S.T. Aruna

Combustion synthesis: an update

Combustion synthesis has emerged as a facile and economically viable technique for the preparation of advanced ceramics, catalysts and nanomaterials. Recent innovations in the combustion and processing parameters have resulted in a better understanding of combustion phenomena and control of microstructure and property of the products.

Preparation of Oil-Encapsulated Microcapsules and Tribological Property of Ni Composite Coating

Microcapsules containing oil are potential candidate materials for preparing electrocomposite coatings with excellent tribological properties. In the present study, the preparation of oil-encapsulated microcapsules and electrodeposition of Ni-microcapsule composite coating are presented along with the properties of the coating. In situ interfacial polymerization method was used for the preparation of lubricating oil-encapsulated urea-formaldehyde microcapsules. The synthesized microcapsules were incorporated into the nickel matrix by electrodeposition using Ni-Watts bath. The Ni-composite coating containing microcapsules exhibited smaller Ni grain size, higher microhardness and lower surface roughness compared to plain Ni coating. Electrodeposited Ni coating containing oil-encapsulated microcapsules exhibited improved tribological properties with lower wear loss and coefficient of friction compared to plain nickel coating.

Solution Combustion Synthesis

Abstract Solution combustion synthesis (SCS) has become one of the most widely used methods for the preparation of a plethora of oxide materials. Advantages of the SCS process are that it is fast, uses relatively simple equipment, permits control over many aspects of the products, leads to the formation of high purity products, permits stabilization of metastable phases, and allows the formation of virtually any size and shape products. SCS-derived powders are very effective for environmental remediation. The possibility of depositing nanocrystalline ionic catalysts on ceramic cordierite honeycombs by a single-step combustion method has been demonstrated.

Carbon plasma immersion ion implantation and DLC deposition on Ni-Ti alloy

ABSTRACT Carbon plasma immersion ion implantation (PIII-C) has been performed on Ni−Ti alloy surface using methane as a precursor gas at low temperature and it has been followed by deposition of diamond-like carbon (DLC) coating. Untreated and coated alloys are characterized with field emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrochemical impedance spectroscopy, and corrosion testing in Hanks’ solution which is simulated body fluid show that corrosion resistance has been enhanced in PIII-C + DLC-coated alloy compared to untreated alloy. The in vitro studies of untreated and PIII-C + DLC-coated alloys have been evaluated using osteoblast-like cells (MG-63). Cellular behavior in terms of cell morphology along with the viability and cell spreading has been evaluated using scanning electron microscopy and in vitro cell culture assay, respectively. In comparison to Ni–Ti alloy, the coated alloy exhibits better cell viability indicating their biocompatibility.

The Corrosion Resistance of Nickel Electrocomposite Coating Containing BaFe12O19 Particles

Electroplating composite coating is an effective method to prepare composite coating through the codeposition of metallic, nonmetallic, or polymer particles with metal to improve properties such as corrosion resistance, hardness, and wear performance. This paper reports the synthesis of a novel Ni-BaFe12O19 magnetic nanocomposite coating exhibiting improved corrosion resistance. In the present paper, BaFe12O19 particles were synthesized by a single-step solution combustion method and characterized for phase, particle size, and morphology. These particles were incorporated in a nickel metal matrix, and the properties of the coatings like nanohardness and corrosion resistance were investigated. The coating microstructure was also studied using field emission scanning electron microscope. A Vickers hardness of 777 HV was exhibited by Ni-BaFe12O19, and plain Ni coating exhibited a hardness of 517 HV. The Ni-BaFe12O19 composite coating exhibited improved corrosion resistance compared to plain Ni coating with an value of 0.034 μA/cm2 compared to 0.361 μA/cm2 for plain Ni. The Ni-BaFe12O19 coating also exhibited higher charge transfer and polarization resistance compared to plain Ni coating.