The porosity of partly sintered nickel iron oxalates

The porosity of co-precipitated iron(II) and nickel(II) oxalate samples was investigated after thermolysis at different temperatures. Specific surface area values of the obtained nickel(II) ferrite samples have been determined by means of the BET method. Maximal values of the specific surface area and pore volume have been fixed for ferrite samples obtained when the thermolysis of oxalates was carried at 500 °C during an hour. Specific surface value in this case was 335 m2/g and pore volume 0.46 cm3/g. At comparatively higher temperatures of thermal decomposition (600 °C) the indicated parameters of porous structure decrease sharply: specific surface area value to 20–25 m2/g and pore volume – to 0.20 cm3/g. A similar picture observed also when thermolysis was carried at 500 °C during 2 h. In this case specific surface area value decreases to 30 m2/g and pore volume – to 0.22 cm3/g.