BR102014004074A2 - surface modification method of titanium alloys and product obtained - Google Patents

Abstract

Summary Method of Surface Modification of Titanium Alloys and Product Obtained It is described the invention of a method of surface modification of titanium alloys employing anodic oxidation in thi-30ta and thi-7.5mo alloys to obtain nanotubes perpendicular to the substrate with a diameter of 80-120 nm and a length of 100 nm-500 nm.

Description

FIELD OF THE INVENTION The present invention describes a surface modification method of titanium alloys and product obtained. More specifically it comprises a surface modification method employing anodic oxidation in Ti alloys. -30Ta and Ti-7.5Mo.

BACKGROUND OF THE INVENTION

Metal alloys intended for implants have been increasingly researched for their microstructural, mechanical and biocompatibility properties.

Despite the emergence of numerous polymeric materials that could perform these functions, titanium and its alloys still represent the wide range of implant, dental and orthopedic applications due to its excellent biocompatibility, mechanical and corrosion resistance, and relative low density. of these materials. The biomaterial for intraosseous use must have biocompatibility and mechanical properties similar to human bone (ZHOU, Y.-L.; NIINOMI, M. Microstructures and mechanical properties of Ti-50 mass% Ta alloy for biomedical applications. Journal of Alloys and Compounds, v. 466, No. 1-2, pp. 535-542, 2008), and should have mechanical properties comparable to that of the natural tissue in which it is inserted so that no additional stress occurs to the surrounding tissue (KURELLA, A .; DAHOTRE , NB Review paper: Surface Modification for Bioimplants: The Role of Laser Surface Engineering Journal of Biomaterials Applications, v. 20, no. 1, pp. 5-50, July 1, 2005). Human bone tissue has mechanical properties such as high fatigue strength, ductility, low modulus of elasticity, wear and corrosion resistance [(BANNON, BP Μ., EE. Titanium Alloys for Surgical Implants. Titanium Alloys for Biomaterial Application: an Phoenix, Ariz; USA, pp. 7-15, Titanium Alloys for Biomaterial Application: An Overview, 1983); (GALANTE, J. O. et al. The Biologic Effects of Implant Materials. Journal of Orthopedic Research, v. 9, no. 5, pp. 760-775, 1991. ISSN 1554-527X); (KOKUBO, T ;; KIM, H.-M .; KAWASHITA, M. Novel bioactive materials with different mechanical properties. Biomaterials, v. 24, no. 13, p. 2161-2175, 2003. ISSN O142-9612); (OH, K.-T .; SHIM, H.-M .; KIM, K.-N. Properties of titanium-silver alloys for dental application. Journal of Biomedical Materials Research Part B: Applied Biomaterials, v. 74B, no. 1, pp 649-658, 2005); (RUCKH, T. et al. Nanostructured as a template for enhanced osseointegration. Nanotechnology, v. 20, no. 4, p. 045102, 2009); (HABIBOVIC, P. et al. Osteoinduction by biomaterials - Physicochemical and structural influences. Journal of Biomedical Materials Research Part A, v. 77A, no. 4, p. 747-762, 2006) and (NIINOMI, M. Recent metallic materials for biomedical applications Metallurgical and Materials Transactions A, v. 33, no. 3, pp. 477-486, 2002)].

