Titanium Plasma Research Articles

Prospective Trial of Sacroiliac Joint Fusion Using 3D-Printed Triangular Titanium Implants: 5-Year Follow-Up.

Prospective, multicenter, single arm study with 5-year follow up. To report long-term (5-year) safety, effectiveness, and radiographic outcomes after sacroiliac (SI) joint fusion (SIJF) with 3D-printed triangular titanium implants (TTI) and compare them with solid titanium plasma spray coated implants. A large literature base supports minimally invasive SIJF with TTI for chronic SIJ dysfunction. SIJF with TTI was performed in 51 subjects and scheduled follow-up occurred at 3, 6, 12, 24 and 60 months. Postoperative visits included quality of life questionnaires and functional tests. A high-resolution CT scan was performed at either 6 or 12 months, and again at 60 months. All CT scans were interpreted by an independent musculoskeletal radiologist. 5-year follow-up was available in 36 of 51 subjects (71%). At 5 years, improvements in SI joint pain (58.1 points [0-100 scale]), SIJ-related disability (Oswestry Disability Index [ODI], 25.4 points) and quality of life (EuroQOL 5D, 0.24 points, and EuroQOL visual analog scale, 13.4 points) were sustained and showed no signs of diminution. The percentage of patients using opioids for SIJ pain decreased markedly from baseline (57%) to 5 years (17%). Physical function tests showed persistent improvements from baseline. There was no evidence of device breakage, migration or subsidence and few late adverse events occurred attributable to the device. Independent analysis of CT scans showed bone opposed to implants in all cases, and evidence of bone bridging in 90% of cases, and no evidence of radiolucency or other adverse bone reactions. Prospective 5-year follow-up showed that SIJ fusion using 3D-printed TTI resulted in immediate, marked, and persistent improvements in pain and quality of life, with improved physical function, reduced opioid use, and a low rate of revision surgery. Radiographic evidence showed implant integration and joint fusion. Level II.

Effect of RF acetylene plasma on the composition and dynamics of a titanium plasma plume in a plasma enhanced pulsed laser deposition system

We report the effect of radio frequency (RF) acetylene plasma on the dynamics and composition of titanium (Ti) plasma plume in a plasma-enhanced pulsed laser deposition (PEPLD) system. The titanium target, mounted inside a capacitively coupled RF discharge, was ablated by using a nanosecond Nd:YAG pulsed laser at 1064 nm with a power density of 2.65 GW/cm2. The experiments were performed at different operating pressures of acetylene. Fast imaging and optical emission spectroscopy were employed to study the physics behind the pulsed laser deposition in both (PLD) and PEPLD systems. A nonlinear dependence of the plasma plume evolution was observed over a range of pressure. Different expansion regimes correspond to the pressure of the experiments. The plume expansion velocity ranges between 6 × 103 m/s and 30 × 103 m/s. Emission spectra reveal the presence of C II and Ti II lines depending on the experimental conditions. The presence of background RF plasma leads to substantial enhancement of the emission intensity of the C II spectral lines. In addition, with increasing RF power and background pressure, the intensities of the C II spectral lines increase; whereas the intensities of the Ti II spectral lines decrease with the increase in RF power. Plasma temperature was estimated from the Ti II lines using the Boltzmann plot method, whereas the electron density was estimated from the Stark-broadened Ti II line at 454.9 nm. The calculated densities and temperatures lie between 1017–1018 cm−3 and 0.8–2.0 eV, respectively. These results show the effects of the different backgrounds (either neutral or RF plasma) on the propagation of the laser-produced plasma (LPP), which we propose to be useful in the thin film deposition process using PLD.

Characterizing Surface Morphological and Chemical Properties of Commonly Used Orthopedic Implant Materials and Determining Their Clinical Significance.

