AUTOMOTIVE PLATING
Manufacturers in the automotive industry are always seeking ways to protect their products from the relentless forces of corrosion. Most of us who have owned a vehicle over a period of several years have probably experienced the onset of rust at some point. Rust can spread quickly, and the ensuing damage can ruin a paint job in no time. We’ve all seen those unsightly holes caused by rust eating through a car’s body!
There are many factors that contribute to the onset of rust on a vehicle. Bird droppings, acid rain, dirt, tree sap and even dead insects can destroy a vehicle’s finish. As the paint and clear coat are “eaten away” by these contaminants over time, the underlying metal body parts become more susceptible to corrosion. Exposure to road or sea salt will significantly hasten the corrosion process. Even a small scratch provides an open invitation to rust. Washing a car once a week can go a long way toward preserving a vehicle’s finish, as it will remove most of these contaminants before they have a chance to inflict their damage.
Corrosion can do much more than cause the premature demise of a vehicle’s finish. It can also infiltrate vital operating systems such as the fuel, brake, electrical and electronic systems. Unlike highly visible external body rust, the corroding of these internal systems often is not evident until extensive damage has occurred.
WHAT ARE THE TRUE COSTS OF CORROSION?
Prior to the 1950s, automotive corrosion was pretty much limited to coastal areas where it was primarily caused by sea salt in the air. However, by the 1970s, the widespread use of de-icing materials on roadways led to a serious corrosion problem in the snowbelt regions of the U.S. While automotive manufacturers have since begun to implement various anti-corrosion techniques into their production processes, CorrosionCost.com reports rust-related damage still costs consumers approximately $23.4 billion per year. Here is a breakdown of these costs:
- $14.46 billion — Vehicle depreciation caused by corrosion
- $6.45 billion — Corrosion-related repair and maintenance costs
- $2.56 billion — Manufacturing costs due to corrosion engineering and the use of anti-corrosion materials that are passed on to the consumer
AUTOMOTIVE METAL FINISHING TECHNIQUES TO COMBAT CORROSION
As mentioned, automotive manufacturers began to place a stronger focus on corrosion protection during the 1970s. This led to the increased use of an automotive metal finishing technique called electroplating. In simple terms, metal plating entails the deposition of metal ions onto the surface of a metal part, which is known as the substrate. These metal ions are one component used to produce an electrolyte solution, commonly referred to as a plating bath. A DC electrical current is used to initiate a reaction that causes the deposition of the metal ions found in the plating bath onto the surface of the substrate, forming a thin, protective metal coating.
At Sharretts Plating Company, we specialize in metal finishing for motorcycles and cars to provide a protective coating against corrosion. For many years, we have provided effective plating solutions that are widely used throughout the automotive industry. In addition to rust protection, we can perform automotive plating that can brighten the finish on metal or non-metal parts and even metallize plastic parts to improve sturdiness. There are a number of metals that are used when implementing electroplating as an automotive metal finishing technique.
ZINC-NICKEL FOR CORROSION PROTECTION
Alloying is the process of combining two or more metals to produce a new material. This is typically done to maximize the properties and characteristics of each metal. Plating with a zinc-nickel alloy provides a potent one-two punch that can stop corrosion in its tracks.In essence, the zinc-nickel serves as a sacrificial barrier coating to prevent rust from reaching the surface of the metal part. The typical zinc-nickel ratio consists of approximately 80-94% zinc to 6-20% nickel.
A reliable way to determine the level of corrosion resistance of a material is through the implementation of salt spray testing. This method involves the placement of the material in an enclosed cabinet where a spray nozzle is used to apply a saltwater solution at high pressure. During salt spray testing, an automotive metal finishing process using a zinc-nickel alloy has been shown to prevent the formation of white rust for up to 500 hours and red rust for as long as 1,000 hours.
The application of a zinc-nickel coating is often followed by a passivation layer that may either be clear or black. Passivation is a technique that involves the deposition of a light coating and is typically used to enhance the corrosion resistance of the finished product. A corrosion-resistance sealer is then applied to complete the process.
Zinc and zinc-nickel plating can also improve the appearance of an automotive part. The zinc component adds a shininess that can brighten the part’s finish, closely resembling a gleaming chrome finish. You can find this type of automotive metal finishing on many types of car and motorcycle parts including under-the-hood components, power steering systems, chassis hardware, brake systems and many others.
PLATING CARS WITH PALLADIUM
Palladium is a lustrous, silver-white metal that plays a key role in the modern auto manufacturing process. A member of the platinum group of metals, which also includes platinum, osmium, iridium, rhodium and ruthenium, palladium is the least dense and features the lowest melting point of all the platinum metals. A key characteristic of palladium is that it will not react with oxygen under normal temperatures, so it will not tarnish when exposed to air. Palladium is also harder than gold and offers excellent resistance against corrosion and wear.
Palladium plating is used in the production of the catalytic converters that transform toxic exhaust gases into less harmful substances. In particular, palladium possesses the remarkable ability to absorb excess hydrogen that can lead to the formation of pungent hydrogen sulfide gas. More than half of the palladium used for manufacturing goes toward the production of catalytic converters.
AUTOMOTIVE GOLD PLATING
Automotive parts may be plated with gold in some instances. One might think of gold primarily in terms of its aesthetic appeal. Automotive gold plating will enhance the appearance of exterior parts,such as emblems, hood ornaments, door handles and wheel rims and is offered by some car dealers as an aftermarket service for car owners who wish to enhance the style of their vehicles.Gold plating will also make these exterior parts much more resistant to corrosion and wear.
