Effect of Environmental Pollution on Corrosion Characteristics of 3003 Aluminium Alloy Exposed in Different Parts of India

Abstract

Corrosion behaviour of 3003 grade of aluminum alloy is investigated by exposing its samples under different climatic and pollution zones of India namely Jamshedpur, New Delhi, Lucknow, Mumbai, Nagpur, Kolkata, Chennai and Palampur. Results indicate that pollutants in the atmosphere, especially PM10, considerably affect the corrosion rate. Electrochemical impedance spectroscopy and direct current anodic polarization studies indicate the formation of very protective film on specimens exposed to cleaner environments. Raman spectroscopy and XRD studies of the passive films formed on exposed samples help to explain the variation in corrosion rate of the metal in different climatic conditions. The deposition of fine particulates on the exposed surface of the samples are observed to act as a reservoir of corroding species by absorbing corrosive gases, moisture and anion and cation species resulting in the formation of corrosion cells. The mechanism for the breakdown of passive film resulting in accelerated rate of corrosion of the alloy exposed to polluted environments is discussed. © 2016, The Indian Institute of Metals - IIM.