SEM and EDS studies of porous coatings enriched in calcium and zinc obtained by PEO with ramp voltage

Transcription

1 Available online at WSN 77(2) (2017) EISSN SEM and EDS studies of porous coatings enriched in calcium and zinc obtained by PEO with ramp voltage Krzysztof Rokosz a, Tadeusz Hryniewicz b, *, Kornel Pietrzak c Division of Bioengineering and Surface Electrochemistry, Department of Engineering and Informatics Systems, Faculty of Mechanical Engineering, Koszalin University of Technology, Racławicka 15-17, PL Koszalin, Poland a-c address: rokosz@tu.koszalin.pl, Tadeusz.Hryniewicz@tu.koszalin.pl, kornel.pietrzak@s.tu.koszalin.pl *Corresponding author: Tadeusz.Hryniewicz@tu.koszalin.pl ABSTRACT In this work, the SEM and EDS results of porous and enriched in calcium or zinc coatings, which were obtained during 3-minute treatments using Plasma Electrolytic Oxidation (Micro Arc Oxidation) processes on CP Titanium Grade 2 at ramp potentials (linear polarization) from 0 up to 650 V DC in electrolytes containing 500 g Ca(NO 3 ) 2 4H 2 O and/or 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4, are presented. It was found that obtained coatings have pores with different shapes and diameters. The Ca/P and Zn/P ratios by atomic concentration are the same and equal to 0.2, what may suggest hydroxyapatite-like structure (M,Ti) x (PO 4 ) y, where M= {Ca, Zn}. Keywords: Plasma Electrolytic Oxidation (PEO), Micro Arc Oxidation (MAO), CP Titanium Grade 2, calcium nitrate Ca(NO 3 ) 2 4H 2 O, zinc nitrate Zn(NO 3 ) 2 6H 2 O, ramp voltage, linear polarization

2 1. INTRODUCTION Nanometric passive films and micrometric coatings are important aims of activity in the field of surface engineering. Various surface treatment techniques have been employed to enhance the mechanical and tribological properties, the corrosion resistance and the bioactivity. Among the different surface modification techniques, electropolishing, anodic oxidation, especially the plasma electrolytic oxidation (PEO), have become increasingly growing due to their advantages over other methods of surface modification [1-5]. The standard electropolishing (EP) [3-7], magnetoelectropolishing (MEP) [7-19] or high-current density electropolishing (HDEP) [20-23] are used to obtain nano-coatings, while the micro-coatings may be formed during the Plasma Electrolytic Oxidation (PEO), also known as Micro Arc Oxidation [1,2,24-38]. The PEO techniques are used to create porous coatings on biomaterials, such as titanium [24-32] and its alloys [1, 33-38], which may be enriched in chemical elements, such as phosphorus and calcium to form the hydroxyapatitelike structure [39-43], with bactericidal copper [44-54] as well as with magnesium, which may accelerate the healing of wounds [55-56]. The aim of this work is to present fabricating and study of porous coatings enriched in calcium and zinc on CP Titanium Grade 2, obtained by PEO treatment under ramp voltage from 0 up to 650 V DC. SEM and EDS studies were used to characterize these coatings. 2. METHOD The samples of CP Titanium Grade 2 with dimensions mm were treated by Plasma Electrolytic Oxidation (Micro Arc Oxidation) for the surface studies. The plasma electrolytic oxidation (PEO) was performed at the ramp voltages from 0 up to 650 V DC in time of 600 s. For the studies, the electrolytes based on orthophosphoric acid H 3 PO 4 with 500 g/l of calcium nitrate Ca(NO 3 ) 2 4H 2 O or copper nitrate Zn(NO 3 ) 2 6H 2 O were used. For each run, the electrolytic cell made of glass was used, containing up to 500 ml of the electrolyte. Scanning Electron Microscope (SEM) FEI Quanta 650 FEG equipped with Energy- Dispersive X-ray Spectroscopy (EDS) for surface analysis was used. The microscope operated under the following conditions: voltage 15 kv, current 8-10 na, beam diameter 6 μm, decreased vacuum in the chamber with the pressure of 50 Pa. The identification of spectral lines was performed by means of a spectral decomposition using the holographic peak de-convolution function. 3. RESULTS AND DISCUSSION In Figures 1-5, the SEM pictures of coating formed on Titanium after PEO treatment at ramp voltages from 0 till 650 V DC (linear polarization) in electrolyte containing of 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4 are presented. The obtained surfaces have closed and opened pores, which are visible specifically in Figures 3-5. The EDS spectrum of the obtained coating is displayed in Figure 6. This way recorded the EDS peaks of phosphorus, titanium and calcium show that formed PEO coating is built mainly of phosphorus-titanium-calcium compounds, what may suggest the existence of hydroxyapatite-like structure

