Mechanical and chemical stability of super-hydrophobic coatings on SMA490BW substrate prepared by HVOF spraying

SMA490BW weathering steel is an important engineering material employed in the bogies of high-speed train. However, the bogies are also subject to ice accumulation, corrosion, sand abrasive, and heterogeneous wear or other hazard. In this paper, the superhydrophobic (SH) surface on SMA490BW steel is fabricated by using High Velocity Oxygen Fuel (HVOF) spraying technology and low surface energy modification. Self-cleaning effect, hydrophobic durability, wear resistance, the weather resistance, PH stability and electrochemical properties were discussed. The results showed that the as prepared coating possesses CA of 154.3 +/- 3 degrees and sliding angle of 4.1 +/- 0.1 degrees. The CA has no obvious fluctuations after immersing in water for different time and at PH in the range of 1 to 7. The CA is still above 150 degrees after abrasion for 2400 mm. The SH coating possesses higher E-corr and lower I-corr compared with SMA490BW substrate and HVOF WC-12Co coating. The SH coating has a long-term water repellency towards environmental conditions during weathering. The SH coating possesses excellent mechanical and chemical stability, which is benefit for applying this coating on the highspeed train bogies.