Chrome plating surface finish is typically applied on various household products such as lock cylinders and other door lock parts. Chrome plating layer can be decorative and functional. To understand more about chrome plating, here we are going to talk about what is chrome plating, how it works and how to remove chrome plating in different ways.
Chrome plating refers to a technique of electroplating chromium on other metals as a coating. Chrome is a natural element and a kind of silvery-white metal with a little blue color, it is easy to passivate in air and forms a thin film on the surface. The chromed layer can provide corrosion resistance, increase surface hardness, simplify cleaning procedures and improve the aesthetic. The chrome plating layer also has high hardness, good heat resistance, and good wear resistance.
Chrome plating is an electroplating technique, requires an electrical charge to trigger the chemical reaction in which the chromium deposits itself onto the surface of the substrate.
Compared with other metal plating types, the composition of chrome plating bath is simple, but the process of chrome plating is complex. The main component of chromium plating bath is not metal chromate, but chromic acid, the oxygen-containing acid of chromium. A certain amount of anions must be added to the chromium plating bath to realize the normal deposition of chromium. The dispersion ability of chromium plating solution is very low. For parts with complex shapes, a conformal anode or auxiliary cathode should be used to obtain a uniform chrome plating layer. High cathodic current density is needed for chrome plating. In addition, the anode of chrome plating does not use metal chrome, but uses an insoluble anode. Lead, lead-antimony alloy and lead-tin alloy are usually used.
There are lots of ways to remove or stripe the chrome plating layer from the substrate, you can use easy-to-use equipment, chemical solutions or household materials to get rid of the coating.
1. Use special equipment. For example. The abrasive or sandblasting machine applies sandblasting, shot peening and other processes using microparticle powder or fine particles to grind materials. Long-time abrasive blasting can remove the chrome coating of objects, but after that, some hard-to-reach areas may need to be treated separately. In some cases, the ultrasonic cleaner can also remove the coating. If you have used other methods to loosen the chromium coating, its cleaning effect will be better. Put the chromium-plated items into the cleaning tank of the ultrasonic cleaning machine and soak them in a clean solution.
2. Use hydrochloric acid. Hydrochloric acid is a strong acid with corrosiveness. The use of a high concentration of hydrochloric acid can remove the chrome coating on metal objects. A concentration of about 30-40% should be enough. The hydrochloric acid and water are mixed in the proportion of 1:3 in the big barrel used for mixing chemical raw materials such as corrosion-resistant plastic barrel to obtain 30% acid solution. You can also buy pre-prepared acid solutions of the required concentration. Immerse the chromium-plated object in the solution until the chromium-plated layer falls off. Wash the object thoroughly with soap and water, rinse and dry.
3. Use sodium hydroxide. The chromium plating on ferrous metals and carbon steel was removed with sodium hydroxide (alkaline solution). Sodium hydroxide, commonly known as lye, is a kind of corrosive alkali chemical. It can dissolve several metal coatings, including chromium, but can react dangerously with water and aluminum. It corrodes aluminum and produces flammable hydrogen. Therefore, it can only be used for articles without aluminum in the base material. Mix 250 ml to 350 ml of sodium hydroxide and 4 liters of water in a vat made of neutral materials such as corrosion-resistant plastic buckets. Immerse the chromium-plated object in the solution until the chromium-plated layer falls off. This may take a long time, so be sure to check the chromium coating off frequently. Wash the object thoroughly with soap and water, rinse and dry.
How to Remove chrome plating at home? Pour baking soda or solid household cleaner into the water to make a grinding paste. Dip it with a soft cloth and rub it on the chrome until the chrome coating falls off. This method has the best effect when it is applied to the very thin and weak adhesion chromium plating layer. But you have to work hard to wipe it off. Pay attention not to scratch the bottom material when wiping.