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Amorphous Ni 3 (SbTe 3 ) 2 compound was prepared from a metathesis between Zintl phase K 3 SbTe 3 and NiBr 2 in solution and its oxidation behavior was investigated in the temperature range of 200–700 °C in air. To characterize the sample, thermogravimetry (TG), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis by X-ray (EDAX) analyses were performed and electrical conductivity was measured as a function of temperature in the range of 25–800 °C in air. The specimen showed a metallic conducting-like behavior below 585 °C while a semiconducting-like behavior above 585 °C. At a first oxidation step of Ni 3 (SbTe 3 ) 2 below 500 °C, TeO 2 phase is formed. Above 500 °C, NiO phase is formed, then some NiO reacts with TeO 2 to form NiTeO 3 and NiSb 2 O 6 is simultaneously formed. Above 700 °C, NiTeO 3 is further reacted with TeO 2 to form NiTe 2 O 5 . Both NiTeO 3 and NiTe 2 O 5 are decomposed above 774 °C. |
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