Production of Metallic Titanium by Electrowinning in Molten Salts of Titanium Oxycarbide Anode

The electrochemical behavior of Ti3+ in LiCl-LiF-TiF3 salt was investigated by cyclic and square wave voltammetries at 853 K. Both methods confirm the presence of a single reduction wave of Ti3+ ions to metal, at a potential of −2.3 V vs. Cl2/Cl−. The closeness of the potentials of TiCxOy dissolution and Ti3+/Ti4+ wave is an issue during the electrorefining of the anode. A low current density has to be applied to stay within the titanium oxycarbide dissolution and avoid the formation of Ti4+. The titanium deposition was studied by electrorefining of a titanium metal plate in LiCl-LiF-TiF3 (0.62 mol/kg). The cathodic deposit analysis by XRD and SEM confirms the formation of titanium metal with an average grain size of 150 µm. The faradic deposition yields are above 85% and constant between 60 and 160 mA/cm2.

Finite Element Analysis of the Effect of Dental Implants on Jaw Bone under Mechanical and Thermal Loading Conditions

Dental implants have been studied over the years to replace missing teeth. One of the conditions for the success of implants is their stability and resistance under the applied forces and minimal tension in the surrounding bone. The purpose of this dissertation is numerical and three-dimensional analysis of jaws with implants under mechanical and thermal loading by the finite element method. For this purpose, implant simulations (including ceramic crown, titanium root, and jaw bone) under dynamic and thermal load have been performed in Abacus software. In this simulation, it is considered that the jawbone is composed of two areas, one area is the superficial bone tissue (cortical) and the other part is the spongy tissue. Implants are usually made of different metals or ceramics with a bone-like structure that are compatible with body tissues. Implants are currently made of titanium metal. Therefore, titanium metal has been used for modeling implants in this dissertation. The implant crown is also considered as a ceramic material. In the simulation, the effect of stresses imposed by the implant on the jawbone is performed. In this simulation, mechanical force is applied to the upper part of the implant and force enters the jawbone through the implant, which causes tension at the junction of the implant to the jawbone. To investigate the effect of thermal loads, different temperature conditions are considered by considering the decrease in temperature and increase in temperature on the tooth surface and its effect on the implant and the jaw bone. After validation and ensuring the accuracy of the modeling, it has been observed that, with increasing mechanical load, the stresses created in all parts of the ceramic coating, titanium implants, and jawbone have increased. It is also observed that the stress created in the titanium implant due to the application of negative heat flux was about twice as much as the stress created due to the application of positive heat flux.

Effect of Argon-Based Atmospheric Pressure Plasma Treatment on Hard Tissue Formation on Titanium Surface

In this paper, we suggest that the atmospheric pressure plasma treatment of pure titanium metal may be useful for improving the ability of rat bone marrow cells (RBMCs) to induce hard tissue differentiation. Previous studies have reported that the use of argon gas induces a higher degree of hard tissue formation. Therefore, this study compares the effects of plasma treatment with argon gas on the initial adhesion ability and hard tissue differentiation-inducing ability of RBMCs. A commercially available titanium metal plate was used as the experimental material. A plate polished using water-resistant abrasive paper #1500 was used as the control, and a plate irradiated with argon mixed with atmospheric pressure plasma was used as the experimental plate. No structural change was observed on the surface of the titanium metal plate in the scanning electron microscopy results, and no change in the surface roughness was observed via scanning probe microscopy. X-ray photoelectron spectroscopy showed a decrease in the carbon peak and the formation of hydroxide in the experimental group. In the distilled water drop test, a significant decrease in the contact angle was observed for the experimental group, and the results indicated superhydrophilicity. Furthermore, the bovine serum albumin adsorption, initial adhesion of RBMCs, alkaline phosphatase activity, calcium deposition, and genetic marker expression of rat bone marrow cells were higher in the experimental group than those in the control group at all time points. Rat distal femur model are used as in vivo model. Additionally, microcomputed tomography analysis showed significantly higher results for the experimental group, indicating a large amount of the formed hard tissue. Histopathological evaluation also confirmed the presence of a prominent newly formed bone seen in the images of the experimental group. These results indicate that the atmospheric pressure plasma treatment with argon gas imparts superhydrophilicity, without changing the properties of the pure titanium plate surface. It was also clarified that it affects the initial adhesion of bone marrow cells and the induction of hard tissue differentiation.