3 Fig. 1. SEM picture of coating formed on Titanium after PEO treatment at ramp voltages from 0 till 650 V DC in electrolyte containing of 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4. Magnification 500 times Fig. 2. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4. Magnification times -244-

4 Fig. 3. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4. Magnification times Fig. 4. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4. Magnification times -245-

5 Fig. 5. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4. Magnification times Fig. 6. EDS result of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4. Done by magnification of 500 times -246-

6 In the PEO coating, apart from titanium (46.5 wt% 37.1 at%), which comes from substrate, of which the signal partly comes from the matrix, phosphorus (42.3 wt% 52.2 at%) and calcium (11.2 wt% 10.7 at%) were also recorded, with the results presented in Table 1. In case of surface characterization, the Ca/P ratio equaling to 0.26 (by wt%) 0.20 (by at%) was found. In Figures 7-11, the SEM pictures of coating formed on Titanium after PEO treatment at ramp voltages from 0 till 650 V DC (linear polarization) in electrolyte containing of 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4 are presented. The obtained surface is similar to that one obtained in electrolyte containing Ca(NO 3 ) 2 4H 2 O, however the shapes and diameters of pores are different, what is shown in Figures The EDS spectrum of obtained coating is displayed in Figure 12. This way recorded the EDS peaks of phosphorus, titanium and zinc show that formed PEO coating is built mainly of phosphorus-titanium-zinc compounds, in which apart from titanium (47.8 wt% 41.4 at%), which comes from the substrate, phosphorus (36.3 wt% 48.5 at%) and zinc (15.9 wt% 10.1 at%) were also recorded, and they are presented in Table 1. In case of surface characterization, the Zn/P ratio equaling to 0.43 (by wt%) 0.20 (by at%) was found. Fig. 7. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4. Magnification 500 times -247-

7 Fig. 8. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4. Magnification times Fig. 9. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4. Magnification times -248-

8 Fig. 10. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4. Magnification times Fig. 11. SEM picture of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4. Magnification times -249-

9 Fig. 12. EDS result of coating formed on Titanium after PEO treatment at voltages from 0 till 650 V DC in electrolyte containing of 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4. Done by magnification 500 times Table 1. EDS results of coating formed on Titanium after PEO treatment at ramp voltages from 0 up to 650 V DC in electrolyte containing 500 g Ca(NO 3 ) 2 4H 2 O and/or 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4 Ca(NO 3 ) 2 4H 2 O Zn(NO 3 ) 2 6H 2 O Element Weight % Atom % Element Weight % Atom % P P Ca Zn Ti Ti Ca/P Zn/P CONCLUSIONS The investigation carried out using SEM and EDS measurements on CP Titanium Grade 2 after PEO processing allowed to formulate the following conclusions: -250-

