This document discusses the vapor deposition processes, specifically Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD), used for coating tools to enhance their performance in manufacturing. It covers the advantages, manufacturing techniques, types, and applications of these coatings, emphasizing their wear resistance and prolonging tool life. CVD and PVD methods are essential for various industrial applications, including cutting tools, semiconductor devices, and automotive components.

1. Vapour Deposition
Muhammad Umair Akram#1
IM-079 (2012-2013)
Industrial & Manufacturing Engineering Department, NED University of Engineering and Technology
University Road, Karachi -75270, Sindh, Pakistan
1
im079um@gmail.com
2
umair.an@ymail.com
Abstract—this document gives information about the vapour
deposition i.e. (CVD and PVD) on tools, the way these tools
manufactured and what affects they produce during usage? When
they are used in different manufacturing operations? High material
removal rate, good surface finish and high productivity rate are the
needs of manufacturing industry i.e. actually an ―efficient tool‖. So,
this document discuss about these tools.
Keywords— CVD, PVD, Deposition, Coating,
I. INTRODUCTION
In recent years, in the machining field, the requirements of
the cutting tools are becoming increasingly diverse, including
higher speed, higher efficiency and also increased
performance stability, extended tool life, and reduced cost to
use under harsher condition ever in normal environment.
Materials such as carbide, Sintered carbide, cemented and
CBN are used but using these tools independently, the diverse
needs are not perfectly obtained. It is therefore, coated tools
were invented. Initially in 1969 the TiC and WC cotted tools
became normal in metal machining industries because these
coating consequently improve the ability and life of tool up to
200 to 300% or more.
In cutting tools it is necessary requirement that a tool must
have high hardness, high strength, abrasion resistant, and as
well as it must be chemically inert to prevent the chemical
reaction between the newly generated surface of work piece
and that of tool. To be effective the coating must be fine
grained free of binders and porosity. Naturally the coating
must be metallurgic to the substrate.
Coated tools are finding wide acceptance in many
manufacturing applications. Coated tools have two or three
times the wear resistance than the best uncoated tools. It is
therefore, these tools have a broader range of applications.
The advancement of the coated carbide tool technology has
greatly attributed the advancement in manufacturing
technology. There are basically two types of coating methods
named as Chemical Vapour Deposition (CVD) and Physical
Vapour Deposition (PVD).
II. CHEMICAL VAPOUR DEPOSITION
Chemical Vapour Deposition (CVD) is an atmosphere
controlled process conducted at elevated temperatures
(~1925° F) in a CVD reactor. During this process, thin-film
coatings are formed as the result of reactions between various
gaseous phases and the heated surface of substrates within the
CVD reactor. As different gases are transported through the
reactor, distinct coating layers are formed on the tooling
substrate. For example, TiN is formed as a result of the
following chemical reaction:
TiCl4 + N2 + H2 1000° C → TiN + 4 HCl + H2
Titanium carbide (TiC) is formed as the result of the following
chemical reaction:
TiCl4 + CH4 + H2 1030° C → TiC + 4 HCl + H2
The final products of these reactions are hard, wear-resistant
coatings, which exhibit a chemical and metallurgical bond to
the substrate. CVD coatings provide excellent resistance to the
types of wear and galling typically seen during many metal-
forming applications.
CVD methods used for coatings deposition are that the
metal carbides and nitrides are formed of gas atmosphere
components on surface of a machined element. In the process
of formation of a layer, substrate’s components take part. The
process is carried out in gas atmosphere usually containing
chemical compounds, vapours of a metal being a basic
component of a produced layer within 900-1100⁰C. High
temperature, necessary for a course of chemical reaction,
significantly reduces a range of the applied CVD methods,
particularly, in case of elements exposed to dynamic loads,
being in service, or tools made of high-speed steels. It reduces
a scope of CVD technology applications mainly for layers
deposition on inserts made of ceramic carbide materials, for
which high temperature of the process does not cause a loss of
their properties. In the last years a few varieties of CVD
processes were developed that generally are called as methods
of chemical deposition from gas phase in the presence of a
glow discharge PACVD, making utilisation of positive
features for CVD high temperature processes possible (high
capacity and quality of received coatings) in connection with
low temperature of coating and beneficial plasma enabling to
clean substrate.

2. A. CVD Materials and Reactions
In general, metals that are readily electroplated are not
good candidates for CVD, owing to the hazardous chemicals
that must be used and the costs of safeguarding against them.
