Blood Corrosion

Any ionic substance that is electrically conductive forms an electrolyte. Muscle contraction in the body is dependent upon electrolyte (calcium, 0.9% sodium chloride, and potassium).

Galvanic Corrosion occurs when two different type of metals touch exposed to an electrolytes like blood.  Blood has almost a gram of salt per 100 milliliters. Solvation (individual components dissociate) happens normally with salty water due to thermodynamic interactions between solvent and solute molocules.  Blood, pus, and other secretions contain chloride ions which lead to metal corrosion most often appearing as dark spots. If blood is left on metal for any period of time (20 minutes or longer), it will mark and stain, especially if these residues are allowed to dry.

M1 GARAND BAYONET

"Icky aint it?"



If corrosion is a problem in your daily life here are some things to remember.

A)  Naval Jelly (phosphoric acid) or citric acid will turn rust black (black phosphate) coating the metal surface which further makes it corrosion resistant due to passivation.

B)  Iron rusts (electrochemical corrosion), ceramic polymers corrode (degradation).

C)  Aluminium melts at 1220℉/ boils at 4566℉ and is low density, also resists oxidation from exposure (blood) with a thin crust of aluminium oxide (passivation).

D)  Parkerizing or blued electrochemical conversion coating process is superficially similar.