top of page

Achieving color uniformity with PVD - for outstanding products in brown, purple, bronze & rosegold

A wide range of colors achievable with PVD technology.

PVD color coatings

Decorative coatings by Physical Vapour Deposition (PVD) satisfy increasingly stringent demands such as

  • attractive but accurately uniform color

  • high hardness

  • wear resistance

  • stability of coated color over time

  • corrosion resistance

  • and uniform over 3-D objects

In fact, quality requirements are ameliorate while production costs are always in decline.

Among all the possibilities of PVD deposition, rectangular cathodic arc and magnetron sputtering certainly plays a critical role, presenting many advantages over the rest of methods.

Magnetron PVD

One among the biggest advantage by decorative PVD is the low deposition temperature (typically < 160°C) offer the possibility to coat the substrates which has the less thermal-resistance (plastics, thin metal springs, porous materials etc).

PVD process offers more and more colors in the recent years owing to the improvements in arc or magnetron design equipped with

  • variable and differential magnetic field

  • extra cooling of targets

  • and auxiliaries allow multiple gas flow options much closer to the target

  • cathode poisoned on axis of the rotating substrate table

  • and 3-D rotation of satellite spindles that can go 45 rotations per one full rotation of substrate axis.

Among all other colors, the most challenging colors are

brown pvd colored watch

  1. brown

  2. rosegold

  3. purple

  4. bronze.

The reason is: these colors are involving oxygen in their process, which add complication to the plasma uniformity.

If you need uniform color over the vertical height or in the curvature of 3-D parts, uniformity of plasma density is mandatory.

Titanium target operated at nitrogen atmosphere and Chromium operated at full acetylene gas load would never create issues in uniformity as breaking of nitrogen molecules and acetylene molecules are not so easy.

Hence, the gradient in the plasma potential would be too low as most of the energy would be spent breaking the reactive gas molecules.

pvd chamber homogenius coating

However, that’s not the case for oxygen, an easily ionizing with subsequent recombination.

Hence maintenance of plasma density throughout vertical and horizontal profile of the substrate table is challenging.

People try multiple ways: either the single or the combination of the following ways

  • magnetic field variation

  • gas feed

  • 3-D rotation of parts

  • High density plasma

  • Central cathode

Central cathode is not so favorable owing to the production and maintenance costs.

If you would like to know more about how to achieving the color uniformity for brown, purple, bronze and rosegold, please do not hesitate to contact me on


Commenting has been turned off.
Beitrag: Blog2_Post
bottom of page