We studied the influence of using different powders and several additives on the shaping process and critical current density of sintered bulk YBa2Cu3OX. It was found that all additives used facilitated the shaping process. Silver and most organic additives influenced the critical current density only little, Zinc reduced it to zero, but an ethylenebisstearoylamide compound doubled the critical current density as compared to samples without additives.
Kuper, A. R., Hoogendam, P., Hemmes, H., Kolster, B. H., & van de Klundert, L. J. M. (1990). The influence of additives on the current carrying capacity of bulk YBa2Cu3OX. Physica B, 165-166(Part 2), 1385-1386. https://doi.org/10.1016/S0921-4526(09)80278-0