Structural, Mechanical and Corrosion Properties of Mg/SiO2 and MgO/SiO2 Multilayer Coatings for Magnesium Implant Devices

Author(s):  
R. Kotoka ◽  
S. Fialkova ◽  
S. Neralla ◽  
S. Yarmolenko ◽  
D. Pai ◽  
...  

In this study, Mg/SiO2 and MgO/SiO2 multilayer coatings with bilayer thicknesses (Λ) 10, 20, 40, 100, 200 and 1000 nm were deposited on glass substrates using DC and reactive pulsed DC magnetron sputtering processes. The aim of these coatings is to control the initial degradation and provide mechanical strength to magnesium implant during handling and installation. The initial thickness calibrations and deposition rates optimization were conducted using stylus profilometer. After deposition of the multilayer coatings, the values of their bilayer thicknesses (Λ) were obtained from X-ray reflectometery. The mechanical properties, surface morphology and roughness of multilayer coatings were studied using nanoindentation, SEM and AFM respectively. The nanoindentation results showed higher hardness of MgO/SiO2 multilayer coatings compared to single layer Mg. The roughness analyses showed improved roughness for bilayer thicknesses (Λ) less than 20 nm. It was observed from the SEM images that SiO2 coatings has pores. By adding Mg and/or MgO in the form of multilayers improves the pores significantly. The Mg/SiO2 multilayer coatings showed controlled degradation rate when immersed in saline solution compared to the monolithic SiO2 coating. In conclusion, conditions for depositing Mg/SiO2 and MgO/SiO2 multilayer coatings has been optimized. Alternating brittle SiO2 ceramic layers with soft and ductile Mg layers significantly improved the hardness of the Mg coating. Hardness of multilayer coatings can be fine-tuned by modifying bilayer thicknesses. Significant improvement in the corrosion and mechanical properties of the multilayer coatings can be used to protect surface of magnesium implant material during handling, storage and installation.

2021 ◽  
Vol 5 ◽  
pp. 18-27
Author(s):  
A. A. Selivanov ◽  
◽  
K. V. Antipov ◽  
Yu. S. Oglodkova ◽  
A. S. Rudchenko ◽  
...  

The results of the development of a new alloy of the Al – Mg – Si system of the 6xxx series, which received the V-1381 grade, are presented. The influence of the composition and modes of heat treatment on the mechanical and corrosion properties of sheets with a thickness of 1,0 and 3,0 mm, manufactured under the conditions of FSUE “VIAM”, was investigated. Average level of sheet properties: UTS = 410 MPa, YTS = 360 MPa, El = 11.5 %; fatigue crack growth (dl/dN) = 0,59 mm/kcycle at ΔK = 18,6 MPa·m1/2, intergranular corrosion ≤ 0,15 mm, exfoliation corrosion 4 points. It was found that the structure of the sheets is recrystallized, the main strengthening phase is the coherent matrix β’(Mg2Si)-phase evenly distributed in the volume of grains with a high density. There is also a heterogeneous origin of β′-phase on dislocations and dispersoids. At grain boundaries there are zones free from emissions with a width of 15 – 20 nm. Dispersoids of various morphologies are observed in the tested samples. Temperature and heat values of phase transformations in ingots and sheets are determined and established liquidus and solidus points. The sheet weldability was evaluated by automatic argon-arc welding and the critical rate of deformation of the weld metal during crystallization was determined, at which no cracks were formed in it. Laser welding mode has been developed to ensure optimal formation of geometric parameters of the weld.


2008 ◽  
Vol 202 (11) ◽  
pp. 2384-2388 ◽  
Author(s):  
M. Balaceanu ◽  
V. Braic ◽  
M. Braic ◽  
A. Kiss ◽  
C.N. Zoita ◽  
...  

2021 ◽  
Vol 27 (4) ◽  
pp. 180-184
Author(s):  
Hasan A. Fattah ◽  
Mohammed Gouda ◽  
Salah Salman ◽  
Ayman Elsayed

Magnesium is a promising lightweight metal required in many industries such as automobile, aerospace, electronics, etc. It is also a biodegradable material, which eliminates the secondary removal procedure of the implant. Furthermore, its mechanical properties are similar to the mechanical properties of human bone.  In this research, eggshells were used as an environmentally friendly composite reinforcement material in the Mg-2.5Zn-1Mn matrix. Composites were prepared using the powder metallurgy route.  The effect of eggshells on the morphology, mechanical, and corrosion behaviour of Mg-2.5Zn-1Mn alloy was investigated. The results revealed an enhancement in grain refining ability and mechanical properties of Mg-2.5Zn-1Mn with eggshell additives. The corrosion behaviour improved at a higher percentage of eggshells (10%).


