Using plating for a finish for a wide range of metal machinery and parts has many benefits that are well known. Plating helps protect that component from wear and damage from corrosion, increases the performance of that part or component, and even increase/decrease the conductivity of a part, too.
This all makes sense, but choosing which plating finish is best for a certain part used in a certain application is more complicated. Other variables to take into consideration are the different types of environments that part is going to encounter, and what the intended use that part has which helps determines which attributes are needed for the finished part.
Two of the more common finishes out there are electroless nickel plating and hard chrome plating. Which one is better has become somewhat of a debate between manufacturers, and so here are a few facts to help better understand the differences between the two finishes. As always, feel free to reach out to PFI Inc. directly to talk to a finishing professional to help better determine which finish makes the most sense per the intended application.
What are some Common Uses for Hard Chrome?
The definition of hard chrome plating is an industrial chrome used to finish parts to be more functional. There is also a decorative chrome finish that is more aesthetic and used for visual appeal on motorcycles and automobiles. While hard chrome is somewhat decorative in nature, it is much more ideal for engineering applications over the decorative chrome finish that is much more common. Some of these applications are machine tools which are sometimes plated with hard chrome to extend the life of the tool. Since hard chrome also provides anti-stick and release capabilities, hard chrome plating is often used on gears and plastic molds. These characteristics also make hard chrome a preferred finish for pistons and shock absorbers for a variety of machines and vehicles.
What are Common Uses for Electroless Nickel Plating?
Unlike hard chrome, and as the name suggests, electroless nickel plating does not require an electric current to apply the finish. Instead, the process uses an autocatalytic chemical reaction to deposit a uniform coating over the intended part. Also, the amount of phosphorus used in the plating can affect characteristics. For example, low phosphorus plating provides the hardest coating but least amount of corrosion protection. Whereas high phosphorus plating is the least hard but best for corrosion protection. Having said that, electroless nickel plating is widely used for a vast amount of components in harsh conditions to protect everything from fuel injectors and cylinders to pump and pipe fittings. Nickel plating is also commonly found in electronics such as hard drives and circuit boards to help protect the processors from corroding over time.
What are some Similarities
Both electroless nickel and hard chrome finishings work well for a variety of substrate materials as the plating process deposits onto all surfaces of the component being finished evenly, making it perfect for plating irregularly shaped objects and those with holes and indentations. The also can both cover a variety of different materials, including stainless steel, copper, brass, and more (even some plastics). Hard chrome and electroless nickel are both extremely durable and designed to last a long time even with constant and consistent mechanical contact. Both also have excellent corrosion resistance properties (though more on that below), and sliding characteristics as both finishes lower the coefficient of friction significantly. Lastly, the appearance of the component–though not usually a major consideration since these applications are used in a more industrial environment–is generally improved through either hard chrome or electroless nickel.
Differences: Which One Do I Choose?
Which is a better – electroless nickel or hard chrome plating? To answer this question, let’s take into consideration four criteria to help choose:
- Wear: how long will the part last over time under similar circumstances (i.e. how often it is used and comes in contact with other machinery)
- Corrosion: how well the finish protects the part from corrosion over time
- Environment: the conditions the part is primarily used under and what kind of exposure will it have to moisture, heat or cold, oil, and other factors
- Motion: is the part being finished a moving part? Does the entire operation need to halt in order to fix or replace the component?
Hard Chrome Plating: Hard chrome does win out in the hardness category and therefore will most likely wear the best. However, the conditions the hard chrome finds itself in can definitely affect this catch-all statement. Hard chrome also retains oil well and marginally has a lower coefficient of friction.
Electroless Nickel Plating: As far as corrosion resistance is concerned, nothing beats out electroless nickel plating. Since the finish is so uniform and smooth, this type of plating leaves absolutely no room for moisture to get through. With hard chrome plating, though it does produce a finish on top of the substrate, chrome may need to be polished away in certain areas to create a more even covering. This also makes electroless nickel the preferred finish for any component that has a lot of holes or is shaped irregularly as the finish is more definite. It also protects the part better in harsher environments, too; another major consideration when determining which finish.
Which is the Better All-Around Finish for End Products?
As with most pros and cons comparisons, it really does depend on the end-use application and specific purpose of the part being finished. Having said that though, here at PFI Inc., we generally prefer electroless nickel as the better all-around finish because, even where hard chrome shows its biggest strengths (hardness, lower coefficient of friction), electroless nickel isn’t very far behind in these categories all things considered. Also, one item not directly discussed above, the price is also an important consideration. Though every part and machine shop is different, generally speaking, it is usually more reasonable to use electroless nickel over hard chrome as a finish. Sometimes this is because, on an intricate part, no secondary operation is needed when using electroless nickel, where with chrome some polishing or light machining may be needed to ensure ultimate protection from the elements.
For over 30 years, Progress for Industry, Inc. has created excellent metal finishing services for the molding industry. Using expert craftsmanship and extensive knowledge to construct precision molds and components, many of PFI’s workers have been there since it’s first establishment in 1982. Visit https://www.pfiinc.com/
