1. Helium serves as a propellant pressurant and booster for liquid-fueled rockets, and is extensively utilized in missiles, spacecraft, and supersonic aircraft.
2. Helium is employed as a shielding gas during smelting and welding processes-a critical application in shipbuilding, as well as in the manufacturing of aircraft, spacecraft, rockets, and weaponry.
3. Possessing excellent permeability, helium is used for cooling nuclear reactors and for leak detection in the piping systems of rockets and nuclear reactors, as well as in various electronic and electrical devices.
4. Helium exhibits the properties of an ideal gas, making it the ideal medium for use in vapor-pressure thermometers designed for extremely low temperatures.
5. Helium features low mass and weight densities and is non-flammable; it is therefore used to fill light bulbs and neon tubes, and serves as an ideal lifting gas for balloons and airships.
6. Liquid helium enables the attainment of cryogenic temperatures approaching absolute zero (-273°C), making it essential for the manufacture of superconducting devices.
7. As an inert gas, helium has a lower solubility in blood than nitrogen; consequently, it exhibits less narcotic effect than nitrogen. For this reason, helium is frequently mixed with oxygen to create a breathing gas mixture for deep-sea divers.
