Biocompatible functional surface of titanium-based implant materials

Metallic biomaterials, such as stainless steels, cobalt–chromium–molybdenum (Co–Cr–Mo) alloys, and titanium (Ti) alloys, have long been used as load-bearing implant materials due to their metallic mechanical strength, corrosion resistance, and biocompatibility. However, their magnetic susceptibility and elastic modulus of more than 100 GPa significantly restrict their therapeutic applicability. In this study, spinodal Zr60Nb40, Zr50Nb50, and Zr40Nb60 (at.%) alloys were selected from the miscibility gap based on the Zr–Nb binary phase diagram and prepared by casting, cold rolling, and aging. Their microstructure, mechanical properties, corrosion resistance, magnetic susceptibility, and biocompatibility were systematically evaluated. Spinodal decomposition to alternating nanoscale Zr-rich β1 and Nb-rich β2 phases occurred in the cold-rolled Zr–Nb alloys during aging treatment at 650 °C. In addition, a minor amount of α phase was precipitated in Zr60Nb40 due to the thermodynamic instability of the Zr-rich β1 phase. Spinodal decomposition significantly improved the mechanical strength of the alloys due to nanosized dual-cubic reinforcement. The Zr–Nb alloys showed an electrochemical corrosion rate of 94–262 nm per year in Hanks’ solution because of formation of dense passive films composed of ZrO2 and Nb2O5 during the polarization process. The magnetic susceptibilities of the Zr–Nb alloys were significantly lower than those of commercial Co–Cr–Mo and Ti alloys. The cell viability of the Zr–Nb alloys was more than 98 % toward MC3T3-E1 cells. Overall, the spinodal Zr–Nb alloys have enormous potential as bone-implant materials due to their outstanding overall mechanical properties, extraordinary corrosion resistance, low magnetic susceptibility, and sufficient bicompatibility. Statement of significanceThis work reports on spinodal Zr–Nb alloys with heterostructure. Spinodal decomposition significantly improved their mechanical strength due to the nanosized dual-cubic reinforcement. The Zr–Nb alloys showed large corrosion resistance in Hanks’ solution because of formation of dense passivation films composed of ZrO2 and Nb2O5 during the polarization process. The magnetic susceptibilities of the Zr–Nb alloys were significantly lower than those of commercial Co–Cr–Mo and Ti alloys. The cell viability of the Zr–Nb alloys was more than 98 % toward MC3T3-E1 cells. The results demonstrate that spinodal Zr–Nb alloys have enormous potential as bone-implant materials due to their outstanding overall mechanical properties, high corrosion resistance, low magnetic susceptibility, and sufficient biocompatibility.

Medium-entropy Zr–Nb–Ti (ZNT) alloys are being extensively investigated as load-bearing implant materials because of their exceptional biocompatibility and corrosion resistance, and low magnetic susceptibility. Nevertheless, enhancing their yield strength while simultaneously decreasing their elastic modulus presents a formidable obstacle, significantly constraining their broader utilization as metallic biomaterials. In this study, three medium-entropy ZNT alloys, i.e., Zr45Nb45Ti10, Zr42.5Nb42.5Ti15, and Zr40Nb40Ti20 (denoted ZNT10, ZNT15, and ZNT20, respectively), were designed based on the miscibility gap in the ZNT phase diagram and prepared by annealing of cold-rolled ingots. Their microstructures, mechanical properties, wear resistance, corrosion resistance, magnetic susceptibility, and biocompatibility were systematically studied. Spinodal decomposition occurred in the cold-rolled ZNT10 and ZNTi15 after annealing at 650 °C for 2 h and resulted in nanoscale Zr-rich β1 and (Nb, Ti)-rich β2 phases, which significantly improved their yield strength and reduced their elastic modulus. The wear resistance of the alloys decreased with an increase in Ti content. Dense ZrO2, Nb2O5, and TiO2 oxide layers were formed during the polarization process in Hanks’ solution, which enhanced the corrosion resistance of the alloys. These ZNT alloys exhibited significantly lower magnetic susceptibility than medical Ti alloys. The ZNT alloys showed a cell viability of more than 94 % toward MG-63 cells after culturing for 3 d Overall, the spinodal ZNT15 showed the best combination of mechanical properties, wear resistance, corrosion resistance, low magnetic susceptibility, and sufficient biocompatibility among the three alloys. Statement of significanceThis work reports on medium-entropy Zr–Nb–Ti (ZNT) alloys with heterostructure. Spinodal decomposition significantly improved their mechanical strength and reduced the elastic modulus of the alloys. The wear resistance of the ZNT alloys decreased with an increase in Ti content. Dense ZrO2, Nb2O5, and TiO2 oxide layers were formed during the polarization process in Hanks’ solution, which enhanced the corrosion resistance of the alloys. The ZNT alloys exhibited significantly lower magnetic susceptibility than medical Ti alloys. The ZNT alloys showed a cell viability of >94 % toward MG-63 cells after culturing for 3 d The results demonstrate that spinodal ZNT alloys have enormous potential as bone-implant materials due to their outstanding overall mechanical properties, high corrosion resistance, wear resistance, low magnetic susceptibility, and sufficient biocompatibility.

