Passivity in Copper‐Nickel and Molybdenum‐Nickel‐Iron Alloys

摘要: Passivity in an alloy appears at a critical composition which for ferrous and copper‐nickel alloys is related to the tendency of d band electronic energy states fill with electrons. According magnetic specific heat data, it known that filled 60 atom % Cu or 40 Ni. Corrosion data show transition from passivity activity occurs this same nickel content. Conditions electron transfer sharing are described binary combinations essentially retained ternary system molybdenum‐nickel‐iron alloys. It shown these alloys, according corrosion 28%, 35% 60% Ni series sulfuric acid, approximately predicted atomic ratio Mo Fe equal 0.2. Molybdenum apparently can passivate either iron both. One example 18/8, 10% contains passivated by 2% 4% Mo. The commercial practice adding minimum 2%Mo confirms calculated value 1.8% based on configuration theory. A similar calculation shows 17.5% amount necessary Hastelloy A, comparable 20% actually employed. Furthermore, maximum percentage permitted passive Mo, balance alloy, be agrees 30% found experimentally. successful correlation configurations atoms theories metallic state behavior suggests new approach general problem metals