Measurement of erosion-corrosion synergism with a slurry wear test apparatus

Abstract

A slurry wear test recently developed by the Bureau of Mines was used for the measurement of wear rates and electrochemical corrosion rates during slurry wear in order to establish relationships between erosion and corrosion of metal specimens. Slurries of silica sand and aqueous solutions were continuously fed into the test chamber, where they abraded and corroded the test specimens, a low alloy steel, a stainless steel, and a wear-resistant low alloy steel. Three types of tests were conducted to determine 1. (1) the total erosive-corrosive wear rate, 2. (2) the wear rate due to erosion only, and 3. (3) the electrochemical corrosion rate. The total wear rate was determined from the weight losses and densities and reported in units of volume loss per unit time. The wear rate due to erosion only was determined while cathodically protecting the specimens. The electrochemical corrosion rate was determined by using polarization scans with the test specimen as the working electrode during slurry wear tests. The test parameters were temperature, solids concentration, and impeller speed. The test results showed that the combined effects of erosion and corrosion resulted in total wear rates that were much greater than the additive effects of each process taken alone, thus showing a strong synergism between erosion and corrosion.