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This paper aims to analyse the surface evolution of pure recycled titanium subjected to isothermal and cyclic oxidation conditions using dry air as oxidant gas. It is important to mention that the cyclic oxidation behaviour of pure titanium is a process that has been barely studied.

An isothermal and cyclic oxidation reactor was built for these purposes. This installation allows the oxidation of material under the action of any atmosphere and for temperatures up to 1,200°C. For this study, the oxidation behaviour of the material was studied at 850°C and 950°C.

Oxide growth under isothermal oxidation conditions in air follows a parabolic behaviour with an activation energy of 118 kJ/mol, and the oxide phase formed on the surface of the metal was rutile. The cyclic oxidation of the material indicates that oxide is spalled from the surface following linear behaviours; this phenomenon is controlled by the thermal stresses experienced by the samples during heating and cooling cycles.

The material is obtained from the production of electrolytic copper, and during its reprocessing practices at high temperature, it was thought that it could experience some abnormal oxidation. In addition, given that pure titanium is currently used for biomedical application, some surface degree can be given by means of oxidation and subsequent spallation process situation that is found during the cyclic oxidation experiments, which could be a low-cost method to engineer a surface for these purposes.

This study aims to prepare UV protection and hydrophobic fabric through modifying cotton fabric by graphene oxide and silane coupling agent. The graphene oxide and silane coupling agent (KH570) are anchored on the cotton fabric by a stable chemical bond.

Graphene oxide was prepared by modified Hummers method. The fabric sample was treated with graphene oxide and silane coupling agent KH570 using simple dipping-padding-drying method. The effects of the dosage of graphene oxide, silane coupling agent KH570 and curing temperature were determined by single variable experiment and orthogonal experiment, The UVA and UVB transmittances in ultraviolet light of the sample fabric were characterized, and the contact angle test method with water was used to indicate the hydrophobicity of the sample fabric. The structure and surface of the fabric were analyzed using Fourier-transform infrared spectroscopy and scanning electron microscopy.

The cotton fabric was successfully modified by graphene oxide and silane coupling agent KH570. Compared with the untreated fabric, the surface of the fabric was smooth, and there was no gap on the fiber. The graphene oxide, silane coupling agent KH570 and cotton fabric combined tightly. The UPF value of the modified fabric was 50+, and the contact angle reached 138.1°. It had excellent UV protection and hydrophobic properties.

Although graphene oxide and silane coupling agents KH570 had successfully endowed the cotton fabric with good UV protection and hydrophobic properties, graphene oxide and silane coupling agent KH570 are expensive and used in large quantities. There are certain limitations in the actual life and production process.

After treating with silane coupling agent, the hydrophilic fabric treated with graphene oxide is being translated into hydrophobic, and graphene oxide bonded with cotton. The modified fabrics also have excellent UV protection. This fabric can be used for outdoor sports such as clothes and tents.

Cotton fabric treated with graphene oxide generally by simple dip-dry-cure method is hydrophilic and graphene oxide is easy to drop. The usage of silane coupling agent KH570 as a crosslinking agent to link graphene oxide and cotton fibers has not been reported yet. The modified fabrics have both UV protection and hydrophobic properties.

The purpose of this paper is to propose and develop PA2200-based composite powder containing 0-15 Wt.% magnesium oxide before directly using it in selective laser sintering (SLS) machine to produce end-use products for low-volume production in the engineering applications with keen focus to meet the functional requirements which rely on material properties.

The methodology reported emphasises PA2200-based composite powder containing 0-15 Wt.% magnesium oxide development for SLS process which starts with preparation and characterisation of composite material, thermal and rheological study of composite material to decide optimum process parameters for SLS process machine to get optimal part properties. Further, to verify composite material properties, a conventional casting methodology is used. The composition of composite materials those possessing good properties are further selected for processing in SLS process under optimal processing parameters.

The process parameters of SLS machine are material-dependent. The effect of temperature in X-ray diffraction profile is negligible in the case of magnesium oxide reinforced PA2200 composite material. The cyclic heating of material increases melting point temperature, this grounds to modify part bed temperature of material every time before processing on SLS machine to uphold build part properties, as well as material. With the rise in temperature, the Melt flow index and rheological property of materials change. The magnesium oxide reinforced PA2200 composite material has high thermal stability than pure PA2200 material. By the addition of small quantity of magnesium oxide, most of the mechanical property and flammability property improves while elongation at break (percentage) decreases significantly.

The proposed PA2200-based composite powder containing 0-15 Wt.% magnesium oxide material development system and casting metrology to verify developed material properties will be very useful to develop new composite material for SLS process with use of less material. The developed methodology has proven, especially in the case where non-experts or student need to develop composite material for SLS process according to the property requirement of applications.

Unlike earlier composite material development methodology, the projected methodology of polymer-based composite material and confirmation of material properties instead of commencing SLS process provides straight forward means for SLS process composite materials development with less use of the material and period of time.

