Introduction
In electroplating, a metal is coated with a thin layer of a different metal using electricity. Although the process has been around for nearly a century, electroplating has been increasingly popular in recent years due to its vast range of potential applications, from corrosion protection to decorative finishes.
However, electroplating is typically a complex, hazardous, and expensive process. This can present a barrier to those who are new to metalworking, especially if they are interested in simple DIY projects. Fortunately, metalworking aficionados have developed methods of plating metals without electricity, known as metal finishing baths. In this article, we will discuss the requirements of a metal finishing bath and provide a recipe for one.
What Is a Metal Finishing Bath?
A metal finishing bath is a liquid solution in which metals can be dipped and left to sublimate in order to produce a thin layer of metal on the surface. While there are many different recipes for these baths, Atotech’s website provides a broad overview of some of the more common materials:
• Acid— typically sulfuric acid, which is often used in etching, pickling, and plating
• Base — typically potassium hydroxide, for neutralizing and cleaning
• Solvent— typically toluene, for reducing surface tension and enhancing absorption
• Additive — typically benzotriazole, for protection against oxidation
• Metallic salts — typically zinc chloride, for depositing zinc onto the surface
• pH balancer — typically potassium phosphate, for regulating the pH balance of the solution.
The pH level, which is a measure of the acidity of the solution, should be maintained in the range of 7.0-9.0. Any changes in the pH balance should be detected and corrected quickly, as this can cause the plating process to be unstable and may even cause damage to the metal.
Instructions
The following method provides a recipe for a bath suitable for plating zinc onto steel:
1. Begin by preparing the solution, adding the following ingredients in the order listed:
• 8 liters of deionized water
• 250 g of zinc chloride
• 250 g of potassium phosphate
• 10 ml of benzotriazole
2. Carefully stir the solution until all ingredients have dissolved.
3. Adjust the pH level to 8.0 by adding potassium hydroxide and Stir the solution until the pH is stabilized.
4. If necessary, adjust the pH level again by adding sulfuric acid.
5. Dip the metal objects into the solution and leave them for a few hours until the desired amount of plating is achieved.
Conclusion
Metal plating without electricity is possible thanks to metal finishing baths. Even those who are just starting out in metalworking can produce a metal-plated surface with this method, although if the process is not done properly it can cause damage to the metal. To do metal plating without electricity, one must first prepare a solution with the necessary ingredients and adjust the pH level before dipping the metal objects in the solution. The recipe provided in this article can be used to plate zinc onto steel surfaces, but keep in mind that other metal finishing bath recipes may vary based on the materials being used.
