PM Vital to Nitinol Ball Bearings
At least one engineer was skeptical that Nitinol, which is made by combining nickel and titanium, would work as a ball bearing. But after a lot of testing – and a failed trial with a casting process – a team of scientists from NASA and Abbott Ball Company found success with powder metallurgy.
Powder metallurgy begins like casting. Instead of allowing molten material to cool in a mold, it is sprayed into a chamber. The tiny droplets solidify and cool into a powder as they fall to the bottom of an inert gas-filled chamber. The powder is collected in steel containers, welded shut and subjected to a high-temperature, high-pressure furnace held just below the alloy's melting point. The particles bond and densify but retain a fine and uniform grain structure.
The end result is high-quality material that won't rust or dent. The Nitinol could be used in the ball bearings for wing components because the metal is impervious to corrosive deicing agents used to treat aircraft in cold temperatures.
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