Measuring techniques for quality assurance of Oerlikon Balzers coatings
Standardized testing procedures ensure that all statements concerning coating quality are always reliable and comparable.
Quality assurance testing methods
| Method | Attribute | Constraints | Precision | Destructive for | |
|---|---|---|---|---|---|
| Spherical abrasion | Coating thickness | Geometry, roughness | 0.3 - 0.5 μm |
Coating yes |
Substrate yes |
| XRF | Coating thickness | Geometry, composition (element) | 0.3 - 0.5 μm | no | no |
| Rockwell hardness (HRC) | Substrate hardness | Substrate hardness Geometry | ± 1 HRC | yes | yes |
| Rockwell test | Coating adhesion | Substrate hardness Geometry | ± 0.5 HF-Class | yes | yes |
| Colour measurement | Colour of the coating | Planar surface | ± 1 CIELAB-unit | no | no |
| Contact stylus profilometer | Roughness | Geometry | * | no | no |
* Function of test conditions
Determination of coating thickness using a spherical abrasion test
In this measuring technique, the dimensions of a spherical indentation, abraded in the coated substrate with a steel ball, are determined and used to calculate coating thickness.
1 Rockwell diamond indenter
2 Coating
3 Substrate
4 Coating with HRC indentation (top view)
Coating thickness determined by spherical abrasion measurement testing.
Adhesion testing using the Rockwell method
A conventional Rockwell hardness test (DIN 50103) is carried out, followed by an analysis of the network of coating cracks and flaking around the edges of the indentation using an optical microscope. Coating adhesion is then assigned to one of six adhesion classes.
1 Rockwell indenter
2 Coating
3 Substrate
4 Coating with spherical indentation (top view)
Coating adhesion testing using Rockwell indentation