Metals suitable for coating by CVD include:
 Tungsten
 Molybdenum
 Titanium
 Vanadium
 Tantalum
Chemical vapour deposition is especially suited to the
deposition of compounds, such as:
 Aluminium oxide (Al2O3)
 Silicon dioxide (SiO2)
 Silicon nitride (Si3N4)
 Titanium carbide (TiC)
 Titanium nitride (TiN)
The commonly used reacting gases or vapours are:
 Metallic hydrides (MHx)
 Chlorides (MClx)
 Fluorides (MFx)
 Carbonyls (M (CO)x)
Where M ¼ the metal to be deposited and x is used to balance
the valences in the compound. Other gases such as:
 Hydrogen (H2)
 Nitrogen (N2)
 Methane (CH4)
 Carbon dioxide (CO2)
 Ammonia (NH3)
are used in some of the reactions. Below some examples of
CVD reactions that result in deposition of a metal or ceramic
coating onto a suitable substrate. Typical temperatures at
which these reactions are carried out are also given.
1. The Mound process includes a CVD process for
decomposition of nickel from nickel carbonyl (Ni(CO)4),
which is an intermediate compound formed in reducing nickel
ore:
Ni (CO)4 200⁰C (400⁰F) Ni+ 4CO
2. Coating of titanium carbide (TiC) onto a substrate of
cemented tungsten carbide (WC–Co) to produce a high-
performance cutting tool:
TiCl4 + CH4 1000⁰C 1800⁰F (excess H2) TiC + 4HCl
3. Coating of titanium nitride (TiN) onto a substrate of
cemented tungsten carbide (WC–Co) to produce a high-
performance cutting tool:
TiCl4 + 0.5N2+2H2 900⁰C 1650⁰F TiN + 4HCl
4. Coating of aluminium oxide (Al2O3) onto a substrate of
cemented tungsten carbide (WC–Co) to produce a high
performance cutting tool:
2AlCl3+3CO2+3H2 500⁰C 900⁰F Al2O3 + 3CO + 6HCl
5. Coating of silicon nitride (Si3N4) onto silicon (Si), a process
in semiconductor manufacturing:
3SiF4 + 4NH3 1000⁰C 1800⁰F 3N4 + 12HF
6. Coating of silicon dioxide (SiO2) onto silicon (Si), a process
in semiconductor manufacturing:
2SiCl3 + 3H2O + 0.5O2 900⁰C 1600⁰F 2SiO2 + 6HCl
7. Coating of the refractory metal tungsten (W) onto a
substrate, such as a jet engine turbine blade:
WF6 + 3H2 600⁰C 1100⁰F W + 6HF
B. Manufacturing Technique for CVD
Chemical vapour deposition processes are carried out in a
re-actor, which consists of
(1) Reactant supply system
(2) Deposition chamber
(3) Recycle/
(4) Disposal system
Although reactor configurations differ depending on the
application, one possible CVD reactor is illustrated in Figure.
The purpose of the reactant supply system is to deliver
reactants to the deposition chamber in the proper proportions.
figure.2: A typical reactor used in chemical vapour deposition
Different types of supply system are required, depending on
whether the reactants are delivered as gas, liquid, or solid (e.g.,
pellets, powders). The deposition chamber contains the
substrates and chemical reactions that lead to deposition of
reaction products onto the substrate surfaces. Deposition
occurs at elevated temperatures, and the substrate must be
heated by induction heating, radiant heat, or other means.
Deposition temperatures for different CVD reactions range
from 250⁰C to 1950⁰C (500⁰F–3500⁰F), so the chamber must
be designed to meet these temperature demands. The third
component of the reactor is the recycle/disposal system,
whose function is to render harmless the by-products of the
CVD reaction. This includes collection of materials that are

3. toxic, corrosive, and/or flammable, followed by proper
processing and disposition.
C. Types of CVD
CVD covers processes such as:
 Atmospheric Pressure Chemical Vapor Deposition
(APCVD). In which the reactions are carried out at or
near atmospheric pressure.
 Low Pressure Chemical Vapor Deposition (LPCVD)
 Metal-Organic Chemical Vapor Deposition
(MOCVD)
 Plasma Assisted Chemical Vapor Deposition
(PACVD) or Plasma Enhanced Chemical Vapor
Deposition (PECVD)
 Laser Chemical Vapor Deposition (LCVD)
 Photochemical Vapor Deposition (PCVD)
 Chemical Vapor Infiltration (CVI)
 Chemical Beam Epitaxy (CBE)
D. Applications of CVD Coated Tools
CVD coatings are used in many manufacturing
applications as a wear-resistant coating: carbide milling and
turning inserts, wear components, some plastic processing
tools, etc. However, the most common application for CVD
coating is for metal-forming tools.