Effect of alloying content on high cycle fatigue behaviour of CuTi alloys

At global level, there is a continuing concern for the research and development of alloys for medical and biomedical applications. Metallic biomaterials are used in various applications of the most important medical fields like orthopedic, dental and cardiovascular. The main metallic biomaterials used in human body are stainless steels, Co-based alloys and Ti-based alloys. Titanium and its alloys are of greater interest in medical applications because they exhibit characteristics required for implant materials, namely, good mechanical properties (less elasticity modulus than stainless steel or CoCr alloys, fatigue strength, high corrosion resistance), high biocompatibility. The aim of this review is to describe and compare the main characteristics (mechanical properties, corrosion resistance and biocompatibility) for latest research of nontoxic Ti alloys biomaterials used for medical field.

An ideal biomaterial is expected to exhibit properties such as a very high biocompatibility, that is, no adverse tissue response. Also, it must have a density as low as that of bone, high mechanical strength and fatigue resistance, low elastic modulus and good wear resistance. It is very difficult to combine all these properties in only one material. Some metals are used as biomaterials due to their excellent mechanical properties and good biocompatibility. Since the metallic bonds in these materials are essentially non-directional, the position of the metals ions can be altered without destroying the crystal structure, resulting in a plastically deformable solid. This is also an advantage when thinking about the device manufacture technology. The principal disadvantage of metals is its corrosion tendency in an in-vivo environment. Most metals can only be tolerated by the human body in small amounts even as metallic ions. The consequences of corrosion are the disintegration of the material implant, which will weaken the implant and the harmful effect of corrosion products on the surrounding tissues and organs. Some metals are used as passive substitutes for hard tissue replacement such as total hip and knee joints, for fracture healing aids as bone plates and screws, spinal fixation devices and dental implants. Some metallic alloys are used for more active roles, as actuators such as vascular stents, and orthodontic archwires. Metallic biomaterials can be conveniently grouped in the following categories:  Stainless steel  Cobalt base alloys  Titanium base alloys  Specialty metallic alloys Examples of ASTM standards for some of these metallic biomaterials are shown in Table 1. The first metal alloy developed specifically for human use was the “vanadium steel” but it was no longer used in implants because its corrosion resistance is inadequate in vivo. Later in the 1950s, 18-8sMo with very low carbon content (known as 316L) stainless steel was introduced and is actually widely used for implant fabrication. This alloy has a very good resistance to chloride solutions and poor sensitization. The castable CoCrMo alloy has been used for many decades in dentistry and, relatively recently, in making artificial joints. The wrought CoNiCrMo alloy is relatively new, now used for making the stems of prostheses for heavily loaded joints such as the knee and hip. Both alloys have excellent corrosion resistance.

Background:Titanium has long been the preferred material for oral rehabilitation due to its excellent mechanical properties and biocompatibility. However, despite its widespread clinical success, implant failures remain a significant concern, primarily due to peri-implant diseases. Studies indicate that over 56% of implants experience complications over time, highlighting the need for improved materials or treatment strategies. While surface modifications to enhance osseointegration by creating bioactive surfaces have shown promise, there remains a need to improve the antimicrobial properties of implant materials. This study explores a novel approach of coating platinum onto the titanium nanotube arrays leveraging its inherent antimicrobial properties, to enhance both biological performance and corrosion resistance. Materials and Methods:Titanium surfaces were anodized to fabricate platinum-doped TNA on titanium alloys, aimed at promoting bioactivity and improving osseointegration. Platinum, known for its antimicrobial and antioxidant properties, was sputtered onto the nanotubes to further support healing and reduce microbial colonization. Surface morphology was analyzed using scanning electron microscopy (SEM), and electrochemical tests were conducted to assess corrosion resistance. Biomineralization potential was evaluated by immersing the samples in Dulbecco's Modified Eagle Medium (DMEM) with fetal bovine serum (FBS) for seven days. ATR-IR spectroscopy was used to confirm the formation of biomimetic structures. Results:SEM images revealed uniformly aligned platinum-doped nanotubes with partial coverage by platinum nanospheres. Corrosion resistance tests demonstrated enhanced stability of the platinum-coated TNA. Immersion studies showed a flower-like biomimetic morphology resembling water lettuce, confirmed by ATR-IR spectroscopy to be formedby proteins and calcium phosphate molecules. Conclusion:In conclusion, platinum-coated titanium nanotube arrays (TNA) enhance antimicrobial properties and corrosion resistance, improving implant performance. This innovative approach offers potential for reduced microbial colonization and better osseointegration, providing a promising solution to reduce implant failures and improve long-term outcomes in oral rehabilitation. Further clinical research is needed.

