Ta Coatings Research Articles

Corrosion and tribological properties of ta-C/ta-C: Ta coatings: Analysis of the influence of Ta-O/Ta-C ratio

Multilayer ta-C/ta-C: Ta coatings with varying total thicknesses (300, 600, and 1000 nm) and layer thickness ratios (1:0.5, 1:1, and 1:2) between the ta-C layer and ta-C: Ta layer were prepared. The study investigated the static corrosion resistance and tribological properties of the coatings in the NaCl solution. The static corrosion resistance positive correlation depended on the coating surface's Ta-O/Ta-C ratio. The lowest friction coefficient of 0.05 was obtained from the coating with a total thickness of 1000 nm due to the formation of the graphitized transfer film on the counterpart surface. A decreased sp2/sp3 ratio and the formation of tantalum oxide on the wear scar contributed to the lowest corrosion current, corrosive defect density, and wear rate.

Corrosion behavior of metallic coatings on titanium bipolar plates of proton exchange membrane water electrolysis

The corrosion resistance, conductivity, and cost of the metallic bipolar plates are the main limitations for the Proton Exchange Membrane Water Electrolysis (PEMWE) commercialization. In the present study, Ta, Nb, and Ti non-precious metallic coatings were deposited by closed-field unbalanced magnetron sputtering to increase the corrosion resistance and conductivity of titanium bipolar plates in PEMWE, respectively. The coating samples suffer from corrosion in a simulated extreme anode operating environment of PEMWE (0.5 M H2SO4 + 5 ppm HF, 80 °C, O2). The surface of the Ti coating forms the micropores due to the high dissolution rate in initial formation stage of the passivation film, resulting in a higher current density (1.41 × 10−6 A cm−2). The hydrolysis reaction of Ta coating causes the adsorption of sulfide ions, thereby affecting the density of the passivation film. Despite the Ta coating exhibiting a favorable current density (4.82 × 10−7 A cm−2), ICR (463.11 mΩ cm2) is lamentably poor. The surface of Nb coating has been completely covered by Nb2O5 and NbO2 in the simulated PEMWE environment. The reoxidation process of NbO2 promotes the rate of passivation film formation and provides excellent conductivity. Therefore, Nb coating exhibits the lowest current density and interfacial contact resistance of 2.23 × 10−8 A cm−2 and 119.78 mΩ cm2, respectively, which is very low compared to the bare titanium bipolar plates.

Influence of a Ta Coating on the Crystallization of Deformed Amorphous Alloys Fe78Si13B9 and Al87Ni8Gd5

Influence of a Ta Coating on the Crystallization of Deformed Amorphous Alloys Fe78Si13B9 and Al87Ni8Gd5

Mechanical, antibacterial and cytotoxic characteristics of nanolayered TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings

Titanium and titanium alloy materials are often made as medical implants. Surface properties of titanium medical implants play decisive roles for antibacterial and biological response and tissue biocompatibility. In this study, cathode arc evaporation (CAE) technology was used to deposit TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings with nanostructures on the Ti–6Al–4V dental abutment screws. The deposited coatings were then oxidized at high temperature to produce different oxides on the surface of the coatings. The mechanical properties, antibacterial properties and biocompatibilities of the coatings were analyzed. The effect of coatings on the abutment screw loosening and removal torque between the abutment screw and the pure titanium implant fixture was studied by removal torque measurement. In addition, Staphylococcus aureus (S. aureus) was used for evaluating the antibacterial properties of coatings, and mouse fibroblasts (L929) were used for ISO 10993-5 cytotoxicity analyses to determine whether it had good biocompatibility.Nanolayered structures and multiphases of polycrystalline TiNb–Zr–Ta were obtained by co-deposition of Ta, Zr and TiNb. When small content of N was introduced, the TiNb–Zr–Ta(N) showed a polycrystalline TiNb–Zr–Ta where N atoms entered the metallic lattice at interstitial sites. After oxidation, oxide phases of Ta2O5, TiO2, Nb2O5 and ZrO2 were formed on the surface of TiNb–Zr–Ta and TiNb–Zr–Ta(N). Ta2O5 was obtained on the surface of the coating prior to other oxides such as TiO2, Nb2O5 and ZrO2. The deposited TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had high contact angle and exhibited a hydrophobic feature, while the annealed TiNb–Zr–Ta–O and TiNb–Zr–Ta(N)–O showed hydrophilicity. The deposited TiNb–Zr–Ta had similar hardness and Young's modulus values to that of the uncoated Ti–6Al–4V. When N was doped, the TiNb–Zr–Ta(N) had the highest hardness and Young's modulus. The hardness of the annealed TiNb–Zr–Ta(N) coating only decreased slightly due to the small oxide layer of ∼140 nm. Compared with the uncoated Ti–6Al–4V, TiNb–Zr–Ta serial coatings deposited on abutment screws had higher removal torques, which prevented the abutment screw of dental implant from loosening after long-term use. The biocompatibility of TiNb–Zr–Ta serial coatings was similar to that of the uncoated Ti–6Al–4V. In addition, the oxidized TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had excellent antibacterial properties. It is speculated that the resulting Ta2O5 of both coatings may inhibit bacterial growth and improve the antibacterial effect. Based on the above advantages, the TiNb–Zr–Ta serial coatings are expected to have the potential to be applied to biomedical implants.

Improving the electrochemical corrosion behavior of stainless steel (316L) through the deposition of tantalum-based thin films

Austenitic 316L stainless steel (SS) is commonly used as a biomaterial for human implant applications. However, its clinical uses are limited due to its relatively high corrosion rate in physiological conditions. Various surface modifications, including coatings, have been developed to enhance its performance. In this study, a thin layer of Tantalum (Ta) was applied to the surface of 316L stainless steel using a DC Magnetron Sputtering (DCMS) system; the thickness of the coating varied from 1.504 to 6.083 µm, achieved by deposition times ranging from 15 to 60 min. The aim was to examine the electrochemical corrosion characteristics of the uncoated 316L SS and the Ta-coated 316L SS, followed by Potentiodynamic Polarization (PDP), Electrochemical Impedance Spectroscopy, and Open Circuit Potential tests. These tests were conducted for 10 min, 60 min, and 90 min to assess their performance over time. The PDP measurements took place in a simulated body fluid (SBF) at a pH of 7.8 ± 0.25 and a temperature of 40 °C, with varying coating durations. The PDP test outcomes revealed that the Ta-coated 316L stainless steel exhibited enhanced resistance to corrosion compared to the uncoated 316L stainless steel sample. The efficacy of Ta coatings on the 316L stainless steel samples was assessed through several techniques, including Optical microscopes, Energy Dispersive X-ray Spectroscopy, Scanning Electron Microscopy, and X-ray Photoelectron Spectroscopy. The findings from SEM and EDS verified the successful application of the Ta coating onto the stainless steel. The composition of the surface oxide film of Ta, the substrate, and the thickness of the coating were determined using the XPS technique, which confirms the effectiveness of the Ta coating in safeguarding 316L stainless steel against electrochemical corrosion, particularly for biomedical applications.

Microstructure and Properties of Monolayer Ta and Multilayer Ta/Ti/Zr/Ta Coatings Deposited on Biomedical Ti-6Al-4V Alloy by Magnetron Sputtering