In high stress metal-forming applications, where the tool's
tolerances and substrate permit, high temperature CVD
coating processes will perform better than "cold" processes
like PVD, thin-dense chrome (TDC), nitriding, etc.
The chemical/metallurgical bonding that results from the
CVD coating process creates adhesion characteristics that
simply cannot be duplicated by a "cold" process. This
enhanced adhesion protects forming tools from the sliding
friction wear-out caused by the severe shearing stresses
generated in heavy metal-forming applications.
Typical Metal-Forming Applications for CVD Coating:
 Punches
 Draw Dies
 Forging Tools
 Trim Dies
 Stamping Tools
 Wire Draw Dies
 Extrusion Dies
 Coining Dies
 Trim Dies
 Swaging Dies
 Sizing Dies
 Form Rolls
 Seaming Rolls
 Cold Heading Tools
 Crimping Tools
 Tube Bending Dies
Table.1: Applications of CVD Tools
Coated Draw Form Insert
Coated Draw Punch
Coated Extrusion Die
Assorted CVD Coated Insert Tooling
CVD has applications across a wide range of industries
are such as:
 Coatings – Coatings for a variety of applications such
as wear resistance, corrosion resistance, high
temperature protection, erosion protection and
combinations thereof.
 Semiconductors and related devices – Integrated
circuits, sensors and optoelectronic devices
 Dense structural parts – CVD can be used to produce
components that are difficult or uneconomical to
produce using conventional fabrication techniques.
Dense parts produced via CVD are generally thin
walled and maybe deposited onto a mandrel or
former.
 Optical Fibers–For telecommunications
 Composites – Preforms can be infiltrated using CVD
techniques to produce ceramic matrix composites
such as Carbon-carbon, carbon-silicon carbide and
silicon carbide-silicon carbide composites. This
process is sometimes called chemical vapor
infiltration or CVI.
 Powder production – Production of novel powders
and fibers
 Catalysts
 Nano-machines

4. E. Advantages of CVD Tools
 High wear resistance
 Economic production of thicker coatings
 Suitable for bore, holes, slots, etc.
F. Disadvantages of CVD Tools
 High processing temperatures
 Coatings with several metals (e.g. TiAlN) are not
possible
 Edges become rounded (coating thickness)
 Uses ecologically problematic, toxic metal chlorides.
III. PHYSICAL VAPOUR DEPOSITION
Physical vapour deposition (PVD) describes a variety
of vacuum deposition methods used to deposit thin films by
the condensation of a vaporized form of the desired film
material onto various work piece surfaces. The coating
method involves purely physical processes such as high-
temperature, vacuum evaporation, with subsequent
condensation, or plasma sputter bombardment, rather than
involving a chemical reaction at the surface to be coated as in
chemical vapour deposition. Physical vapour deposition (PVD)
is a group of thin film processes in which a material is
converted into its vapour phase in a vacuum chamber and
condensed onto a substrate surface as a very thin layer.
Different PVD technologies utilize the same three
fundamental steps but differ in the methods used to generate
and deposit material. The two most common PVD processes
are thermal evaporation and sputtering. Thermal evaporation
is a deposition technique that relies on vaporization of source
material by heating the material using appropriate methods in
vacuum. Sputtering is a plasma-assisted technique that creates
a vapour from the source target through bombardment with
accelerated gaseous ions (typically Argon). In both
evaporation and sputtering, the resulting vapour phase is
subsequently deposited onto the desired substrate through a
condensation mechanism.
figure.3: PVD process distribution
Deposited films can span a range of chemical
compositions based on the source material(s). Further
compositions are accessible through reactive deposition
processes. Relevant examples include co-deposition from
multiple sources, reaction during the transportation stage by
introducing a reactive gas (nitrogen, oxygen or simple
hydrocarbon containing the desired reactant), and post-
deposition modification through thermal or mechanical
processing. PVD is used in a variety of applications, including
fabrication of microelectronic devices, interconnects, battery
and fuel cell electrodes, diffusion barriers, optical and
conductive coatings, and surface modifications.
(PVD) can be used to apply a wide variety of coating
materials: metals, alloys, ceramics and other inorganic
compounds, and even certain polymers. Possible substrates
include metals, glass, and plastics. Thus, PVD represents a
versatile coating technology, applicable to an almost unlimited
combination of coating substances and substrate materials.