Mg alloys, such as AZ91 (Mg-9mass%Al-1mass%Zn), are lightweight materials with excellent mechanical properties. The applications of Mg alloys in automobiles could significantly contribute to reducing carbon dioxide emissions. Mg alloys are fully recyclable and abundantly available, which increases their desirability in light of rising environmental consciousness. However, the low corrosion resistance of Mg alloys is one of the major limitations to further applications.In Mg alloys, corrosion behavior is known to be related to the microstructure. During the real-time in situ observation of the corrosion process under galvanostatic polarization, filiform corrosion proceeded along the outside of the β phase (in lamellar α + β microstructure and along the α-mother phase 1. Furthermore, the β phase exhibited a higher potential in the OCPs of each phase and a small area with the boundary in 0.1 M NaCl at pH 8.0 2. Thus, the surface films of β phases was thought to suppress the corrosion of Mg alloys. Mg alloys can be treated by anodic oxidation or plasma electrolytic oxidation to obtain excellent corrosion resistance. The latter is similar to anodic oxidation but applies a higher voltage, which causes a discharge on the electrode surface and the resulting plasma modifies the oxide film significantly.In this study, anodic oxidation and plasma electrolytic oxidation were performed on AZ91D Mg alloy in alkaline solutions such as sodium phosphate. This study aims to compare the two methods in the same solution and to produce an Al-rich surface film with excellent corrosion resistance.In anodic oxidation, the size of the electrode area was approximately 1 cm2. The surface of the specimen was coated with epoxy resin, followed by paraffin. The reference electrode was Ag / AgCl (3.33 M KCl). The experiments were performed at 25 ℃. The scan rate of potentiodynamic polarization was set at 23 mV min-1. The starting potential was set at 20 mV lower than the open-circuit potential. The anodic oxidation treatments were terminated at 0 V, 3 V, and 5 V. Plasma electrolytic oxidation was performed with a liquid volume of 500 mL. The sample was mounted on a resin holder. The electrode surface was approximately 50 mm2. A Pt plate was used as the counter electrode. The sample and the counter electrode were fixed at a distance of 0.5 cm. A plasma-generating power supply was used. The solution was cooled down to 20 ℃ while the voltage was applied. The frequency and the pulse interval were adjusted. The voltage and type of solution were changed to produce the film. Z. Shao, M. Nishimoto, I. Muto, and Y. Sugawara, Corrosion Science, 192, 109834 (2021).Z. Shao, M. Nishimoto, I. Muto, and Y. Sugawara, Journal of Magnesium and Alloys, 11, 137-153 (2023).

