Negative thermal expansion, electrical and mechanical properties of antiperovskite Mn ₃ Zn _0.5 A _0.5 N ( A = Sn, Ag, Ni)

Thermal expansion, electrical conductivity, hardness and friction property of Mn3ZnN, which had been doped with Sn, Ag or Ni and sintered at 1223 K, were measured. X-ray diffraction analyses show that these compounds have a cubic antiperovskite Mn3CuN-type structure and negative thermal expansion (NTE). The width of NTE operation temperature (ΔT) and the coefficient of thermal expansion are different when Mn3ZnN was doped with different element. A giant NTE coefficient of −81.00 × 10−6 K−1 is obtained from Mn3Zn0.5Ag0.5N while ΔT is 18 K. A broad ΔT of 60 K is obtained from Mn3Zn0.5Sn0.5N with thermal expansion coefficient of −19.05 × 10−6 K−1. The results show that Mn3Zn0.5 A0.5N (A = Sn, Ag, Ni) has good electrical conductivity. The electrical conductivity of Mn3Zn0.5Ag0.5N is the largest among these compounds as 2.45 × 103 S cm−1. The Vickers hardness of these compounds is more than 350 HV. The friction coefficients of Mn3Zn0.5Ag0.5N, Mn3Zn0.5Ni0.5N and Mn3Zn0.5Sn0.5N are 0.5318, 0.4554 and 0.2336, respectively.