Yazar "Golden, Teresa D." seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Computer assisted corrosion analysis of hydroxyapatite coated CoCrMo biomedical alloys(Elsevier Science Sa, 2015) Coskun, M. Ibrahim; Karahan, Ismail Hakki; Golden, Teresa D.Bio-metallic CoCrMo alloys were coated with hydroxyapatite layers by electrodeposition to improve biocompatibility. Surface morphology was analyzed by scanning electron microscopy. Chemical composition was investigated by FTIR. In vitro corrosion performance was examined by electrochemical impedance spectroscopy and Tafel measurements in a simulated body fluid. Corrosion performance of the coatings deposited at various pH values was investigated using Zview and COMSOL computer modeling programs. Both programs successfully modeled EIS results. Increasing the electrolyte pH improved corrosion performance of the biocompatible coatings. Electrolyte pH influenced corrosion properties, chemical composition, and surface morphology of the coatings. (C) 2015 Elsevier B.V. All rights reserved.Öğe Computer-Assisted Optimization of Electrodeposited Hydroxyapatite Coating Parameters on Medical Alloys(Springer, 2016) Coskun, M. Ibrahim; Karahan, Ismail H.; Yucel, Yasin; Golden, Teresa D.CoCrMo bio-metallic alloys were coated with a hydroxyapatite (HA) film by electrodeposition using various electrochemical parameters. Response surface methodology and central composite design were used to optimize deposition parameters such as electrolyte pH, deposition potential, and deposition time. The effects of the coating parameters were evaluated within the limits of solution pH (3.66 to 5.34), deposition potential (-1.13 to -1.97 V), and deposition time (6.36 to 73.64 minutes). A 5-level-3-factor experimental plan was used to determine ideal deposition parameters. Optimum conditions for the deposition parameters of the HA coating with high in vitro corrosion performance were determined as electrolyte pH of 5.00, deposition potential of -1.8 V, and deposition time of 20 minutes.Öğe Effect of TMAB concentration on structural, mechanical and corrosion properties of electrodeposited Ni-B alloys(Elsevier, 2022) Karahan, Ismail Hakki; Aminifazl, Alireza; Golden, Teresa D.The influence of trimethylamine borane (TMAB) concentration as a boron (B) source on the structural and corrosive properties of Ni-B alloy coatings produced by electrodeposition was investigated. The crystal structure of the Ni-B coatings is influenced by the B content in the coating, having a slight (220) preferred orientation. The B content in the coating increased from 16 to 34 at.% with the corresponding increase in the concentration of TMAB from 1 to 20 g/L, while interestingly retaining a crystal structure. The hardness of the coatings increased with increasing B content owing to the formation of smaller crystallites. An increase in B content in the alloy coatings, led to a shift in the Ecorr values to more anodic potentials, indicating increase corrosion protection for the Ni-B coatings. This study achieved to reach 34 at.% B content in Ni-B alloy coatings produced by electrodeposition while preventing amorphization of the coating layer.Öğe Modeling the Effect of Temperature and Potential on the In Vitro Corrosion Performance of Biomedical Hydroxyapatite Coatings(Springer, 2016) Coskun, M. Ibrahim; Karahan, Ismail H.; Yucel, Yasin; Golden, Teresa D.CoCrMo biomedical alloys were coated with a hydroxyapatite layer to improve biocompatibility and in vitro corrosion performance. A fast electrodeposition process was completed in 5 minutes for the hydroxyapatite coating. Effect of the solution temperature and applied potential on the in vitro corrosion performance of the hydroxyapatite coatings was modeled by response surface methodology (RSM) coupled with central composite design (CCD). A 5-level-2-factor experimental plan designed by CCD was used; the experimental plan contained 13 coating experiments with a temperature range from 283 K to 347 K (10 A degrees C to 74 A degrees C) and potential range from -1.2 to -1.9 V. Corrosion potential (E (corr)) of the coatings in a simulated body fluid solution was chosen as response for the model. Predicted and experimental values fitted well with an R (2) value of 0.9481. Response surface plots of the impedance and polarization resistance (R (P)) were investigated. Optimized parameters for electrodeposition of hydroxyapatite were determined by RSM as solution temperature of 305.48 K (32.33 A degrees C) and potential of -1.55 V. Hydroxyapatite coatings fabricated at optimized parameters showed excellent crystal formation and high in vitro corrosion resistance.Öğe Optimization of electrochemical step deposition for bioceramic hydroxyapatite coatings on CoCrMo implants(Elsevier Science Sa, 2016) Coskun, M. Ibrahim; Karahan, Ismail H.; Yucel, Yasin; Golden, Teresa D.CoCrMo metallic implants were coated with a bioceramic hydroxyapatite layer using a modified step electro-deposition at room temperature. Response Surface Methodology (RSM) and Central Composite Design (CCD) were used to model and optimize the step deposition parameters, such as initial potential, scan rate and peak potential. Interactions between step deposition parameters and in vitro corrosion performance of the coatings were modeled by response surface plots. Predicted and experimental values were fitted with high accuracy. The effects of the step deposition parameters were evaluated within the limits of lowest applied potential (-0.03 to -1.17 V), scan rate (3.43-116.57 mV/s) and highest applied deposition potential (-1.08 to -1.92 V). A 5-level-3-factor experiment plan was used to optimize step deposition parameters. Optimum conditions for the modified step deposition parameters were determined as initial potential of -0.76 V, peak potential of -1.67 V and scan rate of 59.33 mV/s. (C) 2015 Elsevier B.V. All rights reserved.
