Impact of machining strategy on OFE copper for SRF applications

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Impact of machining strategy on OFE copper for SRF applications

BELKHIR F., KOLENIC M., RECH J., PÉREZ FONTENLA A. T., ROSAZ G., MOROS A., GARLASCHÈ M., LEITH S., NAISSON P., CARLOS C.P.A.

Abstract. The study evaluates the impact of various milling strategies – on the surface and subsurface quality of an Oxygen-Free Electronic (OFE) copper substrate, and subsequently on the niobium (Nb) coating performance- for Superconducting Radio Frequency (SRF) cavities. Several cutting tools, cutting conditions and machining paths are compared, given their paramount influence in the final ‘SRF’ quality of the machined surfaces. The near surface region is evaluated by different means: surface roughness and shape accuracy are measured using a profilometer and Coordinate Measuring Machine (CMM) respectively; the thickness of the layer affected by machining on the OFE copper substrate is estimated by Focused Ion Beam Scanning Electron Microscopy (FIB – SEM). The dislocation density in the near surface layer is assessed by Grazing Incidence X-Ray Diffraction (GI-XRD) in both the OFE copper substrate and afterwards in the niobium coating. Main investigation results are discussed, and conclusions drawn for new guidelines on machining strategy and for future research developments.

Keywords
Surface Integrity, Machining, SRF, Cavity, OFE Copper, Niobium, SEM, FIB, GIXRD, FCC

Published online 4/24/2024, 10 pages
Copyright © 2024 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: BELKHIR F., KOLENIC M., RECH J., PÉREZ FONTENLA A. T., ROSAZ G., MOROS A., GARLASCHÈ M., LEITH S., NAISSON P., CARLOS C.P.A., Impact of machining strategy on OFE copper for SRF applications, Materials Research Proceedings, Vol. 41, pp 1945-1954, 2024

DOI: https://doi.org/10.21741/9781644903131-215

The article was published as article 215 of the book Material Forming

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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