bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Pretreatment on the Corrosion Resistance of Superheater Materials
Authors: Lehmusto Juho , Yrjas Patrik , Hupa Mikko
Published: January 2015

In order to improve the power production efficiency of biomass-fired boilers, power plants must be operated at higher steam temperatures than nowadays. One of the main factors hindering the rise of the steam temperatures is the corrosive nature of the flue gases and fly ash towards the superheaters. In this study, the high-temperature corrosion resistance of three commercial superheater steels exposed to potassium chloride was compared. The focus was on the effect of pre-oxidation on the protective properties of different steels, whereupon various variables were used during the pre-oxidation.
The Formation of TBCs Using LPPS, CVD and PS-PVD Methods on CMSX-4 Single-Crystal Nickel Superalloy
Authors: Góral Marek , Pytel Maciej , Drajewicz Marcin
Published: January 2015

In the paper new type of thermal barrier coatings characterized by good oxidation and hot corrosion resistance were presented. Bond coats were formed by overaluminizing of an MeCrAlY type coating deposited by low pressure plasma spraying (LPPS). The outer ceramic layer of yttria stabilized zirconia (Metco 6700) was deposited by plasma spray physical vapour deposition (PS-PVD). Rene 80 nickel superalloy was used as base material. The research showed that double-layer bond coat was formed with external NiAl phase layer and inner MeCrAlY layer. The outer ceramic layer was characterized by columnar structure similar to that obtained in the EB-PVD process. The presence of secondary reaction zone (SRZ) was noted.
The Influence of Overaluminizing on TGO Formation on Thermal Barrier Coatings Deposited by Low Pressure Plasma Spraying and Chemical Vapour Deposition Methods on Rene 80 Nickel Superalloy
Authors: Góral Marek , Pytel Maciej , Cmela Wojciech , Drajewicz Marcin
Published: January 2015

The paper presents results of research into isothermal oxidation test of thermal barrier coatings characterized by high oxidation resistance and hot corrosion. Bondcoats were deposited by overaluminizing of MeCrAlY–type coating deposited by LPPS method. The outer ceramic layer of yttrium oxide stabilized zirconia oxide (Metco 6700) was deposited by plasma spray physical vapour deposition (PS-PVD). For comparison purposes additionally LPPS-sprayed were MeCrAlY bondcoats, which were not subsequently aluminized.. The isothermal oxidation test at 1100oC for 1000h shown that thickness of the TGO layer in overaluminized bondcoat was significantly thicker in comparison with conventional LPPS-sprayed MeCrAlY bondcoats.
Microstructure and Isothermal Oxidation Resistance of Thermal Barrier Coatings Deposited by LPPS, CVD and PS-PVD Methods on Inconel 617 Nickel Superalloy
Authors: Kotowski Sławomir , Sieniawski Jan , Drajewicz Marcin
Published: January 2015

The paper presents results of research into thermal barrier coatings characterized by higher oxidation resistance. Bondcoats were formed by overaluminizing of the MeCrAlY coating, deposited by low pressure plasma spraying (LPPS). The outer ceramic layer of yttrium oxide stabilized zirconia oxide was deposited by plasma spray physical vapour deposition (PS-PVD). For comparison purposes additionally formed were MeCrAlY bondcoats, which were not subsequently aluminized. The research showed that during CVD overaluminizing there was formed an additional layer built of the β-NiAl phase, which protects the base material from oxidation. Preserved below it increased chromium content ensures resistance to hot corrosion. The outer layer was characterized by columnar structure, similar to that obtained in the EB-PVD process. The isothermal oxidation tests showed that thickness of the TGO layer into overaluminized bondcoat significantly thicker in comparison with conventional LPPS-sprayed MeCrAlY bondcoats.
Heat Resistance and Heat Capacity of the Selected Nickel Superalloys
Authors: Przeliorz Roman , Góral Marek
Published: January 2015

