Azizul Helmi Bin Sofian

Investigation on wear characteristic of biopolymer gear

Polymer is widely used in many mechanical components such as gear. With the world going to a more green and sustainable environment, polymers which are bio based are being recognized as a replacement for conventional polymers based on fossil fuel. The use of biopolymer in mechanical components especially gear have not been fully explored yet. This research focuses on biopolymer for spur gear and whether the conventional method to investigate wear characteristic is applicable. The spur gears are produced by injection moulding and tested on several speeds using a custom test equipment. The wear formation such as tooth fracture, tooth deformation, debris and weight loss was observed on the biopolymer spur gear. It was noted that the biopolymer gear wear mechanism was similar with other type of polymer spur gears. It also undergoes stages of wear which are; running in, linear and rapid. It can be said that the wear mechanism of biopolymer spur gear is comparable to fossil fuel based polymer spur gear.

The Investigation of Zinc-Rich Paint (ZRP) Behavior in NaCl Solution by Electrochemical Methods

Zinc-rich paints are coating materials designed to improve corrosion especially in marine and saline environments. Two types of zinc-rich paints (ZRPs) were employed in this research: 74 % ZRP and 96 % ZRP. The effectiveness of zinc coating systems has been analyzed in 0.5 M NaCl solution. Corrosion protections of coated metallic substrates were investigated using polarization measurement and electrochemical impedance spectroscopy (EIS). Electrochemical test showed that metallic substrates coated with 96 % ZRP have better corrosion resistance (galvanic protection) while those coated with 74 % ZRP have better barrier effect.

Electrochemical Impedance Behavior of Various Composition Quaternary Ni Alloy in 3.5 Wt% NaCl

Zinc and copper addition into electroless Ni-P alloy matrix produces quaternary Ni alloy that exhibits lower corrosion resistance behavior compared to Ni-P and Ni-Cu-P alloy in 3.5 wt% NaCl solution. The corrosion behavior of the alloy is previously studied using the anodic polarization curve measurement. The results show that the corrosion potential of different alloy composition is almost similar to each other for electroless Ni-Zn-Cu-P alloy. However, the surface resistance of the alloy needs to be confirmed by using electrochemical impedance spectroscopy. The alloy was first deposited on an iron substrate using electroless Ni alloy deposition method approximately similar thickness at different plating bath pH of 8.50 and 9.50. The Ni alloy coated substrate was used as working electrode immersed into a solution of 3.5 wt% NaCl. The electrochemical cell consists of Pt and Ag/AgCl/KCl (saturated) as counter and reference electrode respectively. Electrochemical impedance measurement was done at open circuit potential. The measurement started from 100 kHz to 10 mHz with 10 mV of sinusoidal perturbation applied to the cell. Other types of alloy including Ni-P, Ni-Cu-P and Ni-Zn-P, were compared with Ni-Zn-Cu-P alloy. From the results, the Ni-Zn-Cu-P exhibits the lowest corrosion behavior compared to other Ni alloy due to low charge transfer resistance (Rct) observed small inductive loop at low frequency region of the Nyquist plot. Furthermore, the Nyquist plot for Ni-Zn-Cu-P for pH 8.50 and 9.50 showed comparable result; hence, the effect of pH has less effect on corrosion resistance of the electroless Ni-Zn-Cu-P alloy.

Corrosion Analysis of Zinc Rich Epoxy Coatings on Steel in NaCl Solution

Zinc rich epoxy coatings are coating material intended to improve corrosion related persistency in marine and salinity environments. Two different percentages of zinc rich epoxy paints were used in this research 74%-zinc rich paint (ZRP) and 96%-ZRP. The performance of coating systems with different types of zinc rich paints has been analyzed in 0.5 M NaCl solution. The anticorrosive properties of coated samples were investigated polarization technique and electrochemical impedance spectroscopy (EIS). The results of electrochemical test showed that 96%-ZRP coating provides effective corrosion resistance compared to 74%-ZRP.