In this study, the effect of AL2O3 addition as a diluent during mechanically activated self-propagating high temperature synthesis (MASHS) of AL2O3-ZrB2 COMPOSITE was investigated. For this purpose, the thermite mixture of Al, ZrO2, H3BO3 and different amounts of AL2O3 (0, 3, 6, 9 wt.%) were used as the raw materials and mechanically activated for 5 h, then furnace sintering was performed at 650oC. The results showed that by increasing the AL2O3 content up to 6 wt. %, the intensity of exothermic peak in the DSC curves increases, but for higher additive contents it decreases. In this case, more homogenous distribution of ZrB2 particles with finer grain size was observed.

In the present research, nanoparticles based on the alumina-yttria system were synthesized using a sol-gel method. Then, the effect of heat treatment on the phase evolution and crystallite size in this COMPOSITE system was investigated. The produced COMPOSITE powder was characterized using X-ray diffraction and scanning electron microscopy. Scherrer equation was used to investigate the effect of temperature on crystallite sizes. The COMPOSITE powder was cold isostatically pressed and subjected to a pressureless sintering process at different temperatures to evaluate its density changes. The X-ray diffraction results showed that the powder sample was initially amorphous. By increasing the temperature, the components of this COMPOSITE system reacted and Alpha-AL2O3 and Y3Al5O12 phases are formed. The crystallite size of the Theta-alumina phase grew with increasing temperatures up to 1000 C. At higher temperatures, crystallite size decreased due to the decomposition of theta-alumina. The density of the samples increased by increasing the temperature up to 1600 C so that the samples reached a relative density of about 96%. The densification curve of the COMPOSITE showed three different stages during sintering. Examining the hardness of the samples showed that the hardness increases with the increase of the sintering temperature, and in the sample sintered at 1600 C for 3 hours, the Vickers hardness reached about 14 GPa.

In this study, Al-AL2O3 COMPOSITE coating produced by cold spray method on Al-7075-T6 sheet. The pure Al powder is blended with different amount of AL2O3 powder including 25, 50 and 75 wt. %. The feedstock is sprayed on sand blasted substrate using nitrogen gas at a constant temperature of 300 ° C, pressure of 30 bar and the stand-off distance of 20 mm. The effect of different values of AL2O3 on the deposition behavior of the Al-AL2O3 powders are investigated. Microstructural characteristics of the coatings are evaluated by scanning electron microscopy, image analysis software, microhardness and X-ray diffraction tests. The results showed that the high velocity of particles leads to the AL2O3 particle breaking during the process. This phenomenon increases the porosity of the coatings Furthermore, the higher value of reinforcement in the initial powder leads to the homogenous distribution of them and the higher coating hardness. The hardness of the Al-75AL2O3 coating is 104 HV, which is increased by 85% compared to pure Al coating. X-ray diffraction test indicated the fine-grained structure, no-oxidation and no phase transformation in the pure and COMPOSITE coatings.

The strength of aluminum Al5083 laminated COMPOSITE in accumulative roll bonding (ARB) is increased using AL2O3 nanoparticles. For this purpose, the ARB process was conducted at room temperature without lubricants in four consecutive passes. A thickness reduction of 50% in each pass was considered with no heat treatment between sequential passes. In each pass, AL2O3 nanoparticles were placed between the layers. Finally, the produced metal COMPOSITE was evaluated for microstructural and mechanical properties using optical microscopy, and uniaxial tensile, microhardness, and peeling tests according to the relevant standards. The primary objective of this research was to enhance the tensile strength of the COMPOSITE after work hardening by incorporating nanoparticles and annealing in the final cycle. The results showed that with an increase in accumulative roll bonding cycles, tensile strength and hardness increased, and this increase occurred more prominently in the initial cycles. Furthermore, the amount of elongation decreased at the end of the first pass and then increased until the end of the fourth pass. These changes in mechanical properties during the ARB process are due to the dominant mechanisms of work hardening and strain hardening in the initial cycles and the improvement in microstructure and refinement of grains in the final cycles of this process. The highest tensile strength and microhardness, which increased by 48.1% and 55.9%, respectively, compared to the initial sample were measured at the end of the fourth cycle. Additionally, comparing the heat-treated sample with AL2O3 nanoparticles to the base metal showed a 34.9% increase in strength and a 30.8% decrease in elongation.

