Interface coatings electrophoretic deposition

Pang X, Casagrande T, Zhitomirsky I (2009) Electrophoretic deposition of hydroxyapatite-CaSi03-chitosan composite coatings. J Colloid Interface Sci 330(2) 323... 

A novel processing route uses in situ electrophoretic deposition of submicron sized colloidal particles of borosilicate sol onto nickel coated carbon fibers to give a dense fully infiltrated product, which is followed by pressureless sintering. Catastrophic crack growth was prevented by constrained plastic deformation of the interface, fiber debonding and pullout [136]. 

A number of assembly methods employ self-assembly of nanoparticles at the air-water interface. Monolayers (and subsequent multilayers) can be formed at the interface due particle interaction and transferred to a solid substrate by controlled dip-coating and vertical deposition methods similar to Langmuir-Blodgett film deposition [81-86]. Regular monolayers of polymer colloids can also be assembled via an electrohydrodynamic route, whereby electrophoretically deposited particles between two electrodes can be manipulated to cluster in the presence of an electric field. On application of an AC or DC field, contrary to electrostatic norms, the like-charged particles are observed to coalesce producing large close-packed 2D crystalline domains [87]. 

This chapter reviews the novel fabrication process of continuous SiC SiC composites based on electrophoretic deposition (EPD). EPD process is very effective for achieving relatively homogeneous carbon coating with the thickness of several tens to hundreds nanometers on SiC fibers. Carbon interface with the thickness of at least 100 nm formed by EPD acts effectively for inducing interfacial debonding and fiber pullout during fracture, and the SiCj/SiC composites show excellent mechanical properties. From these results, it is demonstrated that the fabrication process based on EPD method is expected to be an effective way to control the interfaces of SiC SiC composites and to obtain high-performance SiC SiC composites. 

It can be concluded from the above-mentioned differential capacitance curve and cathodic polarization curve analyses that the mechanistic model of electrolytic codeposition of Hquid microcapsules is associated with the stable chelation of—OH and -O groups of the wall material (e.g., PVA, gelatin) with metal ions (e.g., Ni ", Cu +), and this gives rise to positively charged microcapsules. This in turn helps to accelerate the electrophoretic migration of microcapsules in the plating solution. The liquid microcapsules were also adsorbed onto the electrode due to the presence of a surfactant. Consequently, it is feasible for microcapsules to enter the electrical double layer at the interface and to become embedded in the co-deposited coating. 

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