DOI: 10.5061/dryad.m6909
title: Data from: Chromium oxide coatings with the potential for eliminating the risk of chromium ion release in orthopaedic implants

description: Chromium oxide coatings prepared by radiofrequency reactive magnetron
 sputtering on stainless steel substrates were exposed to Ringer's
 physiological solution and tested for their electrochemical corrosion
 stability using an open circuit potential measurement, potentiodynamic
 polarization, electrochemical impedance spectroscopy and Mott–Schottky
 analysis. The coatings were found to be predominantly Cr2O3, based on the
 observation of the dominance of A1gA1g and Eg symmetric modes in our Raman
 spectroscopic investigation and the Eu vibrational modes in our Fourier
 transform infrared spectroscopic measurements on the coatings. We
 investigated for the presence of chromium ions in Ringer's solution
 after all of the above electrochemical tests using atomic absorption
 spectroscopy, without finding a trace of chromium ions at the ppm level
 for coatings tested under open circuit and at the lower potentials
 implants are likely to experience in the human body. The coatings were
 further exposed to Ringer's solution for one month and tested for
 adhesion strength changes, and we found that they retained substantial
 adhesion to the substrates. We expect this finding to be significant for
 future orthopaedic implants where chromium ion release is still a major
 challenge.
description: Raman spectroscopy
 investigation of chromium oxide coatingThe raw data was
 generated with a thermo-scientific DXR Raman microscope using the Omnic
 software that was supplied with equipment.Electronic file for figure 1
 Raman Spectra of chromium oxide coatings prepared at various deposition
 powers and constant oxygen flow rate of
 10sccm.pdfFTIR investigation of
 chromium oxide coatingThe raw data were
 generated with Nicolet is50 FTIR equipment using the omnic software that
 was supplied with the machine.Electronic file for figure 2
 The FTIR spectrum of chromium oxide coatings deposited on silicon wafer at
 various deposition powers and constant oxygen flow rate of
 10sccm.pdfXPS Survey scan of
 chromium oxide coatingScienta ESCA 300
 spectrophotometer equipped with a monochromatic Al Kα (1486.6 ev) x-ray
 source were utilised for the measurements.Electronic file for Figure 3
 (a) Survey scan.pdfXPS Cr2P doublet for
 chromium oxide coatingScienta ESCA 300
 spectrophotometer equipped with a monochromatic Al Kα (1486.6 ev) x-ray
 source were utilised for the measurements. The obtained XPS data was
 analysed with CasaXPS software, Shirkley method was used for the
 background subtraction and the binding energy calibration was implemented
 by using the C1s peak taking it as 285eV. A mixture of Gaussian and
 Lorentzian model was used in the fitting of the
 spectrumElectronic file for Figure 3
 (b) Cr2P doublet.pdfXPS O1S peak for
 chromium oxide coatingScienta ESCA 300
 spectrophotometer equipped with a monochromatic Al Kα (1486.6 ev) x-ray
 source were utilised for the measurements. The obtained XPS data was
 analysed with CasaXPS software, Shirkley method was used for the
 background subtraction and the binding energy calibration was implemented
 by using the C1s peak taking it as 285eV.Electronic file for Figure 3
 (c) O1S peak.pdfStructural
 characterization of chromium oxide coating using XRDThe raw data were
 generated with Siemens D5000 X-ray Diffractometer using Diffrac plus XRD
 commander software supplied with the machineElectronic file for Figure 5
 The XRD data for chromium oxide coatings prepared on glass slides at
 various oxygen flow rates and constant deposition power of
 500W.pdfPotentiodynamic
 polarisation curves of chromium oxide coated and uncoated stainless steel
 substrates in Ringers solution at 37The experiment was
 performed with VoltaLab 40 PGZ301 manufactured by Radiometer analytical,
 France. VoltaMaster 4 software supplied with the equipment was used for
 data acquisition and analysisElectronic file for Figure 6
 Potentiodynamic polarisation curves of chromium oxide coated and uncoated
 stainless steel substrates in Ringers solution at
 37.pdfEIS plots for chromium
 oxide coated and uncoated stainless steel in Ringers solution at 37 (a)
 Nyquist plotsThe experiment was
 performed with VoltaLab 40 PGZ301 manufactured by Radiometer analytical,
 France. VoltaMaster 4 software supplied with the equipment was used for
 data acquisition and analysis.Electronic file for Figure 8
 EIS plots for chromium oxide coated and uncoated stainless steel in
 Ringers solution at 37 (a) Nyquist
 plots.pdfEIS plots for chromium
 oxide coated and uncoated stainless steel in Ringers solution at 37 (b)
 Bode plots (Magnitude versus frequency)The experiment was
 performed with VoltaLab 40 PGZ301 manufactured by Radiometer analytical,