COMPOSITE fibers (YAG/AL2O3 ) were prepared by sol-gel method using water as the solvent. They were synthesized from aluminium salt, aluminium metal and yttrium oxide. Transparent fibrous gels were obtained by immersing a thin wire into the viscous solution, then pulling it up by hand. Effect of yttria on crystallization and microstructure of fibers were also investigated. When yttria content was increased, the crystallization of YAG shifted to a lower temperature, whereas the transformation temperature to a-Al2 O3 shifted to a higher temperature. However, the same temperature (1400 oC) was required to obtain the fibers containing a-Al2 O3 and YAG. The COMPOSITE fibers were denser than alumina fibers. As the yttria content increased, the fiber diameter increased but grain size and densification of fibers decreased.

In this research, alumina - titania nanoparticles in thin-film forms and in different alcoholic environments such as ethanol, butanol and isopropanol were coated on API5-GrB steel substrates by electrophoretic process. coating operations was performed at different voltages, as well as chronoamperometry method was used to investigation of the mechanism of nucleation and surface qualities of coatings. in order to measurement of coating thickness and adhesion to the substrate, optical microscope was used. in the measurment the weight of the coating test showed that the weight of the coating increased via increasing voltage. by applying low voltage, the highest coverage was created in the presence of the butanol suspension, but via increasing the voltage, the maximum coverage was formed in the presence of the ethanol suspension. in the measurement results of coatings weight and their quality viewing showed that coating weight changes with voltage (electrical field intensity) and time follow the Hamaker relationship.

The mixed metal nanoCOMPOSITE MgO∙AL2O3∙ZnO has been prepared by coprecipitation method. The product was characterized by XRD. The average particle size was found to be 34.89 nm from XRD data. SEM and SEM-EDS were studied for evaluating surface morphology and elemental composition. The FTIR spectrum of prepared mixed metal nanoCOMPOSITEs MgO∙AL2O3∙ZnO and MgO∙2∙ZnO-curcumin were studied. The optical properties of the nanoCOMPOSITEs were studied by PL (Photoluminescence). The quantum efficiency (F) of MgO∙AL2O3∙ZnO and MgO∙AL2O3∙ZnO-curcumin was found to be 0.86 and 0.31, respectively in acetone. The photocatalytic activity of the nano COMPOSITE, MgO∙AL2O3∙ZnO was investigated over methyl violet 6b (MV) dye under UV-Visible light irradiation. The photocatalytic activity was assessed with various parameters including variation of pH, effect of H2O22 and reusability. The dye degradation efficiency of nanoCOMPOSITE was observed to be 48.7% and 93.42% for catalyst and catalyst with H2O2 at pH 9. The efficiency was 86.96% for catalyst with H2O2 at pH 7.

Numerous research works have been carried out in resent years to investigate mechanical alloying and combustion synthesis processes for the synthesis of advanced materials. In this work, AL2O3-TiN COMPOSITE were produced using mechanical alloying and combustion synthesis method. TiO2 and Al powders were used as raw materials to prepare AL2O3-TiN COMPOSITE. Powders were milled under nitrogen atmosphere (5 at pressure). Combustion were performed in the tube furnace under nitrogen atmosphere. The results of mechanical alloying indicated a two step mechanism. Titatium oxide were reduced to Ti at the first step followed by reaction with nirogen to produce TiN. When Al/TiO2 molar ratio in the starting powder was 1.2 or 1.3, TiN was produced after 20 hrs of milling, as observed in the XRD results. The results of combustion synthesis experiments indicated that aluminum and titanium oxide powders were combusted at 900oC and titanium nitride was formed.

Microwave processing is one of the novel methods for combustion synthesis of intermetallic compounds and COMPOSITEs. This method brings about a lot of opportunities for processing of uniquely characterized materials. In this study, the combustion synthesis of TiAl/AL2O3 COMPOSITE via microwave heating has been investigated by the development of a heat transfer model including a microwave heating source term. The model was tested and verified by experiments available in the literature. Parametric studies were carried out by the model to evaluate the effects of such parameters as input power, sample aspect ratio, and porosity on the rate of process. The results showed that higher input powers and sample volumes, as well as the use of bigger susceptors made the reaction enhanced. It was also shown that a decrease in the porosity and aspect ratio of sample leads to the enhancement of the process.