Study on Corrosion Behavior of 4032 Aluminum Alloy Piston in High Temperature Ammonia Environment

Abstract

In recent years, ammonia (NH3) has received widespread attention as a fuel for internal combustion engines.Ammonia combustion produces a large amount of water, but incomplete combustion of ammonia may cause corrosion to engine piston components in medium to high temperature environments with water present.In this work, taking 4032 aluminum alloy piston material as the research object, the corrosion behavior in a 25%(mass fraction) ammonia solution was analyzed at a constant temperature of 200 ℃, and the corrosion weight loss, corrosion product morphology and corrosion electrochemical properties of aluminum alloys were explored emphatically at different time scales.Results showed that the corrosion rate of 4032 aluminum alloy in medium to high temperature ammonia environment exhibited a trend of first increasing and then decreasing with the prolongation of soaking time, and the corrosion products were mainly Al(OH)3.With the extension of soaking time, the corrosion potential Ecorr and polarization resistance Rp of 4032 aluminum alloy increased gradually, while the corrosion current density Jcorr decreased gradually, which further analyzed the corrosion mechanism.

Keywords

• ammonia fuel engine；4032 aluminum alloy；medium and high temperature ammonia environment；electrochemical corrosion；corrosion behavior