The goal of the study was to compare the surface characteristics of typical implant materials used in orthopedic surgery and traumatology, as these determine their successful biointegration. The morphological and chemical structure of Vortex plate anodized titanium from commercially pure (CP) Grade 2 Titanium (Ti2) is generally used in the following; non-cemented total hip replacement (THR) stem and cup Ti alloy (Ti6Al4V) with titanium plasma spray (TPS) coating; cemented THR stem Stainless steel (SS); total knee replacement (TKR) femoral component CoCrMo alloy (CoCr); cemented acetabular component from highly cross-linked ultrahigh molecular weight polyethylene (HXL); and cementless acetabular liner from ultrahigh molecular weight polyethylene (UHMWPE) (Sanatmetal, Ltd., Eger, Hungary) discs, all of which were examined. Visualization and elemental analysis were carried out by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Surface roughness was determined by atomic force microscopy (AFM) and profilometry. TPS Ti presented the highest Ra value (25 ± 2 μm), followed by CoCr (535 ± 19 nm), Ti2 (227 ± 15 nm) and SS (170 ± 11 nm). The roughness measured in the HXL and UHMWPE surfaces was in the same range, 147 ± 13 nm and 144 ± 15 nm, respectively. EDS confirmed typical elements regarding the investigated prosthesis materials. XPS results supported the EDS results and revealed a high % of Ti4+ on Ti2 and TPS surfaces. The results indicate that the surfaces of prosthesis materials have significantly different features, and a detailed characterization is needed to successfully apply them in orthopedic surgery and traumatology.

Very early migration of a calcar-guided short stem: a randomized study of early mobilization and the influence of a calcium phosphate coating with 60 patients

This study analyzed the migration of a calcar-guided short stem to determine the course of very early migration, as well as evaluated the effect of an additional calcium phosphate (CP) coating on a titanium plasma spray (TPS) coating, which has not been analyzed previously. Sixty patients were enrolled in this study and were treated with the A2 calcar-guided short stem. The implant coating was randomized with either the TPS or an additional CP coating, and radiostereometric analysis was performed with the baseline measurement before initial weight-bearing, along with follow-up examinations at 1 week, 6 weeks, 3 months, and 6 months. Implant migrations were 0.27 mm (standard deviation [SD], 0.13 mm) and 0.74 mm (SD, 1.11 mm) at 1 week and 6 months post-surgery, respectively, and 65% and 87% of the implants reached their final position 1 week and 6 weeks after surgery, respectively. After 6 weeks, 3 months, and 6 months, a significant increase was noted in the migration of the CP coating group vs. that of the TPS coating group. Upon the final observation at 6 months, the groups displayed on average a 0.74-mm migration. Most of the analyzed implants ceased migration within the first week post-surgery, but the CP coating demonstrated a higher and more prolonged migration compared to the TPS coating.

Comprehensive Analysis of Indoor Formaldehyde Removal Techniques: Exploring Physical, Chemical, and Biological Methods

This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments, which is a significant concern for indoor air quality. The study systematically examines physical, chemical, and biological methods to ascertain their effectiveness in formaldehyde mitigation. Physical methods, including air circulation and adsorption, particularly with activated carbon and molecular sieves, are assessed for their efficiency in various concentration scenarios. Chemical methods, such as photocatalytic oxidation using titanium dioxide and plasma technology, are analyzed for their ability to decompose formaldehyde into non-toxic substances. Additionally, biological methods involving plant purification and microbial transformation are explored for their eco-friendly and sustainable removal capabilities. The paper concludes that while each method has its merits, a combined approach may offer the most effective solution for reducing indoor formaldehyde levels. The study underscores the need for further research to integrate these methods in a practical, cost-effective, and environmentally sustainable manner, highlighting their potential to improve indoor air quality significantly.

An investigational time course study of titanium plasma spray on osseointegration of PEEK and titanium implants: an in vivo ovine model

