(95ac) Rhodium Electroplating Background, Procedure and Improvement

Rhodium is used in the jewelry industry to brighten base metals and make jewelry more corrosion resistant, making a simple piece of jewelry jump in price. A thin layer is electroplated over less expensive base metals, shielding the less resistant metal from the elements. A literature review was conducted in order to obtain all of the background information regarding general electroplating, cleaning, nickel plating, and rhodium plating. Rhodium plating resulted in a bright plate under varying conditions with greater frequency than nickel electroplating. Once the substrate had been plated it was analyzed using three separate analytical techniques; Faraday's law to calculate efficiency, the naked eye, and a quantitative measurement of the reflectivity using a 0.1 watt, 530 nanometer, and 1.0 centimeter beam sodium laser. One downfall to this process is a very low efficiency resulting in higher energy costs. Rhodium electroplating is usually 8-12% efficient under normal conditions, with much of the energy used in side reactions that produce hydrogen and oxygen. Efficiency is increased using ultrasonic waves while electroplating. The observed effects of the ultrasonic waves on the process are altered surface morphology and up to 75% plating efficiency.