Research with Ti CP (commercially pure titanium) and titanium and its alloys has been carried out in order to reach the ideal biomaterial for use in dental implant, with the Ti6AI4V alloy being the most used. However, the low mechanical strength of CP titanium and the cytotoxic effects attributed to the use of the T6AI4V alloy such as Alzheimer's disease [(BALAZIC, M.ef al.Review: titanium and titanium alloy applications in medicine. International Journal of Nano and Biomaterials, v. 1, no. 1, pp. 3-34, 2007); (BOZIC, K. et al. The Epidemiology of Revision Total Knee Arthroplasty in the United States. Clinical Orthopedics and Related Research®, v. 468, no. 1, pp. 45-51, 2010); (BOZKUS, I .; GERMEC-CAKAN, D .; ARUN, T. Evaluation of Metal Concentrations in Hair and Nail After Orthognathic Surgery.Journal of CraniofaciaISurgery, v. 22, No. 1, pp. 68-72 10.1097 / SCS.0b013e3181f6c456, 2011); ELLINGSEN, JE; THOMSEN, P.; LYNGSTADAAS, SP Advances in dental implant materials and tissue regeneration (Periodontology 2000, v. 41, no. 1, pp. 136-156, 2006); (LIU, X .; CHU, PK; DING, C. Surface modification of titanium, titanium alloys, and related materials for biomedical applications. Materials Science and Engineering: A: Reports, v. 47, no. 3-4, p. 49-121, 2004); (MJÖBERG, B.efa / Aluminum, Alzheimer's disease and bone fragility. Acta Orthopaedica, v. 68, no. 6, p. 511-514, 1997); (WANG, K. The use of titanium for medical applications in the USA. Materials Science and Engineering: A, v. 213, no. 1-2, pp. 134-137, 1996); (ZAFFE, D .; BERTOLDI, CONSOLO, U. Accumulation of aluminum in lamellar bone after implantation of titanium plates, Ti-6AI-4V screws, hydroxyapatite granules. Biomaterials, v. 25, no. 17, pp. 3837-3844, 2004)] have taken the development of metals by the addition of non-toxic alloying elements such as tantalum (Ta), zirconium (Zr), niobium (Nb), hafnium (Hf), molybdenum (Mo) and tin (Sn) [( EISENBARTH, E. et al., Biocompatibility of [beta] -stabilizing elements of titanium alloys (Biomaterials, v. 25, no. 26, pp. 5705-5713, 2004); (JIANTING, G .; RANUCCI, D .; GHERARDI, F. Precipitation of β phase in the particles of superalloy nickel-base. Metallurgical and Materials Transactions A, v. 15, no. 7, p. 1331-1334, 1984); (MARECI, D. et al., Comparative corrosion study of Ti-Ta alloys for dental applications. Acta Biomaterialia, v. 5, no. 9, pp. 3625-3639, 2009); (MIYAZAKI, T. et al. Bioactive tantalum metal prepared by NaOH treatment. Journal of Biomedical Materials Research, v. 50, no. 1, pp. 35-42, 2000); (MIYAZAKI, T. et al. Effect of thermal treatment on apatite-forming ability of NaOH-treated tantalum metal. Journal of Materials Science: Materials in Medicine, v. 12, no. 8, pp. 683-687, 2001); (MIYAZAKI, T. et al. Enhancement of bonding strength by graded structure at interface between apatite layer and bioactive tantalum metal. Journal of Materials Science: Materials in Medicine, v. 13, no. 7, p. 651-655, 2002); (NIINOMI, M. Recent metallic materials for biomedical applications. Metallurgical and Materials Transactions A, v. 33, no. 3, p. 477-486, 2002); (TAKAO, H. Recent development of new alloys for biomedical use. Trans Tech, Stafa-Zurich, SUISSE Materials Science forum. 512, p. 243-248, 2006); (VARIOLA, F. et al. Improving Biocompatibility of Implantable Metals by Nanoscae Modification of Surfaces: An OverView of Strategies, Fabrication Methods, and Challenges. Small, v. 5, no. 9, p. 996-1006, 2009); (ZHOU, Y.-L.; NIINOMI, M. Microstructures and mechanical properties of Ti-50 mass% Ta alloy for biomedical applications. Journal of Alloys and Compounds, v. 466, no. 1-2, p. 535-542 (ZHOU, Y.-L.; NIINOMI, M. Ti-25Ta alloy with the best mechanical compatibility in Ti-Ta alloys for biomedical applications. Materials Science and Engineering: C, v. 29, no. 3, 1061-1065, 2009); (ZHOU, YL; NIINOMI, M .; AKAHORI, T. Effects of Ta content on Young's modulus and tensile properties of binary Ti-Ta alloys for biomedical applications. 371, No. 1-2, pp. 283-290, 2004b) (YAO, Q. et al Influence of Nb and Mo contents on phase stability and elastic property of [beta] -type Ti-X alloys. Nonferrous Metals Society of China, v. 17, no. 6, pp. 1417-1421, 2007) and (WEI, D. et al. Structure of calcium titanate / titania bioceramic composite coatings on titanium alloy and apatite deposition on their surfaces in a simulated body fluid Surface and Coatings Technology, v. 201, no. 21, p. 8715-8722, 2007)].

