Abstract

MARTINEZ, Neil J; SCHWEDA, Eberhard; MOLINA, Aurora  and  CORDERO, Francis. The oxidation behavior of ytterbium scandium zirconium nitrides under  nonisothermal conditions . Rev. LatinAm. Metal. Mater. [online]. 2014, vol.34, n.2, pp.275-281. ISSN 0255-6952.

Ytterbium codoped scandium stabilized zirconia, Zr0,60Sc0,175Yb0,225O1,8 was synthesized and nitrided for 48 h under an ammonia atmosphere. The compound obtained was nominally Zr0,60Sc0,175Yb0,225O0,0627N1,157 with a red color and a cation deficient rocksalt structure. Its stability and reoxidation behavior was studied by differential thermal analysis (DTA) and thermogravimetric analysis (TG) under non-isothermal conditions. For evaluation of the experimental data, the Coats Redfern method [1] was used and revealed that the decomposition of the nitride to form ytterbium scandium zirconium oxide is diffusion controlled. The activation energy for the decomposition process was found to be 506 KJ/mol compared to 103 KJ/mol for ZrN [2]. The results indicate that scandium-zirconiumnitrides co-doped with lanthanide metals undergo a reduction in O^2-and N^3-mobility in the crystal and consequently a delay in the reoxidation process.

Keywords : Thermal stability of nitrides; non-isothermal TG/DTA/DDTA; ytterbium; scandium zirconium.

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