European journal of solid state and inorganic chemistry vol:32 issue:7-8 pages:711-718
The freeze drying method for preparation of YBa2Cu3O7-x is described and documented. The obvious advantages of high purity and good stoichiometry control are retained while homogeneity of the resulting material is optimised. Details of the drying process are studied by use of DSC, TGA and XRD measurements. Both copper nitrate and yttrium nitrate are responsible for phase segregation during secondary drying of the freeze dried material. Extending the vacuum calcination cycle to a higher temperature circumvents possible localised melting.