Journal of Material Sciences & Engineering

The corrosion behavior of Al 7075 was investigated in Hydrochloric acid over a range of acid concentration electrochemical techniques like Tafel extrapolation and electrochemical impedance spectroscopy were started and the studies have revealed that the corrosion rate of Al 7075 samples increase with increase in concentration of Hydrochloric acid in the medium.

The present study deals with the effects of gettering process on the structural and mineralogical composition of Tunisian phosphate rock. The treated samples were characterized to investigate the variation of physical structure and chemical composition as compared to the reference phosphate rock. The quantitative analysis of the impurities concentration before and after gettering treatment using energy-dispersive (EDX) reveals a significant reduction of impurity concentration (more than 75%) such as Al, Si, S, Na, and Mg. Scanning electron microscopy (SEM) shows that gettering process promoted structural alterations of phosphate rock sample due to fusion of impurities. The XRD patterns show that the chief mineral constituent of treated sample is only fluorapatite, while those in the reference ore were calcite, dolomite, quartz and carbonate-fluorapatite. FT-IR characterization show a disappearance of the bands related to calcite at 714 cm-1 as well as B carbonate situated at 1430 cm-1, 1458 cm-1 after gettering treatment. This result is in good correlation with Raman analysis.

The dynamic viscosity was measured for water-phenol binary mixture at several concentrations and temperatures to determine the critical concentration and critical temperature. The critical concentration was determined at XC=3.90% by weight of phenol, the critical temperature was TC=67.0°C using the viscosity measurement while TC=67.8°C from an indication of electrical conductivity measurements. The electrical conductivity measurements were recorded for water-phenol binary mixture at different temperatures and concentrations. The electrical conductivity measurements for various concentrations (0.00%, 10.17%, 20.80% and 50.00%) by weight of phenol were fitted by using Arhenius equation. The activation energy and the electrical conductivity at infinite temperature were calculated for several concentrations. The electrical conductivity as a function of temperature was fitted by using power law above the critical temperature. The noncritical part of the measured electrical conductivity was found to be 30.26 μS/cm and the critical exponent value was 0.0321. The molar electrical conductivity was calculated and plotted by using Walden rule. The slope of Walden plot was found to be 0.9439 so the water – phenol mixture was classified as a poor ionic mixture.

The systematic study of the activity of the catalyst suspended with ferroalloys additives in catalytic hydrogenation of glucose over a wide variation of process parameters is given in this article. Since nickel catalysts were studied sufficiently, we limited to the data of the phase composition and structure; specific surface of alloys and catalysts based on aluminum-nickel alloys, modified ferroalloys. Results of the study of phase, chemical, particle size distribution and structure of nickel alloys and catalysts have shown that modifying metals affect to the ratio of NiAl3/Ni2Al3 in the alloys, crush crystals, increase catalyst particle size, surface area and large size pore volume and simultaneously increase the micro- and supermicro pore ratio. Highly active, stable and selective catalysts based on nickel for the sorbitol synthesis process was developed.

Zinc titanate powder was synthesizd by an organic free co-precipitation peroxide technique. Zinc chloride and titanium (IV) isopropoxide were used as the primary material with the ratio of Zn:Ti was 1:1 and the later compound was prepared by mixing titanium chloride with isopropanol. The stoichiometric ratio of the synthesized zinc titanate was measured by using AAS. The synthesized powder was calcined at 800°C for 3 hours using the X-ray diffraction and the calcined zinc titanate powder crystalline phase formation was found to be cubic. FTIR was used for studying the bonding characteristics of ZnO and TiO2. Disintegration temperature was analyzed by means of Thermogravimetric analysis. The photocatalytic activity was measured based on the degradation of methyl orange in aqueous solution in the presence of metallic sodium. The results showed that ZnTiO3 particle exhibited good photocatalytic activity under visible range radiation.

Many different types of destructive attack can occur to marine structures, ships and other equipments used in sea water service. Year upon year the cost of marine corrosion has increased until it is estimated today at 4% of the Gross National Product. Aluminium alloys are important materials and commonly used in marine applications. In this aluminum 2024 were subjected to seawater. Sodium Benzoate was used as corrosion inhibitors for aluminium alloy in aggressive marine environment. In order to study the corrosion behavior of aluminum alloy AA2024 in seawater, the electrochemical behavior of aluminum alloy was investigated with different inhibitor concentrations, potentiodynamic polarization and electrochemical spectroscopy (EIS). The morphology study was carried out to observe the development of thin film on the specimen and this study was performed using Scanning Electron Microscopy (SEM). EIS data showed that the mechanism of corrosion depends on inhibitor concentration.

