Problem Solving Guide for Black Oxide
June 21, 2011
|
PROBLEM |
INVESTIGATE |
| Non-Uniform or Spotty Coatings | Cleaning/Surface Prep (oxides, scale, buffing or drawing compounds) |
| Scum on the Surface of the Black Oxide Bath | |
| Parts Nesting Together | |
| Selective Heat Treatment | |
| Inadequate Control of Black Oxide Temperature | |
| Light Gray Coatings | Bath Temperature Too Low |
| Heat Treatment (nitrided or carbonitrided steel) | |
| Blackening Time Too Short | |
| Inadequate Surface Activation | |
| Red/Mahogany Coatings | High Silicon Content in the Base Metal |
| Parts Were Previously Phoshate Coated | |
| Non-Ferrous Metal Contamination in the Black Oxide Bath | |
| Brown Rub-Off | Bath Temperature Too High |
| Slow Transfer Time to the Rinse After Black Oxide | |
| High Concentration of Colloidal Iron in the Black Oxide Bath | |
| Unremoved Stamping or Forming Lubricant | |
| White Residue | Poor Rinsing After the Black Oxide Bath |
| Carbonate Bleed Out - Powdered Metal Components, Blind Holes or Assemblies |
Contact us for more troubleshooting information on black oxide processing.