Corrosion Resistance Of Ti Research Articles

Biomechanical and Biocorrosion Properties of Nanostructured Titanium

The nanostructured titanium was fabricated via the surface mechanical attrition treatment (SMAT) process and the effect of nano-crystalline structure on the biomechanical and biocorrosion properties were studied. It was found that the Young’s modulus of nanostructured Ti decreased significantly and thus the biomechanical property was improved. The electrochemical results revealed that the corrosion resistance of Ti became worse after SMAT process, which is contributed to the higher activation of the nanostructured surface.

Elastic modulus and in vitro biocompatibility of Ti−xNb and Ti−xTa alloys

The effect of niobium and tantalum on the elastic modulus and the in vitro biocompatibility in binary titanium alloys was studied. The Young's modulus of titanium was effectively lowered with additions of Nb or Ta, depending significantly upon the microstructure. Martensitic microstructures such as α' and α" decreased the elastic modulus, while the ω phase increased it. Ti−10%Nb, Ti−30%Nb and Ti−30%Ta alloys exhibited very low elastic moduli of 74, 80, and 58 GPa, respectively. The corrosion resistance of Ti−xTa was slightly higher than that of Ti−xNb, which was comparable to that of CP Ti or Ti−6A−4V. No ion release was detected in Hank's solution, while Ti ions were released in 0.1% lactic acid ranging from 0.03 to 0.11 μg/ml for both the Ti−xNb and Ti−xTa alloys. MG63 osteoblast-like cell proliferation on Ti−30%Ta was less active compared with Ti−30%Nb, CP Ti or Ti−6Al−4V.

Electrochemical corrosion of novel beta titanium alloys

Electrochemical corrosion behaviors of novel beta titanium alloys, Ti−30Ta−10Nb−10Zr, Ti−40Ta−10Nb−10Zr and Ti−40Ta−10Nb−4Sn were characterized in naturally aerated Hank's solution at 37°C compared with currently used biomedical titanium alloys. Ti−30Ta−10Nb−10Zr and Ti−40Ta−10Nb−10Zr exhibited comparable corrosion resistance to CP Ti or Ti−6Al−4V, while the corrosion resistance of Ti−40Ta−10Nb−4Sn was greatly inferior to the other alloys. An EIS data analysis confirmed that the resistance of passive film for Ti−30Ta−10Nb−10Zr and Ti−40Ta−10Nb−10Zr was comparable to CP Ti or Ti−6Al−4V. Ti−30Ta−10Nb−10Zr and Ti−40Ta−10Nb−10Zr alloys are promising metallic biomaterials for the future, owing to their very low elastic modulus and good corrosion resistance capabilities.

The effect of fluoride on the electrochemical behavior of Ti and some of its alloys for dental applications

AbstractTitanium is the best metal for making dental implants and restorations. In the last decade, new titanium alloys have been developed in different areas of dentistry. Concurrently, treatments using fluoride supplementation, such as odontology fluoride containing gels, have also been widely used in odontology.The aim of this study is to investigate the electrochemical behaviour of a new titanium alloy containing Cu and Ag, in fluoride‐containing media, and compare it with the behavior of Ti and Ti6Al4V, which are used frequently as biomaterials. Open circuit potential, polarization resistance and electrochemical impedance spectroscopy measurements revealed that the corrosion resistance of titanium and its alloys is controlled by the fluoride ion concentration and the pH of the solution. The presence of F− ions in neutral solution does not hinder the formation of a protective layer of Ti and its alloys. Thus, the corrosion resistance of Ti is maintained in this medium. However, the corrosion of Ti and its alloys are enhanced in an acidic environment, because F− ions in the solution combines with H+ ion to form HF, even in low fluoride concentration.

