Helium

Introduction

In the spark ablation process, a carrier gas is required in addition to electrodes made of the material one would like to obtain nanoparticles of. The role of the carrier gas is to facilitate controlled sparking and transport the produced nanoparticles out of the system. In general, noble gasses as well as nitrogen may be used as carrier gases for the spark ablation process. Currently, the most used carrier gases are nitrogen (N) and argon (Ar), but others have been used as well.

The key differences between the various gases with respect to spark ablation is a property known as the breakdown voltage of a gas. The various noble gases and nitrogen have different breakdown voltages that affect the characteristics of the sparks in the process and thereby affect the formation of nanoparticles. For example, a carrier gas with a higher breakdown voltage allows for more power per spark, ablating more of the electrode material.

Elements such as hydrogen and oxygen may be added to the carrier gas used to create hydride and oxide nanoparticles or to prevent oxidation. For example, a common combination is to use argon as carrier gas with a small fraction of hydrogen to strip the gas of any oxygen, preventing the oxidation of the nanoparticles.

Basic data

NameHelium (He)
Configuration1s2
Electrons2
Group18 (Noble gases)
AbundanceNegligible
Magnetic typeDiamagnetic
Melting point-272 ℃
Boiling point-269 ℃

Interesting reads

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