Research & Development for
Vacuum Hard Coatings
Simply put a coating is a structure composed of primarily a metal and a gas. A titanium plate
reacted with a Nitrogen plasma field creates Titanium Nitride or TiN. If you add Aluminum (Al)
you get TiAlN or Titanium Aluminum Nitride. If the Al concentration is greater than the Ti then
you have AlTiN or Aluminum Titanium Nitride. For many applications we are able to customize
the formulation to maximize your performance potential. Our commercial products are designed
to be versatile and effective over the greatest array of applications.
At Dayton Coating Technologies, LLC our engineers and scientists strive to use every
resource at our disposal to accommodate you technical specifications.
Our layout and technical support makes Dayton Coating Technologies, LLC
the ideal partner for research initiatives.
Sputtered Reactive and Elemental Coatings
Generally smoother than Cathodic Arc coatings, these materials are more specialized and
require specific applications to maximize their benefit. With deposition energy approximately
80eV less than Cathodic Arc coatings, Sputtering is a strong contender for applications where
the physical properties of Cathodic Arc materials stemming from its deposition mechanism
inhibit maximum performance. Thickness control is greater and there are far more possible
formulations available.
Interpreting the Composition and
Structure of Your Product
Arc PVD Coating at a Glance
PVD arc coatings are simple to understand. PVD stands for physical vapor deposition.
The PVD process involves pulling a vacuum on a very tightly sealed chamber with your
clean parts inside. Enough vacuum is pulled that there is a huge distance between atoms
in the chamber (free mean path). In essence the chamber is empty like outer space. This
means an excited ion can travel very far (proportional to its size) without encountering
another atom with which it would collide and loose its energy.
The machine is a simple chamber with what is called a metal cathode (plates) inside.
The parts being coated are also inside along with various gages and devices used to
control a reaction.
Inside this machine there is a vacuum and the metal plates that have an electric arc running
loose on its surface. This causes the surface to be excited and metal ions launch off of the
surface traveling at high energy levels through the open 'free mean path' inside the machine
until they encounter a plasma field around the parts being coated. This plasma field is simply
a highly charged group of particles that emit a certain color depending on the gas used
(think neon light bulb, HID automotive head lights or even plasma arc cutter) This excited
gas (lets say is made from Nitrogen) is encountered by the emitted metal ion from the metal
plate in the beginning of this explanation. The metal ion (lets say Titanium Ti+) plus the
Nitrogen plasma field (N) creates titanium nitride (TiN). The coatings are simple a
combination of a metal and a glass.
For Example:
- Titanium + Nitrogen = TiN
- Aluminum + Titanium + Nitrogen = AlTiN
- Titanium + Aluminum + Nitrogen = TiAlN
- Titanium + Nitrogen + C2H2 (Acetylene) = TiCN
- Chromium + Nitrogen = CrN
- Cr + Ti + C2H2 (Acetylene) + Nitrogen - CrTiCN
Titanium Based Materials (TiN, TiCN)
Basic hard coating provided with PVD process creating a hard smooth band of
wear resistant material. See table for TiN properties as a base line of comparison to
other PVD materials.
Carbon Content (TiCN)
The 'C' in TiCN and TiAlCN is injected into the PVD systems via a hydrocarbon gas
(Propane, Acetylene, or even Methane) were the Hydrogen is removed and the remaining
Carbon in the plasma field is implanted. For example, the TiN (titanium nitride) process is
injected with a little C2H2 (Acetylene) where the hydrogen is eliminated and the remaining
Carbon is placed within the TiN structure creating TiCN. This same method also exposes
TiAlN into TiAlCN or AlCrN into AlCrCN and many other metal ion and gas composite
coatings.
The result of the carbon influence in this form (process parameters) is lower coefficients
of friction, increased toughness, and also decreased temperature resistance.
Aluminum
If the coating has more aluminum than titanium it is called AlTiN. If it has more
Titanium than Aluminum then its considered TiAlN. You can also have Chromium
instead of Titanium making AlCrN or CrAlN.
The effect of Al on performance is simply heat resistance. As the material becomes hot
from use the surface is exposed to air creating AlO that is very hard and wear resistant.
This AlO (Aluminum Oxide) is actually a product of the TiAL or AlTi based material breaking
down under immense pressure and contact temperatures. This is why often customers in
cutting applications are actually asked to push a tool harder to make it work better.
It creates more heat and corresponding AlO.
