Corrosion of Steel by Chlorinated Solvents and its Inhibition I. Factors affecting the decomposition of CCl 4 and its action on mild steel

Abstract

The corrosion of mild steel by chlorinated solvents has been investigated. The evidence of acid formation as a result of decomposition of CCl₄ and of the corrosive action of the degraded solvent on mild steel has been reported. In the presence of water in CCl₄ a number of metals produced acid, both when exposed in the liquid or in the vapour, more in the latter case. In general, the catalytic activity of different metals in decomposing CCl₄ was in the following decreasing order: mild steel, aluminium, copper, zinc. Nickel, stainless steel and brass did not decompose the solvent. Higher temperatures (> 10°C), longer test periods, a higher water content, the presence of inorganic contaminants and exposure to UV radiation caused more decomposition of CCl₄ and greater attack on mild steel. Boiling solvent (containing H₂O) or the vapour therefrom prodūced greater corrosion. Hot condensate either flowing past the metal specimens or wetting and drying them alternately produced maximum corrosion.