8 documents found, page 1 of 1
As-cast and extruded Mg Zn Ca systems for biodegradable implants: Characterizat...
Moreno, Lara; Matykina, Endzhe; Yasakau, Kiryl A.; Blawert, Carsten; Arrabal, Raul; Mohedano, MartaThe aim of the present study is to evaluate the effect of alloy processing and composition as well as the pH control and testing medium on the in vitro corrosion performance of Mg –Zn –Ca systems for biodegradable implants. The grain size and secondary phases were analyzed by optical microscopy, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. Scanning kelvin probe force mi...
Investigation of Local Conduction Mechanisms in Ca and Ti-Doped BiFeO3 Using Sc...
Ivanov, Maxim S; Khomchenko, Vladimir A.; Silibin, Maxim V.; Karpinsky, Dmitry V.; Blawert, Carsten; Serdechnova, Maria; Paixão, José A.In this work we demonstrate the role of grain boundaries and domain walls in the local transport properties of n- and p-doped bismuth ferrites, including the influence of these singularities on the space charge imbalance of the energy band structure. This is mainly due to the charge accumulation at domain walls, which is recognized as the main mechanism responsible for the electrical conductivity in polar thin ...
The effect of iron re-deposition on the corrosion of impurity-containing magnesium
Hoeche, Daniel; Blawert, Carsten; Lamaka, Sviatlana V.; Scharnagl, Nico; Mendis, Chamini; Zheludkevich, Mikhail L.This article provides a contribution towards the mechanistic understanding of surface phenomena observed during the corrosion of Mg-based substrates particularly in the low anodic polarization range. The concept considers the recent literature explaining cathodic hydrogen evolution from noble acting areas even during global anodic polarization. Heavy metal impurities in the ppm range or intermetallics are alway...
Formation of photocatalytic plasma electrolytic oxidation coatings on magnesium...
Lu, Xiaopeng; Schieda, Mauricio; Blawert, Carsten; Kainer, Karl Ulrich; Zheludkevich, Mikhail L.Photocatalytically active plasma electrolytic oxidation coatings on AM50 Mg alloy are reported in the present work. The photocatalytic activity was achieved via introduction of anatase (TiO2 particles) to the treatment bath. The photocatalytic performance of the coating was evaluated by measuring the degradation rate of aqueous methylene blue solution and was primarily related to the anatase content on the coat...
Plasma electrolytic oxidation coatings with particle additions - A review
Lu, Xiaopeng; Mohedano, Marta; Blawert, Carsten; Matykina, Endzhe; Arrabal, Raul; Kainer, Karl Ulrich; Zheludkevich, Mikhail L.Plasma electrolytic oxidation (PEO) processing for light metals is known for decades and has been established as a well-known industrial surface treatment offering a reasonable wear and corrosion protection. However, long-term protection is compromised by the intrinsic porosity and limited range of composition in the PEO layer. A novel approach is to introduce particles to the electrolyte, aiming at their in-si...
Influence of surface pre-treatment on the deposition and corrosion properties o...
Zhang, Yufen; Blawert, Carsten; Tang, Shawei; Hu, Jin; Mohedano, Marta; Zheludkevich, Mikhail L.; Kainer, Karl UlrichCalcium stearate based hydrophobic coatings were deposited on pre-treated Mg alloy substrates. The influence of four different pre-treatments including plasma electrolytic oxidation (as prepared and etched), anodizing and hydrothermal treatment was studied. The results indicate that the pre-treatments have strong influences on the morphology, thickness, and wettability of the coatings, without affecting their p...
Characterisation and corrosion behaviour of plasma electrolytic oxidation coati...
Muhaffel, Faiz; Mert, Faruk; Cimenoglu, Huseyin; Hoeche, Daniel; Zheludkevich, Mikhail L.; Blawert, CarstenIn the present study, the influence of minor cerium (Ce) additions (up to 1 wt.%) to AM50 magnesium alloy on the plasma electrolytic oxidation (PEO) process and the corrosion performance of the PEO coatings were studied. Therefore, a silicate-based PEO coating was deposited on AM50 containing 0, 0.5 and 1 wt.% Ce under the same processing conditions. The resulting surface morphology, cross-sectional microstruct...
Degradation behavior of PEO coating on AM50 magnesium alloy produced from elect...
Lu, Xiaopeng; Sah, Santosh Prasad; Scharnagl, Nico; Stoermer, Michael; Starykevich, Maksim; Mohedano, Marta; Blawert, Carsten; Zheludkevich, Mikhail. L.Amorphous plasma electrolytic oxidation (PEO) coating with sealed discharge channels can be formed in alkaline phosphate electrolyte containing montmorillonite clay particles. The effect of various concentrations of phosphate and hydroxide ions in the clay-containing electrolyte on the microstructure of the coatings was studied in the present work and correlated with the corrosion behavior. The clay particles w...