Background ContextMethods to improve osseointegration of orthopedic spinal implants remains a clinical challenge. Materials composed of poly-ether-ether-ketone (PEEK) and titanium are commonly used in orthopedic applications due to their inherent properties of biocompatibility. Titanium has a clinical reputation for durability and osseous affinity, and PEEK offers advantages of a modulus that approximates osseous structures and is radiolucent. The hypothesis for the current investigation was that a titanium plasma spray (TPS) coating may increase the rate and magnitude of circumferential and appositional trabecular osseointegration of PEEK and titanium implants versus uncoated controls. PurposeUsing an in vivo ovine model, the current investigation compared titanium plasma-sprayed PEEK and titanium dowels versus nonplasma-sprayed dowels. Using a time course study of 6 and 12 weeks postoperatively, experimental assays to quantify osseointegration included micro-computed tomography (microCT), biomechanical testing, and histomorphometry. Study Design/SettingIn-vivo ovine model. MethodsTwelve skeletally mature crossbred sheep were equally randomized into postoperative periods of 6 and 12 weeks. Four types of dowel implants–PEEK, titanium plasma-sprayed PEEK (TPS PEEK), titanium, and titanium plasma-sprayed titanium (TPS titanium) were implanted into cylindrical metaphyseal defects in the distal femurs and proximal humeri (one defect per limb, n=48 sites). Sixteen nonoperative specimens (eight femurs and eight humeri) served as zero time-point controls. Half of the specimens underwent destructive biomechanical pullout testing and the remaining half quantitative microCT to quantify circumferential bone volume within 1 mm and 2 mm of the implant surface and histomorphometry to compute direct trabecular apposition. ResultsThere were no intra- or perioperative complications. The TPS-coated implants demonstrated significantly higher peak loads at dowel pullout at 6 and 12 weeks compared with uncoated controls (p<.05). No differences were observed across dowel treatments at the zero time-point (p>.05). MicroCT results exhibited no significant differences in circumferential osseointegration between implants within 1 mm or 2 mm of the dowel surface (p>.05). Direct appositional osseointegration of trabecular bone based on histomorphometry was higher for TPS-coated groups, regardless of base material, compared with uncoated treatments at both time intervals (p<.05). ConclusionsThe current in vivo study demonstrated the biological and mechanical advantages of plasma spray coatings. TPS improved histological incorporation and peak force required for implant extraction. Clinical SignificancePlasma spray coatings may offer clinical benefit by improving biological fixation and osseointegration within the first 6 to 12 weeks postoperatively- the critical healing period for implant-based arthrodesis procedures.

High Oxygen Sensitivity of TiO2 Thin Films Deposited by ALD.

The gas sensitivity and structural properties of TiO2 thin films deposited by plasma-enhanced atomic layer deposition (ALD) were examined in detail. The TiO2 thin films are deposited using Tetrakis(dimethylamido)titanium(IV) and oxygen plasma at 300 °C on SiO2 substrates followed by annealing at temperatures of 800 °C. Gas sensitivity under exposure to O2 within the temperature range from 30 °C to 700 °C was studied. The ALD-deposited TiO2 thin films demonstrated high responses to O2 in the dynamic range from 0.1 to 100 vol. % and low concentrations of H2, NO2. The ALD deposition allowed the enhancement of sensitivity of TiO2 thin films to gases. The greatest response of TiO2 thin films to O2 was observed at a temperature of 500 °C and was 41.5 arb. un. under exposure to 10 vol. % of O2. The responses of TiO2 thin films to 0.1 vol. % of H2 and 7 × 10-4 vol. % of NO2 at a temperature of 500 °C were 10.49 arb. un. and 10.79 arb. un., correspondingly. The resistance of the films increased due to the chemisorption of oxygen molecules on their surface that decreased the thickness of the conduction channel between the metal contacts. It was suggested that there are two types of adsorption centers on the TiO2 thin films surface: oxygen is chemisorbed in the form of O2- on the first one and O- on the second one.

Spectroscopic Assessment of Electron Temperature and Density of Open-Air FHG Laser-Induced Zinc Titanium Plasma

This work used spectroscopic plasma emission analysis to investigate the parameters of ZnTi plasma formed in the atmosphere by a Q-switched Nd:YAG nanosecond laser system emitting infrared (1064 nm) laser light with an energy output spanning 200-500 mJ. The spectrometer was used to examine and record the emission spectrum profiles of (ZnTi), which helped to extract crucial plasma characteristics (i.e., [Formula: see text] and [Formula: see text]. The electron density was measured using the Stark broadening, and the plasma temperature was calculated using the Boltzmann plot technique. The electron temperature was between 2.04 and 2.15 eV, and the electron density was between (15.72 and 18.99) × 10[Formula: see text] cm[Formula: see text]. The Debye length ([Formula: see text], the number of particles in the Debye sphere ([Formula: see text], and the plasma frequency ([Formula: see text] can all be estimated from the electron temperature ([Formula: see text] and the electron density ([Formula: see text] ([Formula: see text].

