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An Introduction to Vacuum Coating

https://www.youtube.com/watch?v=c5MaX905ibk
Engineer Shakeel Dalal on Vacuum Coating

Vacuum coatings are used to protect everything from medical tools to aerospace parts. They help objects resist wear, friction, harsh chemicals, and heat so they’ll last longer.  Unlike other protective coatings, thin-film deposition (vacuum) coatings don’t bring unwanted side-effects – Other coating techniques run the risk of knocking a tool out of tolerance or adding too much thickness so that the part doesn’t perform like it was designed to.

Vacuum coating technologies give you the best of both worlds, performance and protection. But what is a vacuum coating exactly?…

What is Vacuum Coating?

Vacuum coating, also known as thin-film deposition, is a vacuum chamber process whereby a very thin and steady layer of coating is applied to the surface of a substrate, protecting it from forces that might wear it down or decrease its efficiency. Vacuum Coatings are thin, ranging from 0.25 to 10 microns (0.01 to 0.4 thousandths of an inch) thick. 

It’s like a suit of armor that protects a knight and improves his performance.

There are several types and uses of Vacuum Coatings. The following is a quick overview to get you familiar with the technologies used and a few of the possible applications. If you want an expert’s opinion on what’s best for your specific situation, click here to request a conversation with our technical team. 

Types of Vacuum Coatings

PVD Coating

Physical Vapor Deposition Coating (PVD) is the vacuum chamber coating process we use most often. The part to be coated is placed inside a vacuum chamber. The solid metal material that will be used as the coating is vaporized under vacuum. Atoms from the vaporized metal travel at near the speed of light and embed themselves into the surface of the parts in the vacuum chamber. To ensure the correct areas of the object are coated, the part is carefully positioned and rotated during the PVD process.

PVD Coating isn’t adding another layer to the object that will chip or crack with time (think old paint). It’s impregnating the object. 

Sputtering

Sputtering is another type of PVD coating used to deposit coatings of conductive or insulating materials on objects. This is a “line of sight” process, as is the cathodic arc process (described below.)  In sputtering an ionized gas is used to ablate, or slowly remove, the metal from the target material (the material that will coat the part). This ablated metal then travels through the vacuum chamber and coats the desired part which is positioned above or below the target.

Cathodic Arc

Cathodic Arc is a PVD method that uses electrical arc discharges to evaporate a material like titanium nitride, zirconium nitride, or silver, among others. The evaporated material coats the part that is in the vacuum chamber with it. 

Atomic Layer Deposition

Atomic Layer Deposition, or ALD, is great for silicon coatings and for medical devices with complex dimensions. By alternating the chemicals present in the chamber, the chemistry and thickness of the coating can be controlled with atomic precision. That means it can provide one of the most complete coating types, even for parts with very complex dimensions.

Uses of Vacuum Coatings

Injection mold 

Many companies struggle with parts sticking to their injection mold when they should be ejected. This problem is solved by the lubricity of vacuum coatings. Parts release easily from a thin-film coated mold, allowing the production process to go on efficiently. In other words, it saves time and money. Molds are more likely to stay within spec with a vacuum coating, too. 

Semiconductor

Vacuum coatings extend consumable lifetime and reduce chamber downtime for those in the semiconductor industry. Materials for coating range from fused quartz to yttria stabilized zirconia, and coatings are optically transparent & chemically inert. All this means lower cost of ownership by synching maintenance cycles. 

Additive manufacturing

The additive manufacturing industry is ever-evolving. New applications for 3D printing are emerging almost daily. The limiting factor at the moment is the performance capabilities of the substrates being used. PVD and ALD thin-film coatings have the potential to enhance and improve the surface characteristics of additive parts to make them more flexible and capable. 

Medical tools

Black titanium nitride applied via PVD coating is becoming a standard for medical tools. The coating reduces friction, provides biocompatibility for implants, is antimicrobial, and it serves as a chemical barrier for those with a sensitivity to nickel (which can often be found in the tool). Not to mention, black titanium nitride medical tools look fantastic. 

Manufacturing tools

Thin-film coatings are ideal for manufacturing tools because they can withstand extremely harsh conditions without knocking a tool out of tolerance. Remember, the coating is designed to become part of the tool. It’s not cosmetic, meaning it won’t wear with time or knock a key part out of tolerance. And that’s critical in manufacturing. If a tool is knocked out of tolerance, it can create a bottleneck and ripple effect that negatively impacts the whole organization. 

Aerospace

If a part is going to fly through the sky at more than 600 miles per hour, it better be wear resistant. Vacuum coating is a crucial component for aerospace parts subjected to heat, friction, and harsh environments. 

Automotive

Screeching brakes, corrosion, rust, rubber to metal bonding issues, and engine components overheating… These are some of the problems a strong vacuum coating can help with on automotive parts. You can coat steering column components, exhaust gaskets, brake clips, and many other parts. 

Protection and Performance

The bottom line is that the critical parts you use and make need to last. Vacuum coating technologies achieve this goal. Making a part last isn’t just about extending its life though; it’s about maintaining a high level of performance throughout the life of that part. 

As opposed to other coatings that chip, crack, wear, or knock tools out of tolerance, vacuum coatings are a shining armor for your parts, providing a strong and thin coating for a variety of applications. Consult our technical team for advice on how to proceed with a coating for your next project. 

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