Recent research has investigated the Ti-Ta and Ti-Mo binary system to find out the optimal ratio of tantalum and molybdenum addition for better mechanical and biocompatibility properties.

In addition to establishing compatible physical properties, the favorable implant / tissue interface is also critical to the long-term success of implantable bone devices. Modification in the surface morphology of a biomaterial has been shown to improve cellular interactions and stimulate healthy tissue formation (SHIMOJO, N. et al., 2003. Adhesion, spreading, and proliferation of human gingival fibroblasts. Bio-Medical Materials and Engineering, v. 17, no. 2, pp. 127-135, 2007) and (ALLAM, NK; FENG, XJ; GRIMES, CA Self-Assembled Fabrication of Vertical Oriented Ta205 Nanotube Arrays, and Membranes Thereof , by One-Step Tantalum Anodization, Chemistry of Materials, v. 20, no. 20, pp. 6477-6481, 2008).

Different surface modification techniques for metallic biomaterials have been proposed in recent years seeking a better biological response after their implantation. Surface modification approaches include techniques such as anodization [LLAM, N. K .; FENG, X. J .; GRIMES, C. A. Self-Assembled Fabrication of Vertical Oriented Ta205 Nanotube Arrays, and Thereof Membranes, by One-Step Tantalum Anodization. Chemistry of Materials, v. 20, no. 20, p. 6477-6481, 2008) and (WANG, K. The use of titanium for medical applications in the USA. Materials Science and Engineering: A, v. 213, no. 1-2, pp. 134-137, 1996).

Techniques employed for surface modification can be classified into mechanical, physical and chemical according to the surface-modified layer formation mechanism of the material (BURAKOWSKI, T, WIERZCHON, T. Surface Engineeringof Metals, Principies, Equipment, Technology. CRC Series in Materials Science and Technology, 1999). The various surface treatments in titanium implants and their alloys are shown in Table 1. TABLE1: Surface treatment methods in titanium implants and their alloys (Adapted from LIU, X .; CHU, PK; DING, C. Surface modification of titanium , titanium alloys, and related materials for biomedical applications Materials Science and Engineering: A: Reports, v. 47, no. 3-4, pp. 49-121,2004).