Two types of coatings, i.e., monolayer Ta and multilayer Ta/Ti/Zr/Ta coatings, were deposited on biomedical Ti6Al4V (TC4) alloy by magnetron sputtering to improve its performance. To evaluate the effect of the two coatings on the alloy properties, the microstructure, composition, mechanical and tribological properties, in vitro biocompatibility, and corrosion resistance were investigated. The results showed that α-Ta exists in the monolayer Ta coating, while α-Ta and β-Ta phases coexist in the multilayer Ta/Ti/Zr/Ta coating. The multilayer Ta/Ti/Zr/Ta coating possessed the highest hardness and the monolayer Ta coating had the lowest friction coefficient compared to the Ti6Al4V alloy. The friction and wear tests revealed that the anti-wear performance of the Ta coating is the best, followed by that of the Ta/Ti/Zr/Ta coating, while the anti-wear performance of TC4 alloy is relatively poor in comparison with the Ta and Ta/Ti/Zr/Ta coatings. The wear resistance of the multilayer Ta/Ti/Zr/Ta coating under low normal load is better than that under high load normal load. Finally, the in vitro and electrochemical corrosion tests showed that the Ta coating modification provides better biocompatibility and corrosion resistance than those of the uncoated Ti6Al4V alloy.

Effect of annealing on the mechanical properties and cytocompatibility of CoCrMo alloy with tantalum coating

Cobalt–chromium–molybdenum (CoCrMo) alloy is frequently utilized to replace artificial joints and dental components. Tantalum (Ta) coating is used to improve the osteogenic property of CoCrMo alloy. Annealing treatment can increase the Ta coating adhesion and further improve wear resistance and biocompatibility. In this study, two kinds of thicknesses of Ta coatings were applied on CoCrMo alloy substrates via magnetron sputtering technology. The average thicknesses of the Ta coatings were 4.3 and 9.5 μm. The Ta coatings were annealed for 5 h at 800 °C, 900 °C, and 1000 °C, respectively. Results indicated that heat treatment improved the adhesion of the coatings. The Ta coatings were composed of stable body-centered cubic phase (α-Ta) and metastable tetragonal phase (β-Ta). The Ta coating with a thickness of 4.3 μm exhibited excellent wear resistance after being annealed at 800 °C, with little variability in the friction curve and a low average coefficient of friction. The adhesive force of the two coated samples increased initially and subsequently dropped as the annealing temperature increased. At 900 °C, the Ta-coated samples exhibited the highest adhesive force; after being annealed, the rate of cell proliferation increased. At 900 °C, samples with Ta coatings exhibited the highest rate of cell multiplication and the best cell compatibility compared with the other samples. Ta coatings' adhesive force, wear resistance, corrosion resistance, and cytocompatibility were all significantly enhanced at various annealing temperatures. Thus, the results of this work are a useful benchmark for the surface modification of metal implants used in medical procedures, and Ta coatings are a practical orthopedic material for the replacement of joints and bones.

Deuterium and helium retention in W and W-Ta coatings irradiated with energetic ion beams

Different studies reveal the behaviour of Ta alloying to decrease deuterium retention in tungsten bulk materials aiming to be used for nuclear fusion applications. In this work, W and W-5 %Ta coatings were produced via magnetron sputtering techniques. The elemental composition of the samples and the spread of Ta in the W lattice was confirmed by GDOES, PIXE and by μ-PIXE, respectively. Sets of W and W-Ta coatings were simultaneously irradiated with a single 2H2+ or with sequential 4He+/2H2+ ion beam implantations using incident energies of 30 keV and ion fluences of 5 × 1017 ion/cm2. The irradiated samples were analysed by NRA/RBS and by ToF-ERDA to quantify the retained deuterium and helium amounts. The results reveal significantly lower contents of both isotopes in W-Ta.

Comparative Study on Wear Behaviors of Monolayer and Heterogeneous Multilayer Ta Coatings in Atmospheric and SBF Environments

Monolayer Ta and multilayer Ti/Zr/Ta and Zr/Ti/Ta coatings were prepared by magnetron sputtering on TC4 substrates to improve the surface friction and wear properties in a simulated body fluid (SBF) environment and an atmospheric environment. Optical microscopy, scanning electron microscopy, laser scanning confocal microscopy and nano scratch testing were employed to establish the structure-property-environment relationships. By controlling the preparation parameters, the outermost layer of all three samples was Ta coating, and the total coating thickness of each sample was about 3 μm. Friction and wear testing revealed that, compared to bare TC4 substrate, and multilayer Ti/Zr/Ta and Zr/Ti/Ta coatings, the monolayer Ta possessed the lowest friction coefficient as well as the minimum wear rate (i.e., calculation result of the wear track width and wear depth). This was mainly attributed to excellent adhesion strength, a particular structure and solid lubrication of the monolayer coating. The same coating sample exhibited a stronger wear resistance in the SBF environment than in the atmospheric environment. Furthermore, the wear behaviors and mechanisms of various coatings under different experimental environments are also discussed.

