The process of electroplating, or using an electric current to deposit one metal onto another, dates to the early 1800s. Some metals, such as zinc, provide corrosion resistance when plated to the surface of an underlying metal. The plating process generally involves immersing the metal to be coated, and a sacrificial piece of the metal that will be plated onto the first metal's surface. It is dipped into an electrolytic solution and the two metal electrodes are connected to a DC power source. The electrolytic solution contains a dissolved salt of the plating metal. Commercially available kits contain all of the necessary parts and ingredients for a hobbyist to electroplate zinc at home. Eventually, however, the electrolyte solution will require replacement.
Cut three pieces of waxed paper about 3 inches by 3 inches and fold them in half. These pieces will serve as "weighing paper" on which the chemicals will be measured and transferred to a container.
Unfold a piece of waxed paper and place it on the balance's weighing pan, then zero the balance.
Measure 12.0 grams of ammonium citrate onto the waxed paper, then carefully transfer the powder to a 500-mL plastic bottle. Repeat this process to weigh out and add 7.5 grams of ammonium chloride and 30.0 grams of zinc sulphate heptahydrate to the bottle.
Measure 100ml of distilled water into a 100-mL graduated cylinder and pour it into the plastic bottle containing the measured chemicals. Repeat this process two additional times for a total of 300ml.
Cap the bottle tightly and shake it until all of the powder has dissolved. The electrolyte solution is ready for use in zinc electroplating.
If more or less than 300ml of solution is desired, then this process is directly scalable. That is, simply multiply all measured quantities by two to prepare 600ml or divide by two to prepare 150ml, etc.
Always wear protective eyewear and latex gloves when handling chemicals.
Tips and warnings
- If more or less than 300ml of solution is desired, then this process is directly scalable. That is, simply multiply all measured quantities by two to prepare 600ml or divide by two to prepare 150ml, etc.
- Always wear protective eyewear and latex gloves when handling chemicals.
Things you need
- Waxed paper
- Balance capable of measuring to 0.1g
- 12g ammonium citrate
- 7.5g ammonium chloride
- 30g zinc sulphate heptahydrate
- 1 gallon distilled water
- 100-mL graduated cylinder
- 500-mL or larger plastic bottle with cap