Increasing Zirconium's Resistance to Stress Corrosion Cracking and Intergranular Attack in Hot Concentrated Hydrochloric Acid

Previous studies have shown that Zr702 Zirconium (UNS R60702) is one of the best choices for use in hot concentrated hydrochloric acid.  While zirconium’s corrosion resistance far exceeds that of most metals, it is susceptible to stress corrosion cracking (SCC) and intergranular attack (IGA) under certain conditions.  This paper presents results of testing in 36% HCl with the addition of 100 ppm ferric chloride at temperatures near boiling.  The addition of ferric chloride is intended to increase zirconium’s susceptibility to both SCC and IGA.  Various heat treatments and surface conditions will be ranked according to their effectiveness in preventing SCC and IGA in this environment.