Aull, S. Junginger, T. Knobloch, J. Sublet, A. Valente-Feliciano, A-M. Venturini Delsolaro, W. Zhang, P. JACoW Geneva, Switzerland 978-3-95450-178-6 10.18429/JACoW-SRF2015-TUBA03 English 494-500 TUBA03 ECR niobium ion SRF cavity Contribution to a conference proceedings 2015 2015-12 http://dx.doi.org/10.18429/JACoW-SRF2015-TUBA03 http://srf2015.vrws.de/papers/tuba03.pdf The Q-slope of niobium coated copper cavities at medium fields is still the limiting factor for the application the Nb/Cu technology in accelerators. This paper presents a dedicated study of a niobium coating with bulk-like characteristics which shows a Q-slope comparable to bulk Nb at 400 MHz and 4 K. Combining the bulk like film with recent findings of the HIE Isolde indicates that the film microstructure and the Nb/Cu interface are the key aspects to understanding the Q-slope.