“…For the systematically movement of the plasma gun over the substrate surface, it was attached to a six axis robot. All the controlling parameters of APS process mentioned in Table 1 have been chosen according to the literature [23-26]. Figure 2 3D surface topography of the sand blasted substrate before coating.…”
In the current work, by using NiTi plasma spray, superhydrophobic property is developed for compressor parts used in aerospace engine. The durability of the coating enhances in case of droplet impingement in cold condition (temperature = 25 °C). For the hot condition the aforesaid coating needs to become hydrophilic for the retention of high durability characteristic. The discussed switching is achieved by keeping the coating with in an influence of electric field. The results revealed that the surface roughness (12.4 µm) of the coating supports the attainment of superhydrophobic characteristic depicting contact and rolling angle of 164°± 1.5 and 8°± 1, respectively at normal condition. By applying electric field, the coating is converted to hydrophilic in hot condition noticed by impact mapping of droplets. Furthermore, it has been observed that the coated steel plate shows better efficiency as compared to uncoated steel plate under electric field.
“…For the systematically movement of the plasma gun over the substrate surface, it was attached to a six axis robot. All the controlling parameters of APS process mentioned in Table 1 have been chosen according to the literature [23-26]. Figure 2 3D surface topography of the sand blasted substrate before coating.…”
In the current work, by using NiTi plasma spray, superhydrophobic property is developed for compressor parts used in aerospace engine. The durability of the coating enhances in case of droplet impingement in cold condition (temperature = 25 °C). For the hot condition the aforesaid coating needs to become hydrophilic for the retention of high durability characteristic. The discussed switching is achieved by keeping the coating with in an influence of electric field. The results revealed that the surface roughness (12.4 µm) of the coating supports the attainment of superhydrophobic characteristic depicting contact and rolling angle of 164°± 1.5 and 8°± 1, respectively at normal condition. By applying electric field, the coating is converted to hydrophilic in hot condition noticed by impact mapping of droplets. Furthermore, it has been observed that the coated steel plate shows better efficiency as compared to uncoated steel plate under electric field.
“…The shape memory thin-film NiTi alloys are produced by different methods, such as magnetron sputtering, pulsed laser deposition, electron beam evaporation, ion beam deposition, plasma spray technique, ion plating, and flash evaporation [30]. However, detail study of the film structure obtained from all those techniques says that those processes face some inherent limitations such as low deposition rates, inhomogeneous composition, and incompatibility with MEMS processes etc.…”
Section: Fabrication Of Niti Sma Thin Filmsmentioning
This paper discussed the fundamentals of NiTi shape memory alloy and its applications in advanced scientific fields. Currently, the world is focusing on miniaturized systems for various industrial and functional applications. The thin-film shape memory NiTi alloy plays a crucial role in MEMS/NEMS industry in fabrication of microdevices. In this article, the NiTi phase diagram along with the shape memory effect and superelasticity has also been explained. Among several types of fabrication techniques for NiTi thin films, magnetron sputtering, which yields a better homogeneous film, has been discussed. Both the operational parameters (target type, Ar pressure, applied power, target-substrate distance, substrate rotation, substrate temperature, plasma stability, deposition rate) and the material's parameters (deposition pattern, orientation of adatom, film thickness, film stress, crystal structure, grain size, intermetallic formation, oxide formation, phase transformation) have been correlated in this article. The utilization of shape memory behavior in various industrial applications has been discussed here, also the advantages and limitations of SMA have been briefly discussed.
“…They found that the coating form some intermetallic (such as NiTi, Ni 9 Ti and Ni 4 Ti), which increases hardness five times compared to substrate (mild steel) hardness. Again, Swain et al [16] studied the tribological effect of NiTi APS coating by varying different stand-off distances (40, 80, 120, 160 and 200) mm and obtained that all the properties (such as deposition efficiency, adhesion strength and hardness) is maximum at 120 mm stand-off distance due to better chemical bonding and mechanical interlocking between the splats of coating. Roshan et al [17] reviewed article on NiTi plasma spary process and concluded that preheating temperature affects the splat morphology, increase the hardness due to dense packed coating and crack may be form at coating surface due to thermal mismatch.…”
Atmospheric plasma spraying (APS) is one of the most preferred coating processes, which comes under thermal spraying technology. It has a wide range of applications due to its versatility in surface modifications. By the APS technique, different high-temperature application materials like cermets, and ceramics, can be coated on a substrate whose surface properties have to be modified in an extreme environment. Ni50Ti50 (at.%) alloy became more focus of interest for researchers and industrialists due to their two extraordinary smart properties such as shape memory effect (SME), and superelasticity (SE) which can protect any structural materials from catastrophic failure. Compared to various deposition routes, APS is an economical process to apply NiTi on mild steel. NiTi smart alloy also exhibits good wear resistance, corrosion resistance, damping behaviour, and high load-bearing capacity. In terms of mechanical properties, it has high strength and hardness at high temperatures. Owing to these properties, NiTi alloy can be used to protect structural materials such as mild steel from catastrophic failure. In this study, mild steel was coated at 100 °C, 200 °C, 300 °C and 400 °C preheating temperatures by APS techniques using an equiatomic NiTi alloy. The surface and interface characterization were performed using an optical microscope, SEM, XRD, Hardness test and 3D optical profilometer. It was found that along with the desired NiTi phase, some of the intermetallic and oxide phases are responsible for the mechanical strength. The surface and interface morphologies show that NiTi splat formation by APS results in better surface bonding and dense coating. With increase in the substrate temperature, the hardness of a coating interface increases with decrease in the number of pores at coating interface.
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