Conversion & Pretreating

Electropolishing is a similar chemical process, but the reverse of, electroplating. The process of electropolishing streamlines the microscopic surface area and smooths out the surface of metal objects such as the 304, 316, and 400 series stainless steel. This results in a metal surface area that is microscopically featureless. The main benefit of electropolishing, besides the smoothness of the metal surface is that electropolishing selectively removes microscopic high points or peaks faster than the rate of attack on the corresponding micro-depressions or “valleys”.

Iron phosphate is the most preferred form of conversion coating for the surface treatment and finishing of ferrous and non-ferrous metals. This is due to the low cost, speed of operations, and the ability to afford excellent corrosion resistances, wear resistance, adhesion, and lubricative properties. The application is the result of phosphate salts dissolved in a phosphoric acid solution chemically reacting with the surface of the part to form an insoluble, crystalline phosphate.

Manganese phosphate coatings are used for corrosion protection, anti-galling, and lubricity. Of the coatings available, manganese phosphate coatings are the hardest of coatings and provides unbeatable corrosion and abrasion protection. Its wear resistance properties are useful when preventing metal-to-metal contact, such as cylinder liners, camshafts, and piston rings, and transmission gears, and also has an excellent oil-retentive properties giving it its lubricity and corrosion resistance. Applications for manganese phosphate coating include the production of bearings, bushings, fasteners, and other common industrial products.

Parts washing is a critical step to the plating process, especially for components being electroplated. Electroplating is particularly sensitive to part cleanliness, since molecular layers of oil can prevent adhesion of the coating. We wash our parts in accordance to the ASTM B3222 standards guide for metals being electroplated. To maintain our top quality service to customers, we continuously make sure all of our components are rigorously cleaned and up to specification standards before applying any processes.

For stainless steel components, the passivation process protects against corrosion and oxidation. During the passivation a transparent film forms on the surface of the component. This film occurs naturally on stainless steel, but the film occurs uniformly and quickly through the passivation process.

The passivation process is determined by the part geometry. A full range of passivation methods are provided to meet the requirements of the industry and industrial standards. As this is a process that finishes safety critical and high reliability components, a fully staffed chemistry lab continuously monitors the passivation process at every step. Inspection and testing are performed to ensure that the passivation process is complete and the parts are free of surface defects.

Zinc phosphate coatings (Type Z) 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. Zinc phosphate provides maximum corrosion protection and extended service life. The coatings provide good corrosion protection by bonding the final finish (stain, oil, wax or paint) to the treated material. The most commonly used applications for Zinc Phosphate are pulleys, springs, slides, and fasteners.