HOT BLACK OXIDATION OR COLD COLOURATION? A COMPARISON OF THE PROCEDURES WILL HELP YOU.
| DEWE Brünofix cold colouration method | DEWE Brünofix hot black oxidation | |
| Characteristics | A black conversion coating is generated, based on various heavy metal precipitations. | Chemical oxidation process according to DIN 50938: A black iron mixed oxide (Fe3O4) is formed on the surface. |
| Quality of colouration | black and uniform on smaller surfaces a uniform, deep black surface cannot be guaranteed on larger surfaces | deep black uniform surface, even on larger components |
| Corrosion protection | comparatively lower | comparatively higher |
| Treatment plant | low outlay | higher outlay due to heated vessels exhaust air system |
| Treatment duration | approx. 30 to 45 minutes | 45 to 60 minutes |
| Chemical consumption | comparatively high | comparatively low |
| Service life | shorter, limited life and regeneration | unlimited through regeneration |
SUMMARY
Quality comparison
Small components are suitable for cold colouration. Larger components tend towards uneven staining and are less suitable for cold colouration.
Comparison of economic efficiency
The cold colouration bath has a limited service life that is dependent on the surface. The coating costs per m² are generally over 50 % higher in cold colouration compared to hot black oxidation.
Conclusion
- Small components, low volumes and cast materials are ideally suited for cold colouration, particularly if these components previously had to be black oxidised outside the company.
- The same applies to hot black oxidation customers who only need to operate their black oxidation plant sporadically to blacken their small components over the short term.
Decision aids
- Our service – your decision
- Free sample treatment and evaluation of quality in our company
- Information and advice also provided for alternative solutions