10 it is possible to obtain the porous surface enriched in calcium and phosphorus in electrolyte containing 500 g Ca(NO 3 ) 2 4H 2 O in 1 L H 3 PO 4 by applying a linear polarization (ramp voltage) from 0 till 650 V DC it is possible to obtain the porous surface enriched in zinc and phosphorus in electrolyte containing 500 g Zn(NO 3 ) 2 6H 2 O in 1 L H 3 PO 4 by applying a liner polarization (ramp voltage) from 0 till 650 V DC obtained coatings have pores with different shapes and diameters the Ca/P and Zn/P ratios by atomic concentration are the same and equal to 0.2, which may suggest hydroxyapatite-like structure (M,Ti) x (PO 4 ) y, where M = {Ca, Zn}. Acknowledgements This work was supported by subsidizing by Grant OPUS 11 of National Science Centre, Poland, with registration number 2016/21/B/ST8/01952, titled "Development of models of new porous coatings obtained on titanium by Plasma Electrolytic Oxidation in electrolytes containing phosphoric acid with addition of calcium, magnesium, copper and zinc nitrates". Assoc. Prof. Jan Valíček and Dr Dalibor Matýsek from Technical University of Ostrava - VŠB-TUO, Czech Republic, are given thanks for providing access to the SEM/EDS apparatus allowing to perform the studies. References [1] D. Quintero, O. Galvis, J.A. Calderón, M.A. Gómez, J.G. Castaño, F. Echeverría, H. Habazaki, Control of the physical properties of anodic coatings obtained by plasma electrolytic oxidation on Ti6Al4V alloy, Surface and Coatings Technology, 283 (2015) [2] Sezgin Cengiz, Aytekin Uzunoglu, Lia Stanciu, Mehmet Tarakci, Yucel Gencer, Direct fabrication of crystalline hydroxyapatite coating on zirconium by single-step plasma electrolytic oxidation process, Surface and Coatings Technology, 301 (2016) [3] Hryniewicz T., Hryniewicz Z., On the solution of equation of diffusion in electropolishing, Journal of the Electrochemical Society, 136(12) (1989) [4] Hryniewicz T., Concept of microsmoothing in the electropolishing process, Surface and Coatings Technology, 64(2) (1994) [5] Hryniewicz T. On the surface treatment of metallic biomaterials (Wstęp do obróbki powierzchniowej biomateriałów metalowych), Koszalin University of Technology Publishing House (in Polish), Koszalin [6] Rokicki R., Hryniewicz T., Enhanced oxidation-dissolution theory of electropolishing, Transactions of The Institute of Metal Finishing, 90(4) (2012) [7] Hryniewicz T, Rokosz K, Zschommler Sandim HR (2012) SEM/EDX and XPS studies of niobium after electropolishing, Applied Surface Science, 263 (2012) [8] Rokicki R., Hryniewicz T., Rokosz K., Modifying Metallic Implants by Magnetoelectropolishing, Medical Device & Diagnostic Industry, 30(1) (2008) (INVITED PAPER)

11 [9] Rokosz K., Electrochemical Polishing in magnetic field (Polerowanie elektrochemiczne w polu magnetycznym), Koszalin University of Technology Publishing House (in Polish), Koszalin [10] Hryniewicz T., Rokicki R., Rokosz K., Co-Cr alloy corrosion behaviour after electropolishing and "magnetoelectropolishing" treatments, Surface and Coatings Technology, 62(17-18) (2008) , DOI: /j.matlet [11] Hryniewicz T., Rokosz K., Analysis of XPS results of AISI 316L SS electropolished and magnetoelectropolished at varying conditions, Surface and Coatings Technology, 204(16 17) (2010) , DOI: /j.surfcoat [12] Hryniewicz T., Rokicki R., Rokosz K., Magnetoelectropolishing for metal surface modification, Transactions of The Institute of Metal Finishing, 85(6) (2007) , DOI: / X [13] Hryniewicz T., Rokicki R., Rokosz K., Corrosion and surface characterization of titanium biomaterial after magnetoelectropolishing, Surface and Coatings Technology, 203(9) (2008) ; DOI: /j.surfcoat [14] Hryniewicz T., Rokosz K., Polarization characteristics of magnetoelectropolishing stainless steels, Materials Chemistry and Physics, 122(1) (2010) , DOI: /j.matchemphys [15] Rokosz K., Hryniewicz T., Raaen S., Characterization of passive film formed on AISI 316L stainless steel after magnetoelectropolishing in a broad range of polarization parameters, Journal of Iron and Steel Research, 83(9) (2012) [16] Hryniewicz T., Rokosz K., Investigation of selected surface properties of AISI 316L SS after magnetoelectropolishing, Materials Chemistry and Physics, 123(1) (2010) [17] Hryniewicz T., Rokosz K., Corrosion resistance of magnetoelectropolished AISI 316L SS biomaterial, Anti-Corrosion Methods and Materials, 61(2) (2014) 57-64, [18] Hryniewicz T., Rokosz K., Valiček J., Rokicki R., Effect of magnetoelectropolishing on nanohardness and Young s modulus of titanium biomaterial, Materials Letters, 83 (2012) 69-72, DOI: /j.matlet [19] Hryniewicz T., Rokosz K., Rokicki R., Prima F., Nanoindentation and XPS Studies of Titanium TNZ Alloy after Electrochemical Polishing in a Magnetic Field, Materials, 8(1) (2015) , DOI: /ma [20] Rokosz K., Hryniewicz T., Simon F., Rzadkiewicz S., Comparative XPS analysis of passive layers composition formed on AISI 304 L SS after standard and high-current density electropolishing, Surface and Interface Analysis, 47(1) (2015) 87-92, DOI: /sia.5676 [21] Rokosz K., Lahtinen J., Hryniewicz T., Rzadkiewicz S., XPS depth profiling analysis of passive surface layers formed on austenitic AISI 304L and AISI 316L SS after highcurrent-density electropolishing, Surface and Coatings Technology, 276 (2015) , DOI: /j.surfcoat

