Study on fabrication and foaming mechanism of Mg foam using CaCO3 as blowing agent

Using CaCO3 as blowing agent and via melt foaming method, Mg foams with closed-cells have been fabricated successfully. It has been proved that the blowing gas to foam melted Mg is not CO2 but CO, which is released from the liquid–solid reaction between Mg and CaCO3. The releasing temperature of CO is more than 100 °C lower than the decomposition temperature of CaCO3, which leads to melted Mg being foamed much more easily and the foaming process can be accomplished in a temperature range of 665–750 °C.