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CERTESS® Carbon
Diamond-like-Carbon (DLC)
Tribological coatings
Extreme Hardness + Very low friction =
Exceptional Wear Resistance
PVD Coatings Overview
Physical Vapor Deposition (PVD) coating involves the deposition of thin (2-10 microns; 0.0001"-0.0004")
films on the surface of components. The PVD coating process, conducted under high vacuum conditions,
can be divided into three stages:

 Evaporation - Removal of material from the target, source or cathode. Material is usually extracted
from a high-purity solid source, such as Titanium, Chromium etc., by sputtering or by an arc-discharge.

 Transportation - Travel of evaporated material from the source to the surface of the component to be
coated. The transportation step is through a plasma medium. Plasma is a collection of charged particles
(ions), whose constituents can be influenced by magnetic fields and tend to travel in straight lines or
"line of sight" from source to substrate. Different characteristics are imparted to the plasma depending
upon the technique used to generate it.

 Condensation - Nucleation and growth of the coating on the component surface. A PVD coating is
formed when plasma constituents and reactive gases, such as nitrogen, combine on the component sur-
face to form thin and very hard coatings such as Titanium nitride (TiN) and Chromium nitride (CrN).

Besides its specific chemical constituents and the architecture of the sub-layers, the properties of a PVD
coating depend upon: ion energy; the degree of ionization of the metal ions; and mobility of the atoms con-
densing on the component surface. If instead of a solid source, a hydrocarbon gas is utilized as the source
material - a very hard, ultra low-friction Diamond-like-Carbon (DLC) coating can be deposited. This gas
based process is referred to as PACVD - Plasma Assisted Chemical Vapor Deposition.
HEF PVD/PACVD coatings are deposited using two different technologies:
PEMS: Plasma Enhanced Magnetron Sputtering
HEF patented PEMS is a magnetron sputtering process enhanced by an auxiliary plasma source. This triode
system allows independent control of material flux, ion energy and substrate bias. PEMS can provide a mul-
titude of high performance coatings with application customized hardness, density and toughness.
CAM: Coating Assisted by Microwaves
CAM permits the deposition of hard and ultra-low friction coatings at a very low temperature. Another ma-
jor advantage is the ability to coat at low pressure, allowing more efficient use of the coating chamber and
improved productivity.

Attributes of PVD Coatings

Hardest (1500 – 4500 HV) Thin (2 to 5 microns) coatings – Low coating temperature (150 – 250°
known synthetic materials minimal impact on size tolerance C) – no distortion or core hardness loss
Low friction coefficients (0.1 – Line of sight process – difficult to High Adhesion to a wide range of
0.5) – minimize friction losses coat cavities or IDs steels, copper-alloys, plastics, glass……
Ability to deposit alloyed and Possible to mask regions on com- Zero environmental impact – no efflu-
multilayered coatings ponent where no coating is desired ents or toxic chemicals
DLC Coatings
In recent years, a new generation of PVD + PACVD (plasma-assisted CVD) coatings has gained wide-
spread commercial success. As is well known, in nature carbon can exist in two allotropic forms. Car-
bon, in a Diamond crystal structure, is one of the hardest know materials. Carbon, in a Graphite crys-
tal structure, is very soft and lubricous. Carbon-based coatings, referred to as Diamond-like-Carbon
(DLC) coatings, combine these two different properties of diamond and graphite - hence possess
high hardness levels - in the range of conventional tribological PVD coatings (1500 - 3200 HV), cou-
pled with a coefficient of friction which is 200-500% lower than that of conventional PVD coatings.
These DLC coatings are generally amorphous (without a regular crystal structure) in nature.

What is a Diamond-Like-Carbon (DLC) Coating?

DLC coatings can be deposited

using a diverse range of technol-
ogies and alloyed with elements
such as hydrogen and metals
such as chromium. These con-
stituent elements and deposi-
tion technique can have a sig-
nificant impact on the proper-
ties and structure of the DLC
coating.
DLC COATING DEPOSITION: Simplified, Schematic view
HYBRID PVD – PACVD deposition (CrN – aC:H)

In order to meet the diverse operating

conditions encountered by engineered
components used for automotive and
other generic industrial applications,
HEF has developed a family of dia-
Topography of the top carbon layer depends on the mond-like-carbon DLC coatings. These
morphology & and structure of the underlayer
coatings usually include several
layers of different materials
such as Cr, CrN, W, WC-C, Si
with a top layer of amorphous
carbon, with hydrogen. The se-
lection of the under-layer is
based upon several factors such
as: adhesion requirements,
wear mode and contact mode,
friction regimes encountered
during operation, load carrying
capacity, and other metallurgi-
cal considerations.
Diamond-Like-Carbon (DLC) Coating Properties
The properties of DLC coatings in terms of hardness; coefficient of friction; roughness; adhesion lev-
el; load carrying capacity; resistance to humidity influenced degradation; fatigue tolerance, etc. can
be tailored over a wide range depending upon deposition parameters, deposition technology and
the combination of materials constituting the coating. Some of the more common commercial vari-
ants of WCC and DLC coatings from HEF are as follows:

