Polymer-metal chelate precursor reduced its firing temperature and time for preparing yttrium barium cuprate powder

• Published in: Journal of materials science 1996-12, Vol.31 (24), p.6389-6394
• Main Authors: NAKA, K, HAGIHARA, K, TANAKA, Y, TACHIYAMA, Y, OHKI, A, MAEDA, S
• Format: Article
• Language: English
• Subjects: Chemistry; Elements and non-metal compounds (oxides, hydroxides, hydrides, sulfides, carbides, ...); Exact sciences and technology; Inorganic chemistry and origins of life; Preparations and properties
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/bf00356240

Bulk YBa2Cu3Ox was prepared by a polymer chelate precursor method using poly(N,N-dicarboxymethyl)allylamine) as a chelating polymer of molecular weights 3 x 10 exp(4) (PDAA-L) and 3 x 10 exp(5) (PDAA-H). XRD of the precursor from PDAA-H shows that Y123 phase appeared after being calcined at 750 C for 5 h and the mixture was completely converted to tetragonal Y123 phase after being calcined at 800 C for 5 h. The phase evolution of the precursor from PDAA-H during isothermal experiment at 800 C showed that pure tetragonal Y123 was produced even after the polymer chelate precursor was heated for 2 h in air, although a very small amount of BaCO3 was recognised. This BaCO3 phase was hardly recognised after 4 h calcination. The precursor prepared from PDAA-L was fully converted to pure tetragonal Y123 after 3 h calcining at 800 C. In contrast, the sample prepared from metal nitrate solution without PDAA was not fully transferred to Y123 phase after heating at 800 C for 10 h. Large amounts of Y2O3, BaCO3 and CuO were observed. These results indicated that the greater homogeneity in the polymer chelate precursor leads to reduced firing times and temperature compared with the metal nitrate precursor. 11 refs.