Experimental set up for determining the temperature-oxygen partial pressure conditions during synthesis of spinel oxide nanoparticles

International audienceNanometric spinel oxide powders, Fe 3 MaO4, where M is a transition element, have been synthetized by soft chemistry. This method generally leads to a non-stoichiometric phase, Fe 3 ~M O~+~ where 6 is the deviation from stoichiometry so that further annealing at low temperatures around 450°C and low oxygen partial pressure around 10-25 Pa given by N2/H2/H20 gas mixtures is required: this enables a stoichiometric compound to be obtained and a nanometric size to be maintained. The complete set up consisting of a gas mixer, a thermogravimetric apparatus and a preparative furnace is described. Some results concerning the conditions of temperature and oxygen partial pressure leading to stoichiometry are given in the case of vanadium ferrites containing or without Co