| PARAMETERS | BLACK OXIDATION | PHOSPHATING |
| Coating composition | iron (II)-,(III) oxide | - manganese phosphate
- secondary and tertiary
- also included: secondary and tertiary iron phosphates
|
| Layer thickness | 0,5 to 2 µm | 3 to 10 µm (up to approx. 20 µm possible) |
| fitting problems | - none, because application/removal are equal
surface structure is maintained
| must be considered beforehand as layer formation from +2 µm to +30 µm |
| Coating structure | amorphous | fine crystalline |
| Other layer properties | - bend and pressure resistant
- resistant to solvents and varnishes
- alkalis do not attack the coating
- acids attack the coating
| - good sliding properties, reduction of sliding friction during non-cutting work
- corrosion protection oils and varnishes are taken up well and hardly removed during handling, this ensures high corrosion protection
- good isolation resistance
- practically no undermining of damaged coating with rust formation
|
| Coating colour | black | grey to black |
| Working temperature | 120 to 150 °C | approx. 80 ± 15 °C |
| Exposure time | 5 to 20 minutes | 8 to 15 minutes |
| Quantity of chemicals for a 100 l bath formulation | 50 to 70 kg | 15 ± 5 kg |
| Salt spray resistance without oiling | up to 30 minutes | up to 3 hours |
| Salt spray resistance with oiling | up to 70 hours | up to 200 hours |
| Rust protection | - relatively good in dry indoor air
- poor in humid, acidic air
| very good because deep penetration of corrosion protection oil into the pores of the fine crystalline coating is possible |
| Hazardous materials | - highly alkaline – strongly corrosive
- toxic due to sodium nitrite component
| corrosive – but only slightly acidic due to nitrate and acid component |
| Waste water | Neutralisation and detoxification | Neutralisation |
| Health and safety at work | high temperatures and high alkalinity require corresponding precautionary measures | weakly acidic, low temperatures |
| DIN standard | DIN 50938 | DIN EN 12476 |
