scholarly journals Nano-hydroxyapatite Coating Improves Bioactivity of Additively Manufactured Ti-6Al-4V Alloy Surface

2021 ◽  
Vol 10 (4) ◽  
pp. 251-255
Author(s):  
Ryota WATANABE ◽  
Hiroyuki TAKAHASHI ◽  
Toru UEMUKAI ◽  
Yasumichi KOGAI ◽  
Aira MATSUGAKI ◽  
...  
Keyword(s):  
Hydroxyapatite Coating ◽  
Alloy Surface

Reduction of the biodegradation rate of MgZnSrCa alloy by use of a biomimetic apatite coating

2016 ◽  
Vol 63 (3) ◽  
pp. 226-230 ◽  
Author(s):  
Yajing Zhang ◽  
Guian Shi ◽  
Yue Liu ◽  
Qin Wu ◽  
Wenhao Yang ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Hydroxyapatite Coating ◽  
Alloy Surface ◽  
Potential Candidate ◽  
Content Type ◽  
Biomimetic Apatite ◽  
Apatite Coating ◽  
Wastage Rate ◽  
Biomimetic Hydroxyapatite ◽  
Biodegradable Magnesium

Purpose The purpose of this study is to develop new biodegradable magnesium alloy. Magnesium possesses similar mechanical properties to natural bone; it is a potential candidate for resorbable implant applications. However, in physiological conditions, the degradation rate of Mg is too high to be used as an implant material. Design/methodology/approach In this research, Zn, Sr and Ca were chosen as alloying elements; a coating was deposited on the MgZnSrCa alloy surface by means of a biomimetic technique. The corrosion rates of the uncoated and coated specimens were tested in simulated body fluid. Findings The hydroxyapatite coating formed on the MgZnSrCa alloy surface and the hydroxyapatite layer markedly decreased the corrosion rate of the MgZnSrCa alloy. Originality/value A homogenous hydroxyapatite coating was formed on the MgZnSrCa alloy surface by using a biomimetic coating technique. The biomimetic hydroxyapatite coating markedly reduced the corrosion rate of the MgZnSrCa alloy, and the largest decrease in wastage rate was 44 per cent.

Electrodeposition of hydroxyapatite coating on Mg alloy modified with organic acid self-assembled monolayers

2019 ◽  
Vol 44 (3-4) ◽  
pp. 212-220
Author(s):  
Ivana Škugor Rončević ◽  
Nives Vladislavić ◽  
Marijo Buzuk ◽  
Maša Buljac
Keyword(s):  
Calcium Phosphate ◽  
Organic Acid ◽  
Electrochemical Impedance ◽  
Physiological Solution ◽  
Mg Alloy ◽  
Hydroxyapatite Coating ◽  
Alloy Surface ◽  
Corrosion Properties ◽  
Self Assembling ◽  
Assembled Monolayers

Calcium phosphate coatings are used in orthopedics due to their excellent bioactivity, which improves the bonding between the metal implant and the bone. The use of self-assembling monolayers of long-chain organic acids can induce calcium phosphate growth. In this article, the self-assembling monolayers of stearic acid and octadecylphosphonic acid formed on the Mg alloy surface were additionally modified with electrodeposited hydroxyapatite coating to increase the bioactivity and biocompatibility of the Mg alloy in a physiological solution. Hydroxyapatite coating was prepared by a two-step reaction: hydrogen phosphate formed by electrodeposition at constant potential was converted into hydroxyapatite coating through an acid–base reaction. The results obtained by voltammetry and electrochemical impedance spectroscopy have shown a beneficial effect of organic acid self-assembling monolayer and especially of organic acid self-assembling monolayer modification by hydroxyapatite electrodeposition on the corrosion properties of Mg alloy in physiological solution. Fourier transform infrared spectroscopy and scanning electron microscopy were used to verify the existence of the organic acid SAM|HAp film on the Mg alloy surface and their morphology.

Utilisation of High-Energy Heat Sources in Magnesium Alloy Surface Layer Treatment

2013 ◽  
Vol 58 (2) ◽  
pp. 619-624 ◽  
Author(s):  
M. Szafarska ◽  
J. Iwaszko ◽  
K. Kudła ◽  
I. Łegowik
Keyword(s):  
Surface Layer ◽  
Magnesium Alloy ◽  
Physicochemical Properties ◽  
Treatment Effectiveness ◽  
High Energy ◽  
Alloy Surface ◽  
Heat Sources ◽  
X Ray ◽  
Additional Equipment ◽  
Alloy Surface Layer

The main aim of the study was the evaluation of magnesium alloy surface treatment effectiveness using high-energy heat sources, i.e. a Yb-YAG Disk Laser and the GTAW method. The AZ91 and AM60 commercial magnesium alloys were subject to surface layer modification. Because of the physicochemical properties of the materials studied in case of the GTAW method, it was necessary to provide the welding stand with additional equipment. A novel two-torch set with torches operating in tandem was developed within the experiment. The effectiveness of specimen remelting using a laser and the GTAW method was verified based on macro- and microscopic examinations as well as in X-ray phase analysis and hardness measurements. In addition, the remelting parameters were optimised. The proposed treatment methodology enabled the achieving of the intended result and effective modification of a magnesium alloy surface layer.

Study of Electrochemical Behavior of Some Dental Alloys

2018 ◽  
Vol 69 (6) ◽  
pp. 1598-1602
Author(s):  
Alice Arina Ciocan Pendefunda ◽  
Constanta Mocanu ◽  
Doriana Agop Forna ◽  
Cristina Iordache ◽  
Elena Luca ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Electrochemical Behavior ◽  
Base Alloy ◽  
Artificial Saliva ◽  
Surface Condition ◽  
Continuous Process ◽  
Metal Alloys ◽  
Alloy Surface ◽  
Dental Alloys ◽  
Dental Restorations

The purpose of the study is to investigate the electrochemical behavior of two dental alloys: palladium alloy (Palidor) and Ni-Cr alloy (Verasoft) in three types of artificial saliva. Determination of corrosion potential and recording of linear and cyclic polarization curves were performed with PGP201 potentiostat (VoltaLab 21- Radelkis Copenhagen. In order to study the modifications produced on the surface of the electrodes, a complex optical microscope MC 1 research type (IOR, Romania) was used, adapted to a digital camera, which was connected to a computer for the digital acquisition of images . Two metal alloys based on Ag-Pd and Ni-Cr were used for the experiments. The materials used came from different types of dental restorations removed from the oral cavity of the patients after a 5-15 years period. As corrosion environments, three artificial saliva were used: Fusayama, Afnor and Rondelli. The Pd-Ag dental alloy exhibits a very good corrosion resistance and the treatment in the Afnor saliva does not affect the surface of the alloy. Electrochemical behavior in Fusayama-Meyer�s saliva of the alloy surface results in a series of spots representing deposits of insoluble salts resulting from the oxidation process, while in the Rondelli saliva there is a series of small corrosion points on the alloy surface. The behavior of the Verasoft alloy in the Afnor and Rondelli saliva is similar; In both solutions, the potential breakthroughs are very close, but in Fusayama-Meyer�s saliva, the potential for initiation of corrosion points is very low (206 mV), a potential that can be encountered in the oral cavity. All metals and metal alloys, even the noble and semi-precious ones, are susceptible to corrosion, forming compounds with properties different from those of the metal or base alloy, which change their surface condition. Metallic dental restorations are permanently affected by the factors of the oral environment (physical-mechanical, chemical and biological), being subjected to a continuous process of degradation.

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