Material Spotlight: Nickel Based Superalloys
Nickel-based superalloy coatings are known to provide tensile strength, high temperature resistance as well as have the ability to develop high temperature strength through solid solution strengthening. In addition, nickel-based superalloys are encapsulated by a layer of protective oxide which enables them to be resistant to oxidation and corrosion. Superalloys are also known to contain other bases such as cobalt and nickel-iron.
Understanding Nickel Based Superalloys
Known as a high-performance alloy, nickel-based superalloys exhibit great mechanical strength and have excellent surface stability. In addition, these alloys can be either precipitation strengthened or solid solution. Applications that require only modest strength will require only solid solution strengthened alloys while more demanding applications, such as hot sections of gas turbine engines, will require precipitation strengthened alloy.
The basic composition of most nickel-based alloys consist of Cr (10-20%), AI (up to 8%), Ti (up to 8%), Co (5-10%), as well as small amounts of C, Zr and B.
Examples of nickel-based superalloys include:
- Alloy C-276 (common trade name: Hastelloy® C-276)
- Alloy 718 (common trade name: Inconel® 718)
- Alloy 20
- Alloy X (common trade name: Hastelloy® X, Inconel® HX)
Common Industrial Applications of Nickel Based Superalloys
Nickel-based superalloys are most commonly utilized in load-bearing structures. For common alloy systems, these superalloys will be used to the highest homologous temperature, which is 90% of their melting point or Tm = 0.9. Here is a list of common industrial applications for nickel-based superalloys:
- Gas turbines
- Power generation turbines
- Waste remediation units
- Heat exchangers
- Reciprocating compressors
- Furnaces
- Chemical/petrochemical processing units
- Storage tanks
- Piping
- Equipment in pulp and paper plants
- Jet or rocket engines
- Submarine components
- Industrial gas turbines
- Nuclear reactor components
- Heat exchanger tubing
Nickel based Superalloys are Also Found in Aircraft Engines
Advanced aircraft engines need to be continually improved in multiple areas such as emissions, operating temperatures and performance. Therefore, it has been a key driver of the development of nickel-based superalloys for many years. Aircraft engines also require these superalloy coatings as they contain an unusual class of metallic materials that can shield components from potentially harmful environmental effects and stresses. In addition, intensive alloy and process development activities have been taking place over the years, which resulted in single crystal nickel-based superalloys being able to tolerate an average temperature of more than 1000°C.
Using Nickel Based Superalloys for Thermal Spray Coatings
A&A Coatings is an industry leader in the thermal spray coating industry for over seven decades. If you are unsure whether spray coating nickel-based superalloys will be best way to sustain the lifespan of your critical parts; or you just want to find out more on our various in-house capabilities such as our High Velocity (HVOF) spraying equipment, plasma transferred arc equipment or metallurgical lab, do not hesitate to contact us to schedule a consultation to discuss your thermal spray needs.
