Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering

Quinternary phosphate-based glasses of up to 2.67 μm, deposited by radio-frequency magnetron sputtering, were degraded in distilled water and phosphate-buffered saline (PBS) to investigate their degradation characteristics. Magnetron- sputtered coatings have been structurally compared to their compo...

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Main Authors: Stuart, Bryan, Gimeno-Fabra, Miquel, Segal, Joel, Ahmed, Ifty, Grant, David M.
Format: Article
Published: American Chemical Society 2015
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Online Access:https://eprints.nottingham.ac.uk/34759/
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author Stuart, Bryan
Gimeno-Fabra, Miquel
Segal, Joel
Ahmed, Ifty
Grant, David M.
author_facet Stuart, Bryan
Gimeno-Fabra, Miquel
Segal, Joel
Ahmed, Ifty
Grant, David M.
author_sort Stuart, Bryan
building Nottingham Research Data Repository
collection Online Access
description Quinternary phosphate-based glasses of up to 2.67 μm, deposited by radio-frequency magnetron sputtering, were degraded in distilled water and phosphate-buffered saline (PBS) to investigate their degradation characteristics. Magnetron- sputtered coatings have been structurally compared to their compositionally equivalent melt-quenched bulk glass counterparts. The coatings were found to have structurally variable surfaces to melt-quenched glass such that the respective bridging oxygen to nonbridging oxygen bonds were 34.2% to 65.8% versus 20.5% to 79.5%, forming metaphosphate (PO3)−(Q2) versus less soluble (P2O7)4− (Q1) and (PO4)3− (Q0), respectively. This factor led to highly soluble coatings, exhibiting a t1/2 degradation dependence in the first 2 h in distilled water, followed by a more characteristic linear profile because the subsequent layers were less soluble. Degradation was observed to preferentially occur, forming voids characteristic of pitting corrosion, which was confirmed by the use of a focused ion beam. Coating degradation in PBS precipitated a (PO3)−metaphosphate, an X-ray amorphous layer, which remained adherent to the substrate and seemingly formed a protective diffusion barrier, which inhibited further coating degradation. The implications are that while compositionally similar, sputter-deposited coatings and melt-quenched glasses are structurally dissimilar, most notably, with regard to the surface layer. This factor has been attributed to surface etching of the as-deposited coating layer during deposition and variation in the thermal history between the processes of magnetron sputtering and melt quenching.
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spelling nottingham-347592020-05-04T17:24:21Z https://eprints.nottingham.ac.uk/34759/ Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering Stuart, Bryan Gimeno-Fabra, Miquel Segal, Joel Ahmed, Ifty Grant, David M. Quinternary phosphate-based glasses of up to 2.67 μm, deposited by radio-frequency magnetron sputtering, were degraded in distilled water and phosphate-buffered saline (PBS) to investigate their degradation characteristics. Magnetron- sputtered coatings have been structurally compared to their compositionally equivalent melt-quenched bulk glass counterparts. The coatings were found to have structurally variable surfaces to melt-quenched glass such that the respective bridging oxygen to nonbridging oxygen bonds were 34.2% to 65.8% versus 20.5% to 79.5%, forming metaphosphate (PO3)−(Q2) versus less soluble (P2O7)4− (Q1) and (PO4)3− (Q0), respectively. This factor led to highly soluble coatings, exhibiting a t1/2 degradation dependence in the first 2 h in distilled water, followed by a more characteristic linear profile because the subsequent layers were less soluble. Degradation was observed to preferentially occur, forming voids characteristic of pitting corrosion, which was confirmed by the use of a focused ion beam. Coating degradation in PBS precipitated a (PO3)−metaphosphate, an X-ray amorphous layer, which remained adherent to the substrate and seemingly formed a protective diffusion barrier, which inhibited further coating degradation. The implications are that while compositionally similar, sputter-deposited coatings and melt-quenched glasses are structurally dissimilar, most notably, with regard to the surface layer. This factor has been attributed to surface etching of the as-deposited coating layer during deposition and variation in the thermal history between the processes of magnetron sputtering and melt quenching. American Chemical Society 2015-11-02 Article PeerReviewed Stuart, Bryan, Gimeno-Fabra, Miquel, Segal, Joel, Ahmed, Ifty and Grant, David M. (2015) Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering. ACS Applied Materials and Interfaces, 7 (49). pp. 27362-27372. ISSN 1944-8252 Phosphate glass Bioresorbable Bioactive Thin Films Osseointegration Dissolution Sputtering PVD http://pubs.acs.org/doi/10.1021/acsami.5b08957 doi:10.1021/acsami.5b08957 doi:10.1021/acsami.5b08957
spellingShingle Phosphate glass
Bioresorbable
Bioactive Thin Films
Osseointegration
Dissolution
Sputtering
PVD
Stuart, Bryan
Gimeno-Fabra, Miquel
Segal, Joel
Ahmed, Ifty
Grant, David M.
Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering
title Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering
title_full Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering
title_fullStr Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering
title_full_unstemmed Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering
title_short Degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering
title_sort degradation and characterization of resorbable phosphate-based glass thin-film coatings applied by radio-frequency magnetron sputtering
topic Phosphate glass
Bioresorbable
Bioactive Thin Films
Osseointegration
Dissolution
Sputtering
PVD
url https://eprints.nottingham.ac.uk/34759/
https://eprints.nottingham.ac.uk/34759/
https://eprints.nottingham.ac.uk/34759/