Most PVD coatings are thin, hard refractory nitrides (e.g., CrN, TiN). These materials are naturally chemically inert and resistant to corrosion, which is why PVD coatings are often claimed to be corrosion resistant. However, most of the commercially available PVD coatings are being deposited at less than 3 microns (μm), which is relatively thin for the purpose of corrosion protection. Moreover, a typical PVD coating contain intrinsic defects (such as pinholes and craters) due to the nature of the deposition process. The thin PVD layer with these defects can expose the substrate, leaving it vulnerable to corrosion.

Firearms are intricate machinery aimed at delivering projectiles through a firing mechanism. From a mechanical point of view, all the moving parts of firearms affect the safety, accuracy, and durability through a single or a combined phenomenon of wear, tear, and oxidation. For years, firearm users have tried a variety of material selections and treatment processes to enhance the functionality of shooting. PVD (Physical Vapor Deposition) technology emerged from the cutting tool industry and finds its way into the firearm sector with its superior wear and corrosion resistance.

Depending on service requirements, tools and components can be improved in wear and corrosion resistance by heat treatment, electroplating, and PVD coating process. These are all surface-oriented material enhancement technologies.

We are more or less familiar with the TiN coating by PVD process for tool life improvement. Variations such as TiCN, TiAlN, AlTiN, TiCrN, etc., are, in fact, all descending from the good old TiN. The extra element added to TiN serves unique purpose of either enhanced thermal stability or better hardness and wear resistance.

Sometimes people get confused about whether they should choose the good old TiN, the stronger TiCN, the popular AlTiN, or the exotic AlTiSiN coating for their machining jobs. The problem is that it is just too many choices. These four coatings and many other Ti-containing coatings are members of the same family. In terms of ultra-thin films, you should choose the right one for your cutting needs based on their functionality, availability, appearance, and cost.