Microstructure, mechanical strength, chemical resistance, and antibacterial behavior of Ti-5Cu-x%Nb biomedical alloy

Development of Ti-10Nb alloy by powder metallurgy processing route for dental application

Titanium and its alloys are used to make dental implants because of its low density, high strength, and corrosion resistance. This paper describes the development of a potential biomaterial Ti-10Nb by powder metallurgy utilizing four different compaction pressures and analyses its microstructural, physical, mechanical, electrochemical, biological, and tribological behavior under various situations. The alloys were fabricated using four different compaction pressures, that is, 600, 650, 700, and 750 MPa, and sintered in a vacuum atmosphere at 1000°C for 1.5 h. The density of the samples was measured using Archimedes principle. X-ray diffraction and scanning electron microscopy equipped with energy dispersive spectroscopy were used to investigate the phase composition and microstructure, and a profilometer was used to examine the surface roughness of various samples. Vickers hardness tester was used to evaluate hardness, and a universal testing machine was used for compression testing. Corrosion and wear behavior were examined using a potentiostat and a Bio-Tribometer, respectively. This Ti-10Nb alloys consist of α + β phase, and have 16% highest porosity in sample compacted at 600 MPa. The samples compacted at 750 MPa achieved highest hardness, yield strength, compressive strength, and elastic modulus of 450 ± 29.72 HV, 718.22 ± 16.37 MPa, 1543.59 ± 24.37 MPa, and 41.27 ± 3.29 GPa, respectively. In addition, it also possesses highest corrosion and wear resistance with lowest icorr of 0.3954 ± 0.008 μA/cm2 and wear volume of (31.25 ± 0.206) × 10-3  mm3 . These results indicate that the developed alloys have a variety of desirable properties, including high hardness, adequate compressive strength, good corrosion and wear resistance, apatite-forming capability, and a low elastic modulus, which is advantageous for avoiding stress shielding. Therefore, it may be recommended to use it as a dental implant material.

Corrosion and wear behavior of Ti-5Cu-xNb biomedical alloy in simulated body fluid for dental implant applications

The present study examined the corrosion and tribological behavior of novel Ti-5Cu-xNb alloy synthesized via powder metallurgy as a new biomedical material in a simulated bodily fluid (SBF) solution. The electrochemical impedance spectroscopy (EIS) study reveals the formation of two protective layers on the surface of alloys during the test. The alloys spontaneously produce a passivating oxide coating on their surfaces, and the breakdown potential (1.14-1.17 V) and re-passivation current density (2.07-3.04 μAcm^-2) were observed during the potentiodynamic polarization test. The highest corrosion resistance was observed for the alloy Ti-5Cu-10Nb (i_corr = 21.44 nA-cm^-2). The SEM and XPS analysis of the corroded surface showed the formation of oxide on the surfaces of the alloys. The samples were tested at 10 N, 15 N, and 20 N loads against the zirconia counterpart to investigate the effect of loading on friction and wear. The lowest coefficient of friction was obtained for Ti-5Cu-5Nb (0.25-0.41) at 20 N loading, while the maximum for Ti-5Cu-10Nb at 15 N load falls in the range of (0.71-0.25). Additionally, they present the wear rate in the range of (5.3 × 10^-8-1.45 × 10^-6 mm³/mm), in accordance with the change in microstructure and mechanical properties. However, the wear rate increases with the addition of niobium and reaches the maximum for Ti-5Cu-15Nb at 20 N loading condition, but it is relatively deficient compared to commonly used implant material. Therefore, it is suggested that this β-type Ti-5Cu-xNb alloy is a promising candidate, more suitable than the commercially used Ti and Ti-6Al-4V for dental applications.