Evaluation of Surface Roughness of Some Biomedical Titanium Alloys by Pack Cementation Coating

Titanium possesses a unique ability to bind with bone and living tissue, making it an ideal material for orthopedic implants such as knee and hip replacements. Because of the strength to weight ratio, hermeticity, biocompatibility and light weight makes titanium and its alloy the best choice for implant. The main goal focused on studying the influence of surface coating of some titanium base alloys by Nano (ZrO2&Y2O3) to the surface roughness of implant alloys. Preparation of samples was accomplished by using powder technology technique, in which the raw materials was pure titanium, 10%cobalt,50% nickel, and 30% tantalum powders. The samples were cleaned by ultrasonic device the surface pre- treated by chemical etching, then deposition of nano (ZrO2 with Y2O3) accomplished by pack cementation process. After samples characterization by (X-ray diffraction, hardness test, porosity percentage and Surface roughness). The result showed that diffraction patterns gained for the samples were the phases developed as a result of sintering and after deposition, There are likely no presents of pure metals that prove the time and temperature of sintering utilized in this work results in full sintering reactions, the XRD patterns of samples after (ZrO2,Y2O3) deposition by pack cementation process. It is obvious that Amorphous behavior was observed in the XRD after deposition nearly at 2θ (15.799) for all samples. It is evident that the porosity percent of the samples after (ZrO2, Y2O3) deposition was largely decreases due to the pack cementation process. There was considerable increasing in hardness value, finally the roughness values obtained from the AFM it was found that there are large changes in the roughness value of samples after coating due to full the surface by Nano ceramic material deposition.

A Combined Scientometric and Critical Approach in Reviewing TiZr Implant Alloys and Coating Performances

This review article was developed based on the scientometric analysis of the evaluated studies conducted on titanium−zirconium (TixZr) alloys from 2000 to the present. The scientometric data obtained helped us to identify the most researched topics and these topics were further analyzed and discussed. An increasing number of researchers are considering TixZr alloys as opposed to the traditional ones because these alloys present improved mechanical properties and in some cases improved corrosion resistance and biocompatibility. Due to the natural layer of oxides formed on these alloys, multiple surface modification methods can be applied to solve some of the challenges faced in the field of implantable materials. A significant number of studies are now focusing on surface modifications at the nanometer scale or various coatings for improved corrosion resistance and biological interactions. Although not yet commercially available, a TiZr alloy with a nanostructured surface and embedded biologically active substances, such as antibiotics or coated with hydroxyapatite, may become a future option.

Surface treatment on cobalt and titanium alloys using picosecond laser pulses in burst mode

The authors report on the results of surface treatment experiments using a solid-state amplified laser source emitting laser pulses with a pulse duration of 10 ps. The laser source allows the generation of pulse trains (bursts) with an intra-burst pulse repetition rate of 80 MHz (pulse-to-pulse time interval about 12.5 ns) with up to eight pulses per burst. In this study a wavelength of 1064 nm was used to investigate both ablation of material and laser-induced surface modifications occuring in metallic implant alloys CoCrMo (cobalt-chromium-molybdenum) and TiAlV (titanium-aluminum-vanadium) in dependence of the number of pulses and fluences per pulse in the burst. By using the burst mode, a smoothing effect occurs in a certain parameter range, resulting in very low surface roughness of the generated microstructures. It is demonstrated that at fluences per pulse which are smaller than the material-specific ablation threshold, a self-organized pore formation takes place if a defined number of pulses per burst is used. Thus, the advantage of the MHz burst mode in terms of a possible surface modification is established.

Perspective on “Corrosion and Passivity of Ti-13% Nb-13% Zr in Comparison to Other Biomedical Implant Alloys,” S.Y. Yu, J.R. Scully, Corrosion 53, 12 (1997): p. 965-976

Corrosion of biomedical implants is a risk for safe applications of metals for healing in the body. Therefore, for implants that are designed to be permanent (in contrast to biodegradable implants), highly corrosion resistant metals and alloys are used—most notably titanium and its alloys. This perspective discusses a paper that reported on the corrosion behavior of a number of Ti-based implant alloys, from a viewpoint of materials science and a detailed mechanistic understanding of passivity.

Elementary characterization of Ti metal alloys used in implant dentistry

The main goal of present work is analytical characterization of standard dental implants broadly used by Brazilian dentists. An ideal biological alloy for dental implants must have very high biocompatibility, which means that such material should not provoke any serious adverse tissue response. Dental implants are generally marketed as commercially pure titanium (TiCP) due to their excellent mechanical and physical properties. However, sometimes other alloys are employed and consequently it is essential to study the chemical elements present in those alloys that could bring prejudice for the health. Present work investigated TiCP metal alloys used for dental implant manufacturing and evaluated the presence of elements. For alloy characterization and identification of elements it was used EDXRF technique. This method allows to perform the qualitative and quantitative analysis of the materials using the spectra of the characteristic X-rays emitted by the elements present in the metal samples. The experimental setup was based on two X- ray tubes, Mini X model with Ag and Au targets and X-123SDD detector (AMPTEK) and a 0.5 mm Cu collimator, developed due to specific sample geometrical and topography characteristics. Obtained results showed that implant alloys are not exactly TiCP but were manufactured using Ti-Al-V alloy, which contained Fe, Ni, Cu and Zn. The presence of such metals as Al and V in all studied samples shows very clear that studied implants were not manufactured from TiCP alloy. Moreover, according to the American Society for Testing and Materials (ASTM), these elements should not be present in TiCP.

Effects of thermomechanical history and environment on the fatigue behavior of (β)-Ti-Nb implant alloys

This study examined the fatigue properties of a newly developed cast and thermomechanical processed (β)-Ti-40Nb alloy for a possible application as biomedical alloy due to exceptional low Young’s modulus (64-73 GPa), high corrosion resistance and ductility (20-26%). Focusing on the influence of two microstructural states with fully recrystallized β-grain structure as well as an aged condition with nanometer-sized ω-precipitates, tension-compression fatigue tests (R=-1) were carried out under lab-air and showed significant differences depending on the β-phase stability under cyclic loading. Present ω- precipitates stabilized the β-phase against martensitic α’’ phase transformations leading to an increased fatigue limit of 288 MPa compared to the recrystallized state (225 MPa), where mechanical polishing and subsequent cyclic loading led to formation of α’’-phase due to the metastability of the β-phase. Additional studied commercially available (β)-Ti-45Nb alloy revealed slightly higher fatigue strength (300 MPa) and suggest a change in the dominating cyclic deformation mechanisms according to the sensitive dependence on the Nb-content. Further tests in simulated body fluid (SBF) at 37°C showed no decrease in fatigue strength due to the effect of corrosion and prove the excellent corrosion fatigue resistance of this alloy type under given test conditions.