Studies On The Inhibitor Of Zinc In Mud Acid Solution

The corrosion of zinc in mud acid is very serious, so galvanized equipment cannot be cleaneded by mud acid, impact seriously on economic benefit, therefore, the development of inhibitor of zinc in mud acid is very necessary. At present, the Inhibitor of zinc in mud acid that can be used in industry has not been reported. Therefore, this work has great significance.This paper studied respectively the corrosion velocity and inhibition efficiency of zinc in 2.5% mud acid(1.75%HCL+0.75%HF)with a few of compounds by weight-loss method, then three types of compounds with good corrosion inhibition effect have been selected from which, including: surfactants, quaternary, heterocyclic compounds.Choose isoquinoline,benzalkonium chloride,cinnamaldehyde,benzalkonium bromide as study objects, study their corrosion inhibition effect to zinc in 2.5% mud acid(1.75%HCL+0.75%HF)in different temperatures by adsorption theory and polarization curve theory, and analyze the mechanism of corrosion inhibition. It is known from the experiment that the inhibition efficiency of these compounds are: 99.52%,97.13%,98.92%和98.87%.Analysis shows: these types of substances mainly produce monolayer adsorption in the zinc surface, and the adsorption is basically consistent with the Langmuir isotherm law in the temperature range studied. Adsorption process is exothermic, with the temperature increased, the adsorption capacity decreased, inhibition efficiency decreased.However, As the inhibition efficiency of single-component decreased after the temperature increased, which can not meet the practical application, because it often require a high temperature in practical industrial applications. Therefore, this paper Compound several substances by the orthogonal experimental method to acquire a very good compound inhibitor, and evaluate its performance in different temperature, different time and different concentration of mud acid.The results showed that the inhibitor did not Invalid at 90℃, 20% mud acid, react 24 hours and other indicators of disturbance, and the corrosion rate of Zinc can all meet the national standards. SEM showed there are no pitting corrosion, inter-granular corrosion and other non-uniform corrosion on zinc surface. Polarization curves showed that the inhibitor is a cathode inhibitor. Taking all factors, the inhibitor is known as an excellent soil corrosion of zinc in acid medium.