Influence of various sterilization methods on hardness, grain size and corrosion rate of a Mg6Ag-alloy

AbstractSterilization is a necessary step for all implant materials. Different methods can influence the materials properties. Especially important for magnesium as degradable materials is the determination of the corrosion properties. In this study the influence of 70% ethanol, glutaraldehyde, autoclaving, dry heat, UV-, gamma- and electron beam-irradiation on mechanical and corrosion parameters were analyzed. As mechanical parameters hardness and grain size were determined. The corrosion rate under physiological conditions, weight of the corrosion layer and corrosion morphology was determined. It could be demonstrated that irradiation treatments and 70% ethanol are suitable methods, as they decrease the corrosion rate. Heat-introducing methods (autoclaving and dry heat) acted as incomplete ageing treatments on this alloy and therefore increased the corrosion rate. Furthermore, osmolality showed a better correlation to the actual corrosion rate than the pH. Therefore an optimum ratio between alloying system, implant and sterilization method has to be established, depending on the intended application.

Download Full-text

Corrosion Behavior of As-Cast Binary Mg-Dy Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.690.417 ◽

2011 ◽

Vol 690 ◽

pp. 417-421 ◽

Cited By ~ 6

Author(s):

Lei Yang ◽

Frank Feyerabend ◽

Karl Ulrich Kainer ◽

Regine Willumeit ◽

Norbert Hort

Keyword(s):

Corrosion Rate ◽

Optical Microscope ◽

Direct Chill ◽

Second Phase ◽

Alloying Element ◽

High Solubility ◽

Corrosion Properties ◽

Corrosion Morphology ◽

Filiform Corrosion ◽

Very High

The addition of rare earth elements (REE) is an effective way to improve the corrosion properties of magnesium alloys. Dysprosium has a very high solubility in Mg (25.3 wt.% at 561 °C) and could therefore be a promising alloying element for Mg based implants. In this study, four binary Mg-xDy (x=5, 10, 15 and 20 in wt.%) alloys were prepared by permanent mould direct chill casting. Microstructure and Dy distribution were investigated using optical microscope and EDX analysis. Corrosion rate was measured with hydrogen evolution method and corrosion morphology was observed after immersion for different time in 0.9 wt% NaCl solution with optical and SEM. The results show that with the increase of Dy, the amount of Dy in Mg matrix and area of Dy segregation are both increased. At the same time, the amount of second phase is also increased. Filiform corrosion is reduced while pitting corrosion is increased with the increment of Dy. As a result, lowest corrosion rate is obtained at Mg-10Dy alloy.

Download Full-text

Determination of the Relationship between the Factor of Grain Size Factor and the Corrosion Rate of Structural Steel

Metal Working and Material Science ◽

10.17212/1994-6309-2020-22.3-106-125 ◽

2020 ◽

Vol 22 (3) ◽

pp. 106-125

Author(s):

Roman Sokolov ◽

◽

Vitaly Novikov ◽

Kamil Muratov ◽

Anatolii Venediktov ◽

...

Keyword(s):

Grain Size ◽

Corrosion Rate ◽

Structural Steel ◽

Size Factor ◽

The Relationship

Download Full-text

Electrochemical Corrosion Properties of 316LSS and Titanium in Various Corrosion Media

International Journal of Emerging Science and Engineering ◽

10.35940/ijese.g2326.016720 ◽

2020 ◽

Vol 6 (7) ◽

pp. 1-4

Keyword(s):

Corrosion Rate ◽

Electrochemical Corrosion ◽

Corrosion Damage ◽

Corrosion Products ◽

Corrosion Properties ◽

Corrosion Studies ◽

Spectroscopy Studies ◽

Selection Of ◽

Metal And Alloys

The work was carried on biomedical implants and the selection of correct methods for corrosion studies and study of the corrosion products, electrochemical methods are used to determine the metal and alloys corrosion rate and to characterize the corrosion damage. Microscopy and spectroscopy studies are used for characterization and determination of thickness and nature of the corrosion products.

Download Full-text

Study on Corrosion Properties of Medical Mg-Zn Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.777.607 ◽

2018 ◽

Vol 777 ◽

pp. 607-611

Author(s):

Zhi Ling Wang

Keyword(s):

Simulated Body Fluid ◽

Corrosion Rate ◽

Body Fluid ◽

Body Fluids ◽

Corrosion Products ◽

Corrosion Properties ◽

Corrosion Morphology ◽

Zn Content ◽

Simulated Body Fluids ◽

Zn Alloy

Casting Mg-Zn alloy was corroded on the surface and analyzed the corrosion morphology and corrosion properties under different corrosion conditions. The results show that Mg-Zn alloy is unevenly by corrosion in simulated body fluids and the corrosion products are brittle and easy to break. With the increase of Zn content in Mg-Zn alloy, the corrosion rate of casting Mg-Zn alloy in simulated body fluid is improved obviously.

Download Full-text

Determination of corrosion characteristics of steel protected by a latex coating in Nyquist coordinates

Proceedings of Irkutsk State Technical University ◽

10.21285/1814-3520-2021-4-519-527 ◽

2021 ◽

Vol 25 (4) ◽

pp. 519-527

Author(s):

A. А. Yakovleva ◽

E. A. Antsiferov ◽

S. V. Sadlovsky

Keyword(s):

Corrosion Rate ◽

Electrochemical Impedance ◽

Protective Layer ◽

Corrosion Process ◽

Working Environment ◽

Corrosion Properties ◽

Corrosion Studies ◽

Limiting Stage ◽

Reference Samples

This paper investigates the corrosion process of steel St3 protected by latex coating 69Б-2к produced by Kapitel Ltd (Irkutsk). Electrochemical impedance spectroscopy of steel samples with a threefold latex coating was carried out by a PGSTAT302 + FRA2 potentiostat-galvanostat equipped with NOVA 1.8. Corrosion studies were carried out under thermostating (25 ± 0.2°C) of the working environment. The corrosion rate was determined by gravimetric tests with the recording of mass changes over a controlled period of time (up to 10 h). A 3% sodium chloride solution was used as the electrolyte. In most cases, the mechanism of the corrosion process can be reliably described by an equivalent electrochemical circuit with Warburg and Cotangent Hyperbolic elements, which simulates the reaction at the electrodeelectrolyte interface. According to the conducted visual, gravimetric and electrochemical studies of the St3 steel surface protected with the 69B-2k latex coating, the impedance remains almost unchanged for a prolonged period of time. It is obvious that the surface process is associated with the limiting stage of solvent diffusion through the protective layer. Thus, the electrochemically determined corrosion rate was low and amounted to ~ 0.164 mm/year (for reference samples – 0.75 mm / year). Our studies confirmed high protective qualities of latex 69B-2k. The corrosion properties of the coating under study are related to its composition, the components of which not only exhibit good adhesion, but are also active with respect to other interactions, including chemical interactions of the components with each other and with metal surface crystallites. The model calculation of the process, carried out using the developed equivalent electrochemical circuit, describes experimental curves in Nyquist coordinates almost comprehensively.

Download Full-text