Trivalent Chromium Plating
Trivalent Chromium Plating
Today, industrial parts manufacturers can make their products more competitive in the marketplace by using a variety of surface treatments. This capability enables designers of some metal components to alter or modify specific exterior qualities, such as electrical conductivity, texture, color, and more. Frequently, companies choose to apply several surface treatments during the finishing stage in order to produce metal parts meeting specific objectives. Trivalent chromium plating has become a widely-used surface treatment in some industries.
About Chromium Plating
Since at least 1924, chromium plating has played an important role in the finishing of metal parts and components. It offers both practical and aesthetic benefits. Manufacturers perform "hard" chrome plating by applying a thick layer of chromium to metal parts to enhance wear resistance. They may alternatively apply a thinner layer of chrome for primarily decorative purposes. For instance, electroplating a thin layer of chromium over nickel surfaces can help create a brighter, even shinier metal exterior to enhance a product's aesthetic appeal to consumers. Considerable differences exist between hard chromium plating and decorative plating, however. Chromium plating increases surface hardness and makes it easier to maintain metal surfaces in a clean condition. It also often produces aesthetic changes which give products an attractive silvery sheen.
The two most widely used forms of chromium plating solutions rely upon hexavalent or trivalent electrolytes. During electroplating, a manufacturer typically places a metal component in a chromium solution and applies an electrical current to cause the deposition of chromium onto the surface of the metal work piece. Experts recommend using different plating tanks for hexavalent and trivalent chromium plating. In the past hexavalent chromium solutions enjoyed widespread use, although more recently trivalent chromium electroplating solutions have gained greater popularity.
Trivalent Chromium Plating
Typically, trivalent chromium electroplating solutions rely upon either chloride or sulfate-based electrolytes. The process of trivalent chromium electroplating usually requires several steps. Variations exist in production technologies. Usually, a manufacturer must first thoroughly clean a work piece to remove debris and grease. Depending upon the composition of the part, fabricators apply one or more pretreatments. For instance, many fabricators first electroplate parts with nickel prior to applying decorative chromium plating.
Then, to apply the chromium, the metal part manufacturer places the work piece in a chromium industrial electroplating vat and heats the solution to a designated temperature. The application of an electrical current for a specified period of time causes chromium to bond to the surface of the work piece. By regulating parameters such as the time the piece remains in the electrolytic solution, the fabricator can control the thickness of the chromium. In recent years, some companies have developed proprietary formulations of brush-on paints which may offer products the appearance of chrome electroplating.
Applications And Materials
Today trivalent chromium electroplating has gained widespread acceptance as a way to apply a lustrous chrome finish to metal components. Manufacturers use this process in a variety of industries.
Industrial trivalent chromium plating around the world occurs in both highly automated and low tech settings. It requires the use of electroplating equipment and access to a source of electrical current. Typically, manufacturers rely upon chromium chloride or chromium sulfate-based electrolyte baths as important sources of chromium. Metal parts which undergo chromium electroplating sometimes include ferrous alloy, nickel, copper, brass and stainless steel components.
Hard chrome plating enhances wear resistance and increases the useful longevity of parts. It may help ensure metal surfaces benefit more fully from lubrication. It has become a popular surface treatment in the production of some metal items. Popular applications for this process include the fabrication of gun bores and mold surfaces. In addition, automotive engine parts often benefit from trivalent chromium plating. Parts manufactured using this surface treatment may include gears, engine piston rings, brake discs, fasteners, suspension assemblies, rollers, and hydraulic cylinder rods. The auto manufacturing industry in the past relied heavily upon decorative chrome plating, and some auto makers still utilize decorative chrome to enhance vehicle bumpers, door handles and brand icons. Trivalent chromium plating also contributes to useful applications in many other industries, including the construction, industrial machinery, transportation, plumbing, aerospace, electronics, agricultural and aviation sectors.
Advantages of Trivalent Chromium Plating
Trivalent chromium plating has increased in popularity in recent years because it offers distinct benefits as a surface treatment.
- The deposition of thicker deposits of chromium significantly enhance the ability of metal parts to sustain wear, This surface treatment may increase the anticipated useful lifespan of a component, for instance.
- A thick outer layer of chromium on a metal part provides improved corrosion resistance in many situations. Manufacturers of products subjected frequently to contact with damaging environmental conditions may seek to provide this extra level of protection. Hard chromium electroplating improves the performance of some metal components, such as piston rings within automotive assemblies, for example.
- Applying hard chromium surface treatments also enhance a metal part's ability to withstand higher temperatures. Components may perform more effectively after undergoing this surface treatment. One illustration exists in the creation of durable metal molds subjected to frequent hot environments.
- Using chromium plating enables some manufacturers to essentially salvage parts which they might otherwise discard. Some companies rely upon trivalent chromium electroplating to help restore heavily worn metal components and make them useful once again. This process may prove more cost-effective than recycling worn components.
- Hard chromium electroplating reportedly helps some metal components endure friction better. It remains a popular engine component surface treatment.
- Decorative chromium surface treatment may enhance a metal part's appearance. This process often helps beautify automotive exteriors.