12 [22] Rokosz K., Hryniewicz T., Simon F., Rzadkiewicz S., Comparative XPS analyses of passive layers composition formed on Duplex 2205 SS after standard and high-currentdensity electropolishing, Tehnicki vjesnik - Technical Gazette, 23(3) (2016) , DOI: /TV [23] Rokosz K., Hryniewicz T., Rzadkiewicz S., XPS study of surface layer formed on AISI 316L SS after high-current-density electropolishing, Solid State Phenomena, 227 (2015) , DOI: / [24] Rokosz K., Hryniewicz T., Chapon P., Raaen S., Zschommler Sandim H.R., XPS and GDOES characterisation of porous coating enriched with copper and calcium obtained on Tantalum via Plasma Electrolytic Oxidation, Journal of Spectroscopy, 2016, Article ID , 7 pages, [25] Han Y., Hong S.H., Xu K.W., Structure and in vitro bioactivity of titania-based films by micro-arc oxidation. Surface and Coatings Technology, 168 (2003) [26] Simka W., Sadowski A., Warczak M., Iwaniak A., Dercz G., Michalska J., Maciej A., Modification of titanium oxide layer by calcium and phosphorus, Electrochimica Acta, 56(24) (2009) [27] Rokosz K., Hryniewicz T., Raaen S., Chapon P., Dudek Ł., GDOES, XPS and SEM with EDS analysis of porous coatings obtained on Titanium after Plasma Electrolytic Oxidation, Surface and Interface Analysis, 49(4) (2016) , DOI: /sia.6136 [28] Han Y., Hong S.H., Xu K.W., Synthesis of nanocrystalline titania films by micro-arc oxidation, Materials Letters, 56 (2002) [29] Fei C., Hai Z., Chen C., Yangjian X., Study on the tribological performance of ceramic coatings on titanium alloy surfaces obtained through microarc oxidation, Progress in Organic Coatings, 64(2009) [30] Aliasghari S., Plasma Electrolytic Oxidation of Titanium. PhD thesis of Faculty of Engineering and Physical Sciences, The University of Manchester, School of Materials, 2014 (223 pages). [31] Teh T.H., Berkani A., Mato S., Skeldon P., Thompson G.E., Habazaki H., Shimizu K., Initial stages of plasma electrolytic oxidation of titanium, Corrosion Science, 45 (2003) [32] Wang Y., Jiang B., Lei T., Guo L., Dependence of growth features of microarc oxidation coatings of titanium alloy on control modes of alternate pulse, Materials Letters, 58(12-13) (2004) [33] Simka W, Nawrat G., Chlode J., Maciej A., Winiarski A., Szade J., Radwanski K., Gazdowicz J., Electropolishing and anodic passivation of Ti6Al7Nb alloy, Przemysł Chemiczny, 90(1) (2011) [34] Krząkala A., Mlynski J., Dercz G., Michalska J., Maciej A., Nieuzyla L., Simka W., Modification of Ti-6Al-4V alloy surface by EPD-PEO process in ZrSiO4 suspension, Archives of Metallurgy and Materials, 59(1) (2014)

