Organic coatings electrodeposition

Where changes in appearance are of paramount interest, as in the case of metallic and organic coatings on steel or other metals, visual examination is most desirable. To facilitate ratings on such a basis, photographic standards have been employed, as, for example, in tests on chromium-plated steel undertaken by ASTM Committee B-8 on Electrodeposited Metallic Coatings . These ratings are supplemented by a shorthand description of the nature of the deterioration observed. 

Beck, F "Fundamental Aspects of Electrodeposition of Paint", in "Progress in Organic Coatings", 1976,4,1 Elsevier Sequiola S. A., Lasagna. 

Industry Specific Technical Guidance Documents for Estimating Releases Electrodeposition of Organic Coatings... 

Wessling RA, Settineri WJ, Wagner EH, Studies in cathodic electrodeposition, American Chemical Society Division of Organic Coatings and Plastics Chemistry, 31(1), Mar-Apr 1971. 

Electroless nickel coatings containing PTFE particles have been discussed by Tulsi, and non-stick coatings of electrodeposited nickel containing 30% by volume PTFE particles are described by Naito and Otaka . They found that the addition of organic additives to increase the hardness of the nickel matrix to 500-600 Hy reduced the incorporation of the PTFE to 10-15% by volume. 

Relatively little attention has been devoted to the direct electrodeposition of transition metal-aluminum alloys in spite of the fact that isothermal electrodeposition leads to coatings with very uniform composition and structure and that the deposition current gives a direct measure of the deposition rate. Unfortunately, neither aluminum nor its alloys can be electrodeposited from aqueous solutions because hydrogen is evolved before aluminum is plated. Thus, it is necessary to employ nonaqueous solvents (both molecular and ionic) for this purpose. Among the solvents that have been used successfully to electrodeposit aluminum and its transition metal alloys are the chloroaluminate molten salts, which consist of inorganic or organic chloride salts combined with anhydrous aluminum chloride. An introduction to the chemical, electrochemical, and physical properties of the most commonly used chloroaluminate melts is given below. 

Many of the finishes applied to other types of metal products can also be applied to zinc die castings, although some differences in formulation as well as occasional differences in method of application may be desirable. The types of finishes applicable to zinc die castings include mechanical finishes (buffed, polished, brushed, and tumbled) electrodeposited finishes (copper, nickel, chromium, brass, silver, and black nickel) chemical finishes (chromale, phosphate, molybdate and black nickel) and organic finishes (enamel, lacquer, paint and varnish, and plastic finishes). Electrodeposited coatings of virtually any metal capable of electrodeposition can be applied to zinc die castings. 

Titanium can likewise be electrodeposited from nonaqueous organic electrolytes. At circa 18 °C, 1-75 iim thick coatings are deposited from electrolytes containing dimethylsulfoxide (DMSO) [169]. The baths utilized do not exhibit high stability. Zirconium, hafnium, niobium, and aluminum are also expected to afford electroplated coatings from similar composite systems. Electroplating of titanium from electrolytes based on aromatic solvent mixtures has recently been reported [171]. 

---