The paper presents results of tests into heat resistance and specific heat capacity of nickel-based superalloys: Rene 80, Mar-M-200+Hf i Mar-M-247+Hf. Heat resistance tests were carried out with the use of a cyclic method. Each cycle involved a 23-hour period of heating at 1100oC, followed by 1-hour air cooling. The DSC method was applied to determine specific heat. Scale microstructure was examined with the use of an electrone microscope. The tested alloys have been proven to enjoy relatively good resistance to corrosion. The Mar-M-200+Hf alloy enjoys the highest specific heat capacity, while the lowest value of specific heat has been recorded for the Mar-M-247+Hf alloy.
Microstructure of Thermal Barrier Coatings Deposited by Low Pressure Plasma Spraying and Chemical Vapour Deposition Methods on Rene 80 Nickel Superalloy
Authors: Góral Marek , Pytel Maciej , Cmela Wojciech , Kotowski Sławomir
Published: January 2015

The paper presents results of research into thermal barrier coatings characterized by high oxidation resistance and hot corrosion. Bondcoats were formed by overaluminizing of an MeCrAlY–type coating deposited by low pressure plasma spraying. The outer ceramic layer of yttrium oxide stabilized zirconia oxide (Metco 6700) was deposited by plasma spray physical vapour deposition (PS-PVD). For comparison purposes additionally LPPS-sprayed were MeCrAlY bondcoats, which were not subsequently aluminized. Used as base material was Rene 80 nickel superalloy. The research has shown that as a result of aluminizing by the CVD method there was formed in the bondcoat a deposit zone built of the β-NiAl phase which protects from oxidation. Preserved below increased chromium content ensures resistance to hot corrosion. The outer ceramic layer was characterized by columnar structure similar to that obtained in the EB-PVD process.
Oxidation Behavior of Aluminide Coated Ti-Al-Cr-Nb-Zr-Y Alloys at High Temperatures
Authors: Basuki Eddy , Prajitno Djoko , Pawawoi Pawawoi
Published: January 2015

In this study the oxidation behavior of diffusion aluminide coating containing layers of TiAl3 and TiAl2, develop on a substrate of Zr-Y doped α2-Ti3Al/γ-TiAlCrNb intermetallic alloy using pack aluminizing method, was investigated isothermally at 800°C, 900°C, and 1000°C under atmospheric air pressure. The pack cementation was carried out at 850°C for 25 hours in a pack containing 20%-wt Al, 2%-wt NH4Cl, and 78%-wt Al2O3.The phases in the coatings and oxide layers were examined by optical and scanning electron microscopy as well as X-ray diffraction method, while chemical composition of the oxides and phases were examined with EDS attached on the SEM. The experimental results showed that the addition of Zr and Y increases the oxidation resistance of the coating by formation of complex oxides mainly of Al2O3 at the coating surfaces and sub-surface. Combination of oxidation and interdiffusion process cause transformation of TiAl3 layer to TiAl2 that decrease the oxidation resistance through the formation of TiO2 rod crystals on the junction between TiAl2 and Al2O3 in the outer layer.
Degradation of Diffusive Aluminide Coating after Service in ZhS6K Superalloy
Authors: Chmiela Bartosz , Kianicova Marta , Sozańska Maria
Published: January 2015

We considered the degradation of hollow turbine blades made of ZhS6K nickel-based superalloy after service in an aircraft engine. The blades were coated with a diffusive aluminide coating (Al-Si) to improve resistance to oxidation and hot corrosion. Turbine blades work under extreme conditions and a complex state of stress. During service, creep and fatigue occur. The interaction among hot combustion gases causes oxidation of the surface layer, hot corrosion, and micro-cracking of the coating. Moreover, changes occur in the morphology of the γ’ phase just under the coating, and transformations of the primary carbides take place. The factors limiting the lifetime of a turbine blade are the quality of the aluminide coating and the microstructure of the superalloy, depending on the service parameters (the temperature and the duration service). We found that exposure to high temperatures above the critical value for several seconds substantially decreased the engine power and its durability. We analysed the microstructure, chemical composition, and phase composition of turbine blades after service. An evaluation of the extent of degradation was performed using scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDS), and electron backscatter diffraction (EBSD). The EBSD technique was used to analyse the phase composition in micro-areas, especially to identify carbides before and after transformations.
Resistance to Electrochemical Corrosion of Extruded Magnesium Alloy AZ31
Authors: Przondziono Joanna , Hadasik Eugeniusz , Walke Witold , Szala Janusz
Published: January 2015

