Impact of Plating Conditions on Electroplating
Electroplating is an intricate process that involves depositing a metallic coating over another metal for protection, aesthetics, and to increase electrical contact. It is a highly complicated process that is extremely sensitive to plating conditions. The electroplating process has been used for centuries, and the application is still essential to our modern day-to-day life. It is used to create the body of vehicles, appliances, and other industrial components. Even in its most basic applications, electroplating requires several critical parameters to be controlled precisely, including time, current, temperature, and chemical concentrations.
Time
The plating time is likely the most important element to consider when electroplating. This time is used as a measure of duration and will vary depending on the current used, the plating bath temperature, and the chemical concentrations. Generally, times range from a few seconds to tens of minutes. If the coating time is too short, it may not be possible to get the desired thickness of deposited metal. Plating too long can cause the base metal to corrode. In addition, excessive plating time is associated with increased electrical consumption and increased material costs.
Current
The current density is the amount of electricity that passes through a given unit area of a plated part. It will typically vary from a few milliamps for decorative finishes to 100 amps for thicker deposits of conductive metals. The current density determines the rate of deposition and influences the quality and thickness of the coating. If the current density is too low, the coating may appear patchy or pitted but plating at too high a current can result in localised burning or the formation of trees, or raised branches, on the surface of the plated part.
Temperature
Temperature is another variable that can have a profound effect on the electroplating process. If the plating temperature is too low, corrosion may occur and the electrical conductivity of the solution may be compromised. On the other hand, excessive heat can cause the plating solution to boil, leading to the formation of bubbles and porosity in the deposit. The temperature of the plating solution also affects the speed of deposition. Higher temperatures generally increase the deposition rate and improves the coverage of the substrate.
Chemical Concentrations
The chemical composition of the plating bath is vital to the electroplating process. Sulfuric acid is generally used as the electrolyte, but this can be influenced by the addition of other compounds, such as ammonium chloride and boric acid, in order to control the pH and improve the composition of the coating. Improper chemical concentrations can lead to unexpected results, with cracks in the deposit, a decrease in brightness, and poor adhesion to the substrate.
The electroplating process is a delicate yet powerful one. The plating conditions play a crucial role in the success of a job, and any alteration can have serious consequences. As such, it is essential to maintain the specified plating conditions throughout the process in order to achieve the desired results.
