Preparation of YBa2Cu3O7-x superconducting thick films by the electrophoretic deposition method

Abstract

YBa 2 Cu 3 O 7-x thick films have been realised by the Electrophoretic Deposition method (EPD). The influence of several parameters (powder and iodine concentrations in the suspension, applied voltage and deposition time) on the EPD process has been studied by measuring the conductivity of the suspension and the amount of YBa 2 Cu 3 O 7-x particles deposited on the electrode. Superconducting coatings onto silver substrates have been produced by a multilayer process during different deposition times. The highest critical current density value of these coatings measured by the four-point probe method is about 10 3 A/cm 2 (77 K), in a suitable range for magnetic shielding applications.

YBa2Cu3O7−x dispersion in iodine acetone for electrophoretic deposition: Surface charging mechanism in a halogenated organic media

“…Conductivity values at such low solid contents are similar to those registered for iodine solutions in figure 4a, suggesting that the formation of triodine and CH 3 CH 2 ICOH + ions after I 2 dissolution (equations 4-6) results in the largest contribution to the conductivity of 0.1 g/l YBCO suspensions. However, lower conductivity values have been also reported [10,20] for 10 g/l YBCO suspensions prepared with similar amounts of I 2. Actually, charged particles should increase the number of conductive species in the suspension contributing to increase its conductivity [1,73].…”

“…Actually, charged particles should increase the number of conductive species in the suspension contributing to increase its conductivity [1,73]. However, reported results for concentrated suspensions [10,20] verified the decrease of conductivity with the addition of YBCO particles. Considering the ionic species solved in the suspension (Ba 2+ , I 3 -and CH 3 CH 2 ICOH + ) the formation of Ba(I 3 ) 2 [74] could be the cause of the suspension conductivity decrease.…”

“…In this sense EPD should be considered as a potential applicable technique, offering a real possibility of industrial scalability and reliability. In fact, EPD has been successfully considered for applications such as magnetic shielding in low frequencies [6][7][8][9][10][11][12]. However, much effort is still necessary to understand and control the complex colloidal behaviour and the surface reactions occurring when YBCO powders are dispersed in a liquid.…”

“…acetone [10,12,[19][20][21][22][23][24][25][26][27][28][29][30][31][32], isobutylmethylketone [11], propanol and butanol [31,32], acetone being the most used solvent. In acetone, a negative value of zeta potential for 0.01 g/l YBCO suspensions have been determined by Koura et al [20], while more concentrated suspensions promote a positive surface charge, leading to cathodic deposition [12, 21-35, 31, 32].…”

“…In acetone, a negative value of zeta potential for 0.01 g/l YBCO suspensions have been determined by Koura et al [20], while more concentrated suspensions promote a positive surface charge, leading to cathodic deposition [12, 21-35, 31, 32]. Other studies show that it is customary to use iodine (I 2 ) as stabiliser in acetone [10,12,19,20,[27][28][29][30]. Zeta-potentials of YBCO in acetone-I 2 solutions are always positive, forming also cathodic deposits.…”