Zinc and aluminum are the two metals recommended for the galvanic protection of iron and steel against corrosion, both in the atmosphere and when immersed in either fresh or salt water. Zinc wire is 99.9% pure and is not contaminated in the flame spray process. As a result, flame sprayed zinc coatings are much purer than those applied by hot dip galvanizing, for instance, since the molten zinc used in galvanizing picks up considerable iron, because of the nature of the process.
Zinc wire is particularly useful on work where all areas are not readily accessible since small, uncoated areas and voids are protected electrolytically better by zinc than by aluminum. Zinc coatings are recommended for use in the pH range of 6 to 12 and are much more resistant to hard water than to soft water. Zinc coatings, however, have poor resistance to almost all organic and inorganic acids and have poor resistance in any water type above 60° C (140° F). For exposure to acid conditions, soft water or hot water, aluminum coatings are the better choice. Zinc is recommended as a primer on surfaces which will be painted, to form electrically conductive surfaces on glass and ceramics.
|Melting Point||787° (approx.)|
|Tensile Strength||13,000 psi|
|Coating Texture||200-350 ra (as sprayed)|
|Coating Density||6.36 gm/cc (91%)|
Most anti-corrosive coatings of sprayed zinc (as with aluminum) are put into service without additional machining.