 France. VoltaMaster 4 software supplied with the equipment was used for
 data acquisition and analysis.Electronic file for Figure 8
 EIS plots for chromium oxide coated and uncoated stainless steel in
 Ringers solution at 37 (b) Bode plots (Magnitude versus frequency)
 .pdfEIS plots for chromium
 oxide coated and uncoated stainless steel in Ringers solution at 37 (c)
 Bode plots (phase angle versus frequency)The experiment was
 performed with VoltaLab 40 PGZ301 manufactured by Radiometer analytical,
 France. VoltaMaster 4 software supplied with the equipment was used for
 data acquisition and analysis.Electronic file for Figure 8
 EIS plots for chromium oxide coated and uncoated stainless steel in
 Ringers solution at 37 (c) Bode plots (phase angle versus
 frequency).pdfMott Schottky plots of
 chromium oxide coatings prepared at different oxygen flow rates in Ringers
 solution at 37The experiment was
 performed with VoltaLab 40 PGZ301 manufactured by Radiometer analytical,
 France. VoltaMaster 4 software supplied with the equipment was used for
 data acquisition and analysis.Electronic file for Figure
 10.Mott Schottky plots of chromium oxide coatings prepared at different
 oxygen flow rates in Ringers solution at
 37.pdfMott Schottky plot of
 uncoated stainless steel in Ringers solution at 37The experiment was
 performed with VoltaLab 40 PGZ301 manufactured by Radiometer analytical,
 France. VoltaMaster 4 software supplied with the equipment was used for
 data acquisition and analysis.Electronic file for Figure 11.
 Mott Schottky plot of uncoated stainless steel in Ringers solution at 37
 .pdfchromium ion release in
 Ringers solutionA Perkin Elmer Analyst
 300 Atomic absorption spectroscopy facility was used to probe the Ringer’s
 solution from the corrosion test for a determination of chromium ion
 concentrations released into the solution.Electronic file for Figure 12
 chromium ion release in Ringers
 solution.pdfMeasured crack spacing
 for coating strained to 20 and 25 percentThe measured crack
 spacing obtained from substrate straining was analysed statistically using
 SPSS software to obtained the frequency distribution of the crack spacing.
 The observed crack distribution was fitted to the normal, lognormal and
 weibull probability distribution function. The function that gave the best
 fit was used to calculate the mean crack spacing of the
 coatings.Electronic file for figure 14
 Measured crack spacing for film strained to 20 and 25
 percent.pdfFitting of the observed
 spacing distribution to various distribution functionsThe measured crack
 spacing obtained from substrate straining was analysed statistically using
 SPSS software to obtained the frequency distribution of the crack spacing.
 The observed crack distribution was fitted to the normal, lognormal and
 weibull probability distribution function. The function that gave the best
 fit was used to calculate the mean crack spacing of the
 coatings.Electronic file for figure 15
 Fitting of the observed spacing distribution to various distribution
 functions.pdfcrack spacing frequency
 of chromium oxide in Ringers solution for 1 monthThe measured crack
 spacing obtained from substrate straining was analysed statistically using
 SPSS software to obtained the frequency distribution of the crack spacing
 for the films exposed to Ringers solution for 1 month. The observed crack
 distribution was fitted to the normal, lognormal and weibull probability
 distribution function. The function that gave the best fit was used to
 calculate the mean crack spacing of the coatings exposed to Ringers
 solution.Electronic data for figure 16
 crack spacing frequency of chromium oxide in Ringers solution for 1
 month.pdfObserved spacing
 distribution at saturation in the chromium oxide films soaked in Ringers
 solution for 1 monthThe measured crack
 spacing obtained from substrate straining was analysed statistically using
 SPSS software to obtained the frequency distribution of the crack spacing
 for the films exposed to Ringers solution for 1 month. The observed crack
 distribution was fitted to the normal, lognormal and weibull probability
 distribution function. The function that gave the best fit was used to
 calculate the mean crack spacing of the coatings exposed to Ringers
 solution.Electronic data for figure 17
 Observed spacing distribution at saturation in the chromium oxide films
 soaked in Ringers solution for 1
 month.pdfthe change in
 interfacial shear strength for chromium oxide coatings exposed to Ringers
 solution for period of one month.Adhesion strength was
 calculated using the relation adopted from shear-lag model which relate
 the mean crack spacing, fracture strength and thickness of the
 coatingElectronic file for Figure 19
 showing the change in interfacial shear strength for chromium oxide
 coatings exposed to Ringers solution for period of one
 month..pdf