PVD Coatings
PVD is an acronym for “physical vapor deposition” which is a family of coating processes based on physical (as opposed to chemical) vaporization. PVD coatings usually involve the condensation of a metal vapor on the object to be coated. PVD coating generally falls into two sub-categories: evaporation and sputtering. Each of these contains several techniques, such as cathodic arc, HiPIMS, e-beam, and magnetron to name some of the most common. PVD coating is produced by condensing metallic materials combined with various gases. PVD coating depositions are done in vacuum chambers, with typical pressures ranging from 10-2 to 10-4 torr.
Inside the vacuum chamber, base materials (such as titanium,chromium, aluminium, and other metals) are converted from solid state into a gas state. Evaporative techniques, such as cathodic arc, rely on thermal (heat) energy and use repeated vacuum arc discharges to strike the metal target to vaporize the coating material. Sputtering techniques, such as magnetron, use kinetic energy to convert the target by bombarding it with high-energy gas ions.
Depending on the required coating properties, a reactive gas (such as nitrogen or oxygen) can be added to the chamber. This forms a compound coating which gets deposited on the substrate, for example, Titanium Nitride (TiN). To create uniform coating thickness, parts are typically rotated using planetary fixtures spinning at uniform speed around multiple axes. PVD coatings are typically very thin (between 10nm and several microns), and feature highly controllable properties such as hardness, structure, chemical and temperature resistance, and adhesion.
The end product is a coating with tailored optical, electrical, magnetic, mechanical and/or chemical characteristics. This coating bonds strongly to the component and improves its physical, structural and tribological properties accordingly.
Advantages of PVD Coating
PVD coating offers benefits that simply aren’t available through other coating processes. Specifically, PVD coating provides atomic-level control that enables you to more precisely determine coating characteristics, such as stoichiometry, crystallinity, and uniformity across the substrate. PVD coating and PECVD coating also produce fewer defects than other methods.
Another benefit of PVD coating is its technological maturity. Vacuum deposition has been around since the 19th century, but the late 20th century to the present day has seen a tremendous abount of technical expertise and technological development in the field, and that progress has been applied directly to manufacturing. The result is a highly cost-effective coating process that delivers superior results.
Advantages of working with Acree
Acree scientists have over five decades of direct experience in PVD coating. Chances are, we have either solved your problem, or one very much like it, before. Acree’s founder, Dr. Mike McFarland, “cut his coating teeth” in semiconductors, which has the smallest “process window” in just about any major industry. Acree’s processes and technologies are rooted in the same drive for precision, which improves manufacturing with increased efficiency and throughput.
Acree also has comprehensive and highly developed systems that enable an exceptional level of control over coating properties, especially when compared to the large “coating houses.” Typically, the larger firms don’t have an interest in developing custom solutions or in smaller jobs.
Acree also has some very specialized and unique processes that most other coaters do not. For example, Acree is one of only a handful of companies that specializes in energetic deposition processes. These techniques create a lower defect rate, which not only increases efficiency, but allows faster deposition times resulting in increased throughput.
In fact, Acree’s expertise in PVD coating for apparently diverse industries such as defense, biomedical, and semiconductors has cross-pollinated our abilities in each. We’ve honed our products, technologies, and expertise in these adjacent markets, and have developed unique capabilities as a result.
