Electrocoating materials

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 ... 

The most unconventional yet most Important feature to be built into electrocoating materials is "throwing power", or the ability to form electrodeposited films of such uniform thickness that even the most recessed areas of a workpiece are covered. 

The solvents used for electrodeposition resins perform three functions. First, the solvent facilitates handling during the preparation of the aqueous solution since these carboxyl containing materials are either resinous or sticky semi-solids. Second, the solvent may accompany the vehicle during deposition and therefore can influence the flow characteristics during post-deposition bake or cure. Third, the solvent can confer better water solubility characteristics on the resin and thus help to maintain bath stability, a factor of prime importance in electrocoating. 

Metallic objects are first cleaned to remove impurities and materials associated with metal forming, welding, temporary rust protection, etc. In many instances phosphate and/or chromate treatments are applied. Overall, any electrically conductive surface preparation will impart benefits to electropainted articles similar to the benefits imparted to spray painted or dip-coated articles. The workpieces go from pretreatment to the electrocoating tank either water wet or dried. 

Aluminum alloys with niobium and tantalum Nb and Ta can be obtained in elemental form from high-temperature molten salts. Nb and Ta are widely used as coatings for corrosion protection as they form - like Al - thin oxide layers that protect the underlying material from attack. 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... 

Wheels are electrocoated engine blocks are coated with heat-resistant, usually waterborne materials. Other parts (e.g., steering equipment and shock absorbers) are painted with two-pack, one-coat epoxy systems that are usually solventborne use of waterborne systems is, however, increasing. 

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). 

E-coat A coating applied by electrophoretic deposition (electrocoating). Usually an organic material but may be particles of inorganic materials such as glass. See also Electrocoating. 

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