Process CVD - Chemical Vapour Deposition
Used for very uniform coatings of also inner side of very deep holes. It provides hardness (diamond, CBN - cubic boron nitride), wear and corrosion resistance (nozzles, rolls, working and forming tools).

Chemical process, which require high temperatures (800-1100 C) to start the reaction, restricting the choice for the substrate. It provides good adhesion, with risk of deformation (no good tolerances), and necessity of pre- and post- heat treatments.

Unlike PVD, selective coating is not possible. Therefore, when required, the material needs to be removed by further costly post-machinings. Typical thickness between 5 and 15 micron (0,01-25 micron/min).
Danish Name CVD
Category Surface treatments, Gas-phase deposition
Materials Coating materials:
Ceramics (e.g. Aluminium oxide Boron nitride (CBN) Titanium carbide (TiC) Titanium nitride (TiN) Diamond etc.)
Typical products Solar cell
Competing processes PVD
PACVD
References Deutsche Geselleshaft für oberflächen technik
Industrihærderiet A/S
Price notes CVD coating is approximately 50 percent more expensive than PVD (see PVD). The high temperatures involved imply pre- and post-hardening and continuous checking of tolerances, which increases substantially the global cost (up to 3-4 times that of PVD).
Price date March 1997
Environmen- tal notes Creation: For nitrides, carbides, oxides, silicides and borides wear resistant coatings, the reactants are frequently poisonous.
Additional info For selective coating, post-removal of the coating is required. Machinings involved in this operation are very expensive and contribute to make CVD an expensive solution.
Photo Thomas Nissen (Computer graphics)
Copyright © 1996-2003 Torben Lenau
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