One of the major problems associated with the use of metallic biomaterials is their corrosion. Corrosion reactions, which are unavoidable in metals, cause not only deterioration or fracture of the products but also serious harm to living tissue. Nevertheless, metallic biomaterials are commonly used in the fields of medicine and dentistry because of their superior mechanical properties: an excellent combination of strength and ductility, resulting in high fracture toughness can not be substituted by other materials. Therefore, highly corrosion-resistant metals and alloys such as Ti, Ti alloys, Co-Cr alloys, and stainless steels are used for implant devices. All of them show superior corrosion resistance results from the formation of a passive film on the surface of the metal. However, very small quantities of the metallic ions actually dissolve through the passive film on these metallic biomaterials. There are already many literatures about the corrosion resistance of metallic biomaterials about the breakdown of the passive film. However, only limited information is available concerning the corrosion with extremely small rate accompanying metal ion release via stable passive film. Therefore, in this study, long-term measurement of in-situ electrochemical impedance spectroscopy, dissolution test, and surface analysis were performed to clear the difference in the corrosion behaviors of various metallic biomaterials.Disk shaped specimens of pure Ti (Ti), Ti-33.5Nb-5.7Ta beta-type Ti alloy (Ti-Nb-Ta), Ti-Ti-50.8mol%Ni super elastic alloy (Ti-Ni), Co-20Cr-15W-10Ni alloy (L605, ASTM F90) (Co-Cr), type 316L stainless steel (316 SS), and pure Zr (Zr) were prepared. The specimens for corrosion tests were mechanically ground to #800 grit SiC abrasive paper. The specimens for XPS were additionally polished and mirror-finished with 9 μm diamond paste and 0.04 μm colloidal silica. The specimens were then ultrasonically cleaned in acetone and ethanol. In this study, the simulated body fluid, 5.85 gL-1 NaCl and 10.0 gL-1 lactic acid, as a corrosion test solution was prepared. The pH of the solution was checked in advance and was confirmed to be within the range of 2.30 ± 0.05 just after preparation. This solution was intended to be an accelerated body fluid for rapid testing of corrosion measurements of dental metallic materials prescribed by ISO 10271. EIS measurement was performed with an electrochemical measurement system. A couple of the specimen disks were prepared and embedded in cold-mounting epoxy resin. After grinding the surface, the electrodes were immediately immersed in the test solution and placed face-to-face at a constant distance. EIS measurement was started with an alternative potential of 10 mV in amplitude just 10 min after immersion. The measurement was continued for at least 48 h. For Ti-Nb-Ta, the measurement was further extended and continued for up to 28 d. The dissolution test was performed to evaluate the corrosion rate and amounts of the released metal ions during the immersion in the test solution. Twenty mL of the test solution was then put into the glass bottle, followed by the specimen. The bottle was completely sealed and kept for 7 d. The concentrations of the metal ions were measured with ICP-AES.After the measurement of EIS, curve fittings could be performed using conventional equivalent circuit models. The corrosion rates of all specimens decreased during the immersion period. However, the declines in the corrosion rates of Co-Cr and Zr were much larger than those of Ti, Ti-Nb-Ta, Ti-Ni, and 316 SS. It means that the growth rate of the passive film of each alloy showed much different tendency in initial period. From the result of the dissolution test, it was found that the amounts of the released ions from 316L were much higher than those of another specimens. Ti-Ni released certain amount of Ni ions which are very hazardous for metal allergy. On the other hand, the amounts of the ions from Co-Cr and Zr were almost same level as detection limit of ICP-AES. It indicates that the protective performances against mass transfer via the passive films of Co-Cr and Zr are superior to those of other biomaterials. From the long-term EIS measurement of Ti-Nb-Ta, the maturation of the passive film originated from both film growth and compositional change was observed. The corrosion inhibition effects of Nb and Ta in Ti alloy was confirmed by long-term EIS measurement. Therefore, this technique provides a useful diagnostic of the long-term biosafety of metallic biomaterials, which are required to have an extremely higher level of corrosion resistance.

Titanium (Ti) alloys are widely utilized in orthopedics owing to their excellent mechanical properties and biocompatibility. To improve their resistance to corrosion and ion release properties, substrates of Ti alloy have been produced employing powder metallurgy by adding alloying elements (Si and Nb) at 5 wt% along with CP-Ti. Two torch flame sprays have been utilized for coating the Ti-5Nb and Ti-5Si alloys with two kinds of nanocoating: HAp+25%SiC (type-A) and ZSM5 + 25%ZrO2 (type-B). These nanocoating combinations represented bioactive and bioinert to combine the biological and mechanical properties of the implant surface. Different tests and characterization techniques have been carried out, including SEM, XRD, AFM, AAS, hardness, adhesion strength, and corrosion resistance. The results manifested that the coatings (types A and B) improved the properties of Ti alloys; however, ZSM5 + 25%ZrO2 has better properties than type-A in terms of less porosity, higher crystallinity%, higher hardness, higher adhesion strength, lower corrosion rate, and less Ti ions release. Comparing the results of the two Ti alloys, Ti-5Si has higher hardness, corrosion resistance, and less ionic release than the Ti-5Nb alloy. Hence, the Ti-5Si coated by ZSM5 + 25%ZrO2 (B coated Ti-5Si) is the best sample in this study.

