Influence of Nitrogen Flow Rate in Reducing Tin Microdroplets on Biomedical TI-13ZR-13NB Alloy (original) (raw)
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STUDY ON MICRO DROPLET REDUCTION ON TIN COATED BIOMEDICAL TI-13ZR-13NB ALLOY
Cathodic arc physical vapor deposition (CAPVD) is one of the physical Vapor deposition (PVD) techniques used to coat titanium nitride (TiN) on biomedical implants due to its good adhesion and high evaporation rate. However, this technique emits micro droplets which have can detrimental effect on the coating performance. Previous studies reported that micro droplets can be controlled through proper deposition parameters. In this paper, the PVD coating was performed on the Ti-13Zr-13Nb biomedical alloy with different substrate temperatures. Scanning electron microscopy (SEM) was used to characterized the surface morphology and coating thickness while X-Ray Diffraction (XRD was employed to evaluate the crystal phase of the coated substrates. Image analysis software was used to quantify micro droplets counts. The results show that higher substrate temperature able to decrease a significant amount of micro droplets and concurrently increase the thickness of TiN coating. A mixed crystal planes of (111) and (200) are obtained on the coated substrates at this setting which exhibits denser structure as compared to substrates coated at lower substrate temperature. Abstrak Cathodic arc physical vapor deposition (CAPVD) merupakan salah satu teknikPhysical vapor Depostion (PVD) yang digunakan untuk menyaluttitanium nitrida (TiN) di implan bioperubatan disebabkan kekuatan lekatan yang baik dan kadar sejatan yang tinggi. Walau bagaimanapun, kaedah ini menghasilkan titisan mikro yang mempunyai kesan yang tidak baik ke atas salutan. Kajian lepas menunjukkan bahawa titisan mikro boleh dikawal melalui parameter salutan yang sesuai. Dalam kajian ini , salutan PVD telah dilakukan ke atas aloi bioperubatan Ti-13Zr-13Nb dengan suhu substrat yang berbeza.Mikroskop imbasan elektron (SEM) telah digunakan untuk menilai morfologi permukaan dan ketebalan lapisan manakala fasa kristal salutsubstrat telah diuji dengan menggunakan X-Ray Diffraction (XRD). Perisian analisis imej telah digunakan untuk mengukur bilangan dan saiztitsan mikro. Hasil kajian menunjukkan bahawa suhu substratyang tinggi dapat mengurangkan sejumlah besar titisan mikro dan dapat meningkatkan ketebalan salutan TiN. Permukaan kristal campuran (111) dan (200) diperolehi pada salutan substrat yang dihasilkan pada aliran N2yang tinggiyang mana mempamerkan struktur yang padat dengan kekuatan lekatan yang lebih tinggi berbanding dengan substrat bersalut yang dihasilkan pada kadar aliran gas N2 yang lebih rendah.
Thin films of Titanium Nitride deposite on substrates used for biomedical applications
Journal of Scientific and Technical Applications
In the present work, thin films of TiN were obtained on AISI 316L stainless steel substrates by DC unbalanced magnetron sputtering with promising characteristics such as resistance to wear and corrosion to be used in biomedical applications by changing the temperature of the substrate and the mixture. of gases. Microstructural characterization was performed using optical microscopy, atomic force microscopy, and scanning electron microscopy (SEM). Scratch tests were performed using an irradiated and non-irradiated ultra-high molecular weight polyethylene (UHMWPE) pin on the coated and uncoated substrates to study and compare the scratch effect, continuing the same circumferential geometry, a stroke length of 200 m and a 5N wet load using pure Milli-Q water (type 1) to simulate body fluids with the pin to test its performance and implant durability showing higher values in the coefficient of friction (COF) in the TiN-coated samples.
Surface and Coatings Technology, 2009
A strategy used to reduce wear of the ultra high molecular weight polyethylene (UHMWPE) component of orthopedic joint implants has been to coat the metallic part with a hard ceramic layer. The advantage of this procedure is to reduce both wear and ion release of the metal while keeping a high mechanical resistance. In the present study, the performance of three titanium nitride coatings: TiN, TiNbN, and TiCN for biomedical applications was assessed in terms of their surface properties and cytotoxicity. The morphology, chemical composition, and wettability were determined through atomic force microscopy (AFM) imaging, X-ray photoelectron spectroscopy (XPS) and contact angle measurement, respectively. The tribological behaviour of the coatings rubbing against UHMWPE in lubricated conditions was investigated using a pin-on-disk apparatus. Albumin adsorption on the three coatings was studied with a quartz crystal microbalance with dissipation (QCM-D) and AFM scratching. Cytotoxicity was determined both in direct or indirect contact of the cells with the coating materials. The results demonstrate that the three coatings have similar surface properties and are not cytotoxic. TiNbN seems to have the best tribological performance in the presence of albumin, although albumin adsorption is slightly higher on TiN.