2017 ◽  
Vol 270 ◽  
pp. 205-211 ◽  
Author(s):  
Drahomír Dvorský ◽  
Jiří Kubásek ◽  
Dalibor Vojtěch

Magnesium and its alloys are considered for application as materials for biodegradable implants as they have mechanical properties similar to bone tissue. High demands on corrosion and mechanical properties are made on these alloys. While mechanical properties of magnesium are usually enhanced by alloying, corrosion properties may deteriorate. This paper is focused on the comparison of magnesium alloys AZ31 (3 wt. % Al, 1 wt. % Zn) and WE43 (4 wt. % Y, 3 wt. % Nd) which are considered for biomedical applications. Besides the type of alloying elements, the preparation process has also great impact on final mechanical and corrosion properties. Alloying elements may be dissolved in magnesium matrix or they can form intermetallic phases, which alter final properties. Microstructure, mechanical and corrosion properties of AZ31 and WE43 were studied and compared with pure magnesium.


2004 ◽  
Vol 467-470 ◽  
pp. 217-222 ◽  
Author(s):  
R. Badji ◽  
B. Belkessa ◽  
H. Maza ◽  
M. Bouabdallah ◽  
Brigitte Bacroix ◽  
...  

Duplex stainless steels 2205 are widely used in constructional and petrochemical applications because of their good mechanical and corrosion properties. The objective of this work was to study the influence of aging at high temperature on the austenite and d ferrite equilibrium. After welding by TIG process, duplex stainless steel was aged in the range of 800 – 1150 °C temperatures for 60 min. The microstructure was characterized by metallography and X-ray methods. The toughness of welded structure was also measured.


Doklady BGUIR ◽  
2019 ◽  
pp. 87-94
Author(s):  
A. T. Volochko ◽  
V. A. Zelenin ◽  
E. O. Narushko ◽  
A. V. Skilandz ◽  
G. V. Markov

The transmission model for optical diapason was developed for multilayer coatings consisting of alternating layers of copper and zirconium dioxide deposited on K8 glass substrates. The model is based on the laws of light interference. It was shown that the transmission in the optical range of a 60 nm thick Cu layer with a surface resistance ρ = 1 Ohm/sq is 4–5 %, and the transmission of the ZrO2/Cu/ZrO2/Cu/К8 coating obtained by dividing a 60 nm thick copper layer into two sublayers at 30 nm with the application of antireflection layers of ZrO2 on them, at ρ = 1.2 Ohm/sq it reaches 25 %. The thicknesses and the number of layers of the Cu-ZrO2 system were calculated, which ensure a transmission in the wavelength range of 400–700 nm of at least 45 %. The permissible thickness of Cu layers (≥ 20 nm) was determined, below which, due to their insular structure and partial oxidation with the formation of Cu2O, the electrical conductivity of the multilayer coating sharply decreases (ρ ≥ 100 Ohm/sq).  


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7847
Author(s):  
Viacheslav Bazhenov ◽  
Anastasia Lyskovich ◽  
Anna Li ◽  
Vasily Bautin ◽  
Alexander Komissarov ◽  
...  

Mg alloys have mechanical properties similar to those of human bones, and have been studied extensively because of their potential use in biodegradable medical implants. In this study, the influence of different heat treatment regimens on the microstructure and mechanical and corrosion properties of biodegradable Mg–Zn–Ga alloys was investigated, because Ga is effective in the treatment of disorders associated with accelerated bone loss. Solid–solution heat treatment (SSHT) enhanced the mechanical properties of these alloys, and a low corrosion rate in Hanks’ solution was achieved because of the decrease in the cathodic-phase content after SSHT. Thus, the Mg–4 wt.% Zn–4 wt.% Ga–0.5 wt.% Y alloy after 18 h of SSHT at 350 °C (ultimate tensile strength: 207 MPa; yield strength: 97 MPa; elongation at fracture: 7.5%; corrosion rate: 0.27 mm/year) was recommended for low-loaded orthopedic implants.


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