In this study ASTM A-36 (mild steel) is selected as specimen for testing various mechanical properties and microstructure change. The effects of heat treatment on the mechanical properties and microstructure characteristics change of selected specimen are analyzed. Annealing, hardening and tempering are the most important heat treatment processes often used to change mechanical properties of engineering materials. The purpose of heat treating is to analyze the mechanical properties of the steel, usually ductility, hardness, Yield strength, tensile strength and impact resistance. The heat treatment develops hardness, softness, and improves the mechanical properties such as tensile strength, yield strength, ductility, corrosion resistance and creep rupture. These processes also help to improve machining effect, and make them versatile. The mechanical properties can easily be modified by heat treating to suit a particular design purpose. In the present study, selected samples are heat-treated at certain temperature above the austenitic region and quenched in order to investigate the effect on the mechanical properties microstructure of the mild steel. The changes in mechanical behavior and microstructure as compared with unquenched samples are explained in terms of changes in tensile strength. Results showed that the mechanical properties of mild steel can be changed and improved by various heat treatments for a particular application.

Brake linings have complex microstructure and consists of different components. The purpose of this research is to optimize the use of brake liner frictional materials with new formulation incorporating micaceous iron oxide and calcium carbonate as a filler material and comparison of improvement in frictional value with other filler materials. This new formulation was tested under various operating conditions with a chase machine friction testing rig. The friction test rig was programmed with different test loops to perform test as per SAE J661. The average coefficient of friction, coefficient of friction with changing speed, temperature and load, thickness loss and weight loss were accounted. Formulation exhibits better thermal stability and wear resistance to the latter.

Nanostructured disordered iron-aluminium-copper alloy of Fe-30% Al-10% Cu composition was prepared by Self-propagating high-temperature synthesis (SHS) and thermel explosin (TE) techniques of mechanically activated mixture of Fe, Al, Cu powders. The transformations occurring in the material during combustion were studied with the use of X-ray diffraction. Auger spectroscopy and atomic emission spectroscopy (AES) was used to determine the phase composition of the phase formation. Finally, the Magnetic properties were also investigated, for combution processers the magnetic behavior slightly softened becoming a semi hard ferromagnetic.

This study investigates the effect of post heat treatment on the microstructure and mechanical properties of IS2062 steels. Similar metal joints of IS2062 weldments are prepared by using MIG welding process. This melting is occurring at edges of the plates because of sufficient amount of heat energy is passing over the plate per unit time and density of energy is supplied to the wire. In this connection, heating and cooling of weldment some of the disturbances in metallurgical and mechanical point of view. To overcome we will choose suitable post weld heat treatment to avoid the disturbances and improve industrial requirement irrespective of the mechanical, microstructure of the weldment. The objective is to determine the optimum post weld heat treatment method for the IS2062 steel. After welding, the effects of post weld heat treatment on weld metal microstructure and mechanical properties including weldment tensile strength, impact and hardness over the room temperature range 32°C are investigated. In particular this study the effect of these properties to understand estimate heat treatments on the tensile impact, Hardness materials are considered as weldments before heat treatment and after post weld heat treatment.

Welding of Low Nickel Chrome-manganese Austenitic and ferritic Stainless Steel is an emerging area of research. Due to nickel price volatility, there was been increased interest in no-nickel or low-nickel economical grades of stainless steel. Chrome -manganese austenitic (“standard 200-series”) and ferritic stainless steel (“standard 300-series”) grades with well-defined technical properties have proved acceptable materials for specific applications for many years. This increase in the use and production of these low nickel grades is not currently matched by a proper level of user knowledge. So there is a risk that they may be used in unsuitable applications. It is very important to cultivate the method of fabrication like welding. This paper looks at the behavior of low nickel chrome-manganese and Ferritic austenitic stainless steel in terms of microstructure and sensitization effects.

During the welding process change of chemical and physical reactions due to the flow of heat in the weldments are varied with respect to rate of cooling time and weld axis. In the dissimilar welded joints, at the welded portion it can be exist in more than one crystalline form and the carbon atom is only 1/30th size of the iron atom. The weldments are underlying their properties so to achieve the better results that are possible through heat treatment processes.