Thermal Expansion of Anti-Perovskite Mn_3Zn_(1-x)Sn_xN Compounds

摘要

The anti-perovskite structured Mn_3XN(X=Cu,Al,Ag,Zn,Ga,Sn,In) have wide perspective and practicability with unique advantages compared with other materials as a new negative thermal expansion (NTE) material. Because of its simple preparation and unique properties of NTE, this kind of compounds aroused scientists' attention. The metallic nitrides Mn_3Zn_(1-x)Sn_xN (x=0.1,0.2,0.3,0.4, 0.5) were prepared by solid-state sintering. The anti-perovskite compound Mn_3Zn_(1-x)Sn_xN has a cubic crystal structure with space group Pm3m. It shows that Zn element is partial replaced by Sn element. The Sn doping in Mn_3Zn_(1-x)Sn_xN compound can cause the thermal expansion behavior of the compound to change between positive and negative by analyzing the curve of thermal expansivity with the temperature. Mn3Zno.7Sno.3N shows a very strong NTE. Its negative thermal expansion coefficients were -4.39*10"4/K from 345.4 °C to 476.2 °C. In addition, the variation of the thermal expansion curve for Mn_3Zn_(0.8)Sn_(0.2)N is almost negligible with the increasing of temperature to 600 °C, exhibiting nearly zero thermal expansion behavior. Therefore, the thermal expansion of Mn_3Zn_(1-x)Sn_xN could be tuned via different contents of Sn in Mn_3ZnN.