Macrodroplet Reduction and Growth Mechanisms in Cathodic Arc Physical Vapor Deposition of TiN Films
Surface Review and Letters, 2008
Cathodic arc physical vapor deposition (CAPVD) a technique used for the deposition of hard coatings for tooling applications has many advantages. The main drawback of this technique is the formation of macrodroplets (MDs) during deposition resulting in films with rougher morphology. The MDs contamination and growth mechanisms was investigated in TiN coatings over high-speed steel, as a function of metal ion etching, substrate bias, and nitrogen gas flow rate; it was observed that the latter is the most important factor in controlling the size and number of the macrodroplets.
Titanium nitride-based coatings on implantable medical devices
2014
Physical and chemical surface properties play an important role in the performance and clinical success of implantable devices. Once a prosthetic device is implanted, its surface becomes a site of various biochemical reactions and bacterial adhesion, as well micromotion and gross sliding. All these events can contribute to a less than optimal host response and eventually lead to the prosthesis failure. Creation of a surface coating is an attractive approach to alter the interaction of the implant with its surroundings since it allows modification of surface characteristics without changing the bulk material properties. Titanium nitride hard coatings have a long history of clinical use, especially on bearing surfaces of joint replacements. Moreover, there is an accumulating body of evidence suggesting that titanium nitride-based thin layers applied to non-articulating surfaces of various orthopaedic and blood-contacting implants result in improved clinical outcomes. Beyond the biological and functional requirements, a durable coating must strongly adhere to the device, i.e. be mechanically and chemically compatible with the substrate. The coating method (deposition vs. diffusion) has an important role to play in the adhesion of titanium nitride films. This paper is an overview of the current state-of-the-art of titanium nitride-based coatings on medical implants, methods of their deposition, in vitro properties, in vivo behavior and clinical performance.
Matéria (Rio de Janeiro)
Introduction: Surface treatment is an important technique to increase adhesion between implants and bones, improving its mechanical characteristics and consequently the patient's comfort. Objectives: Ni-Cr alloys were the object of study in this work, with the purpose of analyzing and evaluating the effect of thin films deposition of titanium nitride via plasma, on its surface and comparing with cathodic cage (CC) and hollow cathode (HC) methods, for dental applications. Methods: Eighteen samples were prepared and the experiment was conducted in two steps: the pre-sputtering (1h, 350 °C, gases: Ar and H) and sputtering (4h, 450 °C, gases: Ar, Ni, and H). To characterize and compare the samples with those of reference, the Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Vickers Microhardness and wettability tests were used. Results: The results presented by SEM showed that during the surface treatment using CC, voids were formed, and using HC, the samples showed a more homogenous behavior. In microhardness tests, using a 25gf load, it was possible to observe that the HC method allowed an increase of 87% when compared to the reference and treated samples. Significance: Lastly, it can be concluded that both methods are suitable for Ni-Cr alloy surface treatment, and the HC technique, a method already used by dental professionals, presents better results due to the formation of a thicker film layer.
