Advanced Materials Research Vol. 1133

Abstract: Polymer conductive films based on poly (ethylene oxide) (PEO), poly (vinyl chloride) (PVC), polyaniline (PANI) were prepared using solution casting method. The effect of polyaniline loading on the tensile properties, swelling behavior, and electrical conductivity of PVC/PEO conductive films were studied. The tensile strength of PVC/PEO conductive films decrease with increasing of PANI loading. The mass swell percentages and electrical conductivity increased with the increasing polyaniline loading of PVC/PEO conductive films.

Abstract: Surface finishes on copper pads have been known to be one of influential factor in the solder joint quality. This due to the difference in interfacial reaction and intermetallic compound formation on solder pad was strongly influence by the type of surface finishes. Deposition times during immersion plating process on copper pads are important as the thickness of coating will decide several properties of surface finish, such as wettability during soldering process. Thus, this study aims to investigate the effect of deposition time of immersion gold coating on wettability of the surface finish and how it affect the formation of intermetallic compounds on solder joint. In this works, deposition time of copper pads in immersion gold solution were varied from 3 minutes up to 15 minutes. The thickness of immersion gold layer that form on Cu pads were then measured using Scanning Electron Microscopy (SEM). As the main objective of this study is to study the effect of deposition time during immersion plating process towards solder joint, the pads were reflowed along with Sn-3.0Ag-0.5Cu solder in furnace under temperature 250 °C for 25 minutes. Then, the cross sections of the solder joints were examined using optical microscope in order to measure the wetting angle and thickness of intermetallic compound formed; which acceptable value in industrial area, should be below 40 ̊ and below 4μm as reflow respectively.

Abstract: The effect of hydrazine, N₂H₄ in the presence of fatty amide as corrosion inhibitor on corrosion of carbon steel in 3.5 wt% NaCl solution was studied by linear polarization resistance method (LPRM) at room temperature and static condition. The specimens’ surface analysis was done using atomic force microscope (AFM). The inhibition efficiency improved to more than 80% when 500, 100 and 2000 ppm of hydrazine were added to the inhibited solution containing 20 ppm fatty amide. The results obtained show that the inhibition effect is increased with increase of hydrazine concentration in inhibited solution. It indicates that hydrazine retards the reduction of oxygen in the corrosion process by reacting with dissolved oxygen in the solution and thus, further it reduces the corrosion rate of carbon steel.

Abstract: Gas turbine compressor blades will age and degrade in their operation. There are a lot of factors that will contribute to the degradation mechanisms and its acceleration. These factors encompass the site location, the site conditions including the aspect of air quality, water washing practice, etc. A study undertaken by Materials Engineering Group of TNB Research Sdn Bhd on 2 units of gas turbine compressor those are located near to the sea around Peninsular of Malaysia, to determine the degradation mechanisms of the blades. All these gas turbine units are located in different industrial environment. The first gas turbine unit, so called GTA is located in coastal, petrochemicals production and crude oil refining environment. The second gas turbine unit, so called GTB, located in coastal and industrial environment. The surrounding industries of GTB including oil refinery, chemical, ship fabrication and etc. This paper reports the degradation type of those gas turbine units’ compressor blades with their contributing factors.

Abstract: Hot gas path component consists of components designed to burn air-fuel mixture in combustion section and provide hot gasses to the turbine section where mechanical power is produced. The aim of this research project is expected to improve the current practices of managing degradation of hot gas path components. Understanding the damage mechanisms is of great interest in reducing the damage and failure risk. In this research, a study was conducted on F-Class type gas turbine hot gas path components assembly. It involved extensive examination and testing of the components which had been in operations for 24,000 hours since the last shutdown. Various factors such as installation, operating conditions, hardness and material of constructions were also investigated. This paper reports the initial findings of the study of hot gas path components degradation. It describes the damage observed on the affected areas of the components and proposes the factors that contribute to the damage processes. Potential solutions for mitigating the damages are also discussed.