A. Manufacturing Techniques for PVD
The simplest form of PVD is evaporation, where the
substrate is coated by condensation of a metal vapour. The
vapour is formed from a source material called the charge,
which is heated to a temperature less than 1000°C. PVD
methods currently being used include reactive sputtering,
reactive ion plating, low-voltage electron-beam evaporation,
triode high-voltage electron-beam evaporation, cathodic
evaporation, and arc evaporation. In each of the methods, the
TiN coating is formed by reacting free titanium ions with
nitrogen away from the surface of the tool and relying on a
physical means to transport the coating onto the tool surface.
All of these PVD processes share the following common
features:
 The coating takes place inside a vacuum chamber
under a hard vacuum with the work piece heated to
200° to 405°C (400 to 900°F).
 Before coating, all parts are given a final cleaning
inside the chamber to remove oxides and improve
coating adhesion.
 The coating temperature is relatively low (for cutting
and forming tools), typically about 842° F (450° C).
 The metal source is vaporized in an inert gas
atmosphere usually argon), and the metal atoms react
with gas to form the coating. Nitrogen is the reactive
gas for nitrides, and methane or acetylene (along
with nitrogen) is used for carbides.
 All four are ion-assisted deposition processes. The
ion bombardment compresses the atoms on the
growing film, yielding a dense, well-adhered coating.
Coating temperatures can be selected and controlled so that
metallurgy is preserved. This enables a coating of a wide
variety of sintered carbide tools, for example, brazed tools,
solid carbide tools such as drills, end mills, form tools, and
inserts. The PVD arc evaporation process will preserve
substrate metallurgy, surface finish, edge sharpness,
geometrical straightness, and dimensions.

5. figure.4: Schematic of PVD arc evaporation process
figure.5: Summary of physical vapour deposition processes
B. Types of PVD
Physical vapor deposition coating is gaining in popularity for
many reasons, including that it enhances a product’s
durability. In fact, studies have shown that it can enhance the
lifespan of an unprotected product tenfold.
Variants of PVD include,
 Cathodic Arc Deposition: In which a high-power
electric arc discharged at the target (source) material
blasts away some into highly ionized vapor to be
deposited onto the work piece.
 Electron beam physical vapor deposition: In which
the material to be deposited is heated to a high vapor
pressure by electron bombardment in "high" vacuum
and is transported by diffusion to be deposited by
condensation on the (cooler) work piece.
 Evaporative deposition: In which the material to be
deposited is heated to a high vapor pressure by
electrically resistive heating in "low" vacuum.
 Pulsed laser deposition: In which a high-power laser
ablates material from the target into a vapor.
 Sputter deposition: In which a glow plasma discharge
(usually localized around the "target" by a magnet)
bombards the material sputtering some away as a
vapor for subsequent deposition.
C. Applications of PVD Coated Tools
A PVD coating (Physical Vapor Deposition) or PACVD
coating (Plasma Assisted Chemical Vapor Deposition) is a
hard, thin layer of metallic coating or ceramic coating by use
of plasma under vacuum on metal, ceramic or plastic
substrates. The best known applications of PVD coating
technology are decorative coatings, tri-bological
coatings (mostly automotive engine components and machine
components) and tool coating. Additionally PVD hard coating
technology is applied in innovative coating concepts in new
markets. PVD coatings are engineered for a specific set of
properties:
 High wear resistance
 High hardness at high operating temperatures
 High oxidation resistance
 Low friction
 Anti-sticking
 Scratch resistant
 Brilliant finish in specified colour
The Typical applications of the PVD tools in the
manufacturing industries are:
Plastic Processing industry
 Extrusion
 Injection die molding

6. Machining Industries
 Cutting tools
 Toothing
 Broaching
Forming Industries
 Forming
 Primary shaping
Semiconductor Industries
 Wafer contact applications
 Components used in positioning systems
Automotive Industry
 Engine components
 Pump applications
Engineering
 Wind energy technology
 Aviation technology
 Medical technology
D. Advantages of PVD Coated Tools
 No environmentally damaging materials and
emissions, no toxic reaction products
 Great variety of coatings can be produced
 Coating temperature below the fineal heat treatment
temperature of most steels.
 Small, precisely reproducible coating thickness
(accurate surface replication, true to size,
 High wear resistance
 Low frictional coefficient
E. Disadvantages of PVD Coated Tools
 Bore holes, slots etc. can only be coated down to a
depth equal to the diameter or width of the opening
 Corrosion resistant only under certain conditions
 In order to achieve a uniform coating thickness, the
parts to be coated must be rotated during processing.
