Improvement of thermally sprayed coating properties by microstructure modification has been considered as a significant solution. Therefore, in this research the effect of dissolved oxygen content and post heat treatment on the formation and distribution of secondary phase particles, particularly in nano-scale in the coatings during spraying and after that were studied. Ni-5 wt% Al powders were...

In this study nanosized TiO2coatings on the 316L stainless steel substrate were prepared by means of dip-coating technique in which thickness of the coating layer increased byrepeating the coating cycles in two different routes: (I) dipping and drying,respectively, were repeated one, three and five times and finally the dried coated sample was heat treated (single); (II) multiple heat treatment...

in this research, b4c-ni cermet coating was sprayed on the surface of 4130 steel from b4c and ni feed-stockpowders using high velocity oxy-fuel (hvof) method. in order to characterize the tribological behavior of thecoating, ball on disk wear tests were done at the ambient temperature and under the loads of 1, 3 and 5 n.phase analysis of the coating after spraying was studied by x-ray diffracto...

Current Process HVOF thermal spray is widely used for coating critical wear parts like landing gear, bearing races, valves and turbine components. Generally, fully or partially molten metal, composite, or ceramic droplets are propelled from a gun or torch onto the workpiece. Multiple passes are required to build up the coating, since each pass only deposits ~ 0.0002 in 0.0005 in thickness of ma...

Pure and 10 wt% 80Al2O3-20TiO2 reinforced hydroxyapatite coatings were successfully deposited on Ti6Al4V substrate by plasma spray technique for bio medical applications. Post coating heat treatment was carried out to study the effect of heat treatment on improvement in micro structure and mechanical properties of coatings. Coating was characterized by SEM/EDAX and XRD analysis. Positive impact...

as we know sol-gel is one of the most important techniques for thin film preparation. in this paper, high transmission silica thin films have been prepared by dip-coating process from a new silicon-alkoxide solution. the prepared sol was stable for 45 days which is very important to characterize the coating process. the optical properties as a function of aging time, withdrawal rate, and heat t...

The phenomenon of evanescent-wave scattering (EWS) is used to design an optical-fiber humidity sensor. Porous solgel silica (PSGS) coated on the surface of a silica optical-fiber core scatters evanescent waves that penetrate the coating layer. Water molecules in the gas phase surrounding the optical fiber can be absorbed into the inner surface of the pores of the porous silica. The absorbed wat...

A novel nanocomposite consisted of nanomaterials as (CuO:NiO) and carbon (fuel ash) were designed to absorb solar energy. Thin films were made via casting and spin coating of the dopants nanocomposite thin films, containing different concentration ratios of CuO:NiO. These thin films are precipitated on a glass and copper substrates. The optical properties of the doped fuel ash films with na...

In photothermal energy conversion the absorbed solar flux is converted to heat which is then used directly or is converted to mechanical or electrical energy. Efficient receiver design requires that thermal losses from the absorber surface, which is the hottest element of the system, be minimised. Receivers are, in fact, generally classified according to their operating temperature ( I , 2). Th...

A number of mater ia ls and techniques have been used t o form se lec t ive s o l a r absorber coatings. Each of the coating processes and the coatings formed has i t s own l imi ta t ions which a r e generally paorly defined. The poor s t a t e of knowledge on the l i m i t a t i o n s of the coating processes and the resu l t ing coatings poses a problem f o r the component design and the mat...