13 [35] Rokosz K., Hryniewicz T., Raaen S., Development of Plasma Electrolytic Oxidation for improved Ti6Al4V biomaterial surface properties, The International Journal of Advanced Manufacturing Technology, 85 (2016) , DOI: /s y [36] Rokosz K., Hryniewicz T., Raaen S., Chapon P., Investigation of porous coatings obtained on Ti-Nb-Zr-Sn alloy biomaterial by Plasma Electrolytic Oxidation: Characterisation and Modelling, The International Journal of Advanced Manufacturing Technology, 87(9) (2016) , DOI /s [37] Rokosz K., Hryniewicz T., Raaen S., Chapon P., Development of copper-enriched porous coatings on ternary Ti-Nb-Zr alloy by Plasma Electrolytic Oxidation, The International Journal of Advanced Manufacturing Technology, 89 (9-12) (2017) , DOI /s z [38] Rokosz K., Hryniewicz T., Raaen S., SEM, EDS and XPS analysis of nanostructured coating obtained on NiTi biomaterial alloy by Plasma Electrolytic Oxidation (PEO), Tehnički vjesnik-technical Gazette, 24(1) (2017) , DOI: /TV [39] Elliott J.C., Structure and Chemistry of Apatites and Other Calcium Orthophosphates. Elsevier, Amsterdam, The Netherlands, 1 st edition, 404 pages, ebook ISBN: , Hardcover ISBN: , [40] Elliott J.C., Wilson R.M., Dowker S.E.P., APATITE STRUCTURES, Advances in X- ray Analysis, 45 (2002) [41] Dorozhkin S.V., Calcium orthophosphates in nature, biology and medicine, Materials, 2(2) (2009) [42] LeGeros R.Z., Calciumphosphate-based osteoinductive materials, Chemical Reviews, 108(11) (2009) [43] Zakharov N.A., Polunina I.A., Polunin K.E., Rakitina N.M., Kochetkova E.I., Sokolova N.P., Kalinnikov V.T., Calcium hydroxyapatite for medical applications, Inorganic Materials, 40(6) (2004) [44] Kolmas J., Groszyk E., and Kwiatkowska-Róhycka D., Substituted Hydroxyapatites with Antibacterial Properties, BioMed Research International, 2014: 1-15, DOI: dx.doi.org/ /2014/ [45] Gallo J., Holinka M., Moucha C.S., Antibacterial Surface Treatment for Orthopaedic Implants, International Journal of Molecular Science, 15 (2014) , DOI: /ijms [46] Xiangyu Zhang, Xiaobo Huang, Yong Ma, Naiming Lin, Ailan Fan, Bin Tang, Bactericidal behavior of Cu-containing stainless steel surfaces, Applied Surface Science, 258 (2012) [47] Hempel F., Finke B., Zietz C., Bader R., Weltmann K.-D., Polak M., Antimicrobial surface modification of titanium substrates by means of plasma immersion ion implantation and deposition of copper, Surface and Coatings Technology, 256 (2014)

14 [48] Xiaohong Yao, Xiangyu Zhang, Haibo Wu, Linhai Tian, Yong Ma, Bin Tang, Microstructure and antibacterial properties of Cu-doped TiO2 coating on titanium by micro-arc oxidation, Applied Surface Science, 292 (2014) [49] Rokosz K., Hryniewicz T., Dudek Ł., Matysek D., Valiček J., Harničarova M., SEM and EDS Analysis of Surface Layer Formed on Titanium After Plasma Electrolytic Oxidation in H 3 PO 4 with the Addition of Cu(NO 3 ) 2, Journal of Nanoscience and Nanotechnology, 16 (2016) [50] Rokosz K., Hryniewicz T., Dalibor M., Raaen S., Valiček J., Dudek Ł., Harničarova M., SEM, EDS AND XPS Analysis of the Coatings Obtained on Titanium after Plasma Electrolytic Oxidation in Electrolytes Containing Copper Nitrate, Materials, 9(318) (2016) 1-12; DOI: /ma [51] Rokosz K., Hryniewicz T., Raaen S., Chapon P., Dudek Ł., GDOES, XPS and SEM with EDS analysis of porous coatings obtained on Titanium after Plasma Electrolytic Oxidation, Surface and Interface Analysis, 49(4) (2016) , DOI: /sia.6136 [52] Rokosz K., Hryniewicz T., Malorny W., Characterisation of porous coatings obtained on materials by Plasma Electrolytic Oxidation, Materials Science Forum, 862 (2016) [53] Rokosz K., Hryniewicz T., Pietrzak K., Dudek Ł., Malorny W., SEM and EDS studies of selected porous coatings obtained on titanium by Plasma Electrolytic Oxidation, World Scientific News, 70(2) (2017) [54] Rokosz K., Hryniewicz T., Raaen S., Malorny W., Fabrication and characterisation of porous coatings obtained by plasma electrolytic oxidation, Journal of Mechanical and Energy Engineering, 1(1 41) (2017) [55] Aina V., Lusvardi G., Annaz B., Gibson I.R., Imrie F.E., Malavasi G., Menabue L., Cerrato G., Martra G., Magnesium- and strontium-co-substituted hydroxyapatite: the effect of doped ions on the structure and chemico-physical properties, Journal of Materials Science: Materials in Medicine, 23(12) (2012) [56] Webster T.J., Ergun C., Doremus R.H., Bizios R., Hydroxylapatite with substituted magnesium, zinc, cadmium, and yttrium. II. Mechanisms of osteoblast adhesion, Journal of Biomedical Materials Research, 59(2) (2002) ( Received 06 June 2017; accepted 22 June 2017 ) -255-