Non-thermal atmospheric pressure plasma treatment increases hydrophilicity and promotes cell growth on titanium alloys in vitro

Most medical implants are made of titanium. When titanium is exposed to air for a long time, hydrocarbons are deposited and the surface becomes hydrophobic. Cell attachment is important for bone ingrowth to occur on the implant surface, and hydrophilicity can enhance this. We examined whether non-thermal atmospheric pressure plasma treatment could increase the hydrophilicity of the titanium surface. Samples coated with four widely used coating types [grit blasting, micro arc oxidation (MAO), titanium plasma spray (TPS), and direct metal fabrication (DMF)] were treated with plasma. Each of the four surface-treated samples was divided into groups with and without plasma treatment. We analysed wettability by surface analysis and evaluation of contact angles, cell proliferation, and adhesion using scanning electron microscopy (SEM), confocal laser scanning microscopy, absorbance tests, and alkaline phosphatase (ALP) activity assay; four different Ti6Al4V surface types were compared. After plasma treatment, the contact angle was reduced on all surfaces, and the carbon content was reduced on all surfaces based on X-ray photoelectron spectroscopy (XPS) surface analysis. Under confocal laser scanning, the cell layer was thicker on the plasma-treated samples, especially in groups TPS and DMF. Cell proliferation was 41.8%, 17.7%, 54.9%, and 83.8% greater for the plasma- than non-plasma-treated grit blasting, MAO, TPS, and DMF samples, respectively. Hydrophilicity increased significantly under plasma treatment, and biological responsivity was also improved.

Average-atom Ziman resistivity calculations in expanded metallic plasmas: Effect of mean ionization definition.

We present calculations of electrical resistivity for expanded boron, aluminum, titanium, and copper plasmas using the Ziman formulation in the framework of the average-atom model. Our results are compared to experimental data, as well as to other theoretical calculations, relying on the Ziman and Kubo-Greenwood formulations, and based on average-atom models or quantum-molecular-dynamics simulations. The impact of the definition of ionization, paying particular attention to the consistency between the definition and the perfect free electron gas assumption made in the formalism, is discussed. We propose a definition of the mean ionization generalizing to expanded plasmas the idea initially put forward for dense plasmas, consisting in dropping the contribution of quasibound states from the ionization due to continuum ones. It is shown that our recommendation for the calculation of the quasibound density of states provides the best agreement with measurements.

Multifunctionalized carbon-fiber-reinforced polyetheretherketone implant for rapid osseointegration under infected environment.

Carbon fiber reinforced polyetheretherketone (CFRPEEK) possesses a similar elastic modulus to that of human cortical bone and is considered as a promising candidate to replace metallic implants. However, the bioinertness and deficiency of antibacterial activities impede its application in orthopedic and dentistry. In this work, titanium plasma immersion ion implantation (Ti-PIII) is applied to modify CFRPEEK, achieving unique multi-hierarchical nanostructures and active sites on the surface. Then, hybrid polydopamine (PDA)@ZnO-EDN1 nanoparticles (NPs) are introduced to construct versatile surfaces with improved osteogenic and angiogenic properties and excellent antibacterial properties. Our study established that the modified CFRPEEK presented favorable stability and cytocompatibility. Compared with bare CFRPEEK, improved osteogenic differentiation of rat mesenchymal stem cells (BMSCs) and vascularization of human umbilical vein endothelial cells (HUVECs) are found on the functionalized surface due to the zinc ions and EDN1 releasing. In vitro bacteriostasis assay confirms that hybrid PDA@ZnO NPs on the functionalized surface provided an effective antibacterial effect. Moreover, the rat infected model corroborates the enhanced antibiosis and osteointegration of the functionalized CFRPEEK. Our findings indicate that the multilevel nanostructured PDA@ZnO-EDN1 coated CFRPEEK with enhanced antibacterial, angiogenic, and osteogenic capacity has great potential as an orthopedic/dental implant material for clinical application.

