Cadmium Plating is a coating process that offers many technical benefits. While cadmium is a byproduct of zinc production, it has been used for almost 100 years as an effective protective coating. It has outstanding corrosion resistance in high-salt and low- thickness environments. In fact, Cadmium Electroplating is the optimal choice for many important and useful applications, especially in the aerospace and military industries.
While Cadmium Plating is used frequently for the aerospace industry, it’s also commonly used in other environments with exposure to high salt concentrations. Cadmium is normally combined with substrate materials like iron, copper, steel and powdered metals.
Cadmium is a soft silvery-white or bluish-gray metal with similar characteristics to zinc and mercury. It is often used in electric batteries, coatings, pigments, and electroplating applications. Due to its protective qualities, Cadmium Plating is the preferred coating process used in the shipbuilding and aerospace industries for critical parts used in the manufacture of aircraft and boats of all sizes.
Cadmium Plating Benefits
Cadmium Plating offers many technical benefits, including:
1) It is extremely pliable and can be soldered almost as well as tin.
2) Cadmium plated surfaces are also resistant to mold and bacteria growth.
3) Corrosion resistance in aquatic environments.
4) It provides low galvanic corrosion levels whenever in contact with aluminum.
5) It also provides excellent lubricity, outstanding conductivity, rust prevention, and low electrical contact resistance. This plating process comes with such good built-in lubricity that it prevents galling and provides a low friction surface.
Two more important benefits to mention are that it can easily coat dissimilar materials, complex shapes, and hard-to-reach contours; and it can also be applied in an ultra-thin, lightweight layer. In fact, its attractive white luster is often compared to silver plating. Cadmium closely resembles Zinc Plating for many applications. It can be clear, dyed in many colors, and works well as either a paint base or final finish. Typical chromates include clear, yellow, olive drab and black. Typical thickness is .0002″ – .0008″ deposit. QQ-P-416F is the Federal standard for Cadmium Plating.
Because of its many advantages and superior protective qualities, Cadmium Plating is widely used in many industries, with particular effectiveness in salt-water settings and the harshest of corrosive environments. The aircraft industry specifically uses Cadmium Plating because it reduces corrosion in their flight-critical steel components. Cadmium is also useful in the transportation industry, electronics, and consumer products.
Cadmium Plating is also the preferred choice for equipment and hardware purchased by the U.S. military. The military learned years ago through past experience that no other coating
provides the corrosion resistance of cadmium for their mission-critical equipment. This process is used to manufacture the millions of screws, nuts & bolts, washers, and a range of other hardware items used in military and aerospace equipment, including Navy ships, submarines, and aircraft.
Cadmium Plating Types
There are several different types of Cadmium Plating options:
- Type I: As plated.
- Type II: Supplementary chromate treatment. Per Federal standards, Type II plating will not show white corrosion products of cadmium, pitting, or basis metal corrosion products at the end of 96 hours (20%) salt spray exposure.
- Type III: Supplementary phosphate treatment. Type III shall conform to Type I of TT-C-490. Type III is commonly used as a paint base.
And there are three classes for thickness:
- Class 1: 0.0005″ minimum thickness
- Class 2: 0.0003″ minimum thickness
- Class 3: 0.0002″ minimum thickness
Cadmium is able to resist a humid environment better than zinc, but it has less protection power than zinc. The most common method of applying a cadmium coating is by electroplating. Cadmium Plating is completed using cyanide baths containing a mixture of cadmium oxide and sodium cyanide in order to produce Na2Cd(CN)4. In an industrial environment, a 25 µm thick coating may last for one year but in a marine environment, the life of the cadmium coated material is significantly increased. In a marine environment, chloride and insoluble carbonates are produced, which do not wash out from the surface. It provides good protection to steel in stagnant conditions, soft waters and acid, or high-alkaline conditions.
In recent years, cadmium has been the subject of scrutiny because it is a toxic substance that needs to be regulated and controlled. While cadmium can be dangerous, banning it as a metal finishing option may create more danger than it prevents. Cadmium is a vital, even life-protecting finish. If cadmium were no longer an option, how would performance and safety be affected in mission-critical military equipment, naval ships, or aircraft?
Our priority is to promote the safe, responsible, and controlled use of cadmium. Aerospace Metals operates with full awareness of all the related environmental and health implications. Cadmium is responsibly controlled and used wisely by environmental-conscientious companies like ours. Cadmium Plating serves a vital function to the many life-critical manufacturing industries mentioned in this article.
If you looking for Cadmium Plating services, Aerospace Metals is your one-stop source. We offer the very best equipment and processed for all your metal finishing and plating needs, including Cadmium Plating. All of our processes use verified best suppliers. And because we know exactly where to find inefficiencies in the outsourcing chain, you can expect less rework and lost parts.
With Aerospace Metals LLC, you won’t hear the typical excuses you’ve probably encountered in the past from other shops. We offer a comprehensive review of your entire outsourcing platform.
We have an extensive network of experienced Metal Fabrication, CNC Machining, Extrusion, Stamping & Metal Finishing companies located throughout North and South America. The companies we work with all maintain a minimum Quality Management System of ISO 9001:2008.