Sievert’s (square root) law states that, at a given temperature, the solubility of a diatomic gas in a melt changes with the square root of its pressure.
The law is therefore significant for the determination of gas solubility in liquid metal.
According to the law, the concentration of a diatomic gas dissolved in the melt is proportional to its partial pressure on the melt. Eq. 1 can therefore be written for the concentration of the hydrogen dissolved in the melt:
C = temperature and alloy-dependent constant; pH2 = hydrogen partial pressure on the melt
The relationship described in Eq. 1 is used, for example, to determine the hydrogen contents in a melt (see also Hydrogen solubility, Hydrogen determination, Chapel process).