EVALUATION OF AND COMPARISON THE GENERAL CORROSION BEHAVIOR OF LOCALLY PREPARED SULFAMIC, AT 298 K

Abstract

The aim of this study is to investigate ,and compare the general corrosion behavior of the locally prepared sulfamic acid (HSO3NH2 ) . Three different alloys were used , commercially pure copper , AISI 1010 plain carbon steel , and AISI 316 Stainless steel Simple immersion test was performed on each of the above mentioned alloys, in two different concentrations of 5% , and 10% by weight( wt ) , 99% purity of locally prepared sulfamic acid of pH (0.4-_0.6 at ), 298K for 120 hr to evaluate corrosion rate by Mil per year (MPY) . For comparison purposes Annlar Sulfuric acid and Hydrochloric acid also were used at the same concentrations of 5%, and 10% by wt, at 298K using the same above mentioned alloys , for 120hr immersion duration. The tests indicates that the general corrosion rate for all the tested three alloys, in locally prepared sulfamic acid is far less ( Minimum MPY values) than that for HCl and H2SO4 , especially for commercially pure copper and AISI 1010 carbon steel. These results are related to the formation of complex water-soluble sulfamate salts for each alloy used during corrosion reaction. While the formation of precipitated corrosion product salt layers causes further corrosion on using each of H2SO4 or HCl acids.This means that sulfamic acid can be used to replace safely H2SO4 and Hcl acid whenever the tested alloys are found at the different industrial applications. For AISI 316SS. Alloy the MPY values are ( 0.1 MPY at 5% wt, and 0.15 value at 10% wt ) in locally prepared sulfamic acid although these values are lower than MPY values when immersing the same alloy is immersed in sulfuric acid . But still MPY values in sulfuric acid are fairly close. This means that sulfuric acid is still competitive to sulfamic acid on using alloy AISI 316SS.