Acid. An acid is a compound that releases ions of hydrogen when it is dissolved in water. It is very reactive. Activation. It is the process of preparing a metal to receive a finishing. Alkali(ne). An alkali receives ions of hydrogen when it is dissolved in water. Anion. An anion is an atom that has become negatively charged because it has gained an electron. It has more electrons than protons. Atom. The smallest unit of an element. It consists of: Proton. A positively charged particle in the nucleus of an atom. Neutron. A particle in the nucleus of an atom that does not have an electrical charge. Electron. A negatively…

The companies of the electroplating and finishing industry are in business because manufactured parts corrode over time. However, why do they corrode? What is the actual chemistry that causes rust to form on parts? Simply put, the atoms in parts oxidize (lose electrons, becoming cations) when exposed to oxygen and water. The more atoms oxidize, the greater the corrosion of the part.

Electroplating is the process of depositing a thin layer of metal onto the surface of a base metal using electricity. Why would you do that? The additional layer protects the base metal from corrosion, reduces friction, makes the base metal stronger and more durable, promotes conductivity and solderability, or improves a part’s appearance. Electricity is used to make the surface layer adhere firmly to the base metal. The anode (positive) is the name given to the metal that is to be deposited onto the base metal. The cathode (negative) is the name given to the base metal. For example, let’s say you had a steel part that you wanted to add…

The typical electroplating process contains the following key steps. Setup of the Tanks. Each tank that will be used in the process is properly prepared. The bath will consist of the correct metal ions (gold, silver, nickel, etc.,) merged with water for the process to be conducted.  Depending upon the metal of the part to be plated (such as steel or aluminum), the correct pH is set for the tank. The tank is heated to the correct temperature and the tank is agitated as required. Additives, such as a brightener, are added to the bath. A properly functioning rectifier is connected to the tank to contribute the correct volts/amps to…

The work that a plating and finishing shop does is difficult to see. Literally. The dimensions requested for a finish are most of the time smaller than what can be seen by the human eye. In the graphic below, the large gray area represents just a small portion of a large circle with a diameter of one inch. There are three small green dots in the bottom righthand corner. The largest dot represents the width of the human hair. The middle-sized dot represents the width of the smallest object that can be seen with the naked human eye. The smallest dot represents a common dimension, 200µ, otherwise noted as 2/10,000…

Maintaining the correct electrical charge in the tank is critical for successful plating and finishing. If the charge is too low, the part will not achieve the minimum dimension required by the customer. If the electrical charge is too high, the finish on the part may exceed the maximum allowed by the engineers. In addition, parts can be “burned” by exposure to excessive electrical charge. Therefore, the calculation of the amps required for a job is essential to the successful finishing of the part. In summary, the process to calculate the amps for a job consists of the following steps: Calculate the surface area of the part. Convert the surface…

In an ideal plating or finishing application, a finish would completely adhere when applied to a part (a substrate). However, the ideal is rarely experienced. Some substrates simply resist the application of a finish because they have oxide films, are highly active, are porous, are littered with defects, or lack conductivity. In order to resolve these issues, an intermediary layer is applied to the substrate. Such a layer is called a “strike”.  The desired finish is then uniformly applied to the strike layer. A strike layer is like a finished layer except that it is restrained. The strike is given just enough time to prepare the substrate for a finished…

pH is a number that determines the acidity or alkalinity of an aqueous solution. The numeric value represents the concentration of hydrogen ions (H+) present in the solution. When the temperature is 77°F, a solution with a pH greater than 7 is considered “alkaline” (such as baking soda), a pH of 7 is “neutral” (such as water), and a pH under 7 is considered “acidic“. These values can shift depending upon the temperature of the solution. While the pH range is typically given as zero to 14, pH can be less than 0 or greater than 14. These numbers represent a ten-fold change in the number of hydrogen ions. A…

Water is essential to the processing of plating and finishing in the electroplating industry. A typical plating shop has dozens of tanks of water, many intentionally mixed with compounds such as metals or acids. These tanks are used in the processing of customer parts. There are many tanks that are set aside for the rinsing of the parts after a stage in the treatment process. What does an environmental-conscious firm like F.M. Callahan & Son do to treat all of these “contaminated” tanks of water? Micro Filtration. We direct this water through an elaborate system of pipes, pumps, and tanks into a micro filtration system that removes suspended solids and…

The electroplating and finishing industry is an essential industry in our economy. The surfaces of parts in our computers, appliances, automobiles, trucks, airplanes, and trains are finished to make the products stronger, more durable, more useful, and less corrosive. However, the process to apply plating or finishings to such parts requires the use of dangerous chemicals. It is to a customer’s advantage to utilize the services of experienced platers and finishers such as the professionals that work at F.M. Callahan & Son. We have over 100 years of experience handling chemicals in such a manner to produce high quality results for our customers, protect our employees from danger, and protect…