IV.EFFECTS ON COATED TOOLS DURING USAGE
In metal cutting process, the condition of the cutting tools
plays a significant role in achieving consistent quality and also
for controlling the overall cost of manufacturing. The main
problem caused during machining is due to the heat
generation and the high temperature resulted from heat. The
heat generation becomes more intensified in machining of
hard materials because the machining process requires more
energy than that in cutting a low strength material. As a result,
the cutting temperatures in the tool and the work-piece rise
significantly during machining of all materials.
At such elevated temperature the cutting tool if not enough
hot hard may lose their form stability quickly or wear out
rapidly resulting in increased cutting forces, dimensional
inaccuracy of the product and shorter tool life. The magnitude
of this cutting temperature increases, though in different
degree, with the increase of cutting velocity, feed and depth of
cut, as a result, high production machining is constrained by
rise in temperature. This problem increases further with the
increase in strength and hardness of the work material and In
dry cutting operations, the friction and adhesion between chip
tool tend to be higher, which causes higher temperatures,
higher wear rates and, consequently, shorter tool lives. Up to
this moment, completely dry cutting is not suitable for many
machining processes. Since cutting fluid is necessary to
prevent the chips from sticking to the tool and causing its
breakage.
In the case of a punch and die application there will be a
focus on the mechanical characteristics of the coating. The
application will subject the punch and die to the following
events:
 A sudden impact with a blank surface that is rough,
relative to the tool.
 A severe deformation of the opposing contact surface
resulting in new contact surfaces being created.
 Complete shearing of blank with rough edges now
moving past the tool faces.
 Possibility of small particles interposed between the
punch and the die as the stroke is completed.
During metal forming the punch and the die will
experience normal and shearing loads applied to their surfaces
and acting through the material. These loads and forces are
process specific and dependant on the geometry of the

7. material to be shaped and also on the properties of the blank.
There are also other considerations such as the required
surface finish from the blank, the size of burr produced and
the geometry of the cutting surfaces to consider. The sudden
nature of the loading and the high loads that are applied will
have a large bearing on the coating that is selected. It must be
able to withstand multiple impacts and the subsequent built up
of internal stresses.
V. COMPARISON BETWEEN PVD & CVD
In the face of multitude of deposition techniques varieties
of coatings there is a necessity of conscious choice for both a
type of coating and a method to deposit it, as the same
coatings deposited by different methods differ in terms of
their service properties.
In the Fig.6 a comparison of coatings’ deposition
techniques is shown, depending on process temperature and
working pressure. A great number of possible techniques
allows to select the most adequate one for a specific
application, for the sake of the required properties of
coating and coated substrate.
figure.6: Comparison of coatings’ decomposition techniques
Putting high demands, for coatings resistant to wear, causes
that materials used to acquire them should be characterized by,
first of all, high hardness in raised temperature, high
resistance to oxidation and good chemical stability. For the
sake of that demands, as coatings’ components resistant to
wear, the most frequently compounds used for the tools are
the following:
 Titanium nitride TiN,
 Titanium carbide TiC,
 Titanium carbonitride TiCN,
 Aluminium nitride TiAlN and
 Aluminium oxide Al2O3
A. Processing Temperature
The process temperatures for our PVD coatings can range
from 385°F-750°F depending upon the particular coating
being deposited. Please note that we recommend draw
temperatures of 750°F+ in order to avoid distortion or
hardness changes. If these draw temperatures are not possible
for your parts, then we recommend you contact us for special
instructions in order to provide for the safe processing of your
parts.
The process temperature for CVD coating will reach
1925°F; therefore, any tool steels or HSS being CVD coated
will be annealed during coating. After coating, we will
vacuum heat-treat all steels in order to achieve the customer’s
required hardness.
B. Coating Thickness
The average thickness of our various PVD coatings is 2-5
microns (.00008-.0002‖).
The average thickness of our various CVD coatings is 5-10
microns (.0002-.0004‖).
C. Others
Some other characteristics of the PVD & CVD processes are
defined in the table shown below.
Table.2: comparison of coating process characteristics

8. VI.CONCLUSIONS
In the recent days it is a top priority of an industry to reduce
the cost of manufacturing rather than increasing the price of
product, to get huge profit margins. Tools play a vital role in
reducing the cost of product. Here we found that vapour
deposition on the tools increases the life, strength as well as
we can obtain our desired properties, which are needed in the
tool for a particular operation. We found that these coated
tools are little expensive than the conventional tools, but at the
back these tools have high strength, high productivity rate,
and have the long life, well wear resistance than the
conventional tools. In these days researchers are paying their
attentions towards the improvement of coating methods and
hence not only the new methods have been discovered. These
coating methods are not only limited for the tool
manufacturing but now these coating methods are also being
used for different things to satisfy the market needs.
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