In the case of browning, a matte black oxide layer is formed on iron or steel, in an alkaline solution of up to 140 ° C.
This is done, to avoid disturbing reflections and has a very decorative effect. Browning offers moderate corrosion protection (rust hazard).
Browning therefore requires constant care (oiling).
Applications: Precision parts made of steel.
Photos: Optical institute Karl Kahles, 1170 Vienna