high nickel alloys are a combination of nickel and other metals like copper, chromium, iron or molybdenum. These other metals alter the alloy's properties by either enhancing or limiting corrosion, oxidation resistance, strength, or high temperature performance. They are commonly used in the offshore oil and gas, chemical processing and nuclear industries.
Nickel-copper alloys, such as Monel 400 (also known as Nicorros or Nickelvac), offer excellent resistance to acidic and alkaline solutions as well as seawater. These alloys are typically found in marine applications such as piping systems and pump shafts.
Alloys with a higher nickel concentration such as Hastelloy C-276, Inconel 625 and Alloy 718 offer exceptional resistance to pitting, crevice and other severe corrosion problems in seawater, hydrofluoric acid, dilute non-oxidizing acids, alkalis and salts. They are widely used in the chemical processing industry, particularly for equipment such as tanks and piping.
Surgical instruments must often be sterilizable with harsh chemicals or at very high temperatures, which is where nickel alloys are especially useful. These alloys also provide good flexibility and soft magnetic properties, which make them a popular choice for orthopedic implants and stents.
Alloys with a higher percentage of nickel, such as Invar 36 (also called Nilo or Pernifer), have the unique ability to exhibit very low coefficients of thermal expansion at room temperature. This property makes them an ideal material for applications where high dimensional stability is required such as precision measuring instruments or thermostat rods. Alloys with even higher concentration of nickel, such as Nitinol, have low coercivity and are therefore useful in soft magnetic applications such as transformers or memory storage devices.
