Binders coating-metal interface

Ferrite pigments appear to protect steel both by creating an alkaline environment at the coating-metal interface and, with certain binders, by forming metal soaps. Kresse [70,80] has found that zinc and calcium ferrites react with fatty acids in the binder to form soaps and attributes the corrosion protection to passivation of the metal by the alkaline environment thus created in the coating. 

Sekine and Kato [81] agree with this soap formation mechanism. However, they have also tested several ferrite pigments in an epoxy binder, which is not expected to form soaps with metal ions. All of the ferrite-pigmented epoxy coatings offered better corrosion protection than both the same binder with red iron oxide as anticorrosion pigment and the binder with no anticorrosion pigment. Examination of the rest potential versus immersion time of the coated panels showed a lag time between initial immersion and passivation of approximately 160 hours in this study. The authors concluded that passivation of the metal occurs only after water has permeated the coating and reached the paint or metal interface [82]. The delay in onset of passivation could perhaps also be explained if, as in EBP, the protection... 

Coated-wire electrode — A polymer film containing an ion-responsive material and a binder, e.g., poly(vinyl)chloride, is coated onto a conductor (e.g., a metal wire or graphite). They show useful response to solution concentrations of measured species in the range 10-5 < c < 0.1 mol dm-3. The processes at the metal polymer interface are still not understood. 

As electrochemical reaction sites, CLs play an extremely important rote in the performance of fuel cell stacks. A CL mainly consists of catalyst, support and binder. The CL is usually coated on the surface of the GDL. Another method has the CL directly applied to the membrane (catalyst coated membrane, CCM). The selection of the components, the proper ratios of those components, the structure of the formed CL and the formation method of the CL are critical factors in the performance of a fuel cell. The stability of the fuel cell performance is directly related to the stabilities of the catalyst, binder and support in flie CL. Degradation of catalytic activity would be due to the agglomeration of the eatalyst particles and their detachment from the support, the degradation of the binder, and the oxidation and corrosion of the support, particularly at the cathode. Further improvement in CL performance is possible. The basic technical considerations include how to maximize the three-phase interface of the CL, how to stabilize the metal particles on the support, and how to reduce the degradation of the components in the CL. 

Ti02, silica and other metal oxide particles are hydrophilic too. They can be incorporated into thin films via the sol gel technique [36], or by layer-by-layer deposition [37] or as a composite coating with a polymer binder [38]. Finally, a fuUy wetted liquid-solid interface should also be beneficial for heat-exchange devices and electrodes, where overheating and over-potential can be minimized. 

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