Blackening techniques for metal
1. Hot Black Oxide
Description:
Hot black oxide is a chemical conversion coating typically used for ferrous metals (iron and steel). The process involves a series of chemical baths, including alkaline cleaners, hot black oxide solutions, and rinsing baths.
* Process:
1. Cleaning: Thoroughly clean the metal to remove oils, dirt, and other contaminants.
2. Rinsing: Rinse the metal to remove any cleaning agents.
3. Blackening: Immerse the metal in a hot alkaline solution (around 285°F to 295°F) containing sodium hydroxide, nitrates, and nitrites. This causes a chemical reaction, forming a black magnetite (Fe3O4) layer on the surface.
4. Rinsing: Rinse again to remove residual chemicals.
5. Sealing: Apply an oil or wax to seal the surface and enhance corrosion resistance.
Keywords
wax
285°
dirt
oils
iron
steel
295°F
series
Sealing
surface
rinsing
process
nitrates
nitrites
Fe3O4) layer
chemical baths
ferrous metals
cleaning agents
black magnetite
sodium hydroxide
chemical reaction
alkaline cleaners
other contaminants
residual chemicals
corrosion resistance
Blackening techniques
hot alkaline solution
hot black oxide solutions
chemical conversion coating
1. Hot Black Oxide Description