The aluminide and CeO₂ and La₂O₃ containing aluminide coatings on carbon steel have been prepared by a pack cementation process. The influence of CeO₂ and La₂O₃ additions on the oxidation rates of aluminide coatings has been investigated. The performance of coatings was studied by measuring oxidation kinetics, metallography, SEM and X‐ray diffraction analysis techniques. The oxidation‐resistance of coated carbon steel is discussed on the basis of a decrease in oxidation rates as well as adherence of oxide scales. The oxidation rates of carbon steel and aluminide coatings were markedly reduced in the presence of CeO₂ and La₂O₃ in the temperature range of 700‐900°C. The oxidation rates were significantly affected by the morphology of oxide scales. In the case where the structure of oxides scales was not seriously disrupted due to decarburisation, the oxidation rates were significantly reduced.

Aims to study inhibitive properties of new compounds that are based on the Wurtzite structure of zinc oxide with an admixture of cobalt using zinc oxide as a reference.

The conditions for the preparation of pigments using different ratios of both cobalt and zinc were investigated. Characterization of these pigments was carried out using spectroscopic methods of analysis via X‐ray diffraction, transmission and scanning electron microscopy. Also, evaluations of the pigments prepared, in terms of oil absorption, specific gravity, water‐soluble matter and pH, using international standard testing methods was performed. The pigments prepared were incorporated in anticorrosive paint formulations based on medium oil alkyd resin as a binder. The physico‐mechanical properties of the relevant paint films were obtained, while their anticorrosive properties were assessed by tests in 3.5 percent NaCl solution for 28 days. Electrochemical measurements based on corrosion rates of paint films also were studied.

The results showed that the anticorrosive protection properties of the pigment prepared were better than with zinc oxide pigment alone.

The pigments prepared can be used as reinforcing filler in different rubber and plastic composites providing them with an intense green color. As the concentration of cobalt oxide exceeds 15 percent, the reinforcing and effects decreased and vice versa.

Zinc chromate is one of the anticorrosive pigments most frequently used in the formulation of primers. However, its environmental aggressiveness and toxicity severely restrict its use and different green alternatives have been proposed in order to replace it. One such alternative is the pigment evaluated in this paper. New pigment applications, such as reinforcing fillers for rubber and plastic composites, also could be attractive.

This paper aims to investigate the reusability of metal/metal oxide-coupled ZnO nanorods (ZnO NRs) to degrade rhodamine B (RhB).

ZnO NRs particles were synthesized by precipitation method and used to remove various types of metal ions such as Cu²⁺, Ag⁺, Mn²⁺, Ni²⁺, Pb²⁺, Cd²⁺ and Cr²⁺ ions under UV illumination. The metal/metal oxide-coupled ZnO NRs were characterized by scanning electron microscope, X-ray diffraction and UV-Vis diffuse reflectance. The photodegradation of RhB dye by these metal/metal oxide-coupled ZnO NRs under UV exposure was assessed.

The metal/metal oxide-coupled ZnO NRs were successfully reused to remove RhB dye in which more than >90% of RhB dye was degraded under UV exposure. Furthermore, the coupling of Ag, CuO, MnO₂, Cd and Ni particles onto the surface of ZnO NRs even enhanced the degradation of dye. The dominant reactive species involved in the degradation of RhB dye were ^•OH- and ^•O₂⁻-free radicals.

The coupling of metal/metal oxide onto the surface of ZnO NRs after metal ions removal could affect the photocatalytic performance of ZnO NRs in the degradation of organic pollutants in subsequent stage.

A good reusability performance of metal/metal oxide-coupled ZnO NRs make ZnO NRs become a desirable photocatalyst material for the treatment of wastewater, which consists of both heavy metal ions and organic dyes.

Metal/metal oxide coupling onto the surface of ZnO NRs particles improved subsequent UV-assisted photocatalytic degradation of RhB dye.

Several solid solution combinations of aluminium oxide and iron oxide, for the preparation of a new pigment, were investigated to study the effect of aluminium oxide to iron oxide ratio on various properties of the resulting pigments.

The conditions for the preparation of the pigments via solid solution interaction at 1,000°C had been estimated. Characterisation of three different combinations of aluminium oxide and iron oxide were carried out using spectroscopic methods of analysis via X‐ray diffraction (XRD), transmission and scanning electron microscopy (TEM and SEM). Also, evaluation of the pigments prepared, in terms of oil absorption, specific gravity, water‐soluble matter, and pH, using international standard testing methods was performed. The pigments prepared were incorporated in anticorrosive paint formulations based on medium oil alkyd resin as a binder. The physico‐mechanical properties of the relevant paint films were obtained, while their anticorrosive properties were assessed by tests in 3.5 per cent NaCl solution for 28 days.

The results showed that the anticorrosive protection properties of the pigment prepared were better than their aluminium and iron counterparts.

The pigments prepared may be used in different applications other than paint formulations. As the concentration of iron oxide increases, the hardness and the anticorrosive protection performance of the paint film increase. As the concentration of aluminium increases, elasticity, impact resistance and ductility also increase. Application of different combinations of these pigments in paint films had been studied. However, investigation of the application of these pigments in other systems such as plastics could also be interesting.