Hydroxyapatite coating on titanium substrate with titania buffer layer processed by sol–gel method

Hydroxyapatite (HA) was coated onto a titanium (Ti) substrate with the insertion of a titania (TiO 2) buffer layer by the sol–gel method. The HA layer was employed to enhance the bioactivity and osteoconductivity of the Ti substrate, and the TiO 2 buffer layer was inserted to improve the bonding strength between the HA layer and Ti substrate, as well as to prevent the corrosion of the Ti substrate. The HA layer coated over the TiO 2 showed a typical apatite phase at 400°C and the phase intensity increased above 450°C. The sol–gel derived HA and TiO 2 films, with thicknesses of approximately 800 and 200 nm, respectively, adhered tightly to each other and to the Ti substrate. The bonding strength of the HA/TiO 2 double layer coating on Ti was markedly improved when compared to that of the HA single coating on Ti. The highest strength of the double layer coating was 55 MPa after heat treatment at 500°C. The improvement in bonding strength with the insertion of TiO 2 was attributed to the resulting enhanced chemical affinity of TiO 2 toward the HA layer, as well as toward the Ti substrate. Human osteoblast-like cells, cultured on the HA/TiO 2 coating surface, proliferated in a similar manner to those on the TiO 2 single coating and on the pure Ti surfaces. However, the alkaline phosphatase activity of the cells on the HA/TiO 2 double layer was expressed to a higher degree than that on the TiO 2 single coating and pure Ti surfaces. The corrosion resistance of Ti was improved by the presence of the TiO 2 coating, as confirmed by a potentiodynamic polarization test.

Plaza of Legacy’s paint to cure sick building syndrome contains apatite-coated TiO 2

Hydroxyapatite (HA) was coated onto a titanium (Ti) substrate with the insertion of a titania (TiO2) buffer layer by the sol–gel method. The HA layer was employed to enhance the bioactivity and osteoconductivity of the Ti substrate, and the TiO2 buffer layer was inserted to improve the bonding strength between the HA layer and Ti substrate, as well as to prevent the corrosion of the Ti substrate. The HA layer coated over the TiO2 showed a typical apatite phase at 400°C and the phase intensity increased above 450°C. The sol–gel derived HA and TiO2 films, with thicknesses of approximately 800 and 200 nm, respectively, adhered tightly to each other and to the Ti substrate. The bonding strength of the HA/TiO2 double layer coating on Ti was markedly improved when compared to that of the HA single coating on Ti. The highest strength of the double layer coating was 55 MPa after heat treatment at 500°C. The improvement in bonding strength with the insertion of TiO2 was attributed to the resulting enhanced chemical affinity of TiO2 toward the HA layer, as well as toward the Ti substrate. Human osteoblast-like cells, cultured on the HA/TiO2 coating surface, proliferated in a similar manner to those on the TiO2 single coating and on the pure Ti surfaces. However, the alkaline phosphatase activity of the cells on the HA/TiO2 double layer was expressed to a higher degree than that on the TiO2 single coating and pure Ti surfaces. The corrosion resistance of Ti was improved by the presence of the TiO2 coating, as confirmed by a potentiodynamic polarization test.

Surface Study of Ti3Al and Ti3Al-11Nb, TiAl and TiAl-2Cr by X-Ray Photoelectron Spectroscopy

Oxide films formed on intermetallics Ti 3 Al , Ti 3 Al -11at.%Nb, TiAl and TiAl-2at.%Cr were studied by X-Ray Photoelectron Spectroscopy (XPS). An addition of 11at%Nb to Ti 3 Al increases the Ti:Al atomic ratio on the surface from 2.8:1 to 20:1. This may explain the better electrochemical corrosion resistance of Ti 3 Al -11Nb than Ti 3 Al . Meanwhile, an addition of 2at.%Cr to TiAl decreases the Ti atomic percentage from 11.8 to 9.5. The Ti:Al atomic ratio changes from 1:0.2 to 1:1.8. The Cr addition enhances the formation of an Al-enriched passive film, which may be the reason for the improved TiAl high temperature oxidation resistance. TiO 2 is the main component of the top oxide layers formed on the intermetallics of Ti 3 Al , Ti 3 Al -11Nb and TiAl. In contrast the top layer of TiAl-2Cr is mainly Al 2 O 3. XPS results show that the compositions are quite different between the bulk materials and the top oxide layer on these intermetallics.

