| Abstract: |
Thermal spray coatings do not provide bright high surface finish coatings. Many coatings have high friction surface as-sprayed. Such coarse coating surface under high temperature applications (incineration plants, boilers, ship and automotive engine, aircraft and land based turbine engines, metal processing, electric utilities, and textile and plastic industries), promotes erosion of the coating and enhances the amount of deposit on the coating surface. Ultimately, the life time of the coating reduces and overall cost of an incineration plant, boilers, ship and automotive engine maintenance increases. This feature article explores the concept of mimicking the lotus (Nelumbo nucifera) effect for thermal spray coatings. A simple and semi-empirical method to bring the multi-scale roughness (micro, sub micron and nano) on steel substrates coated via thermal spraying was developed. This simple and cost effective method enables to increase the water contact angle from less than 90° to higher than 140°. HVOF/SPS (for sub micron and nano scale roughness) techniques were used to realize structures similar to that of lotus leaf. This study provides the underling important parameters, which govern the formation of multi scale structures.
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