Abstract: CO₂ corrosion comprises the majority of material damage, which leads to shutdown in petroleum industries. This phenomenon depends on parameters such as pH and temperature. Monitoring and recording these parameters help industries minimize waste in terms of time and financial resources. The insufficiency of tools for this purpose is noticeable. This study proposed an potentiometric IrO₂–pH microelectrode design in conjuction with a Ag/AgCl refrence electrode for real-time corrosion monitoring that can be used in various industries. Electrodeposition approach was used in the fabrication of a pH sensor. Electrochemical experiments were conducted to characterize the IrO₂–pH sensor as well as monitor the pH on a metal surface in conjunction with the fabrication of a pH microelectrode-designed system. Results show that the proposed pH sensor design can be used for real-time corrosion monitoring by surface pH measurement.

Abstract: Titanium dioxide nanofibers with diameter ranging to several nanometers were synthesized via electrospinning technique. The precursor solution was prepared by mixing the polyvinylpyrrolidone, PVP (MW~1,300,000) in ethanol, meanwhile titanium tetraisopropoxide, TTIP in acetic acid was slowly added into the solution under a vigorous stirring. The precursor solutions were then used in the electrospinning process under high voltage supply. As-spun nanofibers were heat-treated under different temperature 400°C and 500°C. The TiO₂ nanofibers were characterized by using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) and X-ray diffraction (XRD). The results indicated that the heat treated TiO₂ nanofibers consist of anatase and rutile phases. As the calcination temperature increased (400-500°C), the anatase phases are greater than rutile phase and specific surface area are decreases while the calcination process influenced the nanofibers diameter.

Abstract: Electroless Nickel Boron had been appointed as potential coating in several applications in industry like aeronatics, petrochemical industry, electronics and firearms due to its desirable physical and mechanical properties such as high wear resistance and high hardness including provides uniformity in coating thickness. However, in semiconductor sector, the usage of Nickel Boron as coating layer still insufficient due to lack of study in term of its potential as coating on printed circuit board. This study aims to investigate the mechanical and physical properties of electroless Nickel Boron as potential printed circuit board coating layer. The study conducted by cutting Copper substrates to 50mm x 7mm x 1.5mm and then subjected to surface pre-treatment before soak in Nickel Boron plating bath solution that contain of different concentration of Sodium Borohydrate (NaBH₄), 0.4, 0.6,0.8,1.0 and 1.2 g/l. Surface roughness was evaluated using 3D Roughness Reconstruction software. For mechanical properties, the hardness test was conducted by using Vickers Hardness Test MMT-X7 Matsuzawa and surface structure was evaluate using ProgRes C3 IM7200 Optical Microscope and Field Emission Scanning Electron Microscopy (FESEM). It was found that the surface roughness and hardness resistance were affected by Sodium Borohydrate (NaBH₄) that correlate with the surface microstructure.

Abstract: In this paper we report, the characteristics of PTTL after irradiation with ⁶⁰Co gamma rays as a function UV light exposure wavelength, gamma irradiation dose, and UV light exposure time were determined for Ge-doped SiO₂ optical fibers. The efficiency of dose reassessment for this fiber was compared to standard thermoluminescence detector, TLD100. Experiments show that the method works well with the UV lamp of 254 nm within region of doses between 3 to 50 Gy, but could be applied for higher and lower doses as well. The effect of exposure time of UV radiation on the PTTL signal was studied from 5 to 120 minutes to determine the highest sensitivity and the limit of the dose. The efficiency of dose reassessment with 10 Gy of gamma irradiation expose to UV light for 15 minutes relative to PTTL values of about 27.0% and 2.3% for Ge-doped SiO₂ optical fiber and TLD100.

Abstract: The development of optical fibre temperature indicator using epoxy glue as a detection membrane is presented. This study, investigates the effects of epoxy glue from the reaction of epoxy resin, bisphenol A (BPA) (80-05-7) and adhesive epichlorohydrine (ECH) (106-89-8) as a temperature indicator membrane. In this work the response of epoxy glue to excitation source 395 nm is tested and analyzed under cryogenic conditions. A fiber optic temperature sensor for detecting ambient temperature ranging from 15 °C to 80 °C has been examined. The epoxy glue fluoresce when excited with UV-blue light source. The intensity of the fluorescence of the material decreases when the epoxy glue is exposed to an environment of higher temperature. These decrease level of fluorescence signal has been used to indicate temperature. In this paper, the basic principle of operation, development process and emission response characteristics of this sensor are discussed.