Dental implants made from commercially pure titanium and Ti6AI4V with micro-scale surface treatments are available on the market. However, in the long run, these coatings have some drawbacks that may lead to implant loss. Implant surface topography effectively influences the cellular response of the tissue around the implant. Thus, new technologies that provide, from surface modification, a better interaction in the metal / bone interface are the target of several researches. BARTON (BARTON, JE et al. Structural control of anodized tantalum oxide nanotubes. Journal of Materials Chemistry, v. 19, no 28, p. 4896-4898, 2009) investigated the process of tantalum CP anodization with H2S04 + HF3 electrolytes % (30V, 20min), H2SO4 + 1% HF (55V, 20min) and H2SO4 + 2% HF (25V, 20min), with calcination of 750 ° C for 12 hours. EL-SAYED (EL-SAYED, A.A.; BIRSS, VI Controlled growth and monitoring of tantalum oxide nanostructures. Nanoscale, v. 2, no. 5, pp. 793-798, 2010) investigated the process of tantalum anodization CP with electrolyte H2SO4 + HF, 14.5V, between 5s to 60min. ALLAM et al. (ALLAM, NK; FENG, X, J.; GRIMES, CA Self-Assembled Fabrication of Vertically Oriented Ta205 Nanotube Arrays, and Thereof Membranes, by One-Step Tantalum Anodization. Chemistry of Materials, v. 20, n. 20, p 6477-6481, 2008) investigated the anodizing process of tantalum CP with electrolyte H2S04 + HF + ethylene glycol, 15V, 20min, with calcination of 300 ° C for 1 hour. SIEBER (SIEBER, I.; KANNAN, B.; SCHMUKI, P. Self-Assembled Porous Tantalum Oxide Prepared in H2 SO4 / HF Electrolytes. Electrochemical and Solid-State Letters, v. 8, no. 3, pp. J10-J12, 2005) investigated the anodizing process of tantalum CP with electrolyte H2S04 + HF, 20 V for 1 to 4 hours. EL-SAYED (EL-SAYED, AA .; BIRSS, VI Controlled Interconversion of Nanoarray of Ta Dimples and High Aspect Ratio Ta Oxide Nanotubes. Nano Letters, v. 9, 4, p. 1350-1355, 2009) investigated the anodization process of tantalum CP with electrolyte H2S04 + HF, 15V, between 5, 10, 20, 60, 90 and 120 s. TSUCHIYA (TSUCHIYA, H. et al. Anodic oxide nanotube layers on Ti-Ta alloys: Substrate composition, microstructure and self-organization on two-size scales. Corrosion Science, v. 51, no. 7, p. 1528-1533, 2009) investigated the anodizing process of the Titanium-Tantalum binary system, being the Ti-xTa binary, where X = 13.25, 50 and 80%, using as electrolyte H2S04 + HF + H20, at a voltage of 20V within 12000 seconds. at 200 minutes. JHA et al. (JHA,;.; HAHN, R .; SCHMUKI, P. Ultrafast oxide nanotube formation on TiNb, TiZr and TiTa alloys by rapid breakdown anodization. Electrochimica Acta, v. 55, no. 28, pp. 8883-8887, 2010) investigated the anodizing process of the Titanium-Tantalum binary system, being the Ti-35Ta binary, using as electrolyte NaCI04 + NaCI + H20a a voltage of 40V for 2 minutes, with calcination of 700 ° C for 3 hours. CN101773413 describes a method of preparing a titanium dental implant that involves the anodic oxidation process, without mentioning the use of Ti-30Ta alloy.

Accordingly, a surface modification method of Ti-30Ta and Ti-7,5Mo titanium alloys employing anodic oxidation, replacing commercially pure titanium (TI CP) with an alloy with superior properties by volume, is an object of the present invention. and with surface that provides better interaction with bone cells.

SUMMARY The invention provides a surface modification method of titanium alloys that combines the use of anodic oxidation with titanium alloy, not yet commercially employed in the dental field. The invention provides a surface modification method of titanium alloys that reduces the risks of bone / metal bone integration failure. The invention provides a surface modification method of titanium alloys with potential application in dental implant, orthopedic and cardiac prosthesis coatings.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows SEM-FEG micrographs for Ti-30Ta alloy after HF + H2S04 (1: 9) + 5% DMSO-35V-40 min anodization and calcination at 530 ° C for 3 hours. Figure 2 shows SEM-FEG micrographs for Ti-30Ta alloy after glycerol + NH4F-30V-4 hour anodization and calcination at 530 ° C for 3 hours. Figure 3 shows MEV-FEG micrographs for Ti-30Ta alloy after glycerol + NH4F-30V - 6 hours electrode anodization and calcination at 530 ° C for 3 hours. Figure 4 shows SEM-FEG micrographs for Ti-75Mo alloy after glycerol + NH4F electrolyte anodization, being (a) 20V - 34 hours and (b) 20V, 48 hours and calcination at 450 ° C for 1 hour. Figure 5 shows SEM-FEG micrograph images for Ti-75Mo alloy after glycerol + NH4F electrolyte anodization, where (a) 30 V, 24 hours and (b) 30 V, 48 hours and calcination at 450 ° C for 1 hour.

DETAILED DESCRIPTION OF THE INVENTION The surface modification method of Ti-30Ta and Ti-7,5Mo titanium alloys comprises in an initial step the anodic oxidation of the alloy surface with the creation of an oxide film on a metal by dipping. in an electrolyte medium. Table 2 shows the alloys, electrolytes, time, voltage and calcination temperature employed in the anodizing process to obtain the nanotube. TABLE 2: Alloys, electrolyte, time, voltage and calcination temperature employed in the anodizing process to obtain the nanotube.