Microstructure, mechanical and tribological properties of Ta(C, N) coatings deposited on TA15 substrates with different nitrogen partial pressure

PurposeThe purpose of this paper is to obtain the optimal N2/Ar ratio parameters for preparing Ta (C, N) coating. Three coatings with different N2/Ar ratios were prepared on the TA15 substrate, and their effects on the wear properties of the coatings were discussed.Design/methodology/approachTa(C, N) coatings with three different N2/Ar ratios were prepared on TA15 substrates using the double cathode glow metallurgical plasma alloying technique (DGMPA) using a step-by-step diffusion method.FindingsWith the increase of N2/Ar flow ratio, the hardness and elastic modulus of the coating first increase and then decrease. Compared with the S1 sample (N2/Ar gas ratio 25: 75) and the S3 sample (N2/Ar gas ratio 75: 25), the S2 sample (N2/Ar gas ratio 50: 50) has better mechanical properties, with hardness increased by 48.45% and 6.8%, respectively, and elastic strain ratio increased by 22.8% and 28.5%, respectively. Moreover, the wear degree of the S2 sample is less than other samples. The wear rate of the S2 sample was 32.4% lower than the S3 sample at 300°C and 14.3% lower than the S3 sample at 500°C. Therefore, the S2 sample has the best mechanical properties and the best high temperature wear resistance.Originality/valueTa(C, N) coatings were prepared by DGMPA technology, and the wear mechanism of Ta(C, N) coatings with different N2/Ar ratios was investigated to reduce the wear rate.

Effect of substrate rotational speed during deposition on the microstructure, mechanical and tribological properties of a-C:Ta coatings

Rotational speed has an important influence on the performance of coating materials. The a-C:Ta composite coatings were prepared by controlling the substrate rotational speed during deposition process using PVD technique. The results showed that the coating transformed from dense structure to columnar structure. Due to the changes of deposition time and the vapor incident angle of the sputtering ions, the sp2 hybrid structure increased and the C–Ta bonds contents decreased as a function of the rotational speed, which led to the improvement of adhesion force. The average friction coefficient of the composite coatings did not fluctuate significantly for the amorphous carbon matrix and the transfer films formed during friction, while the wear rates were gradually increased. The sample at 0.5 rpm possessed the lowest wear rate, which was mainly associated with the cooperative behavior of the dense structure and the formation of TaC nanoclusters in the composite coating.

Structure of Ti-Ta Alloys Fabricated by Electron-beam Surface Alloying

In the present study, Ta coatings with a thickness of 1.7 and 4.2 μm were deposited on Ti samples through reactive magnetron sputtering. The coatings are furthermore treated by a scanning electron beam in order to form the Ti-Ta surface alloy. A change in the phase composition of the Ti-Ta alloy was observed through X-ray diffraction (XRD). The microstructure and the chemical composition of the samples were studied via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The results indicate that in both cases the thickness of the alloyed zone remains the same at about 50 μm. The concentration of Ta in the alloyed zone increases with the increase in thickness of the pre-applied coating. The sample with the 1.7 μm Ta coating has a single-phase hexagonal closed packed structure, corresponding to the \(\alpha \) phase, whilst the sample with the 4.2 μm coating exhibits a biphasic hexagonal closed-packed structure and a body-centred cubic structure, corresponding to \(\alpha '\) martensitic and β phases.

