Study on stability in the preparation of Co_0.5Ni_0.5Mn₂O₄ by sol-gel auto-combustion process

The detailed studies on the stability in the preparation of Co_0.5Ni_0.5Mn₂O₄ by sol-gel auto-combustion process are given in this paper. It is demonstrated that the formation of precipitation related to the citrate is a main factor to induce the instability of citrate-nitrate solution. There are two necessary conditions to keep the stability. One of the conditions is the formation of the network between the citric acid and EG, which is important to form a stable sol-gel, and the other is the formation of chemical bond between the metal cations and the carboxyl.