Synthesis, crystallization behavior and microstructure of oxynitride glass–ceramics with different modifier elements

M–Si–Al–O–N (M=Y, Ca, Mg) oxynitride glasses were prepared by melting batches at 1600 °C for 2 h under N2 atmosphere in a Si–Mo-heated resistance furnace. The appropriate heat treatment temperatures were selected according to the information provided by the differential scanning calorimeter (DSC) measurement. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to study the crystallization behavior of the glass–ceramics with different modifier elements. The results indicate that for this glass system, heat treatment has an effect on volume fraction of the crystalline phases and the microstructure of the glass–ceramics, whereas the effect on the types of the crystalline phases precipitated is small.