The fly ash based geopolymer is a promising binder by activation of fly ash with an alkaline activating solution. The fly ash based geopolymer prepared was characterized by several methods. The experimental result, studies effect of the porosity and water absorption on compressive strength of fly ash based geopolymer and Ordinary Portland Cement paste for comparison. The porosity studies were determined using the Brunauer, Emmett and Teller method included nitrogen adsorption / desorption plots. Then followed by water absorption and compressive strength tested at 7 and 28 days curing time. The result shows that the porosity of fly ash based geopolymer paste was in the lower surface area, pore volume and pore size compared to Ordinary Portland Cement paste. The small pore size of the fly ash based geopolymer had a significant proportion of a micropores whilst Ordinary Portland Cement paste pores were mostly mesopores. The highest compressive strength of fly ash-based geopolymer can be achieved up to 76.723 MPa at 28 days when less of pore size and water absorption. Therefore, the paste based on geopolymeric materials is a better durability and high resistance to aggressive environment compared Ordinary Portland Cement paste.

The study is carried out to understand the new corrosion protection technique, non-polarization concept, using current/voltage pulses to achieve a potential of zero charges (Epzc) of the metal-solution interface. As a result, a cost-saving and ecological method has been proposed as a new anti-corrosion method. In the methodology, U-bend samples are immersed in a 3.5% NaCl solution with different pH values. The readings prove the occurrence of electrochemical reaction, absence of charges, and the effect of Epzc. An examination on the ZCCP on low-carbon steel in 3.5% NaCl solution was analyze for 120 hours days. This study is carried out to understand the concept of corrosion behaviour and a new corrosion protection technique which applies non-polarization concept. A U-bend mild steel is used to corrosion effect in various pH values under zero charge protection. Samples were then immersed in 3.5% NaCl solution with different pH values. Electrochemical behaviour of steel sample in 3.5% NaCl solution was analysed by means of Tafel extrapolation. It was found that Ecorr and icorr recorded dissimilar readings at different pH values. As Ecorr rises, icorr drops from pH 6 to pH 9, hence corrosion rate also decreases from pH 6 to pH 9. Zero charge corrosion protection (ZCCP) technique is used to study the efficiency of corrosion protection method in different pH values. Readings of alternating current (IAC) and direct voltage (VDC) are recorded throughout the ZCCP experiment. These readings prove the occurrence of electrochemical reaction, absence of charges and the effect of Epzc.

Annealing treatment is an important step of rolling deformation that contributes to microstructural evolution and leads to the significant changes in damping capacity. Damping capacities were analyzed in the parallel to rolling direction at 1 and 10 Hz respectively. It was found that severe plastic deformation at 40 percent reduction has lower damping capacity compared to that of 30 percent and 20 percent reductions respectively. The microstructural results show that the grains of as rolled alloys were changed to almost equiaxed structures after a rolling reduction at 40 percent reduction.

In this paper, a study on the electrochemical behaviour and electrical properties of Al-Zn and Al-Zn-Sn alloys in tropical seawater using open circuit potential (OCP) measurement and electrochemical impedance spectroscopy (EIS) are reported. The results from both the OCP and EIS tests show that surface activation was observed in the Al-Zn alloy with the addition of 1.34 wt.% Sn which can be manifested by the shift of OCP values towards more electronegative direction. The EIS spectra of Al-Zn alloy exhibits a semicircle loop, while the EIS spectra for the Al-Zn-Sn alloy exhibits a semicircle with a semicircle inductive loop. The change in EIS spectra for Al-Zn-Sn alloy is correlated to the increase of surface activation resulting in a less stable passive layer. Equivalent circuits models were proposed to fit the impedance spectra and the corresponding electrical parameters with optimum values were deduced. The modulus impedance in the low frequency region or polarization resistance,Rpolobtained for the Al-Zn-Sn alloy,Rpol= 2.76 kΩ cm2) is slightly decreased compared to the corresponding value of the Al-Zn alloy,Rpol= 3.97 kΩ cm2), indicating a considerable reduction in the protective capability of the oxide layer on the Al-Zn-Sn alloy. It appears that the heterogeneous oxide film and pores formed on the Al-Zn-Sn alloy play a key role in reducing total resistance to the flow of electron at the alloy-electrolyte interface.

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