Korvus Technology

Physical Vapour Deposition for Electrical Contacts

 

Physical vapour deposition (PVD) has become an integral technique in the manufacture of numerous goods, ranging from semiconductors to PET films and cutting tools to reflective films. This process produces highly conductive surfaces ideal for electrical applications — such as electrical contacts. 

In a nutshell, producing a PVD coating for electrical contacts involves depositing thin films of metals onto target materials using a vacuum chamber. PVD for electrical contacts creates the ideal purity, uniformity, and conductivity, proving highly valuable within the development of circuit breakers, electromechanical power switches, and other applications. 

This article summarises the methods and applications of PVD for electrical contacts. 

Why PVD Is Being Used for Electrical Contacts

Electrical contacts are electrically controlled switches that either complete or interrupt an electrical circuit, facilitating an electrical current. They consist of electrically conductive materials, like silver alloys, gold, and platinum-group metals. 

Recently, electrical contact manufacturers have begun using PVD to develop thin metal coatings for contacts. Compared to alternative processes, PVD promotes a higher purity of the deposit layers, low thermal impact, excellent adhesion, and virtually limitless coating materials. 

The benefits of PVD in electrical components, like contacts, include:

Enhanced Conductivity and Performance

Electrical contacts must have a high level of electrical conductivity to carry the electrical current. Manufacturers have begun using PVD for electrical contacts because it creates an electrically conductive surface on a wide range of target materials. The properties of PVD are ideal for enhancing electrical contact performance, ensuring a potential for strong conductivity.

Increased Durability

One of the primary benefits of PVD coating technologies for any application, including electrical contacts, is exceptional durability. PVD coatings are extremely scratch-resistant and durable. This makes them reliable solutions within breaker boxes and other electrical circuits that depend on electrical contacts to stimulate the flow of electricity. With PVD, you don’t need to worry about the coating wearing off over time. 

Corrosion Resistance

PVD coatings also boast extreme corrosion resistance [1], which is a beneficial characteristic for metallic materials. Traditional electrical contacts may corrode over time due to oxidation. But PVD coatings withstand environmental conditions well, contributing to their durability. 

Understanding PVD Technology

PVD is a revolutionary technology that has become integral in applications ranging from home hardware to jewellery and windows to drill bits. At its core, PVD is the process of depositing a thin film coating onto a substrate like metal, glass, or ceramics. The process transitions a material into a vapour phase and then into a thin film condensed phase, which can be deposited on the target material in a thin layer. 

When comparing PVD vs. CVD and other coating technologies, PVD for electrical contacts offers advantages like uniformity, high deposition rates, precision control, and excellent adhesion [2]

Types of PVD Processes

Several types of thin film deposition processes can facilitate physical vapour deposition, including sputtering, thermal evaporation, and organic evaporation. 

Sputtering involves ejecting material from a target onto a substrate using ion or atom bombardment. Thermal evaporation, one of the simplest forms of PVD, uses a resistive heat source to evaporate the material in a vacuum environment. In contrast, organic evaporation uses low-temperature evaporation to form thin films of organic materials. 

Advantages of Using PVD

Physical vapour deposition is a cost-effective, reliable, environmentally friendly method of creating thin coatings and finishes. It doesn’t release any harmful gases or substances and produces no waste. It allows for exceptional precision and control over the exact thickness and composition of the thin film. 

PVD in Electrical Contact Applications

PVD coatings have proven highly effective in a range of electrical contact applications. Using PVD for electrical contact surface finishing improves the electrical and mechanical performance of the contacts and provides long-lasting durability. 

Material Selection for PVD

Metals like gold, silver, and palladium alloys are common choices for PVD within electrical contact applications. Other metals, like titan, chromium, tungsten, and aluminium, are also used.

Chosen metals must have the correct properties to form carbonitride and nitride coatings when combined with reactive hydrocarbon-based gases [3]. However, the versatility of thin film deposition for contacts allows many substrate materials to adhere well to the vapourised metal coatings. 

Application Examples

PVD coatings are ideal for many contact applications within electrical engineering, optoelectronics, optics, and medical technology [4]. This technology can effectively metalise nonconductive materials, allowing manufacturers to create electrical contacts on a wide range of substrates and potentially save money during manufacturing. 

Final Thoughts

Physical vapour deposition boasts numerous benefits for electrical contact applications, including enhanced conductivity, durability, precision, environmental friendliness, and more. Moving forward, researchers expect more and more electrical manufacturers to begin using PVD within their applications. 

Are you looking for a thin film deposition system that can facilitate PVD for electrical contacts or other applications? Get in touch with Korvus Technology today at 01628 201329. We will discuss our HEX series systems and help you find the right system for your organisation. 

 

References

[1] Grechanyuk, N. I., et al. “Properties of Cu-Mo Materials Produced by Physical Vapor Deposition for Electrical Contacts.” Powder Metallurgy and Metal Ceramics, vol. 60, no. 3-4, July 2021, pp. 183+. Gale Academic OneFile, link.gale.com/apps/doc/A679120795/AONEu=anon~b06deda1&sid=googleScholar&xid=f6ead6c5. Accessed 11 Mar. 2024.

[2]  “Physical Vapor Deposition (PVD).” PCB Design & Analysis, Cadence PCB Solutions. https://resources.pcb.cadence.com/blog/2023-physical-vapor-deposition-pvd. Accessed on 11 Mar. 2024. 

[3] Rajan, Vincent Femila, et al. “Chapter 12 – Nano based technologies for antibacterial, antifungal, and antiviral coatings.” Antiviral and Antimicrobial Smart Coatings, 2023, pp. 357-412. https://www.sciencedirect.com/science/article/abs/pii/B9780323992916000013. Accessed on 11 Mar. 2024. 

[4] “Surface Coating Technologies.” Electrical Contacts Wiki. https://www.electrical-contacts-wiki.com/index.php/Surface_Coating_Technologies. Accessed on 11 Mar. 2024

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