STUDY ON ADHESION STRENGTH OF TIN COATED BIOMEDICAL TI-13ZR-13NB ALLOY
One of the crucial factors which determine the success of coated implantation and stability in the long run is the strength of adhesion between the coating and substrate. After implantation, a weakly adhered coating may delaminate and this might seriously restrict the implant's effectiveness and longevity. Based on past studies, the quality of TiN coating is directly influenced by the process parameters. The objective of this research is to evaluate the effect of N2 gas flow rate on adhesion strength of biomedical grade Ti-13Zr-13Nb alloy. In this research, N2 gas flow rate of 100, 200 and 300 sccm were varied while the other parameters (substrate temperature and bias voltage) were fixed. The scratch testing method was used to examine the adhesion strength of the TiN coating. This research used the calibrated optical images to verify the total coating failures on the scratched coated samples. The results indicated that the micro droplet form on the TiN coating decreases as the flow rate of the N2 gas increases. In contrast, the TiN coating's adhesion strength increases with the increase of N2 gas flow rate. It can be concluded that N2 gas flow rate was significant factor in improving the coating properties of TiN on Ti-13Zr-13Nb alloy. Abstrak Salah satu faktor yang penting dalam menentukan kejayaan salutan implan dan kestabilan untuk jangka masa panjang ialah kekuatan lekatan antara salutan dan substrat. Selepas proses implantasi, lekatan salutan yang lemah mungkin akan tertanggal dan ini akan memendekkan jangka hayat dan keberkesanan implan. Berdasarkan kajian lepas, kualiti salutan titanium nitrida secara langsung akan dipengaruhi oleh proses parameter. Objektif kajian ini ialah untuk menilai keberkesanan kadar aliran gas N2 ke atas kekuatan lekatan gred bio-perubatan aloi Ti-13Zr-13Nb. Dalam kajian ini, kadar aliran gas nitrogen 100, 200 dan 300 sccm telah diubah manakala suhu substrat dan voltage bias telah dikekalkan. Ujian cakaran telah digunakan untuk menilai kekuatan salutan TiN. Selanjutnya, kajian ini menggunakan imej-imej optik ditentukur untuk mengesahkan jumlah kegagalan lapisan pada sampel bersalut yang dicakar. Keputusan kajian menunjukkan bahawa titisan mikro daripada lapisan TiN berkurang apabila kadar aliran gas N2 bertambah. Sebaliknya, kekuatan lekatan salutan TiN akan bertambah dengan bertambahnya kadar aliran gas N2.
Nanostructured TiN Thin films suitable for medical applications
Materials …, 2008
Titanium nitride thin films are widely used in biomedical implants because of their biocompatibility, good mechanical properties and high corrosion resistance. Titanium nitride (TiN) thin films on silicon and glass substrates were prepared using a dc magnetron sputtering system under conditions of systematically varying the nitrogen pressure and titanium magnetron power. The nano-structure and microstructure of the coatings was examined using a scanning electron microscope and atomic force microscope. The present studies show that the surface structure, grain size, deposition rate and microhardness of the coatings are strongly dependent on the nitrogen pressure and titanium magnetron power. The grain diameter increased from 35 to 100 nm with the increase in nitrogen partial pressure from 0.4 to 1.0 mTorr. The optimal nitrogen partial pressure found for making gold colour TiN thin films and increased hardness (about 2550 Vickers number) was determined to be between 0.4 -0.6 mTorr. The grain size was found to decrease from 60 to 28 nm and the microhardness increased from 1600 to 2550 (Vickers number) as the titanium magnetron power increased from 100 to 250 W.
Titanium Nitride Coatings on Ti Alloys by PIRAC for Orthopedic Implants
Key Engineering Materials, 2010
In the present work, Ti and Ti-6Al-4V were PIRAC nitrided at the relatively low temperatures of 700-850°C. To obtain thicker TiN layers, 3 stage PIRAC based coating was applied: (1) PIRAC nitriding followed by (2) PIRAC titanizing followed by (3) additional PIRAC nitriding. The microstructure and phase composition of the obtained surface layers were characterized employing X-ray diffraction and scanning electron microscopy with chemical analysis (SEM/EDS). Bending test was employed to evaluate the coatings adhesion to the substrate. Lower PIRAC nitriding temperatures yielded smoother TiN coatings with a more gradual microhardness decrease from the surface to the bulk. All PIRAC TiN based coatings have excellent adhesion to substrate – no delamination of the coating in bending tests was observed. The best combination of microhardness and adhesion was obtained using 3 stage PIRAC process.
Characterization of Ti-C-N coatings deposited on Ti6Al4V for biomedical applications
Journal of Inorganic Biochemistry, 2012
Ti6Al4V alloy is the most commonly employed implant material for orthopedic replacements due to its good mechanical properties close to those of bones, biocompatibility and its good corrosion resistance in biological media. Nevertheless, it does not exhibit good wear resistance, showing friction and wear even with soft tissues. This latter feature can lead to a premature failure of the implant with the subsequent component replacement. Therefore, a system with good tribological resistance is required for several medical applications. One possible alternative to solve tribological problems consists of protecting the alloy surface by means of biocompatible TiC -N coatings. In this work, five types of metallic TiC -N coatings deposited by physical vapor deposition (PVD) cathodic arc method on Ti6Al4V substrate have been studied. Different deposition conditions have been analyzed, and the superficial properties of films have been characterized. Additionally, tribological response of these films have been determined and compared with the substrate one under fretting conditions in simulated body fluid. The results indicate that TiC -N coatings improve the general response of the biomaterial.