Chrome plating
The chromium layer can be decorative, provide corrosion resistance, facilitate cleaning, and increase surface hardness.
Some fume suppressants used to control the emission of airborne chromium from plating baths are also toxic, making disposal even more difficult.
[2] One functional disadvantage of hexavalent chromium plating is low cathode efficiency, which results in bad throwing power.
In general, the process must be controlled more closely than in hexavalent chromium plating, especially with respect to metallic impurities.
This means processes that are hard to control, such as barrel plating, are much more difficult using a trivalent chromium bath.
4.0 M solubility in water at room temperature (i.e. with H2O:Cr molar ratio around 14:1), and such liquids behave like supersaturated electrolytes with a reduced propensity toward hydrogen evolution.
[2] Decorative chrome plating is also very corrosion resistant and is often used on car parts, tools and kitchen utensils.
[5] While decorative chrome is applied primarily for aesthetic purposes with thin layers that provide a shiny finish, TDC, such as Armoloy, focuses on enhancing surface performance.
TDC also avoids the microcracking associated with decorative chrome, making it ideal for industrial applications where durability and friction reduction are necessary.
Thin dense chrome is commonly used in precision tools, aerospace, medical, and food processing equipment.
[2] Increasing plating thickness amplifies surface defects and roughness in proportional severity, because hard chrome does not have a leveling effect.
[citation needed] Modern engineered coatings do not suffer such drawbacks, which often price hard chrome out due to labor costs alone.
Modern engineered coatings applied using spray deposition can form layers of uniform thickness that often require no further polishing or machining.
These coatings are often composites of polymers, metals, and ceramic powders or fibers as proprietary formulas protected by patents or as trade secrets, and thus are usually known by brand names.
[citation needed] Most bright decorative items affixed to cars are referred to as "chrome", meaning steel that has undergone several plating processes to protect it from weathering and moisture but the term passed on to cover any similar-looking shiny decorative auto parts, including silver plastic trim pieces in casual terminology.
In the short production run prior to the US entry into World War II, the government banned plating to save chromium and automobile manufacturers painted the decorative pieces in a complementary color.
In the last years of the Korean War, the US contemplated banning chrome in favor of several cheaper processes (such as plating with zinc and then coating with shiny plastic).
The heat and pressure effects exerted by the hot propellant gasses and friction by the projectile can quickly cause damage by washing away metal at the end of the chamber, freebore, leade and rifling.
Hard chrome-lining protects the chamber, freebore, leade and rifling with a thin coat of wear resistant chrome.
Due to its low cathodic efficiency and high solution viscosity, a toxic mist of water and hexavalent chromium is released from the bath.
This requires a frequent cycle of treating the bath with a wetting agent fume suppressant and confirming the effect on surface tension.
[15] This makes electroplating one of the jobs with the highest risk of occupational exposure to PFAS, but not as high as firefighters using fluorinated aqueous film forming foams.
Methods of plating chromium from Cr3+ solutions that rely on reversed current pulses have been commercialized (allegedly, to reoxidize the H2).
