A nickel based, high silicon alloy exhibits very high corrosion resistance in high temperature sulfuric acid environments. The alloy may be cast and is sufficiently ductile to be fabricated and machined. The alloy is ductile and has sufficient resistance to mechanical and thermal shock to be reliable in service when used as rotating parts. The alloy may have the following composition, in percent by weight:

                Nickel               about 82-86%
                Silicon              about 9-11%
                Niobium              about 3-6%
                Cerium               about 0-0.1%
                Boron                about 0.-0.11%
                Cesium               about 0.1-0.7%
                Lanthanum            about 0.04-0.3%
                Neodymium            about 0.04-0.3%
                Iron                 about 0-0.65%
                Carbon               about 0-0.08%.