Carboxymethyl starch as corrosion inhibitor for mild steel

Abstract

In order to seek wider fields of application of carboxymethyl starch (CMS), the inhibition of CMS on mild steel in hydrochloric acid (HCl) solution has been investigated by polarisation curves and electrochemical impedance spectroscopy. The results show that CMS has a good tendency as a corrosion inhibitor in 5% hydrochloric acid solution at room temperature, 40°C and 60°C. When CMS with a concentration of up to 2 g/l was added, the corrosion rate decreased to 11·19 mm/year and the inhibition efficiency was 80·61%. The corrosion rate increased with the increase in temperature of the medium. CMS is found to be a kind of cathode corrosion inhibitor, and the inhibition efficiency increases with increasing concentration of CMS, and the inhibition efficiency is best at room temperature. Passivation will be accelerated on the surface of the electrode when mild steel electrode is in 5% hydrochloric acid solution at 40°C, which leads to good resistance to corrosion.

Electrochemical Approaches for Material Conservation: Experimental and Theoretical Insights Using a Biopolymer

“…These polymers can effectively control the corrosion process of the metals because of the presence of multiple adsorption sites which has the tendency to easily form a complex with the metal surface. A few available literatures for using biopolymers as corrosion inhibitors are: sodium alginate for API X60 steel [22] pectin for mild steel [23] lignin for 3 different alloys like mild steel alloy, stainless steel alloy and aluminium zinc alloy [24] carboxymethyl starch for mild steel [25]. In continuation of our continuous effort towards corrosion mitigation and hence material conservation, using eco-friendly green inhibitors [26,27] for various types of engineering materials [28,29] we hereby introduce a novel carbohydrate polymer maltodextrin (MLD) for the corrosion control of zinc in sulfamic acid.…”