치과 임플란트 표면처리의 경향과 이해

Objectives: Osseointegration is important to success of dental implants, it is influenced by dental implant surface treatment. Recently, it could be classified into the five generations.&#x0D; Methods: Data were collected using electronic journals and books.&#x0D; Results: Machined type surface belongs to the first generation, the second generation of surface treatment includes blasted, acid-etching and titanium plasma spraying type surfaces. The third generation consists of hydroxyapatite coating type surface, the fourth generation is developed anodizing oxidation the surface that using bioactive factors. Finally, the five generation uses recombinant human bone morphogenetic protein-2 (rhBMP-2).&#x0D; Conclusions: It is thought that more innovative dental implant surface treatment will be developed according to the development of science technology

Combining povidone-iodine with vancomycin can be beneficial in reducing early biofilm formation of methicillin-resistant Staphylococcus aureus and methicillin-sensitive S. aureus on titanium surface.

There is controversial clinical evidence regarding the added antibacterial benefit of locally administering antiseptic solutions or antibiotics to the infected joint space. The objectives of this in vitro study were to test the efficacy of povidone-iodine (PVP-I) and vancomycin in treating premature and developed Staphylococcus aureus biofilms grown on titanium implant surfaces. PVP-I and vancomycin were used to treat immature and developed biofilms formed by two clinical strains of S. aureus (BP043-MRSA, PB011-MSSA). S. aureus strains were grown as immature (3h-old) or developed (24 h-old) biofilm. These biofilms were grown on titanium plasma sprayed discs. The treatment regimens tested were: 0.8% PVP-I, 500 μg/ml vancomycin as well as a combination of vancomycin and PVP-I. PVP-I was tested at 3min, as per current clinical practice, versus 1min treatment times. In addition, the cytotoxicity of the PVP-I and vancomycin was tested using fresh skeletal muscle tissue cores harvested from the rat's abdominal muscles using alamarBlue assay. The combination of PVP-I (3min) and vancomycin (24 h.) showed synergistic interaction and the best efficacy against immature biofilms formed by both clinical strains. This degree of eradication was statistically significant compared to the untreated control, p < .0001. However, this combination therapy had limited efficiency against developed biofilms. Also, PVP-I alone was more effective when exposure time was 3min instead of 1min against immature biofilm for MRSA, p=.02, and MSSA, p=.01. PVP-I and vancomycin were not effective against developed biofilm regardless of exposure time. Also, combining PVP-I and vancomycin was not cytotoxic to muscle tissue. Combining PVP-I with vancomycin is superior in reducing viable S. aureus cells in immature biofilms grown on titanium surface without causing significant cytotoxicity to muscle tissue. Exposure times and biofilm maturity play a role in dictating the efficacy of using local antiseptics and antibiotics to treat biofilms on implant surfaces.

Titanium wear from magnetically controlled growing rods (MCGRs) for the treatment of spinal deformities in children

Magnetically controlled growing rods (MCGRs) are an effective treatment method for early-onset scoliosis (EOS). In recent years, increasing titanium wear was observed in tissue adjacent to implants and in blood samples of these patients. This study aims to investigate the potential correlation between amount of metal loss and titanium levels in blood during MCGR treatment as well as influencing factors for metal wear. In total, 44 MCGRs (n = 23 patients) were retrieved after an average of 2.6 years of implantation and analyzed using a tactile measurement instrument and subsequent metal loss calculation. Titanium plasma levels (n = 23) were obtained using inductively coupled plasma-mass spectrometry (ICP-MS). The correlation of both parameters as well as influencing factors were analyzed. Titanium abrasion on MCGRs was observed in the majority of implants. There was no correlation of metal implant wear or titanium plasma values to the duration of MCGR implantation time, number of external lengthening procedures, patient’s ambulatory status, gender, weight or height. Material loss on the MCGRs showed a positive correlation to titanium blood plasma values. The present study is one of the first studies to analyze retrieved MCGRs using high-precision metrological techniques and compare these results with ICP-MS analyses determining blood titanium values.

