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Optimisation through separation of functions
Since it is the coating that confers high wear resistance and low
friction, the base material can be selected for optimum strength and
toughness.
There is no basic restriction on the coating of steels with the PVD or
PACVD process. The rule for any material is: the temperature of the
final heat treatment* must be higher than the coating temperature**, as
coating is the last processing step.
* for steels, this is usually the tempering temperature
** depending on the coating, 200 °C to 500 °C
Readily coatable materials
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Heat treatable steels |
| • |
Tool steels |
| • |
Austenitic steels |
| • |
Precipitation hardened steels |
| • |
Structural steels |
| • |
Nitrided steels (after pre-treatment) |
| • |
Cemented carbides |
| • |
Nickel and titanium alloys |
| • |
Ball bearing steels* |
| • |
Case-hardening steels* |
| • |
Hardenable chromium steels* |
* only for low-temperature coating < 250 °C
Conditionally coatable materials
| • |
Cast iron
(Lamellar graphite is better) |
| • |
Chromium- and nickel-plated metals
(only for light duty as adhesion between the galvanic plating and the base material is limited) |
| • |
Copper alloys
(cleaning is complex) |
| • |
Aluminium alloys
(low coating temperature required; limited stress resistance) |
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Ceramics
(must be electrically conductive or metallised) |
Not coatable materials
| • |
Sintered metal with open pores
(not vacuum-compatible) |
| • |
Plastics
(not high-temperature resistant and not electrically conductive)
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