Reaction Sintering Process in Granular Composites: Application to a Superconductor/Ferrite System

• Published in: Journal of solid state chemistry Vol. 145; no. 1; pp. 317 - 326
• Main Authors: Kopia-Zastawa, Agnieszka, Gavarri, Jean-Raymond, Suliga, Ireneusz, Fremy, Marie-Angèle, Pischedda, Marie-Hélène, Jasienska, Stanislawa
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.06.1999; Elsevier
• Subjects: Applied sciences; bismuth cuprate superconductors; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; chemical kinetics; degradation; Electrotechnical and electronic ceramics; Exact sciences and technology; ferrite–superconductor composites; high TC superconductors; modeling; reaction sintering process; Technical ceramics; bismuth cuprate superconductors; high TC superconductors; chemical kinetics; modeling; degradation; reaction sintering process; ferrite–superconductor composites; Bismuth Oxides; Nickel Oxides; Experimental study; Oxide ceramics; Composite material; Copper Oxides; Reaction sintering; Iron Oxides; Ferrite materials; Lead Oxides; Granular material; Calcium Oxides; Manufacturing; Strontium Oxides; High temperature superconductor; Electroceramics
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.1999.8279

Granular superconductor–ferrite (S/F) composites have been fabricated using various sintering conditions (volume fraction Φ0 of ferrite, volume fraction Σ0 of superconductor, sintering temperature Tsint, sintering time tsint). The superconducting S phase is the well-known Bi (Pb)–2223 phase (Tc=110 K). The ferrite (F) is NiFe2O4. The reaction sintering process is experimentally described by determining the volume fractions of residual S and F phases from X-ray diffraction experiments. Magnetic measurements are used to analyze the degradation process in both residual ferrite and superconducting phases. Nonlinear evolutions of the Σ and Φ residual volume fractions as a function of initial compositions are observed. To interpret these results, we propose to express the chemical kinetics using two elemental reactions such as: F+n. S→P and S+S→P′. Using various types of kinetics parameters, the solid state reaction in each composite can be modeled as a function of the initial Σ0 and Φ0 volume fractions.