NEW POLYMER CHELATE PRECURSOR SYSTEM TO THE YBA2CU3O7-X SUPERCONDUCTOR USING POLY(N,N-DICARBOXYMETHYL)ALLYLAMINE

Poly(N,N-dicarboxymethyl)allylamine was synthesized and used as a chel ating polymer for Y, Ba, and Cu. Both pH titration and UV curves of th e polymer in the presence of each metal ion showed the chelate formati ons. The clear solution (pH8) containing the polymer and the metal nit rates of Y, Ba, and Cu (1 : 2 : 3 in molar ratio) was poured into etha nol to precipitate the polymer-metal chelate. The chelate formations o f each metal were confirmed by C=O stretching bonds. Scanning electron microscope (SEM) and face and point analyses by electron probe microa nalysis (EPMA) showed that Y, Ba, and Cu elements were uniformly dispe rsed on a scale greater than 1 pm. The polymer-metal chelate precursor was calcined and sintered to develop the pure superconductor (1, 2, 3 ) phase. The sintered sample showed superconductivities of T-c(onset) at 92 K and T-c(end) at 88 K and critical current density (J(c)) of 16 5.9 A/cm(2). (C) 1996 John Wiley & Sons, Inc.