The purpose of the study was evaluation of electrochemical corrosion resistance of extruded magnesium alloy AZ31. Corrosion tests were performed in NaCl solutions featuring chloride ions concentration from 0.01 to 2 M NaCl. Potentiodynamic tests enabled to register anodic polarisation curves. Immersion tests were performed in NaCl solution and time 1-5 days. Electrochemical impedance spectroscopy (EIS) was used to evaluate phenomena that take place on the surface of the tested alloy. Impedance spectra of the system were made in the tests, and obtained measurement data was matched to the equivalent system. The results of all performed tests prove explicitly deterioration of corrosion properties of extruded magnesium alloy AZ31 with the increase of molar concentration of NaCl solution. Options of magnesium alloy AZ31 application in aircraft and automotive industry are connected with the need for application of protective layers on elements made of the tested alloy.
The Influence of Activator on Vapour Phase Aluminizing of TiAl Intermetallics
Authors: Góral Marek , Gradzik Andrzej , Sieniawski Jan , Filip Ryszard , Sieniawski Jan , Wierzbinska Małgorzata
Published: January 2015

The paper presents results of research into the aluminizing process of TiAl intermetallics. The substrate was Ti48Al2Cr2Nb intermetallic alloy. The BPX Pro 325S CVD system was used for aluminizing process. Used in the experimental were four types of activators: AlCl3, AlF3, ZrCl4 and HfCl4. During the aluminizing process 2 kg of Al-Cr granules were put in a container. The deposition process was carried out in argon atmosphere for a duration of 4 hours at the temperature of 1000°C. The XRD and chemical analysis were conducted. The results showed than aluminide coatings contained TiAl2 and TiAl2 phases were formed using an AlF3 activator. In other processes the amount of Al in the coatings was smaller than in the substrate. The obtained results showed that for the aluminizing process use of aluminum fluorides is necessary.
The Influence of the Chemical Composition of Superalloys on the Oxidation Resistance of Aluminide Coating
Authors: Zagula-Yavorska Maryana , Sieniawski Jan , Filip Ryszard
Published: January 2015

The aim of the present work was to determine the influence of chemical composition of the coating protected nickel based superalloys Inconel 713 LC, Inconel 625 and CMSX 4 on the oxidation resistance of aluminide coating. Protective aluminide coatings were deposited in the CVD process. The low activity aluminizing at the presence of AlCl3 and H2 was carried out. Cyclic oxidation test for both coated and uncoated superalloys was performed at 1100°C for 1000 h in the air atmosphere. Microstructure of aluminide coatings after oxidation test was investigated by a scanning electron microscopy (SEM) and an energy dispersive spectroscopy (EDS). The best oxidation resistance shows uncoated Inconel 713 LC superalloy. That is due to a relatively high aluminum content in this alloy. The aluminide coating deposited on the surface of Inconel 625 shows the largest oxidation resistance (insignificnt changes of mass for the whole test duration). Excellent oxidation resistance is a result of Al2O3 scale formation.
Influence of Deposition Parameters on Structure of TDCs Deposited by PS-PVD Method
Authors: Góral Marek , Kubaszek Tadeusz , Kotowski Sławomir , Sieniawski Jan , Dudek Stanislaw
Published: January 2015

The paper presents an advanced technology of Thermal Barrier Coatings (TBCs) deposition called Plasma Spray – Physical Vapor Deposition (PS-PVD). The PS-PVD is a low pressure plasma spray technology to deposit coatings out of vapor phase, which enables obtaining of columnar ceramic coatings. In this paper, the influence of various gas mixtures on properties of deposited coatings has been investigated. The measurement of coating thickness was conducted by a light microscopy method, followed by a statistical analysis. All processes had been conducted at a very low feed rate, which additionally affected ceramic microstructure.
Microstructure of TBC Coatings Deposited by HVAF and PS-PVD Methods
Authors: Szymański Krzysztof , Góral Marek , Kubaszek Tadeusz , Monteiro Paulo Cyhlar
Published: January 2015

