Influência do Tratamento Térmico na Junção YBCO/316L

Abstract

We produced Y Ba2Cu3O7−x ceramic and deposited it in AISI 316L steel in order to develop a superconducting fault current limiter device. The objective of this work is to evaluate the influence of heat treatments on the YBCO/316L junction. We produce a polycrystalline ceramic through solid state reaction. We used Y2O3, BaCO3 e CuO as reagents, which were mixed and macerated before calcination and sintering. The heat treatment of calcination and sintering were both performed at 930◦C for 12h followed by slow cooling. Both treatments took place under oxygen flow. We cut 3mm thick AISI 316L steel plates into small 10mm x 75mm devices. These devices went through a milling process in which a 3mm x 50mm x 1mm groove was created on their surface. At first, we made a preliminary deposition of YBCO on the groove of the AISI 316L device. We then filled two metal samples with YBCO and compressed the powders inside it by using a hydraulic press. The samples remained at 1040◦C (A1040) and 950◦C (A950) for 20min and were slowly cooled to room temperature. Sample A1040 showed severe structural deterioration, evidencing the non-adhesion of the superconductor in its inside. Sample A950 showed structural integrity. We characterize the YBCO produced and the samples deposited through XRD, SEM and EDS. The results show the existence of spurious components in the material though the average grain boundary size reduced significantly.