What is the Galvanizing
Zinc plating refers to the surface of metal, alloy or other materials coated with a layer of zinc in order to play a beautiful, rust-proof surface treatment technology. The main method is hot dip galvanized.
Zinc soluble in acid, but also soluble in alkali, it is called amphoteric metal. Zinc does not change much in dry air. In humid air, the zinc surface produces dense zinc carbonate membranes. In sulfur dioxide, hydrogen sulfide and marine atmosphere, zinc corrosion resistance is poor, especially in high temperature and humidity containing organic acid atmosphere, zinc coating easily corroded. Zinc standard electrode potential of -0.76V, for the steel substrate, the zinc coating is anodic coating, which is mainly used to prevent corrosion of steel, the pros and cons of protective performance and coating thickness has a great relationship. Zinc plating after passivation, dyeing or coating with a light agent, can significantly improve its protective and decorative.
In plating bath containing galvanizing solution, after cleaning and special pretreatment to be plated as a cathode, made of plated metal anode, the two poles were connected with the positive and negative DC power supply. The zinc plating solution is composed of an aqueous solution containing a metal-plating compound, a conductive salt, a buffer, a pH adjuster and an additive. After electrifying, the metal ions in the zinc plating solution move to the cathode to form a plating layer under the action of the potential difference. The anode metal forms a metal ion into the galvanizing solution to maintain the concentration of the metal ion to be plated. In some cases, such as chrome plating, an insoluble anode made of lead and lead-antimony alloy is used only to transmit electrons and conduct current. The concentration of chromium ions in the electrolyte needs to be maintained by periodically adding a chromium compound to the bath. When galvanized, the quality of the anode material, the composition of the zinc plating solution, temperature, current density, power on time, stirring intensity, precipitated impurities, power waveform and so on will affect the quality of the coating and need timely control.
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