In the anodizing process 3 mm x 13 mm discs were used as samples. Prior to the onset of anodic oxidation, the discs were immersed in acetone for 3 minutes, washed three times in isopropyl alcohol and water, manually scrubbed in soap and running water, washed 3 times in distilled water and isopropyl alcohol and sonicated for 7 minutes. immersed in isopropyl alcohol, washed 3 times in isopropyl alcohol and dried with nitrogen gas. It was used as platinum counter electrode and as working electrode Ti-30Ta alloy and Ti-7.5Mo alloy, maintaining a constant distance between the two of 15 mm. The electrodes were connected to a power source with a maximum limit of 400 mA. The anodizing process was performed inside a gas exhaust chapel due to the toxicity of the experiment. Figure 1 shows an electrochemical cell model used in the anodizing process.

Ti-30Ta-HF and H 2 SO 4 Alloy Concentrated HF (48%) and H 2 SO 4 (98%) electrolyte were used, in a 1: 9 volumetric ratio, with the addition of 5% dimethyl sulfoxide (DMSO). Under a voltage of 35 V for 40 minutes. The experiment was carried out at room temperature and during its performance a magnetic bar immersed in the electrolyte with 250 rpm agitation was maintained. At the end of the process the samples were washed three times in isopropyl alcohol and dried with oil free compressed air. After anodic oxidation the samples were calcined in a resistive oven at 530 ° C (1 ° C / min) for a period of 3 hours.

NH4F electrolyte

It was used as glycerol electrolyte and 0.25% NH4F, submitted to a voltage of 30 V for 4 and 6 hours. The experiment was performed at room temperature. At the end of the process the samples were washed three times in isopropyl alcohol and dried with oil free compressed air. After anodic oxidation, the samples were calcined in a resistive oven at 530 ° C (1 ° C / min) for a period of 3 hours.

Ti-7.5 Mo alloy Glycerol and 0.25% NH4F were used as electrolyte, subjected to a voltage of 20 V and 30 V for 24 and 48 hours. The experiment was performed at room temperature. At the end of the process the samples were washed three times in isopropyl alcohol and dried with oil free compressed air. After anodic oxidation, samples were calcined in a resistive oven at 450 ° C (1 ° C / min) for a period of 1 hour.

In both alloys, the anodizing process resulted in nanotubes perpendicular to the substrate with a diameter of 80-120 nm and a length of 100 nm-500 nm, according to scanning electron microscope images shown in figures 1 to 5.

Claims (12)

1. METHOD FOR MODIFYING TITANIUM ALLOY SURFACE characterized by the anodic surface oxidation of Ti-30Ta and Ti-7,5Mo titanium alloys. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-30Ta according to claim 1, characterized in that platinum is used as a counter electrode and Ti-10Ta alloy as a working electrode. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-30Ta according to claims 1 and 2, characterized in that the electrolyte may be a mixture of HF (48%) and H2S04 (98%) in a volumetric ratio of 1 : 9 and up to 5% dimethylsulfoxide may be added. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-30Ta according to claim 1 and 2, characterized in that the electrolyte may alternatively be a mixture of glycerol and 0.25% NH4F. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-30Ta according to claims 1, 2 and 3, characterized in that the anodizing process is carried out by applying a voltage of 35V for 40 minutes. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-30Ta according to claims 1, 2 and 4, characterized in that the anodizing process is carried out by applying a voltage of 30V for a period of 4 to 6. hours METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-30Ta according to claims 1 to 6, characterized in that the calcination of the alloy is performed at 530 ° C for 3 h. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-7,5Mo according to claim 1, characterized in that platinum is used as a counter electrode and Ti-7.5Mo alloy as a working electrode. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-7,5Mo according to claims 1 and 8, characterized in that the electrolyte is a mixture of glycerol and 0.25% NH4F. METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-7,5Mo according to claims 1, 8 and 9, characterized in that the anodizing process is carried out by applying a voltage between 20 and 30V for 24 to 48 hours METHOD OF MODIFYING THE TITANIUM ALLOY SURFACE Ti-7,5Mo according to claims 1, 8, 9 and 10, characterized in that the calcination of the alloy is performed at 450 ° C for 1 h. Products obtained by the process claimed in 1, characterized in that it comprises nanotubes perpendicular to the substrate with a diameter of 80-120 nm and a length of 100 nm-500 nm.