The chrome plating process uses electrolysis to bond a thin layer of chromium to an object, typically made from a metal that is susceptible to corrosion. Chromium is an element that occurs in nature, but by itself it is not resistant. You will never find objects made 100% of this material; however, chrome plating makes metals very bright, shiny like mirrors and is often used for car and motorcycle elements, taps, household and industrial items. The outer layer is resistant to oxidation and protects metals by also reducing the friction between surfaces. The chromic procedure is a highly specialized job that requires the use of very toxic, volatile, carcinogenic substances (such as chromic and sulfuric acid) and which produces very dangerous waste. You may be interested in understanding how the process works, but for security reasons it is strongly discouraged to put it into practice.
Steps
Method 1 of 4: for Decorative Purposes
Step 1. Use chrome plating to protect corrosion-susceptible metal decorations, such as steel, brass, copper, aluminum, and stainless steel
- The chrome layer gives a more intense, brilliant and less distortion "mirror" effect compared to other finishes, such as paint.
- Chrome plating for decorative purposes binds a layer of nickel and chrome on the object thanks to electric plates; with this procedure you can treat the wheel rims or a hood frieze.
- Nickel is the element that makes the surface smooth, shiny and resistant.
- A very thin layer of chromium prevents nickel from blackening, scratching or rusting.
Method 2 of 4: for Large and Functional Objects
Step 1. Apply tough, "industrial" chrome plating to dramatically reduce wear on machinery, such as those made of steel
- This chromium layer is not harder than the others, but thicker to the point where its strength can be tested.
- In this case, the layer is measured in thousandths instead of millionths, as is the case with decorative chrome.
Method 3 of 4: Use a Hexavalent Solution
Step 1. To make 4 liters of solution mix 940 g of chromic acid with 970 ml of distilled water
The proportions may vary slightly depending on the metal to be chromed
Step 2. Stir the solution in a dip tank that is used for testing materials or for chemical treatments
- Thoroughly clean and degrease objects before "bathing".
- When preparing the chromic acid solution, pour the liquids slowly to avoid splashing.
- Remember that this mixture is carcinogenic.
- Handle chemicals carefully and scrupulously manage the entire process, because the solution can start a fire, interact with many other elements and thus become an additional source of risk.
Method 4 of 4: Using an Implant for Electroplating
Step 1. Dissolve the nickel plates in the chromic / sulfuric acid solution
Step 2. Slide the positive charge from the electrical power source through the solution
Step 3. Connect the anode to the object you want to chrome and immerse it in the bath
- Negatively charged attracts metal particles that have a positive charge and stick to the object.
- The thickness of the chrome plating depends on the duration of the bath during electroplating.
- If you need to do decorative chrome plating, keep the solution temperature between 35 and 46 ° C.
- If you need to make an industrial coating, the temperature must be between 50 and 66 ° C.
- Do not prepare or handle chemicals without wearing a respirator and other protective equipment.
Step 4. Rinse the item in a running water bath and proceed with a final rinse
Advice
- Preheat the object by bringing it to the same temperature as the acid bath before immersing it, to ensure an even coating.
- Chromic acid is extremely corrosive, but can be stored in glass containers and filtered before next use.
Warnings
- When working with acid solutions wear protective equipment, including goggles, respirator mask, apron, and industrial rubber gloves.
- Have a first aid kit, emergency numbers ready and know how to intervene.
- The chromic acid solution reacts dangerously with acetone, alcohol, sodium, potassium, ammonia, arsenic, hydrogen sulphide, phosphorus, selenium, sulfur, pyridine and many other chemicals.
- The chromic acid solution reacts rapidly with many materials, including common flammable substances, often causing them to burn and ignite.
- The disposal of acid products is strictly regulated by law; comply with the regulations laid down by your municipality.
- Avoid any type of skin contact with the solutions.
- Be careful not to inhale the vapors.
- Remember that chromic acid solution is carcinogenic.
