The study of isothermal oxidation of Fe-Ni-Cr alloy was done at 900 °C for 500 hours. The effect of oxidation kinetics and oxide growth behavior on Fe-Ni-Cr alloy were investigated on heat-treated Fe-Ni-Cr alloy to understand the oxidation mechanism on different grain size of alloy. The grain size of Fe-Ni-Cr alloy was varying through heat treatment process at three different temperatures, namely 1000 °C, 1100 °C and 1200 °C for 3 hours soaking time followed by water quench. The heat-treated Fe-Ni-Cr alloy was experienced discontinuous isothermal oxidation test at 900 °C up to 500 hours exposure. The oxidation kinetics plot was calculated based on the weight change per surface area over time. The oxide surface morphology was characterized by using scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) spectrometer. The heat treatment process recorded an increasing grain size alloy as the heat treatment temperature increase. 8H10 sample indicate the fine grain size, whereas 8H12 sample indicate the coarse grain size. The oxidation kinetics of all samples exhibit the weight gain pattern with fine grain 8H10 sample recorded the lowest weight gain compared to 8H11 and 8H12 samples. All samples were obeyed parabolic rate law indicating the oxide growth rate followed a diffusion-controlled mechanism. The oxide surface morphology of 8H10 sample displayed a continuous oxide scales with formation of grain boundary oxide along the grain boundary area. Similar oxide structure formed on 8H11 and 8H12 samples, except for the formation of crack on the grain boundary oxide on both samples. In addition, 8H12 sample also formed a porous oxide structure.

Fruit skins are waste and natural fibers which are processed from it can be used as filler material in polymer composites. These natural fibers are surely inexpensive, non-toxic and environmentally friendly. In the other hand, natural fibers are chemically hydrophilic and absorb water. Their nature which are rich cellulose making it hydrophilic in nature. Besides their nature to water, the ability of natural fibers to absorb oil also interesting to be studied. In this paper, natural fibers from several types of fruit skin were used as filler in thermoplastic polyurethane (TPU) composites. The fibers from pineapple skin, coconut shell, coconut husk, corn cob, rambutan, mangoesteen and banana with the percentage of 15% and 20% were incorporated with TPU through melt mixing technique. Every type of natural fiber will absorb oil and water at different rate, as well as the effect of filler content in the composite. Overall, the absorption of water and oil increased its percentage when the filler content increases. Rambutan, pineapple and banana absorb more water than others at 20% filler content in the TPU. Pineapple and rambutan also tend to absorb more engine oil.

The isothermal oxidation behaviour on two different temperature of Fe-33Ni-19Cr alloy was studied in this work. The present paper focuses on the isothermal oxidation behaviour at 700oC and 900oC. The oxidized samples were subjected to oxidation experiment under isothermal conditions for 500 hours. Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD) technique were employed in this study to analyse the oxidation behaviour of oxidized samples. The kinetics of oxidation followed the parabolic rate law which represent diffusion controlled oxide growth rate. Results indicate that Fe-33Ni-19Cr alloy oxidized at 700oC possess a better oxidation resistance with low K_p value of 2.39 x 10^-7 mg²cm^-4s^-1. The oxide scale formed during oxidation were generally complex consists of several oxide phases. The samples morphologies of oxidized samples were influenced by the alloy structure and expose conditions. An elemental EDX line scan analysis of samples oxidized at 900oC indicated four different oxide layers composes of several oxide structure with evidence of internal oxide precipitates composed of Al-rich oxide phase.

Fe-40Ni-24Cr alloy is a Ni-based alloy used at high temperature application. In this study, Fe-40Ni-24Cr alloy had undergo a solution treatment at two different temperatures, namely 1050° and 1150°, for 3 hours soaking times followed by water quench. A solution-treated Fe-40Ni- 24Cr alloy was experienced a high temperature isothermal oxidation test at 500° for 500 hours exposures duration. The growth of oxide scale was characterized in terms of oxidation kinetics and surface morphology using field emission scanning electron microscope equipped with energy dispersive x-ray spectroscopy. The oxidation kinetics of all samples shows an increasing weight gain pattern as the exposure durations increases. The oxidation kinetics was obeyed a parabolic rate law, indicating the oxide growth rate was followed diffusion-controlled mechanism. The surface morphology of oxidized solution-treated Fe-40Ni-24Cr alloy displayed a formation of continuous oxide scale with evidence of overgrown Nb-rich oxide particles distributed along the oxidized samples surface. Oxidized Fe- 40Ni-24Cr alloy which undergo solution treatment at 1150° exhibited the formation of oxide spallation. The spallation has a tendency to occur around the area of overgrown Nb-rich oxide particles.

The effect of solution treatment temperature on the microstructure, phase present and hardness on Fe-33Ni-19Cr alloy was study in this work. The Fe-33Ni-19Cr alloy was experienced a solution treatment process at six different temperatures which are 950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C and 1200 °C for 3 hours soaking time followed by water quench. The average grain size was measured by using linear intercept methods ASTM E112. Microstructure of solution-treated Fe-33Ni-19Cr alloy was characterized by using optical microscope and scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) spectrometer. The phase present was analyzed using x-ray diffraction (XRD) technique. The Vickers hardness was used to measure the hardness of solution-treated Fe-33Ni-19Cr alloy. Increasing the solution treatment temperatures were increase the average grain size of solution-treated Fe-33Ni-19Cr alloy. In addition, all samples exhibited an equiaxed matrix grain with slight distribution of precipitates particles. The hardness of solution-treated Fe-33Ni-19Cr alloy was decrease as the solution treatment temperature increase.

Fe-33Ni-19Cr alloy is the Ni-based alloy used at high temperature condition due to its excellent ability to form protective oxide layer at high temperature. Fe-33Ni-19Cr alloy was undergo a series of solution treatment process to vary the grain size of the alloy. The Fe-33Ni-19Cr alloy was solution-treated at 3 different temperature, namely 1000°C, 1100°C and 1200°C, for 3 hours soaking time, followed by water quench. The solution-treated alloys were then experienced an isothermal oxidation test at 900°C for 500 hours in laboratory air. The oxidized Fe-33Ni-19Cr alloy were characterized in terms of phase analysis and cross-sectional analysis using XRD and SEM-EDX to investigated the effect of different grain size alloy to the oxidation behavior. The solution treatment process was produced varies grain size of Fe-33Ni-19Cr alloy. The solution-treated Fe-33Ni-19Cr alloy at 1000°C exhibited the fine grain size, while solution-treated Fe-33Ni-19Cr alloy at 1200°C produced a coarse grain size. The oxidized Fe-33Ni-19Cr alloy recorded a formation of several oxide phases consists of Cr-rich oxide, Fe-rich oxide, Ti-rich oxide and spinel oxides structure. The cross-sectional analysis displays a several layer of oxide scales formed on the alloy surface with evidence of internal oxide penetration through the grain boundary area.