Microscopy (SEM) apparatus was used to characterize morphology properties. The results show that, porous stainless steel with the composition of 30 wt. % of egg shells added into formulation yields the highest porosity compared to other compositions and the distribution of pores can be classify as micro-pores.