PVD stands for Physical Vapor Deposition and is a process used to apply advanced thin-film coatings. An example of a PVD coating is DLC, diamond-like carbon. Physical vapor deposition allows the application of coatings at the atomic level which gives the opportunity to control the structure, density, and stoichiometry of the coating. Depending on the materials and process used, certain desired attributes like harness, adhesion, lubricity, and more can achieved.
PVD coatings are used in a wide array of industrial, non-industrial, and decorative applications. PVD coatings can be applied on surfaces ranging from metals such as steel and aluminum to non-metallic surfaces such as plastic, glass, and rubber.
Many industries use PVD coatings to enhance their products. Common industrial applications include medical devices, corrosion prone marine components, metal cutting and forming tools, automotive components, and machine components, such as gears, splines, and bearing surfaces. Industries that use PVD coatings to provide increased run time, extended tool life, and a competitive advantage include, food and beverage, medical device manufacturers, automotive component manufacturers, aerospace, military and defense, plastics, weapon manufacturers, and marine components manufacturers.
As the name implies, the PVD process involves the deposition of thin films on the surface of the component being coated. This film on the surface of the coated component is typically on a few microns thick, usually ranging between 3 – 5 microns (0.000118” – 0.00019685”). The coating material can enhance the surface of the coated component by increasing its hardness, decreasing its coefficient of friction, elongating the components lifespan, decreasing wear, altering its appearance for decorative effects, and other desirable properties.
Decreased friction and increased durability are two of the more desirable properties sought in the application of a PVD coating. The selection of the coating material has a great effect on the achieved properties. A popular coating is DLC, which stands for diamond-like carbon. If you’re interested in DLC and other coatings, take a moment to explore our catalog of advanced thin-film coatings.
The PVD coating process involves the vaporization of a solid material in a vacuum and then depositing this vaporized material on a substrate. Because the process transfers the coating as single atoms or at the molecular level, it provides an extremely thin, high-purity, high-performance coating making it preferable where these characteristics are needed.
Sputter Deposition and Evaporative Deposition are the two most common PVD coating processes used.
Evaporative Deposition involves increasing the thermal energy of the coating material causing surface atoms to dislodge and then condense on the substrate being coated. The dislodged atoms have low kinetic energy when they arrive at the substrate.
Instead of using thermal energy to excite the atoms in the coating material Sputter Deposition uses the momentum of sputter gas ions, typically Ar, to transfer energy to the coating material (source). This transfer of energy, through collision, dislodges surface atoms which are then deposited onto the substrate creating a thin-film. Stoichiometry and film thickness are better controlled using Sputter deposition than Evaporative deposition.
The durability of any PVD coating is dependent on multiple factors like:
Each of these factors will affect the durability of the selected PVD coating in different ways. Coating and Substrate selection are crucial to achieve increased durability. If the coating is improperly paired with the substrate, then the desired longevity may not be achieved. For example, components that might be subjected to high point loads should be manufactured with harder substrates and thicker coatings. If the substrate is soft, then deflection of the coating may reach the point of fracture reducing the durability of the coating.
If you would like to learn more about coating durability and substrate/coating pairing, reach out to our solutions team.solutions team.Solutions Team
Often, a desirable property sought when choosing a PVD coating is increased hardness. This increase in hardness is driven by several causes which are: dislocation-induced plastic deformation, cohesive forces between atoms of neighboring grains, and the nanostructure of materials. Ok, so what does that mean in the real world? It means that a PVD coating adds a super hard protective layer over your substrate which helps to prevent wear on the underlying material. This increased hardness also mean that the coating layer is scratch resistant and can even reduce crack propagation. This of how this increased hardness would be advantageous on a smartphone screen, a decorative finish, or camera lens.
Our PVD coatings typically exhibit a hardness of 1500 – 2500 HV (75RC – above 90RC).
The short answer, yes, the PVD coating process is environmentally friendly. While other coating processes may require cleaning with caustic chemicals, use pigments and other materials that can be harmful to the environment, the coating process using physical vapor deposition doesn’t require any of these. The PVD process involves the use of benign metals, inert gas, a vacuum, controlled temperature, and time all of which don’t introduce products or byproducts into the environment that are considered harmful.
Not only is the PVD coating process environmentally friendly, it’s also safer for those who work with the process.
In this brief overview we weren't able to explore all aspects of PVD technology, but the following books provide much more in-depth information about PVD technology. We highly recommend them if you would like to dive deep into the world of physical vapor deposition.