Investigation of gas-solid reactions realised by ball milling

Abstract

The gas-solid reaction process was investigated by ball milling of elemental Ti powder under different atmospheres of H2, N2 and NH3. The pressure variations of the milling atmosphere show that the hydriding and nitriding reactions occur during ball impacts at room temperature. Mechanical activation of the Ti powder using a pre-milling treatment under vacuum, upon subsequent exposure to gas, leads to a slight absorption of gas, but cannot promote gas-solid reactions. Gas-solid reactions can only be realised by ball impacts. This type of room temperature reaction process limits the grain growth of new phases and results in a nanocrystalline structure. Show more