Helium is a monatomic gas and chemically inactive. Helium generally does not produce compounds, and can form He+2, HeH plasma and molecules when excited in a low-pressure discharge tube.
Helium is widely used in military, scientific research, petrochemical, refrigeration, medical, semiconductor, pipeline leakage detection, superconductivity experiments, metal manufacturing, deep-sea diving, high-precision welding, and the production of optoelectronic products.
1, low-temperature cold source: using liquid helium's low boiling point of -268.9℃, liquid helium can be used for ultra-low temperature cooling. And the ultra-low temperature cooling technology in the superconducting technology and other fields have a wide range of applications, superconducting materials need to be in the low temperature (100K or so) in order to show superconducting properties, most of the time only the liquid helium can be relatively easy to realize such extremely low temperature. Superconducting technology has large applications in the transportation industry for magnetic levitation trains and in the medical field for nuclear magnetic **** vibration imaging equipment.
2, balloon inflation: because helium density is much smaller than air (air density of 1.29kg/m3, helium density of 0.1786kg/m3), and the chemical nature of the extremely inactive, safer than hydrogen (hydrogen can be burned in the air, may cause an explosion), helium is commonly used in airships or advertising balloons in the filling gas.
3, inspection and analysis: instrumental analysis of commonly used nuclear magnetic **** vibration analyzer superconducting magnets need to use liquid helium cooling, gas chromatography analysis of helium is often used as a carrier gas, the use of helium permeability is good, non-combustible characteristics of helium, helium is also used in vacuum leak detection, such as helium mass spectrometry leak detector.