**4. Conclusions**

To conclude, we have presented magnetic and microstructural data of a reacted-and-pressed 122 powder sample and performed a comparison of our results with the literature data of a HIP-processed 122 bulk sample and 122 tapes. The obtained critical current densities (which are intragrain only) and the irreversibility fields of the reacted-and-pressed powder sample are much lower as compared to the bulks and tapes. The pinning force scaling of the reacted-and-pressed powder sample is well developed, with a dominant pinning provided by normal-conducting small inclusions (peak position at 0.33), similar to 122 single crystals. This is in contrast to the results obtained on HIP-processed 122 bulks and 122 tapes, where much lower peak positions in the pinning force scaling diagrams are obtained (0.27 and 0.22). This points to a dominant flux pinning provided by grain boundaries, so that *jc*(inter) > *jc*(intra). Therefore, the mechanical deformation and densification processes induced in manufacturing samples for applications are essential to achieve high critical currents and high irreversibility fields in the 122 samples.

**Author Contributions:** Conceptualization, M.R.K.; Formal Analysis, A.K.-V. and M.R.K.; Investigation, A.K.-V., M.R.K. and J.S.; Supervision, M.M.; Writing—Original Draft Preparation, M.R.K.; Writing—Review and Editing, A.K.-V. and M.R.K.

**Funding:** This work is part of the SUPERFOAM international project funded by ANR and DFG under the references ANR-17-CE05-0030 and DFG-ANR Ko2323-10, respectively.

**Acknowledgments:** We thank J. Wiesenmayer and D. Johrendt (LMU, München, Germany) for providing us with the polycrystalline Ba0.6K0.4Fe2As2 sample, C. Chang (IJL Nancy, France) for help with some of the magnetic measurements and K. Berger, Q. Nouailhetas, B. Douine (GREEN, Nancy, France) for valuable discussions.

**Conflicts of Interest:** The authors declare no conflict of interest.
