PVD Finishes - What is it, and why is it used for fixtures?
PVD finishes are often not explained or understood. Often a sink faucet, light fixture, automotive wheel, and even furniture, medical devices, and jewelry are finished using the PVD method.. but what is it?
PVD is an abbreviation for Physical Vapor Deposition.
We have seen products that proudly explain that they are finished using this method. These items are typically a little more expensive compared to similar items without the PVD finish.
Some known brands that use the method to finish their product include:
- Rolex - Used on some watch bezels and faces
- Movado - Used on watch bezels, faces, and components.
- Kraus - Used on faucets and some kitchen sinks
- MAHLE - Supplier of various engine parts for BMW, Mercedes Benz, Volkswagen, Audi, Porsche, among others: Used in pistons, valves and other Auto and Industrial components. (PVD allows for lower friction within internal combustion engines)
These coatings are not simply metal layers though. Instead, compound materials are deposited atom by atom, forming a thin, bonded, metal or metal-ceramic surface layer that greatly improves the appearance, durability, and/or function of a part or product.
According to one source, "Physical vapor deposition, sometimes called physical vapor transport, describes a variety of vacuum deposition methods which can be used to produce thin films and coatings. PVD is characterized by a process in which the material goes from a condensed phase to a vapor phase and then back to a thin film condensed phase."
Benefits of PVD are:
– High surface hardness
– Reproducibility and stability of color and surfaces;
– Non-toxic, hypoallergenic and biocompatible;
– High resistance to wear, scratches, rubbing and corrosion;
– High resistance to the aggressive action of atmospheric agents (eg salt spray, UV rays);
– Resistant to acids, alkalis, solvents and in general to many products for domestic and industrial use;
– Surfaces’ Metallic appearance without requiring a transparent coating to protect the finishing;
A more in-depth explanation - for those who are curious, can be credited to IonBond.com, and is as follows:
"Physical Vapor Deposition (PVD) is a method for producing metal-based hard coatings by means of generation of partially ionized metal vapor, its reaction with certain gases and by forming a thin film with a specified composition on the substrate. Most commonly used methods are sputtering and cathodic arc. In sputtering, the vapor is formed by a metal target being bombarded with energetic gas ions. Cathodic arc method uses repetitive vacuum arc discharges to strike the metal target and to evaporate the material.
All PVD processes are carried out under high vacuum conditions. The Ionbond PVD process is used for the deposition of coatings made of nitrides, carbides and carbonitrides of Ti, Cr, Zr and alloys like AlCr, AlTi, TiSi on a large range of tools and components. Applications include cutting and forming tools, mechanical components, medical devices and products that benefit from the hard and decorative features of the coatings. The typical process temperature for PVD coatings is between 250 and 450 °C. In some cases, Ionbond PVD coatings can be deposited at temperatures below 70 °C or up to 600 °C, depending on substrate materials and expected behavior in the application.
The coatings can be deposited as mono-, multi- and graded layers. The latest generation films are nano-structured and superlattice variations of multi-layered coatings, which provide enhanced properties. The coating structure can be tuned to producing the desired properties in terms of hardness, adhesion, friction etc. The final coating choice is determined by the demands of the application. The coating thickness ranges from 2 to 5 µm, but can be as thin as a few hundred nanometers or as thick as 15 or more µm. Substrate materials include steels, non-ferrous metals, tungsten carbides as well as pre-plated plastics. The suitability of the substrate material for PVD coating is limited only by its stability at the deposition temperature and electrical conductivity."