Properties Coatings
CERTESS CERTESS CERTESS CERTESS CERTESS CERTESS
DT DTMO DLC DCX DDT DCY
a-C:H:W a-C:H:W a-C:H CrN + a-C:H WC + a-C:H:W Cr + WC + a-
(modified) + a-C:H C:H:W + a-C:H
Hardness (HV) 1200 - 1400 1700 - 1900 2000 - 2500 2500 - 3200 2500 - 3200 2500 - 3200

E (GPa) 125 140 200 - 210 200 - 210 200 - 210 200 - 210
Coeff. of Friction
0.20 - 0.25 0.20 - 0.25 0.11 - 0.15 0.11 - 0.15 0.11 - 0.15 0.11 - 0.15
(dry)
Coeff. of Friction
0.10 - 0.15 0.10 - 0.15 0.07 - 0.11 0.07 - 0.11 0.07 - 0.11 0.07 - 0.11
(5W30)
Scratch Lc (N) 60 60 20 25 25 - 30 30
Load Bearing Cap
1 1 3 8 9 9
(arb. units)
Coating Thickness
1-3 1-3 1-3 2-4 2-4 2-4
(microns)
Deposition Temp. °C 150 - 300 150 - 300 150 - 300 150 - 300 150 - 300 150 - 300

Max Usage Temp. °C 300 300 350 350 350 350

Other DLC coatings can be customized based upon the unique combination of wear mode, contact
mode and the friction regime under which the component in operating.
DLC Coating Applications
Automotive Components
POWER-CELL
 Significant friction reduction
 Piston pin: Higher load sustainability without
seizure
PISTON PIN PISTON RING
VALVE-TRAIN
 Improved wear resistance
 Convert sliding contact to
rolling contact: significant
friction reduction

ROCKER ARM PIN VALVE TAPPET ROCKER ARM

FUEL SYSTEM
 Improved sliding wear resistance
 Significant friction reduction

Motion & component holding and transfer mechanisms

 Rails & Guides  Sprockets  Links  Spindles  Collets  Clamping Devices
 Reduced friction on sliding &
rolling surfaces
 Enhanced wear resistance
 Dry, lube-free operations
possible for applications
such as medical, food processing and manufacturing of electronic devices
 High-speed spindles can operate with minimal wear - stable and precision operations

Industrial Gears
 Improved scuffing resistance
 Increase in rolling contact fatigue (pitting re-
sistance)
 Ability to withstand high point contact loads
DLC Coating Applications
Compressor Components
 Vanes  Swash plates  Aerofoils  Impellers  Reciprocating pistons & plungers

 Lower friction coefficient and friction

forces: important for oil-free operations
and dry gas/refrigerant applications
 Improved wear resistance of tight toler-
ance components

Mechanical Seals
 Lower friction coefficient and friction forces minimizes
seal damage
 Lower seal face temperature
 Superior wear resistance for leak free operation and
improved lifetime

Hydraulic & Pneumatic equipment

 Pump Components: Components used in centrifugal; axial; vane; lobe; screw and spindle
pumps. Examples: Spindles, Vanes, Lobes, Gears, Screws, Plungers, Seals
 Valve Components: Components used in Gate, Ball, Needle and Butterfly valves.
Examples: Seals, Seats, Stems, Balls, Glands, Actuator sub-components
 Excellent sliding wear resistance: superior seal performance for leakage free operations
 Low DLC coating temperature and 2-4 micron thickness: ideally suited for high tolerance pump
and valve components - typically used in high-pressure pumping applications
 Improved abrasion resistance when handling erosive liquids and slurries
 Reduced friction levels:
 Lower energy consumption
 Lower torque for valve actuation
 Ability to operate effectively in low lubrication
conditions

Plastic Injection Molding Dies

 Facilitates mold release  Improved wear & corrosion resistance
Medical Instruments & Devices
 Prosthetic devices: orthopedic and spine implants; bone screws and plates
 Surgical instruments and tools
 Cardiovascular devices and implants:
pacemakers; stents; guiding wires
 Dental implants
 CERTESS® Carbon
Diamond-like-Carbon (DLC)
Tribological coatings

HEF Group offers innovative solutions for wear, friction and corrosion reduction through a
diverse selection of surface treatments and hard coatings. We partner with the industry’s
largest and most demanding manufacturers to develop application-specific surface engi-
neering processes that substantially enhance performance and long-term durability. HEF is
currently active in more than 20 countries throughout Europe, Asia, and the Americas and
has 60 operating facilities
Our primary jobbing service offerings include the following:
 Application Engineered Liquid Nitriding / Salt Bath Nitriding: ARCOR®, MELONITE® / QPQ
Treatments
 State-of-the-Art PVD Technology & PVD / DLC Coatings

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