Electrocoating deposition process

Electrocoating materials are acid oligomers RCOOH or more frequently R(C00H)jj for anodic deposition or RoN for cathodic deposition. These" oligomers are water insoluble but can be dispersed in water through the action of acids or bases, used as external solubilizers. The solubilization and deposition processes can be symbolized as follows ... 

Owing to their low cost and environmental friendliness, aqueous electrolytes have been used predominantly in the electrocoating industry. Non-aqueous electrophoretic deposition processes have also been explored for use in the fabrication of electronic components and the production of ceramic coatings... 

In technical processes, several high-temperature molten salts are employed for electrocoating, and the morphology of the deposit is strongly influenced by the composition of the baths. Some attempts have been made to deposit Nb and Ta from ionic liquids [21, 22]. In [21] the authors focused on the electrodeposition of AlNb alloys from room-temperature ionic liquids containing both AICI3 and chlorides of Nb. 

The modem process of electrodeposition can thus be described as a combination of three basic elements (a) Electrophoresis - migration of charged polymer particles to metal surface (b) Deposition - colloidal de-stabilization of particles at the metal-bath interface and (c) Insulation - formation of an adherent, non-conductive layer of resin on the metal surface. The last named element is responsible for the high throwing power which can be achieved with the electrocoating process. 

One area that does appear to be of industrial interest is electrocoating, i.e., the formation of adherent, impermeable coatings on various metal shapes. Here the control of the process gained by the throwing power of the cell and electrodes assures deposition over the total surface. 

The major process in anodic electrocoating will be the evolution of O, leading to an increase in pH and cons iuent deposition of the paint in its acid form, j.e. ... 

Electrodeposition, also called electrocoating, is a process by which organic materials are coated from aqueous suspension, or solution, onto a conductive substrate under the influence of electricity. The process utilizes direct current for depositing resins, so that predominantly electrophoretic processes operate. Electrophoresis in this context is understood to mean the migration of colloidal or suspended particles in an electric field. The particles migrate, according to their charge, to the anode (anaphoresis) or to the cathode (cataphoresis). 

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