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Characteristics Of High Pressure Steel Pipe Galvanizing
Nov 02, 2016

Zinc plating with blue and white appearance, the standard electrode potential for -0.76V, soluble in acid, soluble in alkali, is hyperbolic amphoteric metal. Zinc dry air in the almost not occurred changes, zinc corrosion of critical humidity is greater than 70%, so in wet atmosphere in the can and carbon dioxide and oxygen role generated a layer main by alkali type carbonate zinc composition of film, this layer film has must of sustained corrosion role, zinc and hydrogen sulfide, containing sulfide up reaction generated sulfide zinc; zinc easy by chlorine ion dip corrosion, so in seawater in the not stable.


Zinc in confined or poorly ventilated, and the humidity conditions, volatile matter and non-metallic materials (low molecular weight carboxylic acids, aldehydes, phenols, ammonia, etc) contact, the zinc corrosion-prone to generate white loose corrosion products, commonly known as "white". Zinc in high temperature, high humidity, confined conditions, and bakelite, paint, wood releases volatile contact zinc has a tendency to grow single crystal filaments, commonly known as "long hair".


Standard potential than iron for zinc negative is Anodic coating for steel, can provide reliable electrochemical protection. In industrial atmospheres, rural atmosphere and maritime atmosphere of steel products can be used in select zinc layer, the protective life is almost proportional to the thickness of the zinc layer. In case of industrial air pollution in the atmosphere, and corrosion resistance of zinc coating is superior to the cadmium plating, at sea or in sea water, on the other hand.


After zinc plating with chromate passivation and corrosion resistance can be increased by 6-8 times. The passivation of zinc plating is a necessary step. Organic dye in the film, can be used for file protection---decorative coatings products.


For reduced zinc coating thick and can improve resistance corrosion capacity, both at home and abroad mining following two species measures: a is improve passivation film of quality, as with blue, green, Army Green, black passivation instead of General of rainbow color passivation film, especially to Army Green passivation film resistance corrosion sex best; II is to more thin of containing iron 0.3%--0.6% of Zn-Fe alloy, or containing nickel 6%-10% of Zn-Ni alloy instead of pure zinc coating, resistance corrosion performance improve three times times above, widely for car plate Shang instead of plating zinc.