Titanium alloys (Ti−6Al−4V) are being used in many biomedical applications due to their unique properties of bioactivity, excellent mechanical properties, low toxicity, biocompatibility, and long‐term implant application for their satisfactory corrosion resistance. We have developed a new two‐step fabrication process of zirconium oxide (ZrO 2 ) and Chitosan/Mg−Zn−HAP (Chitosan/M−HAP) bilayer layer coating on Ti alloy for biomedical applications. Flower‐structured bilayers were coated by the electrochemical deposition method. Electrochemically deposited bilayer‐coated Ti alloy specimens were characterized by various analytical techniques like field‐emission scanning electron microscope (FE‐SEM), X‐ray diffraction (XRD), and EDS mapping analysis. Furthermore, the developed bilayer (Chitosan/Mg−Zn−HAP/ZrO 2 ) coated Ti alloy samples improved mechanical properties such as adhesion strength (20.1±0.4 MPa) and hardness (446±4 Hv), compared to other coatings. An investigation of polarization curves showed a positive shift in the polarization values (E corr , and I corr ) of the Chitosan/M−HAP/ZrO 2 bilayer coatings on Ti alloy. Bilayer‐modified Ti alloy samples show good antimicrobial response toward Gram‐negative and Gram‐positive bacteria. Meanwhile, the cell viability and proliferation of the bilayer‐coated samples were evaluated and the exhibited result improved cell proliferation, and bioactivity compared to other coated materials. From the results, it can be evident that the developed Chitosan/Mg−Zn−HAP/ZrO 2 bilayer‐coated Ti alloy could be a good potential candidate for biomedical applications.

3.4 - 3D-printed titanium alloys for orthopedic applications

Metallic biomaterials are widely used in the orthopedic and dental applications owing to their advanced biocompatibility and sophisticated mechanical properties. Many studies are carried out to develop new alloys with high specific strength, high corrosion resistance and high biocompatibility as an alternative to present metallic biomaterials. Mg alloys are potential alloys as a biomaterial, especially because they have low density and high biocompatibility. However, especially the corrosion properties of Mg alloys need to be improved. In this study, the surfaces of AZ31, AZ61 and AZ91 alloys, which are promising as biomaterials, were coated with hydroxyapatite with high biocompatibility, and the effects of the bioceramics coatings on corrosion resistance were comprehensively investigated. Crack-free and porous surface morphologies were obtained in all bioceramic coatings and the presence of the coatings on the surfaces was supported by EDS analysis. As a result of the corrosion tests performed in SBF, it was determined that the AZ91 alloy had the highest corrosion resistance among the uncoated samples. The hydroxyapatite bioceramic coatings also improved the corrosion properties of all samples. However, among all samples, the highest corrosion resistance was obtained in the hydroxyapatite coated AZ91 alloy.

Laser-based fabrication of superwetting titanium alloy with enhanced corrosion and erosion-corrosion resistance

