Journal of Composites and Compounds
Volume:2 Issue: 5, Dec 2020

In this study, TiB2 reinforced Al-matrix composite was fabricated by in situ stir casting route, and the effect of processing parameters was investigated. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) were used to study the composition and microstructure of the samples. Finally, to investigate the tribological and electrochemical behavior of the samples, wear tests (pin-on-disk) and potentiodynamic polarization tests (PDP) were used, respectively. Results showed that by increasing stirring time, both tribological and mechanical behavior of the samples improved. Also, it was found that by increasing the stirring speed of the melt to 180 rpm, the mechanical and tribological behavior of the samples improved, and by further increasing the stirring speed to 300 rpm, they were decreased. Consequently, samples containing lower than 7 wt. % TiB2 showed better metallurgical properties, due to lack of agglomeration.

As a result of great surface area and a great number of energetic sites, ceramic nanocomposites are being considered as good adsorbents and catalysts. Al2O3 nanoparticles are widely used in high-tech applications owing to their excellent properties. Besides, Bi-based oxides have been the center of attention for applications such as remediation of hazardous wastes and wastewater photochemical degradation of organic contaminants and remediation of hazardous wastes. In this research, the synthesis of Bi2O3-Al4Bi2O9 nanocomposite and its mechanical properties as a novel composition were investigated. The results showed that the prepared Bi2O3-Al4Bi2O9 sample exhibited the Al4Bi2O9 crystalline peaks. Additionally, the prepared nanocomposite showed no impurities. The mechanical properties of the Bi2O3-Al4Bi2O9 sample were improved in comparison with Al2O3, Bi2O3, and Bi2O3- Al2O3, which offer it as a promising alternative to Bi2O3-Al2O3 composite ceramic.

Heat transfer efficiency has always been at the center of attractions for many researchers and industries and demand for higher efficiency methods and materials are increased in the last decades. One of the effective methods to enhance the thermal performance of instruments is using nanofluids as a solid-liquid suspension.  In the present paper, the thermal conductivity, viscosity, and heat transfer process of the nanofluids are discussed. The effect of volume fraction, temperature, particle size, shape, base fluid type, and other factors on thermal conductivity, viscosity, and convective heat transfer coefficient of nanofluids are presented. Also, the preparation methods of nanofluids are exhibited and the stability and the effective factors on the stability of nanofluids are brought in the manuscript. Besides, a summarized number of experimental and mathematical studies about the thermal conductivity, viscosity, and stability of nanofluids are listed, compared, and analyzed. The works about the Nusselt number in fluids and nanofluids are presented in detail to determine the future challenges of nanofluids.

Drug delivery is known as the administration of drugs using suitable vehicle for achieving effective treatment with no unwanted effects. In recent years, various composite materials have been developed and evaluated for being used in different biomedical fields such as wound dressings, cardiac prosthesis, tissue engineering, and drug delivery. Zinc is the second most available element after Fe in our body. Nanoparticles based on metal oxides, such as zinc oxides and Zn-containing composites, can be considered as viable platforms for some biomedical uses, especially for drug delivery applications. Mg composite biomaterials are also suggested for diverse biomedical applications due to their good mechanical properties, biocompatibility, and bioactivity. This paper highlights applications of zinc and magnesium-based composites in development of drug delivery systems.

Magnesium has little resistance to corrosion and therefore its production and use are quite limited. The problem of corrosion associated with these alloys has been alleviated to some extent by the advantages obtained from fine coatings. An additional dense barrier against corrosion is created, using coatings obtained from sol-gel. As an alternative for Cr-based conversion coatings, rare-earth elements-based ones are been increasingly investigated for Mg and its alloys due to being eco-friendly. Because of chemical inertness, low friction, and high hardness, diamond-like carbon (DLC) coatings have exhibited the best protection for Mg and its alloys. In this review, we shed light on recent advancements in novel coatings for Mg alloys including hybrid, rare-earth conversion, composite polymeric (polymer composite is a multi-phase material in which reinforcing fillers are integrated with a polymer matrix), and DLC coatings.  

Due to promising properties such as low toxicity against different cell lines, being highly stable fluorescent without showing photobleaching, and good surface properties, nanodiamonds have gained ever-increasing attention for various biomedical applications including bioimaging and therapeutic applications. Various methods are used for the fabrication of nanostructured diamond, the commonly used of which is the denotation technique. Newer approaches are being practiced for the modifcation and functionalization of their surfaces by different biomolecules suitable for interaction with considered targets. In this review, the scope and recent advancement in the feld of nanodiamonds for biomedical applications particularly their application for nanocomposite scaffold and implants are discussed.

One of the most important problems in the manufacturing industry is metal corrosion. Recently, conductive polymers (CPs) have attracted attention due to their economic viability and widespread industrial applications. Upon adsorption, long-chain carbon bonds of polymers provide a blockage for large surface areas of corroding metals. The adsorbed thin films create a barrier between the surrounding environment and the metal substrate. Polypyrrole (PPy), polyaniline (PANI), and polythiophene (PTh) are conducting polymers that are utilized to protect metals and metal alloys against corrosion. A proper selection of synthesis parameters for CPs can improve the anticorrosion behavior of the coatings for metals and metal alloys. This paper has an overview of conducting polymer composite coatings on substrates based on steel, copper, magnesium, aluminum, and their alloys.