Gold plating is also used to improve the electrical conductivity of electronic parts and components. The modern automobile is controlled by various electronic systems. The use of automotive gold plating will enable these systems to operate more efficiently and even increase their lifespan. For instance, the application of a gold coating onto electrical connectors will enable a lower contact resistance. This will improve the long-term reliability and stability of the connector. It will also shield the contact interface from atmospheric deterioration.
Perhaps the biggest drawback in choosing automotive gold plating is the relatively high cost. Gold is classified as a precious metal, meaning it is relatively rare and more expensive than other types of metals. However, because of its many long-lasting protective properties, gold offers the best value in the long run. Most metal finishing experts will recommend the use of automotive gold plating processes wherever appropriate, as long as it fits a company’s budget.
SPC has extensive expertise in the area of automotive gold plating. We can provide sound advice regarding the use of automotive gold plating for your manufacturing processes. We can also recommend a more affordable substitute for certain automotive plating techniques if applicable. For instance, some palladium alloys can provide comparable results to automotive gold plating in electronics applications.
PLATING ON PLASTIC AUTOMOTIVE PARTS
These days, many new and aftermarket exterior auto parts such as grilles, bumpers and wheel rims are made of some type of plastic. This is a way to make vehicles lighter and more fuel-efficient. However, this extensive use of plastics does present certain issues. For instance, parts made of plastic are often not as durable as their metal counterparts. What’s more, plastic is not an electrically conductive material, making its use impractical in the manufacturing of certain electronic automotive components. There’s also the problem of aesthetics. Plastic simply cannot replicate the gleaming appearance of metal on automotive trim and exterior parts.
While difficult to execute properly, electroplating a metal coating onto these non-metallic parts is achievable and can significantly improve their appearance and increase their usefulness. The ““metallization” of plastic parts typically involves the etching of the plastic substrate in a chromic acid-based solution to promote adhesiveness. This is followed by the immersion of the substrate in a nickel- or copper-based plating solution, a process known as electroless plating due to the absence of electricity. The final step is the electrodeposition of the metal of choice, which can be gold, nickel, copper or silver depending on the desired result. SPC is one of the few automotive metal finishing companies that have mastered this challenging process.
AUTOMOTIVE ELECTROLESS PLATING
Plating and metal finishing for cars and motorcycles isn’t limited to electroplating. A process known as electroless plating, which involves the deposition of metal onto a substrate without the introduction of an electric current, is widely used in many automotive manufacturing applications. An electroless plating bath consisting of nickel and a 3-5% boron component can serve as a suitable substitute for chrome plating. As mentioned, electroless nickel plating can also be implemented as a step in the electroplating procedure.
In general, electroless plating offers certain advantages over traditional electroplating processes. Because it does not require the use of electrical power, electroless nickel plating can be a more cost-effective automotive metal finishing solution. It also results in a more even coating of parts and can reach recessed areas and blind holes with greater efficiency. Electroless plating enables a more uniform coating of the substrate and makes it easier to achieve the desired coating thickness. Finally, electroless nickel is regarded as a simpler process, as it requires less in the way of complex or sophisticated machinery.
There are some disadvantages associated with electroless plating. The largest disadvantage of boron electroless nickel plating is that it offers limited corrosion protection. The lifespan of the chemicals used to create the plating solution is also limited. The lack of electricity requires more frequent bath maintenance to avoid the rapid depletion of the chemicals used to produce the desired chemical reaction.
REVIEW OF AUTOMOTIVE PLATING BENEFITS
In summary, metal plating provides a number of important benefits for the automotive industry:
- Corrosion resistance: Perhaps the biggest automotive metal finishing benefit derived from plating is the enhanced protection against corrosion. This enables consumers to keep their vehicles on the road longer and reduces their corrosion-related maintenance and repair costs.
- Wear resistance: Plating of certain automotive parts limits the impact of wear and tear, resulting in longer part life. Longer time between part replacements can lead to lower ownership costs for consumers.
- Tarnish prevention: Certain metal automotive parts have a tendency to tarnish over time. Plating can prevent this from occurring, helping to prolong the attractive appearance of the vehicle.
- Metallization of plastic parts: Plating can make plastic parts electrically conductive, while also improving their appearance by giving them a metallic shine. This will also increase the hardness and durability of the plastic part.
- Promotion of coating adhesion: In the case of electroless plating, the coating can promote the adhesion of an overlying plated metal or other protective coating.
SHARRETTS PLATING COMPANY: THE LEADER AMONG AUTOMOTIVE PLATING COMPANIES
With nine decades of metal finishing experience to draw upon, SPC can develop a customized car or motorcycle electroplating process for any vehicle manufacturing application. We have been at the forefront of automotive metal finishing technology for many years, including the development of a revolutionary automotive gold plating process that can enhance the performance of electrical and electronic operating systems.
At SPC, we take a solutions-oriented approach to the automotive metal finishing process. We work closely with our customers to develop a customized plating process that meets their needs and fits their budget requirements. This often involves an on-site consultation so we can observe your current manufacturing procedures in person. By gaining a comprehensive understanding of how your business operates, we can then recommend the most appropriate plating solution. We can also create a prototype that allows us to fully test a plating method prior to full-scale implementation.
You can also count on us to deliver a high-quality automotive metal finishing solution. SPC has been an ISO-certified company since 1994. This exemplifies our ongoing commitment to providing the best products and services to our customer base. It also demonstrates our non-wavering focus on continuous improvement in everything we do.
*Please note that Sharretts Plating does not plate with chrome. This content is for educational purposes only.
Additional Resources:
- Automation and the Finishing Industry
- Impact Killer Particles in Automotive Manufacturing Finishing
- Zinc Plays a Prominent Role in Today’s Automotive Manufacturing Processes
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