The pigments prepared can be used as reinforcing filler in different rubber and plastic composites, beside its ferro‐magnetic properties. As the concentration of alumina increased, the reinforcing and magnetic effects decreased and vice versa.

Iron oxide is an abundant ore in several world countries; it is an inorganic, environmentally friendly material, which exhibits good Moh's hardness. Adding aluminium oxide which is a very light element having a unique flaky structure to iron oxide gave a new pigment that can be used not only in paint formulations, but also in rubber and plastic composites as reinforcing fillers.

The purpose of this paper is to report the effect of bismuth oxide thick films of various thicknesses on the X band (8‐12 GHz) response of Ag thick film microstrip rectangular patch antenna.

The effect of bismuth oxide thick film overlay of different thickness on Ag thick film microstrip rectangular patch antenna was investigated in the X band (8‐12 GHz). The change in the resonance frequency, amplitude, band width, quality factor, and input impedance of the antenna were studied. Using the resonance frequency the permittivity and conductivity of bismuth oxide thick film was measured.

Thickness of Bi₂O₃ thick film overlay dependent changes in the patch antenna characteristics is obtained. The resonance frequency shifts to higher frequency end due to overlay. The input impedance decreases due to the overlay. The dielectric constant of bismuth oxide thick film calculated from shift in resonance frequency shows thickness dependent values.

The microwave permittivity and conductivity of Bi₂O₃ thick film have been reported for the first time using overlay on thick film patch antenna. Thickness of overlay dependent tuning of the antenna has been achieved.

The purpose of this paper is to present the results of studies on the reaction of metal oxides such as Cr₂O₃ and Al₂O₃ with Na₂SO₄ in flowing SO₂ (g) at 1,100 and 1,200 K.

The oxides chosen for the studies were initial scaling products during the oxidation of industrial alloys and invariably are involved in hot‐corrosion reactions in the presence of molten salts. The thermo‐gravimetric studies for the system were carried out as a function of Na₂SO₄ in the mixture. The different constituents in the reaction products were identified by XRD analysis and morphologies of the reaction products were discussed on the basis of optical metallography and scanning electron microscopic studies. The pH and conductivity of the aqueous solutions of reaction products were measured and an attempt made to functionalize these parameters with Na₂SO₄ concentration in the mixture. Quantitative estimation of the soluble metal was carried out using an atomic absorption spectrophotometer. The formation of products was investigated by thermodynamic computation of free energies of the reactions and the study of relevant phase stability diagrams.

Looking at the complex nature of the reactions, it is difficult to generalize the conductance studies, as many complex species are liable to hydrolyze in the aqueous solution. However, the break in few curves at certain mole fraction of Na₂SO₄ indicates the presence of soluble complex species.

The paper provides information regarding the reaction between a pertinent oxide and Na₂SO₄ and proper identification of reaction products, useful for understanding the occurrence and importance of fluxing reactions and in the interpretation of hot corrosion mechanism and the development of new protective materials.

Metal matrix composites (MMCs) are engineered materials formed by the combination of metal matrix and reinforcement materials. They have a stiff and hard reinforcing phase in metallic matrix. The matrix includes metals such as aluminum, magnesium, copper and their alloys. The purpose of this paper is to describe the development of an aluminum alloy‐aluminum oxide composite using a new combination of vortex method and pressure die casting technique and the subsequent tribological studies.

An aluminum alloy‐aluminum oxide composite was developed using vortex method and pressure die casting technique. The aluminum alloy‐1 wt% aluminum oxide was die cast using LM24 aluminum alloy as the matrix material and aluminum oxide particles of average particle size of 16 μm as a reinforcement material. The friction and wear characteristics of the composite were assessed using a pin‐on‐disc set‐up; the test specimen, 8‐mm diameter cylindrical specimens of the composite, was mated against hardened En 36 steel disc of 65 HRC. The tests were conducted with normal loads of 9.8, 29.4 and 49 N and sliding speeds of 3, 4 and 5 m/s for a sliding distance of 5,000 m. The frictional load and the wear were measured at regular intervals of sliding distance.

The effects of normal load and sliding speed on tribological properties of the MMC pin on sliding with En 36 steel disc were evaluated. The wear rate increases with normal load and sliding speed. The specific wear rate marginally decreases with normal load. The coefficient of friction decreases with normal load and sliding speed. The wear and friction coefficient of the aluminum alloy‐aluminum oxide MMC are lower than the plain aluminum alloy. The wear and coefficient of friction of the entire specimens are lower.

The development of aluminum alloy‐aluminum oxide composite using vortex method and pressure die casting technique will revolutionize the automobile and other industries, since a near net shape at low cost and very good mechanical properties are obtained.

There are few papers available on the development of (or tribological studies of) MMCs including aluminium/aluminium alloy‐ceramic composites developed by combination of vortex method and pressure die casting technique.