Mechanical components, whether stationary or moving are subjected to wear and corrosion. A combined effect of these two is even more deleterious. Thermal spray technique proves to be an effective solution to address these issues. HVOF coatings owing to their inherent characteristics like high hardness, adhesion, density (porosity <1%) its provide enhanced mechanical and tribological performance and so are widely used across industries. Micro-factors like presence of pores, oxides and cracks, matrix and binder properties, addition of Cr, cohesive strength and boundary regions etc. do influence the coating behaviour, besides the deposition parameters. The objective of this paper is to review the effect of above mentioned factors on the wear and corrosive performance of the coatings for industrial and research viewpoint.

Carbon is a favorable alternative as counter electrode material for dye sensitized solar cells (DSSC) as compared to Pt. Various carbon materials such as carbon nanotubes (CNT), activated carbon (AC) and carbon nanofibers have been investigated as counter electrodes for DSSC applications, based on their high electrochemical activity, high specific surface area, chemical inertness and high electrical conductivity. Among various phases of carbon, diamond is the most robust and chemical inert material that can be used for electrode application. It has band gap of 5.5 eV, high thermal conductivity. its electrical resistivity can be tuned by doping such as boron. In this work, we investigate boron doped diamond thin film electrode for DSSCs. The conductive diamond thin electrode films were grown using Blue Wave hot wire chemical vapor deposition (HWCVD) system. The electrical resistance in diamond thin films was tuned by controlling grow temperature, filament power, dopant concentration and sp3/sp2 ratio in the film, it thickness, and initial seeding process. Scanning electron microscopy, Raman spectroscopy and electrical resistivity measurement were used to characterize morphology, diamond quality and electrode conductivity, respectively. Diamond film electrodes with optimized surface morphology and electrical characteristics were used for DSSC fabrication. We used nanocrystalline TiO 2 paste (P25 Degussa) with average particle size of 25nm as an active layer, the electrolyte comprised of a LiI/I 2 electrolyte in acetonitrile (CH3CN), a Ru based metal complex dye [cis-diisothiocyanato-bis(2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium(II) bis(tetrabutylammonium)] OR N719 was used as sensitizer. The photovoltaic performance was determined using J-V characteristics under standard illumination conditions and was compared to a reference DSSC with Pt counter electrode. Results are discussed in the context of diamond electrical and durability and chemical stability of diamond films against most commonly used family of iodine based electrolytes.

Any mechanical component stationary or in relative motion is exposed to severe surface phenomena like corrosion, wear, abrasion etc. To address these issues various surface treatment processes are in industrial practice. In recent times, coatings techniques have been identified as cost effective alternative to other surface modification techniques. Thermal spray technique proves to be the prominent method to among a large variety of processes available. HVOF method owing to its capability to provide wear and corrosion resistant coatings with characteristics like high hardness, adhesion, density (porosity <1%) is widely accepted across industries. Process parameters seems to have significant influence on coating properties like porosity level, oxide content, micro hardness and tribological performance of coating. This paper intends to investigate the effect of above mentioned process deposition parameters on physical, mechanical, wear, erosion and corrosion properties of coating.

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Abstract- CrN and Cr2N (200) in the coatings.