Effects of sintering temperature on microstructure, nitrogen deficiency and densification of spark plasma sintered Mn3Cu0.5Ge0.5N

Single-phase Mn3Cu0.5Ge0.5N bulks were prepared by spark plasma sintering (SPS) in nitrogen atmosphere at different sintering temperatures, and the effects of sintering temperature on microstructure, nitrogen deficiency and densification were studied. It was found that the densification is accompanied by the thermal decomposition of Mn3Cu0.5Ge0.5N. Nitrogen deficiency and porosity due to the thermal decomposition of the compound do not increase with increase of the sintering temperature; the nitrogen deficiency from decomposition is compensated by the diffusion of nitrogen atoms from the N2 atmosphere. When the two processes reach the balance, minimum nitrogen deficiency of Mn3Cu0.5Ge0.5N is achieved together with the highest densification.