Magdalena Szklarska

Localized Electrochemical Impedance Spectroscopy for Studying the Corrosion Processes in a Nanoscale

This work deals with localized electrochemical impedance spectroscopy (LEIS) which is an improved technique of the commonly used electrochemical impedance spectroscopy (EIS). Thanks to modern structural solutions, the LEIS technique ensures local impedance measurement. Therefore, it is used in the research into point corrosion, such as the pitting corrosion, and in the research into protective coatings or into alloys including alloy steels. This review paper presents the basic theory and the usability of the LEIS based on the literature on the newest research in the field of corrosion.

Application of the Scanning Kelvin Probe Technique for Characterization of Corrosion Interfaces

This paper deals with the basic theory and the usability of the scanning Kelvin probe (SKP) being a non-destructive, non-contact method for testing the condition of the surface of conductor, semiconductor and dielectric samples. This technique is based on the electron work function (EWF) characteristic of various test substances and depends, inter alia, on the sample surface condition. During measurement, the so-called surface potential distribution map containing information about EWF value is registered. Key applications of SKP and its various modifications to characterization of corrosion interfaces, have been presented based on the newest literature data covering the past two years of the active research in the field of corrosion in a nanoscale.

On the Use of the Scanning Electrochemical Microscopy in Corrosion Research

This paper deals with the basic theory and the usability of Scanning Electrochemical Microscopy (SECM) in corrosion research. The SECM is the in situ method of surface characterization which is based on the scanning of the tested surface using ultramicroelectrode and simultaneous electrochemical testing of the surface. This technique provides an electrochemical imaging of the surface. Key applications of SECM have been demonstrated based on the newest literature data covering the past two years of the active research in the field of corrosion in a nanoscale.

Characterization of Electrophoretically Deposited Chitosan Coatings on Ti13Zr13Nb Alloy for Biomedical Applications

The chitosan (CH) coatings on a Ti13Zr13Nb alloy substrate were obtained by electrophoretic deposition (EPD). The EPD yield was investigated under different deposition conditions. The microstructure of the CH coatings obtained by cataphoresis was studied by scanning electron microscopy and the chemical composition was examined using EDAX. The functional groups and formed phases were analyzed using Fourier transform infrared spectroscopy and X-ray diffraction, respectively. It was found that the CH coating thickness and porosity can be controlled by time and voltage used for the EPD process. It was ascertained that the studied EPD of the natural biopolymer, chitosan, in aqueous solution is applicable for the surface modification of the Ti13Zr13Nb implants to develop novel bioactive coatings.

Use of Scanning Vibrating Electrode Technique to Localized Corrosion Evaluation

This work presents the basic theory and the usability of the scanning vibrating electrode technique (SVET), especially in the field of corrosion. At present, SVET is to be considered as one of the latest electrochemical testing methods. The essence of determining the current density resulting from corrosion is limited to the measurement of the potential gradient between the two points on the surface of the metal and over it, within the electric field of a local element. SVET has been used to study local, galvanic and intercrystalline corrosion. It is particularly useful in studying the corrosion of alloy steels and welding agents. This paper presents a review of the literature on the newest research in this field.

Effect of Phosphorus on the Structure of Nickel Electrocoatings

The present work deals with the influence of sodium hypophosphite content in the plating bath on the chemical composition and structure of the obtained nickel electrocoatings. Electrodeposition of the Ni-P coatings was conducted under galvanostatic conditions at room temperature from the Watts type bath containing different amounts of sodium hypophosphite (0-30 g dm-3). The chemical and physical characteristics of the obtained Ni-P deposits and comparable Ni coating, were performed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) methods. It was found that the addition of sodium hypophosphite as amorphizator to the Ni-plating bath influences both the structure and chemical composition of the obtained Ni electrodeposits. With increase in the content of sodium hypophosphite in the bath, surface morphology of the amorphous Ni-P coatings becomes more developed what is of key-importance for electroevolution of hydrogen on such electrodes.

Effect of Phosphorus on the Corrosion Resistance of Nickel Electrocoatings

The electrodeposited Ni-P coatings are commonly used for their electrocatalytic properties towards hydrogen evolution reaction. However, their corrosion resistance in concentrated alkaline solutions is still less known. In this work, the effect of phosphorus on the resistance of nickel electrodeposits to electrochemical corrosion in 5 M KOH solution, was studied. Open circuit potential and anodic polarization measurements were performed to determine parameters of the corrosion resistance of the crystalline Ni deposit and amorphous Ni-P electrocoating. It was found that alloying of nickel with phosphorus is the effective manner of the improvement of the corrosion resistance of the nickel coatings. The obtained Ni-P electrode material contained 10 wt.% of P and revealed amorphous structure. The increase in the corrosion resistance of the Ni90P10 system as compared to that determined for comparable Ni polycrystalline electrode was due to phosphate formation responsible for broad passivation potential in alkaline medium and amorphous structure.

A Coulometric Method by Local Anodic Dissolution for Measuring the Thickness of Ni/Cu Multi-Layer Electrocoatings

The coulometric or anodic de-plating technique can be used for measuring the thickness of coatings on virtually all substrates such as steel, non-ferrous metals or insulating material bases. This study reports on application of an electrochemical de-plating technique for measuring the thickness of multilayer Ni/Cu coatings electrodeposited on a steel substrate. Principles of a coulometric method by local anodic dissolution according to ISO 2177:2003 have been explained. The phase analysis of the Ni/Cu multi-layer coatings was performed using GIXD technique. The summary of the GIXD diffraction patterns obtained in this experiment indicates that such electrocoating is composed of two sub-layers of nickel and copper.

Characteristics of the Galvanic Baths for Electrodeposition of Nickel Coatings Using the Hull Cell

Electrodeposition of polycrystalline nickel onto carbon steel substrate has been studied from different types of solutions: (bath I) the Watts nickel plating bath, (bath II) the sulfate-chloride nickel plating bath for production of the SUPER Ni coatings, (bath III) the sulfamate nickel plating bath, and (bath IV) the chloride nickel plating bath. A detailed study has been made on the influence of the bath composition on the mass increment and thickness of the deposited Ni coatings. Cathodic current efficiency of the Ni electrodeposition has been also studied. The electrochemical anodic de-plating technique has been used for measuring the thickness of nickel coatings according to ISO 2177:2003. Evaluation of the effect of bath composition on the quality of the galvanic nickel coatings, was carried out using the Hull cell. In a single test, the range of current densities which provided a desired plating characteristic at a given total current, was previewed. Principles of the electroplating process using the Hull cell have also been explained.