Element number 28 on the Periodic Table is nickel. When combined with other metals, such as steel, this hard but shape-able metal forms useful alloys. These alloys have magnetic properties, resist wear-and-tear, and can withstand very high temperatures. These properties give nickel-based alloys many effective applications in the aerospace industry.
Airplanes and spacecraft are complex machines that are designed and built to precise specifications. In many cases, whether these aircraft work properly and reliably is a matter of life-and-death. With that in mind, aerospace engineers rely on nickel-based alloys to react as desired when they face certain conditions in flight. Here’s a glimpse at how these hybrid metals contribute to the aerospace industry.
Nickel Alloys in Gas Turbines
One of the best uses for nickel alloys is in gas turbines in airplane engines. A turbine is a rotating fan that uses one power source to generate another, as in a hydroelectric dam or a wind turbine. The principle is the same in an airplane’s gas turbine, except pressurized gas generates the energy needed to spin the turbine. An airplane’s turbine creates the thrust that moves the plane forward, off the ground, and through the air.
During World War II, gas turbine engines required frequent maintenance because the high temperatures in the combustion engine corroded the steel alloys rapidly. Scientists and engineers turned to nickel, with its heat and corrosion resistance, to solve this problem.
Airplane engineers replaced stainless steel alloys in turbines with nickel alloys, particularly in the combustion chamber. In the combustion chamber, fuel injectors release a continuous stream of pressurized gas, and the flame holder keeps it burning the entire flight-despite the high volume of wind passing through the turbine. Because of this continuous flame, the combustion chamber must withstand high temperatures for sustained periods of time. Nickel alloys make this possible.
After discovering the value of nickel alloys in gas turbines, aerospace engineers continued to enhance nickel alloys for airplane flight.
Adding other metals to the alloy, such as tungsten and molybdenum, made it even more heat-resistant. Applying aluminum-based coatings gave the nickel alloys greater resistance to corrosion and rust. New methods to cast the alloys gave them needed directional strength.
Today, a jet engine holds about 1.8 tons of nickel alloys. These nickel alloys make it possible for a jet engine to complete about 20,000 flight hours before requiring major maintenance. Compare that to the 5-hour flight life of planes before nickel alloys became standard, and it’s clear that nickel alloys are essential in the aerospace industry.
Nickel Alloys in Other Airplane Parts
Although they’re best known for improving gas turbine efficiency, nickel alloys have applications in other parts of an airplane as well.
Alloy 80A resists changing shape, even at extremely high temperatures and under intense stress. It’s commonly found in an airplane’s exhaust valve, which releases hot exhaust from the engine.
Monel is another nickel alloy used in airplanes. This metal contains 68% nickel, 29% copper, and smaller amounts of iron, manganese, and other elements. Similar to steel in many ways, monel has a high resistance to weight-bearing stress (known as tensile strength) and can be welded. Airplanes have monel in their exhaust manifolds, carburetor valves and sleeves, and the gears and chains that control landing gear. Monel rivets are used to hold nickel-steel alloys in place as well.
Nickel Alloys on the Lunar Module
Nickel-based alloys are so useful in the aerospace industry that they have been to the Moon. During the 1960s, the United States’ Apollo missions allowed 12 men to walk on the Moon. In order to get there, these astronauts used a spacecraft designed specifically for landing on the Moon: the Lunar Module, or LM.
According to the Smithsonian National Air and Space Museum, nickel-based alloys comprise many of the black outer parts of the LM.
These black parts used a nickel-steel alloy to absorb and reflect the Sun’s heat away from the LM. With the help of up to 25 layers of aluminum coating on top of the nickel alloy, these parts also protected the spacecraft from tiny meteoroids.
The nickel-alloys used on the LM were incredibly thin: 0.0021072 mm/0.0000833 in. thick. Compare that to common aluminum foil
which is around 0.2 mm/0.0079 in. thick. A piece of printer paper is typically 0.1 mm/0.0038 in. thick. The 1995 film “Apollo 13” features a reference to these very thin parts of the LM. During the spaceship’s broadcast to Earth, Jim Lovell (portrayed by Tom Hanks) says that “the skin of the LM in some places is only as thick as a couple of layers of tinfoil, and that’s all that protects us from the vacuum of space.”
Clearly nickel alloys have important ties to aerospace history. Without these heat- and corrosion-resistant metal alloys, we could nottravel across oceans so easily today, nor would men have walked on the surface of the Moon. Truly these nickel-based alloys are an indispensable modern metal.
Post time: Dec-19-2022
