PVD (Physical Vapor Deposition)

PVD (Physical Vapor Deposition) coating is a process used to apply a thin layer of material onto a substrate through a vacuum deposition process. In PVD coating, a solid material is vaporized and then deposited onto a substrate through condensation. The process is performed in a vacuum chamber to minimize the presence of impurities and to provide a controlled environment for the deposition process.

There are different types of PVD coatings, each with unique properties and applications. Some common types of PVD coatings include titanium nitride (TiN), chromium nitride (CrN), and diamond-like carbon (DLC). These coatings are commonly used in the manufacturing of cutting tools, molds, and automotive components, as well as in the production of decorative finishes for jewellery, watches, and other consumer products.

Benefits of PVD Surface Coating

Increased Uptime

The primary benefit of PVD high performance surface coatings is durability, measured in time—increased productive uptime; longer mean time between failures; improved viability. However, you define it, critical engineered components last longer with PVD metal form tool coatings.

Decreased Maintenance Costs

Because rework, maintenance, wear, and breakage are reduced, overall costs go down. In addition, stocks of redundant, backup components can be reduced, thereby providing additional savings.

Reduced Scrap

Production line components maintain their “as designed” dimensions longer, which results in higher productivity and fewer rejected parts.

Decreased Substrate Costs

Applying PVD coatings to more conventional and economical substrate materials often can produce components with physical properties equal to or even better than more expensive and harder to handle materials.

Reduced Lubrication Costs and Increased Productivity

Because of the PVD corrosion resistant coating's exceptionally low coefficient of friction, production lines often can run at higher speeds with less lubricant.

Low Temperature Processing

The PVD coating process requires the lowest application temperature of any high-endurance coating. Other tool and die coating processes can subject die substrate materials to very high temperatures. This can anneal tool steels, modify critical dimensions, and compromise physical properties. The low-temperature PVD coating process minimizes substrate changes. PVD coating saves time and money by reducing rework to correct dimensional or metallurgical changes.

Super Thin Coating

PVD processes produce the most uniform coating deposition layer possible. PVD can apply thin-film coatings that outperform thicker, less-uniform coatings. PVD's unmatched level of process control helps to ensure that critical dimensions remain within tolerance, even after coating.

Higher Adhesion

The PVD process results in an unmatched level of molecular adhesion to a variety of substrates, providing maximum toughness and longer coating life.

Smaller, more Uniform Crystalline Structure

PVD is tougher (less brittle) than other similar coatings, due in part to its uniform, nanocrystalline structure. Other coating processes often produce macro particles or columnar structures within the coating. These act as stress concentrators, weakening the coating and decreasing its useful life. PVD's application process produces a more uniform coating structure with much smaller particles. Metallurgically speaking, PVD (physical vapor deposition) coating is a stoichiometric, non-columnar, equixially grained, face-centered cubic crystalline structure with virtually no macro droplets.

Reduced Stress

In extreme-stress machine tools, such as roll forming, forging, and heading dies, PVD coatings extends tool life significantly. Surface hardness is increased without brittleness, allowing components to withstand higher mechanical loads. PVD coatings act as a stress barrier, which can reduce tensile stresses within the tool surface.

Reduced Friction

A key benefit of PVD hard surface coating's nanocrystalline microstructure is its low coefficient of friction. PVD coatings have a COF of less than 0.1 under properly lubricated conditions in an oxidizing environment. PVD coating users report better release properties and fewer cosmetic rejects after coating molds for silicone rubber castings, aluminium casting dies, and precision stamping dies.

Increased Abrasive Wear Resistance

PVD high performance surface coating increases surface hardness and toughness and reduces friction. This combination, plus high microhardness, makes treated surfaces extremely resistant to abrasion. PVD coatings reduce abrasive wear in machine tools and engineered components in harsh environments at elevated temperatures.

Improved Corrosion Resistance

Because of its dense, non-columnar structure, PVD tool coated coatings are chemically inert and provide excellent corrosion resistance. In one extreme example, acid burn was destroying vents in a thermoplastic mold after only 8 hours. After a PVD treatment, the mold was still in “like new” condition after more than 50,000 shots.

Improved Operational Temperature Range

PVD thin-film coatings are chemically and thermally stable in air to at least 850°C.

Longer Productive Tool Life, Regardless of the Number of Recoats

Unlike hot-processed chemical vapor deposition (CVD) coatings, which combine with carbon molecules from the substrate to form a hard layer, PVD metal surface coating is a chemically complete coating, applied to a metal surface using a special high-adhesion process. Typical CVD coatings are applied at more than 982°C in order to increase molecular activity within the substrate. During the CVD coating process, carbon molecules migrate to the surface and combine with the coating material to form a third compound. This can produce a hard coating, but there are drawbacks. Only a small portion of carbon molecules in the substrate are available to migrate to the surface, and they can travel only a short distance. This means that as tools and coatings wear, the second application of a CVD coating usually lasts about 70 percent as long as the first application. A third application generally has a life of only 30 percent that of the original tool. The free carbon molecules are all “used up” after that. When no more carbon molecules can be leached to the surface, the process ceases to provide any benefits. PVD coating does not require molecular action within the substrate to build a hard coating. Instead, the patented physical vapor deposition (PVD) process, with its unprecedented level of process control, applies a chemically complete layer of nano-sized particles onto the surface. The PVD metal surface coatings do not require carbon or any other molecules from the substrate. This means that every re-coat of PVD has the same toughness, and lasts just as long, as the first. Tool life is extended, and the chemical composition of the substrate remains the same, regardless of rework.