Electrochemical behavior of hydrophobic silane–zeolite coatings for corrosion protection of aluminum substrate

Abstract

The anticorrosive properties of a silanezeolite composite coating applied on a 6061 aluminum substrate was investigated. The composite film, deposited by dip-coating technique, was prepared with different contents of SAPO34 powder (60-90 wt%) with the purpose of evaluating the protective action offered by the zeolite-filled silane matrix. Corrosion protection performance, during immersion in 3.5% NaCl solution, was evaluated by means of a potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The coating evidenced good barrier properties and high hydrophobicity. The addition of zeolite in the silane matrix induced, as expected, a reduction of cathodic and anodic current. The zeolite improved the barrier properties of the hybrid sol-gel films, enhancing the resistance to localized corrosion attacks. Better results were observed for the sample with 80 wt% of zeolite filler that evidenced still acceptable protective action after 3 days of immersion in the sodium chloride solution.

Experimental evaluation of the hydrothermal stability of a silicone/zeolite composite foam for solar adsorption heating and cooling application

“…The mechanical performance is enhanced at increasing interfacial adhesion between reinforcement particles and matrix. The aging thermal treatment allows an increase of covalent bonds at the interface between the silanol groups of the zeolite with the siloxane monomers, increasing the crosslinking of the polymeric structure as well as the adhesive and cohesive forces acting at the interface and on the bulk of the material, respectively …”

“…The aging thermal treatment allows an increase of covalent bonds at the interface between the silanol groups of the zeolite with the siloxane monomers, increasing the crosslinking of the polymeric structure as well as the adhesive and cohesive forces acting at the interface and on the bulk of the material, respectively. 39 At the same time, due to the presence of a large number of hydroxyl groups on the surface of the zeolite, there will be an increase in crosslinking combined with a reduction of the foaming ratio which will make the structure more rigid. 35 The composite foam can be schemed consisting of multiple micelles, consisting of a zeolite particle core and an external siloxane shell, chemically interconnected each other (as high crosslinking level of the foam).…”

Corrosion Behaviour of a Silane Protective Coating for NdFeB Magnets in Dentistry

“…Increasing the thickness of the silane layer (SL20 and SL30), the coating barrier is more effective inducing better corrosion performances. At the same time the good interactions occurred between the metal surfaces and the silane film also induces a hydrophobic behavior on the surface of the coating [15] which limits their water absorption capacity aptitude and consequently hinders the electrochemical reaction on the metal-silane interphase. Figure 7 shows the impedance plots after 72 hours of immersion for coated and uncoated magnets.…”

Electrochemical behaviour in synthetic saliva of silane coated Ni/Cu/Ni Nd‐Fe‐B magnet for dentistry applications

“…After 6 h of immersion in SL3 sample the pore coating resistance R1 decreases over half order of magnitude, from 3 Â 10 6 to 0.78 Â 10 6 Vcm 2 . The decrease of pore resistance is related with the formation of preferential pathway in correspondence of hydrophilic region of silane coating that favour the water diffusion and facilitate the activation of degradation phenomena to the surface of the underlying metal [33]. Afterwards at higher immersion time a new slight increase of R1 was observed (R1 ¼ 2.50 Â 10 6 Vcm 2 after 72 h of immersion).…”