Zinc plating provides a protective layer across steel and iron surface ,due to its electronegative character to iron and steel gives excellent corrosion resistance particularly in industries and urban environment.
It is an economic rust prevention solution that has been used for more than 10 decades.
Zinc offers more protection when applied in thin films of 8-15 microns compared with similar coatings like nickel & other cathodic coatings.
Alkaline non cyanide zinc plating process has great advantage that being completely free from cyanide, alkaline non cyanide zinc process has uniform distribution & more throwing power compared with other zinc plating process.
Acid zinc plating solutions are recommended for plating high carbon steels,cast,malleable,wrought and forged iron components,acid zinc produces a mirror-like bright deposit from a weakly acid chloride based solution which is completely free from cyanide or organic complexants.
Zinc-cobalt is one of the alloy plating processes developed in the nineties to replace cadmium and to provide enhanced corrosion resistance. It has greater corrosion resistance than zinc. In salt spray testing the coating will achieve in the range of 500 hours to red rust. Zinc-cobalt like zinc can be combined with chromates and sealers to increase corrosion resistance and improve the appearance. Current method of application at hohman plating is barrel plating.
Zinc Iron is an electrolytic plating process that is proven to combat the corrosion of steel. This process provides additional corrosion resistance compared to standard zinc.
Zinc iron plating offers good corrosion resistance, typically 4 to 5 times better performance than zinc plating and a deep, lustrous black appearance.it is used extensively in applications where its appearance is of key importance
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|HONDA||HES D2003 [MFZN-FE1-K]|
Zinc nickel plating has the ability to offer outstanding corrosion protection, especially when subjected to high temperatures. It is used extensively in automotive under body applications where its temperature and corrosion resistance are vital.the preferred alloy composition of zinc nickel plate is 12 – 15% nickel, with the remainder being zinc. This alloy gives exceptional sacrificial corrosion resistance and can be readily passivated. To achieve this alloy, zinc nickel is usually plated from an alkaline electrolyte
Cadmium coatings are applied to iron, steel, brass and aluminium and give excellent resistance to corrosion in most conditions and especially in marine and alkaline environments. Cadmium, like zinc, also provides sacrificial protection to a substrate such as steel by being preferentially corroded when the coating is damaged and small areas of the substrate are exposed. In addition to corrosion protection, cadmium coatings provide a low coefficient of friction and therefore good lubricity, predictable torque characteristics, good electrical conductivity, protection from galvanic corrosion (in particular when in contact with aluminium), easy solderability, low volume corrosion products and reduced risks of operating mechanisms being jammed by corrosion debris for many components in a wide range of engineering applications throughout industry.
Electroless nickel plating is used in various engineered coating applications: automotive differential pins, brake pistons, slip yokes, oil & gas ball valves, aluminum fuel filters, memory disks, printing rolls, and washers.
Electroless nickel is a dense, nickel alloy composed of nickel and phosphorus. Phosphorus quantities range from 2% to 14%, depending on the specific application and performance requirements.
Phosphate coatings are a crystalline conversion coating for steel and other metals that is formed on a ferrous metal substrate. The process of phosphate coating is employed for the purpose of pretreatment prior to coating or painting, increasing corrosion protection and improving friction properties of sliding components. In other instances, phosphate coatings are applied to threaded parts and top coated with oil (p&o) to add anti-galling and rust inhibiting characteristics.
The phosphating process relies on the basic pickling reaction that occurs on the metal substrate when the process solution comes in contact with the metal. The main benefits that phosphating provides is strong adhesion and corrosion protection. Typically, phosphate coatings used on steel parts but can also be used on aluminum. Metal coatings offers both zinc phosphate and manganese phosphate coating. Our phosphate coatings additionally are offered in both dark gray & black.
Metal coatings offers black manganese phosphate coatings and dark gray manganese phosphate coatings (type m) used for corrosion protection, anti-galling and lubricity. Of the numerous phosphate coating available, manganese phosphate coatings are the hardest, while providing unbeatable corrosion and abrasion protection. In comparison to zinc phosphate coatings, manganese phosphate coatings offer continued wear protection after the breaking in of components that are subject to wearing. These coatings are applied only by immersion. Uses for manganese phosphate applications include the production of bearings, bushings, fasteners and other common industrial products. Use of manganese phosphate is especially useful in projects that require sliding of parts, such as automotive engines and transmission systems.
Zinc phosphate coatings (type z) are also available and are mainly used for rust proofing on ferrous metals. They can be applied by immersion or spraying. Zinc phosphate is a lighter alternative to manganese phosphate, while providing resistance to harsh elements that tend to wear products quickly. We offer both black zinc phosphate coatings and dark gray zinc phosphate coatings.
|COLOR||DARK GRAY / BLACK|
|COATING WEIGHT||2000-3000 MG / SQ. FT|
|TOP COATS||OIL OR PAINT|
Aluminium and aluminium alloys are treated by a corrosion resistant conversion coating that is called "chromate coating" or "chromating". General method is to clean the aluminium surface and then apply an acidic chromium composition on that clean surface. Chromium conversion coatings are highly corrosion resistant and provide excellent retention of subsequent coatings. Different type of subsequent coatings can be applied to the chromate conversion coating to produce an acceptable surface.
Along with providing high corrosion resistance and paint adhesion properties to aluminium surface, it is well known that the visual desirability may be improved by forming a chromate coating by contacting the surface with an aqueous conversion coating solution containing chromium ions and other additives.
quality of surface pre-treatment prior to powder coating is the most important factor that effects to stability of paintings. Properly pre-treated aluminium surfaces become highly protected against corrosion even if the surface is exposed to external impacts ( damage, high temperature, humidity…etc. ). Chromating is generally used as under paint protection. Coating weight on the surface varies between 0.2 -2.0 gr/m² when coating solution is applied to surface by immersion or spraying. Coating weight is variable according to concentration, application time, temperature and ph of the coating solution. Out of proper operation parameters coating weight quality of the coating will reduce. Thicker coating does not mean high quality coating.
Most commonly, chromating is provided by yellow chromating (cr+6), green chromating (cr+3), transparent chromating (cr+3).
Coating quality will be effected positively when surface treated with deionized water after chromating. Refinishing of the rinsing baths also improve the quality of the coating. Chromated and rinsed aluminium workpieces should be dried in driers or ovens but it is important not to set drying temperatures above 70°c. After all these treatment workpieces are painted then cured 10 – 15 minutes at 200°c for subsequent application of powder coating.
Hot dip galvanizing is the process of coating iron or steel with a layer of zinc by immersing the metal in a bath of molten zinc at a temperature of around 842 °f (450 °c). During the process, a metallurgically bonded coating is formed which protects the steel from harsh environments, whether they be external or internal. Galvanized steel is widely used in applications where corrosion resistance is needed without the cost of stainless steel and can be identified by the crystallised pattern on the surface (often called a ‘spangle’). Galvanizing is probably the most environmentally friendly process available to prevent corrosion.