High velocity air fuel (HVAF) is one of the high velocity flame spraying process (HVFS). The HVAF method employs a combination of liquid fuel mixed in a chamber with compressed air to obtain high velocity flows. This technology can provide high deposition levels, adequate bond strength as well as high dense coating structure. The working principle of Plasma Spray – Physical Vapor Deposition (PS-PVD) is based on evaporation of the ceramic powder, which enables advanced microstructure of the deposits. In this paper, microstructure of Thermal Barrier Coating (TBC) deposited by HVAF and PS-PVD method was described.
The Technology of TBC Deposition by EB-PVD Method
Authors: Pędrak Paweł , Nowotnik Andrzej , Góral Marek , Kubiak Krzysztof , Drajewicz Marcin , Sieniawski Jan
Published: January 2015

The role of thermal barrier coatings is to ensure heat resistance of elements in the hot section of turbofan aircraft engines in high temperatures. Stages of the production process are made up of preparing the base material, forming the aluminide interlayer by chemical vapour deposition method and depositing of the ceramic coating. The paper presents results of tests into microstructure of ZrO2 and Y2O3 ceramic coatings formed by EB-PVD method. The microstructure was assessed in several spots of the turbine blade of a high pressure turbofan engine by means of determining the coating thickness as well as height and width of ceramic columns, depending on the forming conditions.
Influence of Surface Condition on Oxides Layer Morphology on NiCrAlY Coating during Oxidation at Temperature 1000°C and 1100°C
Authors: Moskal Grzegorz , Niemiec Dawid
Published: January 2015

Characterization of top-surface of NiCrAlY coating deposited by plasma spraying process on Inconel 625 Ni based superalloys was analyzed in two different completely conditions. First of them was as sprayed state of NiCrAlY coating and the second one was condition after grinding process. The basic aim of this treatment was related to obtain totally different conditions of coatings surface especially from roughness point of view. Those two types of top surface morphology was a base to comparison of oxidation resistant during static oxidation test at temperature of 1000°C and 1100°C. The temperature of static oxidation test was 1000°C and 1100°C. The specimens were moved out from furnace after 25, 300, 500, 750 and 1000 hours of exposition in laboratory air. The range of investigations after each interval included top surface characterization of specimens by SEM, XRD and EDS method. Those investigations showed that different types of top surface conditions had a fundamental influence on oxides layer morphology. Especially in the case of phase`s constituent of oxides zone. More detailed investigations were made on the cross sections of two types of investigated specimens. Analysis of oxides layer morphology showed in this case basic differences in thickness of oxides zone which was much higher in the case of as sprayed NiCrAlY coating.
Studies on the Adhesion of Oxide Layer Formed on Steel Long-Term Operated at an Elevated Temperature
Authors: Gwoździk Monika
Published: January 2015

The paper contains results of studies into the formation of oxide layers on steel long-term operated at an elevated temperature. The material studied comprised specimens of steel taken from an steam pipeline and on the flue gas side. The oxide layer adhesion tests were carried out on an automated Revetest XPress Plus instrument using a diamond Rockwell indenter. The adhesion of oxide layers, friction force, friction coefficient, scratching depth were determined as well as the force at which the layer was delaminated. It has been found that the oxide layer formed under the influence of applied pressure is more degradation in the areas where are a pores and cracks.
Comparison of High-Temperature Oxidation Onset Behavior of Sanicro 28 Steel with KCl, NaCl and K2CO3
Authors: Sui Jing Xin , Lehmusto Juho , Bergelin Mikael , Hupa Mikko
Published: January 2015

This paper presents results from a study regarding the influence of three alkali salts (KCl, NaCl, and K2CO3) on the initial high temperature corrosion behavior of high alloy stainless steel Sanicro 28 (Fe31Cr27Ni) at 535°C. It was found that all three salts were corrosive, however, with clear differences in terms of reaction initiation.
High-Temperature Corrosion Resistance of Welded Joints in Sanicro 25 Steel
Authors: Jamrozik Przemysław , Sozańska Maria
Published: January 2015

The trials conducted in sulfur– and chlorine–rich environment were aimed at simulating the conditions prevalent in operating power boilers. The tests conducted in the temperatures of 700°C and 750°C have been selected in such a way as to enable reference between them and the supercritical parameters of boiler steam. The analysis of the rate of high–temperature corrosion kinetics in the Sanicro 25 steel was carried out for up to 3000 hours. The aim of the tests was to establish the oxidation kinetics and evaluate the destruction of the new generation of Sanicro 25 steel in atmosphere containing Cl and S in temperature of 700°C and 750°C during up to 3000 hours of operation.
High-Temperature Corrosion Resistance of Welded Joints in HR6W Alloy
Authors: Jamrozik Przemysław , Sozańska Maria
Published: January 2015

