Monika Furko

Electrochemical and morphological investigation of silver and zinc modified calcium phosphate bioceramic coatings on metallic implant materials

In our research nanostructured silver and zinc doped calcium-phosphate (CaP) bioceramic coatings were prepared on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was carried out by the pulse current technique at 70 °C from electrolyte containing the appropriate amount of Ca(NO3)2 and NH4H2PO4 components. During the electrochemical deposition Ag(+) and Zn(2+) ions were introduced into the solution. The electrochemical behaviour and corrosion rate of the bioceramic coatings were investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements in conventional Ringers solution in a three electrode open cell. The coating came into contact with the electrolyte and corrosion occurred during immersion. In order to achieve antimicrobial properties, it is important to maintain a continuous release of silver ions into physiological media, while the bioactive CaP layer enhances the biocompatibility properties of the layer by fostering the bone cell growth. The role of Zn(2+) is to shorten wound healing time. Morphology and composition of coatings were studied by Scanning Electron Microscopy, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. Differential thermal analyses (DTA) were performed to determine the thermal stability of the pure and modified CaP bioceramic coatings while the structure and phases of the layers were characterized by X-ray diffraction (XRD) measurements.

Corrosion Resistance of TIG Welded Joints of Stainless Steels

The aim of this work was to analyze the performance of joints made by TIG (Tungsten Inert Gas) welding process in austenitic and duplex stainless steels with special regards to their corrosion resistance. Three different types of stainless steel were butt welded with TIG method. Ferric-chloride test and electrochemical treatments revealed how does the TIG process affects the corrosion resistance depending upon the alloy used for welding the joint. This work focuses on the weldability of the 2304, 2404 and 304 type stainless steel heterogeneous welds.

Corrosion and biocompatibility examination of multi-element modified calcium phosphate bioceramic layers

Multi-ions doped bioactive calcium phosphate (dCaP) layers were developed by pulse current deposition onto surgical grade titanium alloy material (Ti6Al4V). The coatings were electrodeposited from base electrolyte containing adequate amounts of calcium nitrate and ammonium dihydrogen phosphate at 70 °C. After electrodeposition, the pure CaP layers were doped with different ions that possess bioactive and antimicrobial properties, such as Zn2+, Mg2+, Sr2+ and Ag+ ions. The morphology and structure of coatings were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy-dispersive X-ray Spectroscopy (EDX) as well as XRD and FT-IR measurements. The results revealed the pulse current deposited and surface post-treated CaP layer to be mainly in hydroxyapatite phase. The corrosion properties of bioceramic coatings were assessed in conventional simulated body fluid (SBF) in a three electrode open cell by using potentiodynamic polarization measurements over two weeks period. The electrochemical results revealed that the pure calcium phosphate (CaP) coated implant material and the bare implant possess the highest resistivity to corrosion, while the modified calcium phosphate coating showed lower corrosion resistance by at least one order of magnitude. The cell viability measurements showed that the electrochemically deposited CaP layer was biocompatible.

Pulse electrodeposition and characterization of non-continuous, multi-element-doped hydroxyapatite bioceramic coatings

Multi-element-modified bioactive hydroxyapatite (mHAp) coatings were developed onto commercial titanium alloy material (Ti6Al4V) in clusters. The coatings were prepared by applying pulse current deposition technique. The pure HAp layer was doped and co-deposited with Ag+, Zn2+, Mg2+, and Sr2+ ions. Potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) were performed in simulated body fluid (SBF) using three-electrode open cell over a long time period to assess the corrosion properties of bioceramic coatings. The biocompatible characteristics of layers were investigated by seeding osteoblast-like MG-63 cells onto the samples’ surface. The morphology and structure of coatings were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) while cross-sectional analyses were carried out by focused ion beam (FIB). The elemental composition of coatings was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The biocompatible measurements revealed enhanced bioactivity of modified HAp compared to uncoated implant materials and pure HAp bioceramic coating. The corrosion tests confirmed that the coatings were biodegradable.

Mechanical characterization and corrosion behavior of protective TiC/amorphous C nanocomposite coating as surface thin film

The aim of this article is to study the influence of TiC/a:C protective thin film on the corrosion and mechanical properties of sandblasted/polished Ti and TiAl6V4 substrates. The electrochemical corrosion behaviors of the samples were investigated in simulated body fluid (SBF) by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques at 7.4 pH and 37 °C. The metal ion release has been quantified by inductively coupled plasma optical emission spectroscopy (ICP-OES). The experimental results obtained from different electrochemical methods, ICP-OES, and scanning electron microscopy (SEM) showed that the TiC/a:C protective coating on sandblasted implant device improves the corrosion properties of the implant material and it is able to control the metal ion release. It was also shown that the hardness of the bare implant materials is improving by four orders of magnitude with the TiC/a:C nanocomposite coating beside a moderate elastic modulus value. The highest hardness (H) o...

Electrochemical and Morphological Characterization of Silver Doped Bioceramic Layer on Metallic Implant Materials for Orthopaedic Application

This study presents the production of silver doped bioactive calcium-phosphate (CaP) coatings on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was performed by pulse current technique from electrolyte containing the appropriate amount of Ca(NO3)2 and NH4H2PO4 components at 70 °C. In order to modify the CaP layer, Ag+ ions were added to the base electrolyte. The electrochemical behaviour of the coatings was investigated by potentiodynamic polarization method in conventional Ringer’s solution in a three-electrode open cell. The corrosion properties of samples prepared with different parameters were compared. During immersion, the coating comes into contact with the electrolyte and corrosion occurs. Due to the potential difference between layer and the metallic substrate, discrete anodic and cathodic areas can be formed, which result in the release of silver and calcium ions. For antimicrobial applications of the modified CaP coated implant alloys, it is important to maintain a continuous release of silver ions, while the bioactive CaP layer enhance the biocompatibility properties of the layer by fostering the bone cell growth. The morphology and grain size of coatings as deposited have been investigated and confirmed by different methods such as Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX) analysis.

Comparative Corrosion Study on Silver Coated Metallic Implants

Nanostructured silver layer was deposited by pulse current technique onto three different implant materials-TiAl6V4, CoCrMo alloy and stainless steel–that are commonly used in orthopedic surgery. The electrochemical behavior of the coatings in isotonic salt solution was investigated by potentiodynamic polarization measurements over a period of several weeks. The corrosion properties of silver coated different implant materials were compared. Degradation of silver coatings have been traced and confirmed by different methods such as scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) measurements.