Interaction of Si₃N₄ with Mn under Ar or N₂ Atmosphere

Abstract

In relation to the joining of silicon nitride ceramics to metal, the reaction products and reaction mechanism between Si₃N₄ and Mn have been investigated in Ar or N₂ at temperatures from 1073 to 1573K. Using an Si₃N₄-Mn powder mixture, the reaction rate was determined thermogravimetrically, and the reaction products were examined by X-ray diffraction. Under an Ar atmosphere, from 1223 to 1423K, MnSiN₂, Mn_0.815Si_0.815 and Mn₃Si were produced, and above 1423K, MnSiN₂ disappeared. At higher temperatures and on prolonged heating, the suicide composition changed in the following order: Mn_0.815Si_0.185, Mn₃Si, Mn₅Si₃, and MnSi. Under an N₂ atmosphere, the reaction between Mn, Si₃N₄ and N₂ produced Mn nitrides and MnSiN₂. Below 1223K, the reaction products were Mn₆N_2.58 and Mn₄N. At higher temperatures, MnSiN₂ appeared, while Mn nitrides disappeared. Above 1423K, only MnSiN₂ was produced. By relating these results to TG measurements, a full understanding of the reaction mechanism between Si₃N₄ and Mn was acquired.