General
CVD Coatings 
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Richter
Precision Inc. is pleased to provide our standard Chemical Vapor
Deposition (CVD) coating processes as part of our line of wear-resistant
coating for tooling and components. We were one of the first companies
in North America to provide CVD coating services, and we have been
performing this coating process for nearly 25 years.
What
is CVD coating?
Chemical Vapor Deposition, or CVD, is a thin-film coating with a
chemical and metallurgical bond that results from the reaction between
various gaseous phases and the heated surface of a substrate. The
final product is a hard, wear-resistant coating with an extremely
strong bond to the substrate. CVD is sometimes referred to as a
“hot coating” because the process approaches temperatures
around 1925° F. For this reason, special post-coating vacuum
heat-treating processes have been developed for steel components.
What is Titankote™
H CVD coating?
Titankote™ H is the “work horse” of our CVD coating
family. Titankote™ H has been designed to create the best
possible combination of hardness and toughness through the use of
multi-layer deposition. This multi-layer CVD coating consists of
TiN/TiCN/TiC/TiN coating strata.
In high stress
metal-forming applications, where the tolerances and materials allow,
Titankote™ H multi-layer CVD coating has proven itself to
be tough to beat. The higher hardness, greater thickness, and superior
coating adhesion of the chemical/metallurgical bond exhibited by
this CVD coating means that our Titankote™ H multi-layer CVD
coating will out perform any other PVD coating process.
There are several
reasons why this multi-layer design has proven to work so well in
metal-forming applications:
• The cumulative effect of the individual layer’s attribute:
the low coefficient of friction exhibited by TiN; the high abrasion
resistance of TiCN; the superior hardness of TiC.
• Micro-crack propagation will not move from layer to layer;
therefore, the stratified characteristics of Titankote™ H
helps to prevent stresses from breaking down the coating under high
loads.
• The clearly defined layers act as wear indicators. Titankote™
H is a valuable aid to any good preventative maintenance program.
If a company pays attention as the coating wears through the various
layers, then tools can be changed before serious damage occurs to
the substrate: this can save a lot in time and tooling charges.
In addition
to our Titankote™ H coating, Richter Precision Inc. also provides
several other CVD coating processes. Please see our “Technical
Data” page for more information on these other CVD coating
processes.
>>
Click
Here, to see Richter Precision's coatings technical
data
>>
Below is a chart showing comparison of three major coating processes:
CVD |
PVD |
TD |
| Can
be performed in controlled atmosphere or vacuum |
Performed
in a vacuum chamber (10-2 to 10-4 Torr) |
Performed
in an elemental salt bath |
High
temperature process (1925°F) |
Relatively
low process temperature (200° to 800° F) |
High
temperature process (1650° to 1900°F) |
Reactive
gas process coats wherever atmosphere contacts tool
surface |
Line
of sight process: will coat areas directly exposed to
ion source |
Reactive
bath process coats wherever molten bath contacts tool
surface |
Coating
exhibits a chemical & metallurgical bond to the
substrate |
Coating
exhibits a physical bond to the substrate's surface |
Coating
exhibits a diffusion type bond to the substrate |
Average
thickness: 6-10 µm, or .00024-.0004" |
Average
thickness: 2-5 µm, or .00008-.0002" |
Average
thickness: 5-15 µm, or .0002-.0006" |
More
limited range of substrates than for PVD |
Suitable
for a wide range of substrates |
More
limited range of substrates than for PVD, but less limited
than CVD |
Requires
relatively loose tolerances (example: +/-.0005 per 1.0"
diameter) |
Ideal
for closely toleranced components
(+/- .0001” is appropriate) |
Requires
relatively loose tolerances (example: +/-.0005 per 1.0"
diameter) May be more forgiving than CVD |
Post-coating
heat-treating required on steel parts due to high process
temperature |
No
heat-treating required after coating due to low process
temperature |
Post-coating
heat-treating required on steel parts due to high process
temperature |
| Requires
hone on sharp edges due to heavier coating build-up |
Good
for sharp edges: no excessive coating build-up |
Requires
hone on sharp edges due to heavier coating build-up |
| Difficult
to maintain mirror finish (post-coating polishing will
improve finish) |
Coating
will generally replicate existing surface finish - mirror
finishes can be maintained |
Difficult
to maintain mirror finishes; however, ost-coating polishing
can achieve near mirror finishes |
|
|