[Introduction] One of the major problems associated with the use of metallic biomaterials is their corrosion. Corrosion reactions, which are unavoidable in metals, cause not only deterioration or fracture of the products but also serious harm to living tissue. Nevertheless, metallic biomaterials are commonly used in the fields of medicine and dentistry because of their superior mechanical properties: an excellent combination of strength and ductility, resulting in high fracture toughness can not be substituted by other materials. Therefore, highly corrosion-resistant metals and alloys such as Ti, Ti alloys, Co-Cr alloys, and stainless steels are used for implant devices. All of them show superior corrosion resistance results from the formation of a passive film on the surface of the metal. However, very small quantities of the metallic ions actually dissolve through the passive film on these metallic biomaterials. There are already many literatures about the corrosion resistance of metallic biomaterials about the breakdown of the passive film. However, very limited information is available concerning the corrosion rate and the change in the amount of the released metallic ions as a result of the slight corrosion reaction with stable passive film. Therefore, in this study, several corrosion tests and surface analyses were performed in a simulated body fluid to clear the difference in the corrosion behaviors of various metallic biomaterials. [Materials and Method] Disk shaped specimens of pure Ti, Ti-50.8mol%Ni superelastic alloy (Ti-Ni), Co-20Cr-15W-10Ni alloy (L605, Co-Cr), type 316L stainless steel (316 SS), and pure Zr were prepared. The specimens for corrosion tests were mechanically ground to #800 grit SiC abrasive paper. The specimens for XPS were additionally polished and mirror-finished with 9 μm diamond paste and 0.04 μm colloidal silica. The specimens were then ultrasonically cleaned in acetone and ethanol. In this study, the simulated body fluid, 5.85 gL-1 NaCl and 10.0 gL-1lactic acid, as a corrosion test solution was prepared. The pH of the solution was checked in advance and was confirmed to be within the range of 2.30 ± 0.05 just after preparation. This solution was intended to be an accelerated body fluid for rapid testing of corrosion measurements of dental metallic materials prescribed by ISO 10271. An anodic polarization measurement was performed with a potentiostat and a function generator. A saturated calomel electrode (SCE) and a Pt-black electrode were used as a reference and a counter electrode, respectively. The surface area of the working electrode contacting the electrolyte was 0.38 cm2. After immersing the specimens into the test solution at 37°C, the open circuit potential (OCP) was measured for 10 min. Thereafter, the gradient anodic potential was applied at a constant sweep rate of 1 mVs-1from OCP. EIS measurement was performed with an electrochemical measurement system. A couple of the specimen disks were prepared and embedded in cold mounting epoxy resin. After grinding the surface, the electrodes were immediately immersed in the test solution and placed face-to-face at a constant distance. EIS measurement was started with an alternative potential of 10 mV in amplitude just 10 min after immersion. The measurement was continued for 48 h. The dissolution test was performed to evaluate the corrosion rate and amounts of the released metal ions during the immersion in the test solution. Twenty mL of the test solution was then put into the glass bottle, followed by the specimen. The bottle was completely sealed and kept for 7 d. The concentrations of the metal ions were measured with ICP-AES. [Results and Discussion] The polarization curves of all specimens except 316L SS showed clear passive region. Ti-Ni and Co-Cr showed transpassive region from 1.3 and 0.8 VSCE, respectively. Zr occurred pitting corrosion at 0.5 VSCE. On the other hand, 316L SS did not passivate and actively dissolved in the test solution. The amounts of the released ions from 316L were much higher than those of another specimens. However, Ti-Ni released certain amount of Ni ions, which are very hazardous for metal allergy. On the other hand, the amounts of the ions from Co-Cr and Zr were almost same level as detection limit of ICP-AES. It indicates that the protective performances against mass transfer of Co-Cr and Zr are superior to those of other biomaterials. Curve fittings could be performed using a conventional equivalent circuit models. The corrosion rates of all specimens decreased during the immersion period. However, the declines in the corrosion rates of Co-Cr and Zr were much larger than those of Ti, Ti-Ni, and 316 SS. It agrees with the results from the dissolution test.

In this chapter, a novel titanium (Ti) alloy and foam suitable for biomedical applications will be introduced. As we know, Ti and its alloys are widely used as biomaterials especially for orthopedic implants in load bearing sites as dental and orthopedic implants and heart valves, due to their high mechanical properties, corrosion resistance and biocompatibility (Geetha et al., 2009). Pure Ti was once used as biomaterial, but its disadvantage as implant materials is low strength and insufficient hardness. Therefore, the Ti6Al4V alloy is preferentially in clinical use because of its favourable mechanical properties. However, some studies showed that the vanadium (V) and aluminium (Al) release in Ti6Al4V alloy could induce Alzheimer’s disease, allergic reaction and neurological disorders (Mark & Waqar, 2007). Therefore, the exploration of high strength new Ti alloys without Al and V for medical implants has gained great attention in the past years and it is still ongoing. Al and V free alloys containing non-toxic elements such as iron (Fe), niobium (Nb), zirconium (Zr), tantalum (Ta), molybdenum (Mo), nickel (Ni), gold (Au), or silicon (Si), etc. were investigated (Zhang, Weidmann et al, 2010). As long-term load-bearing implants in clinic, the incorporation of porous structures into the Ti and its alloys could lead to a reliable anchoring of host tissue into the porous structure, and allow mechanical interlocking between bone and implant (Li et al, 2005). The porous structure is preferable for Ti and its alloys used as bone implants. Many techniques have been applied to produce Ti foams in recent years. Nevertheless, there are still problems to be solved in the field of Ti foams for biomedical applications (Zhang, Otterstein et al., 2010): the difficulty to create controlled porosity and pore sizes, the insufficient knowledge of porous structure-property relationships, the requirements of new sintering techniques with rapid energy transfer and less energy consumption and so on. The Ti alloys and foams are difficult to be produced from the liquid state due to high melting point, high reactive activity at high temperature above 1000 oC and contamination susceptibility. The production of Ti alloys and foams via a powder metallurgy (PM) route is attractive due to the ability to produce net-shaped components. Because of their stable