Plasma Sprayed Al ₂o₃-13 Wt.%tio₂ Coating Sealed With Organic-Inorganic Hybrid Agent and Its Corrosion Resistance in Acid Environment

Abstract

A novel organic-inorganic hybrid material of γ-methacryloxypropyltrime-thoxysilane (KH570)-SiO 2 was fabricated by Sol-Gel method. The hybrid material was used as the sealing agent for the plasma sprayed Al 2 O 3 -13 wt. % TiO 2 coating. Infrared spectrum and grafted mechanism of the hybrid agent (HA) were studied. Moreover, morphology and porosity, as well as characteristics of immersion plus electrochemical corrosion in acid environment of the coating with and without sealing treatment were evaluated, compared with those of the coating sealed with the conventional silicone resin agent (SRA). The results reveal that KH570 was successfully grafted onto the surface of SiO 2 . The HA film sealed on the surface of the coating presents a little better quality than the SRA film. The porosities of the coatings after the sealing treatment decreased. Furthermore, the sealing treatment can improve efficiently the corrosion resistance of the coating in 5 vol. % HCl solution. The hybrid sealing agent can become a candidate for the plasma sprayed Al 2 O 3 -13 wt. % TiO 2 coating used in acid environment to overcome some disadvantages of organic agents such as severely environmental pollution.

Corrosion Properties and Bond Strength in Normal Strength Concrete of Al2O3 Plasma-Sprayed Plain Bars with ZrCC/Organofunctional Silane Coating

“…The effective necessity of applying ZrCC before applying GPTMS is not evident from the bond strength testing results. The sufficient adhesion and compatibility of organofunctional silane with Al 2 O 3 have been previously demonstrated [34,35,[87][88][89]. However, coating the concrete steel reinforcement of concrete with APSS and subsequently with, e.g., GPTMS increases the slip in the bond strength testing, i.e., even small shear forces can slightly displace the reinforcement and stimulate crack formation in the structure, which may reduce its overall load-bearing capacity.…”