Establishment of hydrogen measurement system for magnesium alloy melt

The equations of hydrogen solubility in pure magnesium and its alloy were deduced based on thermodynamic analysis: for pure magnesium, lgc(H)=0.5lg p(H2)-1 332/T+0.568; for AZ91 alloy, lgc(H)=0.5lg p(H2)-1 332/T+0.483. Based on the above equations, a rapid and reliable measurement system for hydrogen content in magnesium melt was set up with CPU controller and electric circuit. With this instrument, measurement experiments were carried out to determine hydrogen content in AZ91 melt. The results show that the actual hydrogen level of AZ91 melt under gas protection varies from 0.06 mL/g to 0.14 mL/g at the temperature range from 650 ℃ to 750 ℃, and hydrogen content lineally increases with the increase of temperature.