Wear and corrosion characterization of single and multilayered nanocrystalline tantalum coatings on biomedical grade CoCrMo alloy

Osteolysis caused by the worn-off particles of polyethylene (PE), and corrosion of CoCrMo head have been two major concerns in total hip replacement as they lead to its early failure. Here we report on the development of a Ta multilayered coating to improve the corrosion resistance of CoCrMo and minimize the wear rate of PE. Deposition of single-layered and multilayered Ta coatings was carried out at ambient temperature utilizingmagnetron sputtering with deposition pressure ranging from 0.3 Pa to 1.9 Pa. The hardness and Young's modulus of the Ta coatings ranged from 8 to 21 GPa and from 179 to 288 GPa, respectively. Excellent adhesion was observed on the Ta coatings deposited at a high deposition pressure. The PE wear rate was 4% lower when sliding against the Ta multilayered coating than with the uncoated sample. Furthermore, the Ta multilayered displayed a 61% greater corrosion resistance than the uncoated CoCrMo alloy. The results indicate that Ta coatings have great potential for artificial joint applications.

Effects of Cr and Ta additions on microstructure, corrosion-wear and electrochemical performances of laser cladded Fe90-Al2O3 coating in 3.5% NaCl solution

PurposeThis paper aims to investigate the effects of Cr and Ta additions on the friction performance and corrosion-wear mechanism of Fe90-Al2O3 coating in 3.5% NaCl solution.Design/methodology/approachCr and Ta reinforced Fe90-Al2O3 coatings were prepared on Q235 steel by laser cladding. The effects of Cr and Ta addition on the coefficient of friction (COF) and wear rate of Fe90-Al2O3 coating were investigated using a friction tester, and the wear model was established to discuss its corrosion-wear mechanism.FindingsThe average COFs of Fe90-Al2O3, Fe90-Al2O3-10%Cr and Fe90-Al2O3-10%Ta coatings in 3.5% NaCl solution are 0.57, 0.42 and 0.75, respectively, and the corresponding wear rates are 9.42 × 10−7, 5.31 × 10−7 and 7.02 × 10−7 mm3 s−1 N−1, respectively. The corrosion-wear resistance of Fe90-Al2O3-10%Cr coating is the best among the three kinds of coatings, in which the additions of Cr and Ta play a role in solid solution strengthening.Originality/valueThe Fe90-Al2O3 coating was strengthened by the additions of Cr and Ta to improve its corrosion-wear resistance in 3.5% NaCl solution.

Wear, Corrosion, and Biocompatibility of 316L Stainless Steel Modified by Well-Adhered Ta Coatings

Wear, Corrosion, and Biocompatibility of 316L Stainless Steel Modified by Well-Adhered Ta Coatings

Optimization for solderability of large-size single-crystal diamond with heterogeneity alloys by tantalum coating

To ameliorate the solderability of single-crystal diamond with heterogeneity metals/alloys, tantalum (Ta) coatings were prepared on the diamond by utilizing the double glow plasma surface metallurgy (DGPSM) technique. Using Ag-Cu-Ti solder, the Ta-coated single-crystal diamonds were soldered onto cemented carbide (WC-Co) matrixes. The effects of metallization temperatures on the microstructure, phase, and solderability of the Ta-coated diamond were investigated. The results show that uniform and compact Ta coatings with increased thicknesses are obtained with increasing metallization temperatures. Besides, under all the temperatures, the diffusion layers composed of Ta2C and TaC could be formed at the Ta/diamond interface, which is beneficial to enhance the coating adhesion. The average shear strength of the soldered joint with Ta-coating increases first and then decreases with the increase of temperature. The maximum value is 118.7 MPa on the soldered joint with 850 °C Ta coating, which is approximately 57% higher than without Ta coating. Three failure modes occur during the shear process, including the ductile fracture of the soldered seam, brittle fracture in the interior of Ta carbides at the Ta/diamond interface, and brittle fracture of the single-crystal diamond itself. Among them, the ductile fracture of the soldered seam is the dominant fracture mode.