Particle-in-Cell Investigation on Temporal Flow and Expansion Behaviors of Deuterium-Titanium Plasmas From Ion Source to Expansion Cup

By using a self-programed circular cylindrical coordinates 2-D, three velocity component, particle-in-cell (2D3V-PIC) code, the temporal dynamic flow and expansion behaviors of deuterium–titanium plasmas from the ion source to expansion cup are numerically studied in this article. The simulation results demonstrate as follows. There is a notable plasma sheath near the wall of the ion source with the electric field intensity on the order of MV/m in the radial direction; this plasma sheath will accelerate ions and decelerate electrons. Compared with Ti <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> ion, the radial dispersion phenomenon of D <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ion is more obvious. The electric field intensity of plasma sheath is first increased and then decreased, which consistently influences the radial dispersion behavior of ions in the expansion cup. Due to the plasma sheath near the wall of the ion source, the ion radial-accelerating effect always exists. Due to the separation between ion and electron, there is also an ion axial-accelerating phenomenon. Moreover, the ion axial-accelerating effect will decrease and, finally, disappear due to the decrease in the separation effect between electron and ion. In the steady phase, the ion current on the extraction wall is higher than the loss of ion current on the wall of the ion source, and the ion extraction efficiency of Ti <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> is much higher than D <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> .

Enhanced osseointegration through direct energy deposition porous coating for cementless orthopedic implant fixation

Direct energy deposition (DED) is a newly developed 3D metal printing technique that can be utilized on a porous surface coating of joint implants, however there is still a lack of studies on what advantages DED has over conventional techniques. We conducted a systematic mechanical and biological comparative study of porous coatings prepared using the DED method and other commercially available technologies including titanium plasma spray (TPS), and powder bed fusion (PBF). DED showed higher porosity surface (48.54%) than TPS (21.4%) and PBF (35.91%) with comparable fatigue cycle. At initial cell adhesion, cells on DED and PBF surface appeared to spread well with distinct actin stress fibers through immunofluorescence study. It means that the osteoblasts bind more strongly to the DED and PBF surface. Also, DED surface showed higher cell proliferation (1.27 times higher than TPS and PBF) and osteoblast cell activity (1.28 times higher than PBF) for 2 weeks culture in vitro test. In addition, DED surface showed better bone to implant contact and new bone formation than TPS in in vivo study. DED surface also showed consistently good osseointegration performance throughout the early and late period of osseointegration. Collectively, these results show that the DED coating method is an innovative technology that can be utilized to make cementless joint implants.

Dependence of morphology, structure, composition and biocompatibility of Ca- and P-doped TiO &lt;sub&gt;2&lt;/sub&gt; coatings on PEO process parameters

The study covers the influence of bipolar pulsed regime parameters of titanium plasma electrolytic oxidation (PEO): voltage (U), pulse duration (t) and pause duration between pulses on the structure and morphology of TiO2 coatings doped with Ca and P. Threshold values of voltage (U1) and positive pulse duration (t1), which led to pore-free coating formation, were determined. It was shown that an increase in U1 leads to an increase in pore size and Ca and P concentration in the TiO2 coating. A relationship between rutile content in the coating and Ca and P concentrations was identified. It was found that the size and distribution of pores depend ont1. A structure with fine pores evenly distributed over the sample area is formed during a short positive pulse. An increase in t1 leads to the formation of a structure with unevenly distributed large pores. An increase in the values of U2 and t2 leads to a decrease in Ca and P concentrations and rutile content in the coating. It was shown that the surface of PEO TiO2 coatings ensures the growth of crystallites of (Ca, P)-containing phases when kept in a simulated body fluid solution. It was found that the amount of an apatite-like layer depends on the content of Ca and P in the TiO2 layer, as well as the size and distribution of pores.