The trials conducted in sulfur– and chlorine–rich environment were aimed at simulating the conditions prevalent in operating power boilers. The tests conducted in the temperatures of 700°C and 750°C have been selected in such a way as to enable reference between them and the supercritical parameters of boiler steam. The analysis of the rate of high–temperature corrosion kinetics in the HR6W alloy was carried out for up to 3000 hours.
The Morphology of Corrosion Products in FeAl Alloys after Heat-Resistance Tests at Different Temperatures
Authors: Fornalczyk Agnieszka , Cebulski Janusz , Dorota Pasek
Published: January 2015

The alloys based on intermetallic phases involving Al belong to a new group of heat-resistant materials. Their physico-chemical and mechanical properties allow to apply them in the operating conditions in corrosive environment and elevated temperature. Research conducted for many years has shown that these materials can work at temperature up to 1100°C without degradation of their occurrence in the environment containing oxygen and sulphur. Heat resistance of these materials is provided by forming the Al2O3 passive layer on the surface. This layer is a protective barrier, which hinders the oxygen diffusion into the surface. This paper presents the morphology of passive Al2O3 layer depending on the temperature of its formation. The study allows to define the surface condition for corrosion products carried out using scanning electron microscopy together with EDS X-ray microanalysis.
Thermal Properties of YSZ Powders for Plasma Spraying
Authors: Drajewicz Marcin , Dychtoń Kamil , Góral Marek
Published: January 2015

The oxides in the case of theirs properties are important materials for industrial application especially, in aircraft industry for application as thermal barrier coatings. Thermal properties of zirconium oxide stabilized by yttria are better than other ceramic materials. This powder could be stabilized in room temperature by addition of rare earth elements. In this article the thermal analyses of yttria stabilized zirconia (YSZ) oxide are presented as a baseline for future measurements of thermal properties of YSZ powder with addition of rare earth elements. The thermal expansion, specific heat, thermal diffusivity and thermal conductivity of commercially available Matco 6700 powder offered by Sulzer Metco company were analyzed by thermal methods.
Oxidation Resistance of Diffusion Silicide Coatings on Mo and TZM Alloy
Authors: Moskal Grzegorz , Witala Bartosz , Tracz Jarosław , Kałamarz Piotr , Supernak Wacław , Polis Szymon , Jucha Sebastian , Wrona Adriana , Osadnik Małgorzata
Published: January 2015

Characterization of microstructure of pack cemented silicide coatings based on MoSi2 phase was described in this article as well as a short term oxidation resistance of these types of coatings at temperature 1200oC. Silicide coatings were deposited on top surface of Mo and Mo alloys of TZM type by diffusional process of siliconizing in activated powders. Morphology of coatings was characterized by evaluation of chemical and phase’s composition of deposited coatings by EDS and XRD methods respectively. In the case of Mo sheet after diffusion process of siliconizing single layer of MoSi2 type was obtained, but in the case of TZM alloy, in the same conditions of process, double layered coating was generated. Thick outer layer was build form MoSi2 phase, but very thin internal layer consist Mo5Si3 phase. The thicknesses of coatings were ca. 45μm, and were uniform. Morphology of coatings was free from inclusion and contaminations in their cores. The isolated cracks were observed, but their volume was very small. The oxidation test was performed at temperature 1200oC. The specimens were tested at 25, 500 and 100 hours of test. After each period of test characterization of coatings top surface was made. Total destruction of specimens was observed in range between 50 and 100 h of test.
Nonstoichiometry and Chemical Diffusion in Co3O4 Cobalt Oxide
Authors: Grzesik Zbigniew , Kaczmarska Anna , Mrowec Stanisław
Published: January 2015