Increased wear and corrosion resistance of Ti(NCO) layers by annealing in a nitrogen plasma atmosphere

A gaseous mixture composed of tetraisopropoxytitanium, nitrogen and hydrogen in the PACVD process, has been used to obtain Ti(NCO) layers of good performance properties, such as a high hardness and good resistance to corrosion and to frictional wear. The temperature of the process is 500°C. The paper describes a method which permits improving the properties of the Ti(NCO) type and composite nitrided+Ti(NCO) type layers by plasma nitriding treatment. The structure of the layers is described and their wear and corrosion resistance is determined. The results of SEM examinations, microhardness and stereological measurements and X-ray diffraction analysis are discussed. The TiO, TiC and TiN phases have the same crystallographic structure of the NaCl type. The Ti(NCO) layer is a solid solution of these phases with nitrogen atoms in the TiN lattice being replaced by carbon and oxygen atoms. The lattice parameter is strongly related to the chemical composition of the layers. As the nitrogen content increases and oxygen content decreases the lattice parameter can increase to 0.424 nm a value characteristic of pure stoichiometric titanium nitride. The nitrogen content can be increased by reducing the process temperature to 500°C, by using pre-nitrided substrates and by subjecting the Ti(NCO) layers obtained to nitrogen plasma annealing.

Study of the corrosion behavior of titanium and some of its alloys for biomedical and dental implant applications

Abstract The influence of alloying elements and the potential on the corrosion resistance of Ti and other Ti-based biomedical implant alloys under simulated physiological conditions is presented. Ti and its following alloys: Ti10Mo, Ti10Mo10Al, Ti7Al4.5V and Ti5Al4.5V and Ti5Al2.5Fe were studied. Electrochemical impedance spectroscopy was used and the experimental results were compared with those obtained by potentiostatic and potentiodynamic techniques. All the measurements were made in Ringer’s solution at pH 7.8 and at different potentials ( E corr , −650, −500, 0, +200 and +400 mV vs. SCE). Under these conditions, all the Ti-based alloys exhibited spontaneous passivity. It was evident that Mo, V and Fe improved passivity and limited the active corrosion of the β-phase of Ti while Al enrichment of the α-phase was found to be detrimental to the passivity and corrosion resistance of Ti.

Corrosion performance of ion-plated titanium and yttrium-modified TiN coatings

The corrosion behaviour of vacuum-evaporated titanium, ion-plated titanium, ion-plated TiN and yttrium-modified TiN coatings was studied in three corrosive media. Ion-plated titanium coatings exhibited better corrosion resistance than vacuum-evaporated coatings, which may be related to the effect of negative bias which enabled the former to become more compact and less rough. There is no distinguishable difference in the chemical composition and phase constituents of the top surface between TiN and Ti(Y)N coatings, but study of their pole figures revealed that there is a strong (110) texture for TiN coatings, and (112) texture for Ti(Y)N coatings. The latter lattice plane is closer to TiN(111) with the highest degree of microcompactness and may be responsible for the better corrosion resistance of Ti(Y)N coatings.

Corrosion Resistance of Ti and a Ti-Pd Alloy in Hot, Concentrated Sodium Chloride Solutions

Abstract Case histories are described concerning corrosion of titanium in hot concentrated chloride solutions and the results of the laboratory investigation on the corrosion behavior of titanium and titanium-palladium alloy in chloride environments reported. Although passivity of titanium was very stable in solutions of moderate concentration, this stability was found to decrease with increasing temperature, chloride and hydrogen ion concentration. In boiling concentrated chloride solutions, severe corrosion occurred locally in crevices such as interfaces between two titanium sheets or titanium and Teflon sheets which was identical to that encountered in field experience. In contrast to titanium, no crevice corrosion was observed to occur under the same conditions for titanium-palladium alloys. Superior corrosion resistance of the alloy was confirmed by field tests.