Comparative study on the dynamics and the composition between a pulsed laser deposition (PLD) and a plasma enhanced PLD (PE-PLD)

We report the effect of single and dual radio frequency (RF) plasma discharge on the composition and dynamics of a titanium plasma plume produced in a plasma-enhanced pulsed laser deposition (PE-PLD) system. The study was carried out in a nitrogen environment at different pressures. Time-resolved images, optical emission spectroscopy, and interferometry were employed to analyze the plasma. We were able to fit time-resolved images using different expansion models, obtained an expansion velocity between 6 and 30 × 103 m/s. Emission lines from N II, Ti II, were observed by changing the pressure and RF conditions. An increase in emission line intensity from N II was observed by increasing the pressure and RF power. We used Ti II lines to estimate the plasma temperature by using the Boltzmann equation, and we obtained the density from the Ti II line (454.9 nm) through Stark broadening. In addition, a Mach-Zehnder interferometer was employed to make a two-dimensional map of the electron density at early times. The estimated temperatures and densities are between 0.8 and 2.0 eV and 1017 – 1018 cm−3, respectively. The results suggest that increasing RF power enhanced the Ti-N atoms interaction, which is crucial in titanium nitride film applications.

Plasma-Enhanced Atomic Layer Deposition of TiN Thin Films as an Effective Se Diffusion Barrier for CIGS Solar Cells.

Plasma-enhanced atomic layer deposition (PEALD) of TiN thin films were investigated as an effective Se diffusion barrier layer for Cu (In, Ga) Se2 (CIGS) solar cells. Before the deposition of TiN thin film on CIGS solar cells, a saturated growth rate of 0.67 Å/cycle was confirmed using tetrakis(dimethylamido)titanium (TDMAT) and N2 plasma at 200 °C. Then, a Mo (≈30 nm)/PEALD-TiN (≈5 nm)/Mo (≈600 nm) back contact stack was fabricated to investigate the effects of PEALD-TiN thin films on the Se diffusion. After the selenization process, it was revealed that ≈5 nm-thick TiN thin films can effectively block Se diffusion and that only the top Mo layer prepared on the TiN thin films reacted with Se to form a MoSe2 layer. Without the TiN diffusion barrier layer, however, Se continuously diffused along the grain boundaries of the entire Mo back contact electrode. Finally, the adoption of a TiN diffusion barrier layer improved the photovoltaic efficiency of the CIGS solar cell by approximately 10%.

Comparative analysis of titanium coating on cobalt-chrome alloy in vitro and in vivo direct metal fabrication vs. plasma spraying

sBackgroundTitanium surface coating on cobalt-chromium (CoCr) alloy has characteristics desirable for an orthopedic implant as follows: strength, osteointegrative capability, and biocompatibility. Creating such a coated surface takes a challenging process and two dissimilar metals are not easily welded. In our study, we utilized additive manufacturing with a 3D printing called direct metal fabrication (DMF) and compared it to the plasma spraying method (TPS), to coat titanium onto CoCr alloy. We hypothesized that this would yield a coated surface quality as acceptable or better than the already established method of plasma spraying. For this, we compared characteristics of titanium-coated surfaces created by direct metal fabrication method (DMF) and titanium plasma spraying (TPS), both in vitro and in vivo, for (1) cell morphology, (2) confocal microscopy images of immunofluorescent assay of RUNX2 and fibronectin, (3) quantification of cell proliferation rate, (4) push-out biomechanical test, and (5) bone histomorphometry.MethodFor in vitro study, human osteoblast cells were seeded onto the coated surfaces. Cellular morphology was observed with a scanning electron microscope. Cellular proliferation was validated with ELISA, immunofluorescent assay. For in vivo study, coated rods were inserted into the distal femur of the rabbit and then harvested. The rods were biomechanically tested with a push-out test and observed for histomorphometry to evaluate the microscopic bone to implant ratio.ResultFor cell morphology observation, lamellipodia and filopodia, a cytoplasmic projection extending into porous structure, formed on both surfaces created by DMF and TPS. The proliferation of the osteoblasts, the DMF group showed a better result at different optic density levels (p = 0.035, 0.005, 0.001). Expression and distribution of fibronectin and Runx-2 genes showed similar degrees of expressions. The biomechanical push-out test yielded a similar result (p = 0.714). Histomorphometry analysis also showed a similar result (p = 0.657).ConclusionIn conclusion, DMF is a method which can reliably create a proper titanium surface on CoCr alloy. The resulting product of the surface shows a similar quality to that of the plasma spraying method, both in vivo and in vitro, in terms of biological and mechanical property.