Coating Material

ELECTRO ZINC PLATED FASTENERS   Vs   ORGANIC COATED FASTENERS   Vs   CORROSHIELD COATED FASTENERS                     ELECTRO ZINC PLATED FASTENERS Fasteners are dipped in various chemicals & electrodes are introduced & metal in ionic form will migrates from a +ve to a -ve cathode creating a bonding between metal & zinc. Coating bonds well unless process has been compromised. Fading of coating is a common problem. Coating thickness thinnest among three. A common problem for all electro zinc plated fasteners despite efforts to neutralise it with annealing. Annealing not a full proof solution. With presence of zinc, coating becomes self healing when scratch. Will prevent rusts from spreading. Ample resistance for normal non-hostile applications. Thicker coating stronger corrosion resistance. But difficult to strike balance between resistance strength & embrittlement woes. Not recommended for outdoor. Zinc plating on its own will never be able to achieve the test requirements established by the Australian Standards. Durability in neutral salt spray test is only approximately 36 hrs. ORGANIC COATED FASTENERS Using electro zinc plating as base coat, an additional protective coating is added on. Behaves very much like the paint on our domestic vehicles. Base coat adhesiveness good becaused protected by outer coat. But protective coating have tendency to peel or flak after weathering. Problem persists if zinc plating is used as base coat. If zinc plating is not used as base coat, corrosion issues may occur with absence of zinc. With presence of zinc, coating becomes self healing when scratch. Will prevent rusts from spreading. Good combination of base coat and protective coat will provide excellent corrosion resistance. Durability uncertain due to peeling and flaking possibilities. What makes a good combination subjective. Again, with the correct coating combination, achieving this standard is possible. But wrong or compromised coating choices can prove worse than zinc plating as some companies in the industry have demonstrated. CORROSHIELD COATED FASTENERS Using copper fleshing as an adhesive enhancing agent, the CORROSHIELD coating is mechanically deposited. Coating is basically "sand- blasted" onto metal surface. "Sandblasting" effect provides tightest adhesiveness. Coating basically becomes part of metal surface sitting even with- in the uneveness of surface. Mechanical deposition of coating cuts down significantly the dangers of Hydrogen Embrittlement. Almost virtually free from this problem. With presence of zinc, coating becomes self healing when scratch. Will prevent rusts from spreading. Single coat with correct control on porosity of coating can provide excellent corrosion resistance. Add chromate or other protective elements to further strengthen resistance. Good for outdoor use. Coating process control is the main determinent in achieveing this standard. General success rate is high. Safe & economical option to choose. Least chances of running into complication.