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Index
ABOUT PHYSICAL VAPOR DEPOSITION
(PVD) TITANIUM PLASMA COATING
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Overview:
Rather than simply applying a layer of different colorful
substances AND simple gold plating on the metal instruments, the
craftsmen acquired a process that would guarantee long-term
resistance after testing various techniques. Finally they chose
an effective procedure: PVD (Physical Vapour Deposition), which
involves coating the surfaces with a layer of protective
metallic vapours (Ionic plating).
How it Works:
The instruments to be treated are placed on supports in an
air-tight container, which may hold several hundred parts at a
time. The air is pumped out of the container, creating a vacuum
equivalent to one billionth of normal atmospheric pressure, in
other words close to the pressure that exists in space. A flow
of gases, ionized Nitrogen and Argon is introduced into the
chamber. These ionized particles are sprayed on to the
instruments, which causes their surface to heat up. Deposition
material Titanium is flash evaporated and ionized by an electric
arc. This generates a plasma within the chamber of ionized
atomic Nitrogen, Argon and Titanium. A voltage is applied to the
substrates to accelerate the ions in the plasma cloud to the
surface of the parts. This positively charged Titanium plasma is
attracted to the negatively charged parts to be coated. The
Titanium and Nitrogen combine on the surface of the substrate,
Ion by Ion, forming a dense, hard coating of Titanium Nitride (TiN).
The coating bonds to the surface of the substrate, and even
penetrates the surface slightly, to give an outstanding level of
adhesion.
For Gold Coating:
For Gold Coating, the layer of titanium nitride is then covered
with a layer of 23 carat gold to enhance its beauty.
For Color Coating:
For Colour Coating, a special desired color formatting substance
is applied to create the formation of thin layer of color (Blue,
Black, Rainbow etc).
The coating cycle lasts several hours. All process variables are
carefully controlled to insure a high quality coating. Each
coating batch is tested for quality, thickness, and uniformity
before being passed.
In this whole process Titanium Nitrate plays the major role. It
is an extremely dense, compact and a highly resistant substrate.
Today, Both manufacturing and designing engineers recognize the
benefits of thin-film coated products. By applying a carefully
selected 3 ~ 5 micron coating on tools, tool life can be
increase, from 50% to 500% longer.
PVD coating on Multiplex Traders tools is a layer of Titanium
Nitride embellished with perfection, attained by experience. Our
customers will benefit from our experience with the application
of thin-film PVD coatings on our tools.
It may also be mentioned that Physical Vapour Deposition is not
harmful to the environment since it is a procedure that produces
no pollutants, neither directly nor in the form of toxic
residues. |
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Physical Properties of
Titanium Nitride (TiN) Coatings |
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Composition |
TiN. > 99 % purity. |
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Process |
PVD Vacuum Deposited
Coating. |
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Appearance |
Metallic Gold. |
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Thickness |
Ranges from 0.25 to 12
microns. Typical applications are 1 to 5 microns. See the
thickness conversion chart. |
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Uniformity |
Coating conforms
uniformly to the substrate. No buildup occurs on corners (unlike
plating operations). Coating "throws" well into features. In
deep holes, coating tapers off from 1 to 7 diameters of depth. |
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Hardness |
Hardness > 2000 kg/mm2
Knoop or Vickers Microhardness. Values of 2500-3000 are typical.
Equivalent to over 85 Rc. Three times harder than hard chrome
and harder than carbide material. |
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Adhesion |
The coating forms a
metallurgical bond to the substrate that will not flake,
blister, chip or peel. In fact, the coating is actually
implanted slightly into the surface layer of the substrate.
Adhesion is superior to plating and other coating processes
where mechanical adhesion occurs. Several adhesion test methods
are possible, contact BryCoat for more info. |
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Adhesion, Scratch Adhesion Value |
> 3.0 kgf on hard
steel substrates |
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Coefficient of Friction |
TiN generally provides
low friction against steels, carbides, TiN, ceramics, platings,
etc. Published values range from 0.05 to 0.90. A typical value
is 0.6 for TiN against steel. The inert surface creates
outstanding sliding wear performance.
Note: The
coefficient of friction is a system property, not a material
property. It is dependant on many factors such as material,
counter-material, lubrication, temperature, speed, loading
force, surface finish, surface finish of the counter-material,
and type of motion (reciprocating, rotating). Published values
can have large variations. |
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Non-stick |
TiN is an excellent
non-stick surface against most other materials. |
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Toxicity |
Non-toxic. Meets FDA
guidelines and has been approved for use in numerous
medical/surgical devices, including implants. Meets requirements
of FDA and USDA for food contact. |
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Temperature Resistance |
Begins to oxidize at
600° C. (1100° F.) in air. More resistant in an inert
atmosphere. |
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Melting Temperature |
2950° C. |
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Deposition Temperature |
Ranges from 200 to
450° C. Standard process is 400° C. and provides the toughest
coating. See also the temperature reference page. |
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Electrical Resistivity |
25 µOhm-cm. To
determine resistance, multiply by length and divide by cross
sectional area. |
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Chemical Resistance |
Highly inert to acids,
bases, solvents, caustic, etc. |
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Thermal Expansion Coefficient |
9.4 x 10-6 /°C. |
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Thermal Conductivity |
0.046 Cal/sec.-cm-°C. |
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Density |
5.22 g/cm3. |
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Crystal Structure |
Face Centered Cubic. |
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Residual Compressive Stress |
xxx |
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Young's Modulus, Modulus of Elasticity |
600 GPa. |
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Poisson's Ratio |
0.25 |
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Heat
of Formation |
80,750 Cal/mole. (3.5
eV/molecule). |
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Band
Gap |
3.35 - 3.45 eV |
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Articles:
1-
About PVD Titanium Plasma Coating / Plasma color coating, how it
works.
2-
About Electro Polishing / Electrolysis
3-
About Grade 440C Stainless steel
4-
About Grade 420 J2 Stainless steel
5-
About Damascus Steel
6-
How to care Haircutting Scissors
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