Study on Nb APC Nb-Ti Superconductor Made by Powder Metallurgy

The incorporation of Artificial Pinning Centers (APC) into Nb-Ti superconductors has been demonstrated as an effective method for enhancing their performance. Typically, APC Nb-Ti superconductors are fabricated using the Powder-Metallurgy technique, which involves the utilization of fine Nb-Ti powder and APC powder as precursors. The efficacy of APCs is largely determined by their size, quantity, and distribution, which are crucial factors influencing the Critical Current Density (
J_c
) of APC Nb-Ti superconductors. In this study, various batches of Nb-Ti and Nb powder with particle sizes ranging from 15 to 150 microns and different ratios were employed to produce APC Nb-Ti superconductors. We explored the influence of Nb particle size and shape on the superconducting properties and microstructure of APC Nb-Ti superconductors. Experimental findings indicate that Nb-APC Nb-Ti superconductors exhibit enhanced Critical Current Density at lower magnetic fields. Furthermore, reducing the processing strain notably improves the Critical Current Density. The Critical Current Density of Nb-APC Nb-Ti superconductors reached 7730 A/mm
²
at 2T, following a heat treatment of 400 °C for 20 hours, repeated three times, and utilizing Nb powder with sizes between 50 and 150 μm.