Hydrogen reduction of Cu-Mn-Fe-O spinel solid solutions

ISSN： 0020-1685

Source： Inorganic Materials, Vol.41, Iss.3, 2005-03, pp. : 272-278

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

The crystal-chemical transformations accompanying the hydrogen reduction of Cu_xMn₁ - xFe₂O₄ (x = 0.2, 0.5, 0.8) solid solutions are investigated, and general equations describing these processes over the entire composition range (0 ≤ x ≤ 1) are derived. The results on the character of the processes involved differ radically from earlier findings. The equilibrium oxygen pressure is evaluated for the low-oxygen phase boundary of the spinel solid solutions throughout their stability region. For $$\left( {MnFe_2 O_4 } \right)_{x_1 } \left( {Cu_{0.5} Fe_{2.5} O_4 } \right)_{1 - x_1 - x_2 } $$ solid solutions, which are of practical interest, the $$\log p_{O_2 } \left( {{1 \mathord{\left/ {\vphantom {1 T}} \right. \kern-\nulldelimiterspace} T}} \right)$$ data are well represented by the equation $$\log \left( {{{p_{O_2 } } \mathord{\left/ {\vphantom {{p_{O_2 } } {Pa}}} \right. \kern-\nulldelimiterspace} {Pa}}} \right) \pm 0.4 = 12.8 - 3.7x_1 - 2.8x_2 - {{10280} \mathord{\left/ {\vphantom {{10280} {T,}}} \right. \kern-\nulldelimiterspace} {T,}}$$ , which is of importance in controlled synthesis of single-phase materials in this system.