Overview of Phygen’s FortiPhySM PVD-Based, Chromium Nitride (CrN) Tool Coating
Phygen Coatings, Inc. has developed a patented Physical Vapor Deposition
(PVD) coating technology based upon the principles of plasma
acceleration. This process results in higher plasma density
and an intense, low energy ion bombardment during coating
deposition. Coatings formed by this process exhibit unprecedented
toughness and lubricity, as well as outstanding uniformity.
 Phygen PVD technology allows deposition of a wide variety of coatings (metals, alloys, and compounds). One example is Phygen’s new FortiPhySM Chromium Nitride coating, which exhibits extreme hardness and toughness superior to that of the best conventional PVD-based coating. Phygen’s PVD surface coating technology provides a combination of superior coating properties by creating a dense, non-columnar coating structure having the highest possible adhesion level.
Coating microstructure is precisely controlled by Phygen's
process parameters. As a result, FortiPhy high performance surface coating constitutes a single-phase,
stoichiometric, nanocrystalline chromium nitride having a
dense, highly textured structure. The fine-grained structure
and high cohesive strength of Phygen chromium nitride coatings
permit deposition of extremely tough and hard coatings with
much higher abrasive wear resistance than provided by conventional
PVD processes.
Unlike hot-processed CVD (chemical vapor deposition) and
TD (thermal diffusion) coatings, which combine with carbon
molecules within the substrate to form a hard layer, FortiPhy
is a chemically complete tool coating, applied to a surface
using a special high-adhesion process.
Typical CVD and TD coatings are applied at temperatures
above 1800°F in order to increase diffusion activity within
the substrate. During the hot coating process, carbon atoms
move 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 limited amount carbon in the
substrate is available to migrate to the surface, and it can
travel only a short distance. This means that as tools and
coatings wear, a second application of the coating usually
lasts only about 70 percent as long as the first application.
A third application generally will have a useful life that
is only 30 percent as great as the original tool coating.
After that, free carbon is all “used up.” When no additional
carbon can be leached to the surface, the re-coating process
ceases to provide any benefit. Furthermore, decarburization
of the substrate weakens material near the surface, thereby
increasing the likelihood of chipping.
FortiPhy hard surface coating does not require diffusion
within the substrate to build a hard coating. Instead, the
patented Phygen process, with its exceptional level of process
control, applies a chemically stoichometric layer of nano-sized
particles onto the surface. No carbon or other molecules are
leached from the substrate. This means that every re-coat
of FortiPhy tool and die coating has the same toughness and
lasts as long as the first. More importantly, no decarburization
or weakening of the substrate occurs. Tool life is extended,
and chemical composition of the substrate remains unchanged,
regardless of rework.
FortiPhy high performance surface coating is an industrial
coating, not a decorative coating. However, its appearance
may be enhanced, if necessary, by the addition of a TiN or
other color overlay. While FortiPhy is primarily intended
to reduce wear in severe stress and temperature applications,
it also is highly corrosion resistant. In a recent test, a
purposely substandard application of very thin and porous
FortiPhy tool coating on mild steel provided significant
protection by cutting the corrosion rate and by creating a
passivity range with a pitting potential of more than 800mV.
In the same test, a uniform coating of FortiPhy further decreased
the corrosion rate by several orders of value. In real-world
applications, FortiPhy provides unprecedented corrosion protection.
In an injection mold, for example, a coating of FortiPhy provided
a 600-percent increase in the life of mold vents that previously
had been destroyed by caustic thermoplastic byproducts.
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