Reaction behaviour of Ni^sub 1-x^M^sub x^O's (M = Li, Na) formation and its thermoelectric properties

Issue Title: Featured Issue: Lead-Free Solder and Packaging Reaction behaviour of the mixed reactant powder of NiO and M^sub 2^CO3 (M = Li, Na) for the formation of Ni^sub 1-x^M^sub x^O (M = Li, Na) was investigated. Ni^sub 1-x^M^sub x^O (M = Li, Na) compacts were fabricated by sintering green compacts of the mixed reactant powder at 1,173 K for 5 h in air. The results indicated that Ni^sub 1-x^M^sub x^O (M = Li, Na) was successfully synthesized when the sintering temperature was approximately above 800 K. In addition, the resultant Ni^sub 1-x^M^sub x^O (M = Li, Na) kept the same crystal structure with that of NiO (except for x = 0.4), but the diffraction peaks were found to shift to larger diffraction degrees compared with that of NiO. Interestingly, Li ions distribute in the lattice of NiO uniformly. Meanwhile, the electrical resistivity of the sintered compacts decreased and their semiconductor behaviour was always maintained with the increase of doping Li or Na. The power factor was increased significantly and exceeded 1.8 × 10^sup -4^ Wm^sup -1^ K^sup -2^ at 823 K.[PUBLICATION ABSTRACT]