Effect of UV irradiation on oxygen desorption in ta-C:Ta coatings

In recent years, the demand for lubrication in the atmosphere has been increasing, and carbon-based hard coatings Diamond-like Carbon (DLC) have been attracted attention. A tetrahedral type of DLC with tantalum (ta-C:Ta) has been exhibited ultra-low friction approximately 0.07 in the atmosphere. The friction coefficient is thought to decrease due to an increase in the graphite structure at the topmost surface which was formed by desorption of oxygen from carbon or tantalum and restructuring of carbon structure. Which is assumed to be driven by energy from the application of frictional heat or shearing. If the oxygen desorption phenomenon described above can be realized by applying energy other than friction, low friction can be obtained without friction beforehand. It has been reported that irradiating CNx coatings with ultraviolet light desorbs nitrogen atoms from the surface of the CNx coating, reducing the initial friction period by 91 %.

Microstructure, Mechanical and Tribological Properties of Ta(C,N) Coatings Deposited on Ta15 Substrates with Different Nitrogen Partial Pressure

Microstructure, Mechanical and Tribological Properties of Ta(C,N) Coatings Deposited on Ta15 Substrates with Different Nitrogen Partial Pressure

Microstructure and biocompatibility of porous-Ta/Ti-6Al-4 V component produced by laser powder bed fusion for orthopedic implants

Tantalum is attracting more attention as an outstanding orthopedic implant material due to its excellent corrosion resistance and biocompatibility. However, the high melting point and strong oxygen affinity of tantalum make its preparation more difficult and costly. In addition, the high cost of raw materials also limits the wider application of tantalum. To break these limitations, porous tantalum coatings with different pore sizes were successfully prepared on Ti-6Al-4 V base by Laser Powder Bed Fusion, constructing an integral porous-Ta/Ti-6Al-4 V component with excellent bioactivity and osteointegration capacity. A strong metallurgical bonding was formed between tantalum and Ti-6Al-4V, and the bonding strength is more than 460 MPa. The porous tantalum coating is designed as diamond-like structure with strong symmetry. The porosity of tantalum coatings is 70%, and the pore size ranges from 447 to 865 μm. Its deformation characteristics are extremely similar to those of natural cancellous bone. The average compressive yield strength of the porous Ta coatings ranges from 5.8 to 24. 2 MPa. And the average compressive elastic modulus of porous Ta coatings (0.6–1.5 GPa) was close to that of cancellous bone. Corrosion resistance tests proved that the Ta-coated Ti-6Al-4 V alloy had an excellent chemical stability in simulated body fluid. In vitro tests showed that Mouse calvarial preosteoblasts presented a good adhesion and growth behavior on porous Ta coatings. Therefore, it is preliminarily determined that the customized porous-Ta/Ti-6Al-4 V component by Laser powder bed fusion can be a candidate material for orthopedic implantation. • A novel high-interface-strength porous Ta/Ti6Al4V component was successfully manufactured using Laser Powder Bed Fusion. • The mechanical properties of the component met the requirements of ideal orthopedic implant materials. • The component had a good chemical stability and an excellent biocompatibility in simulated body fluid.

Osteoinduction Evaluation of Fluorinated Hydroxyapatite and Tantalum Composite Coatings on Magnesium Alloys.

Magnesium (Mg) alloys have a wide range of biomaterial applications, but their lack of biocompatibility and osteoinduction property impedes osteointegration. In order to enhance the bioactivity of Mg alloy, a composite coating of fluorinated hydroxyapatite (FHA) and tantalum (Ta) was first developed on the surface of the alloy through thermal synthesis and magnetron sputtering technologies in this study. The samples were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS) mapping, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and water contact angle measurement (WCA), which characterized the surface alternation and confirmed the deposition of the target FHA/Ta coating. The results of cell morphology showed that the MC3T3-E1 cells on the surface of Mg/FHA/Ta samples had the largest spreading area and lamellipodia. Moreover, the FHA coating endowed the surface with superior cell viability and osteogenic properties, while Ta coating played a more important role in osteogenic differentiation. Therefore, the combination of FHA and Ta coatings could synergistically promote biological functions, thus providing a novel strategy for implant design.