Nonstoichiometry and chemical diffusion in Co3O4 oxide have been studied as a function of temperature (973-1173 K) and oxygen pressure (30-105 Pa), using thermogravimetric techniques. It has been found that at very low oxygen pressures, close to the dissociation pressure of the oxide, interstitial cations and quasi-free electrons are the predominant point defects, while at high pressures cation vacancies and electron holes predominate. This behaviour is reflected in complex dependence of the deviation from stoichiometry, y, in the Co3±yO4 oxide on oxygen pressure. At low pressures, namely, deviation from stoichiometry decreases with increasing oxygen pressure, reaching virtually constant value in intermediate pressures and increases at highest pressure range. Finally, these data as well as the results of kinetic rate measurements of Co3±yO4 formation have been utilized in calculating the chemical diffusion coefficient as a function of temperature.
The Influence of Reinforcement Purity on Corrosion Resistance of AM50/SiC Composites
Authors: Kamieniak Kinga , Malik Marcin A.
Published: January 2015

The microstructure and corrosion behaviour of AM50/SiC magnesium matrix composites reinforced with SiC particles were investigated. Composites containing 10 wt. % of SiC were fabricated by means of gravity casting. Technical grade silicon carbide used for the composites fabrication was subjected to a purification procedure leading to the removal of iron containing impurities from its surface. The corrosion resistance of the composite with purified SiC particles was compared to the corrosion resistance of the one containing crude technical grade silicon carbide as well as to the corrosion resistance of the matrix alloy. Voltammetry and an electrochemical noise technique as well as hydrogen evolution rate measurements were utilized for that purpose. Corrosion tests were performed in 0.5 mol dm3 NaCl saturated with Mg (OH)2. It has been demonstrated that the composite containing purified SiC was less susceptible to corrosion than the one containing crude SiC particles. Both composites were less resistant to corrosion than their matrix itself. Regardless of a purity level of SiC which was used for the composites fabrication, the same constituents were revealed in their microstructure, namely: α-phase (a solid solution of aluminium in magnesium), fully divorced eutectic α + γ (where γ-phase is Al12Mg17), intermetallic compound Al8Mn5 and SiC particles uniformly distributed in the whole volume of the matrix.
Corrosion and Mechanical Behavior of Biodegradable Metallic Biomaterials
Authors: Vojtěch Dalibor , Kubásek Jiří , Capek Jaroslav , Michalcova Alena , Pospíšilová Iva
Published: January 2015

Biodegradable alloys are currently studied as prospective biomaterials for temporary medical implants like stents and fixation devices for fractured bones. Among biodegradable metals, only magnesium, zinc and iron meet general requirements of biocompatibility and relative non-toxicity. In the present paper, Mg-, Zn- and Fe-based biodegradable alloys are compared. Advantages and disadvantages of the three kinds of alloying systems are demonstrated regarding the corrosion behavior, mechanical performance and biocompatibility. From the corrosion behavior point of view, Zn- and Fe-based alloys appear as promising alternatives to Mg-based alloys.
Corrosion Study of Amorphous Mg67Zn29Ca4 Alloy
Authors: Nowosielski Ryszard , Cesarz-Andraczke Katarzyna , Babilas Rafał , Maciej Artur , Nawrat Ginter
Published: January 2015

The aim of this paper was investigating the corrosion resistance of Mg67Zn29Ca4 metallic glass and evaluating the ability of use studied amorphous alloy for medical applications as biodegradable implants. For comparative purposes the corrosion studies of the amorphous Mg67Zn29Ca4 samples were performed in a few simulated body fluids at 37°C. The immersion tests were performed in Ringer’s solution, PWE (multielectrolyte physiological fluid) and 3%NaCl water solution. The amount of evolved hydrogen[ml/cm2] and a corrosion rate Vcorr [g/(day·m2)] of studied Mg67Zn29Ca4 alloy were compared. Surface morphology of metallic glass after corrosion study was performed using the scanning electron microscopy.In aim determination dissolution rate and amount of evolved hydrogen was simulated the environment of human body fluids during immersion tests. The work presents structure characterization and corrosion properties analysis of Mg67Zn29Ca4 bulk metallic glasses in the form of plates. Samples structure was analyzed by means of X-ray diffraction. Fractographic study a cross section of the sample in plates form was performed using scanning electron microscopy
Electrochemical Behaviour of Co-Cr and Ni-Cr Dental Alloys
Authors: Loch Joanna , Łukaszczyk Alicja , Augustyn-Pieniążek Joanna , Krawiec Halina
Published: January 2015

The purpose of this paper was to study the corrosion resistance of Co-Cr and Ni-Cr dental alloys in simulated artificial saliva by means of electrochemical techniques. Co and Ni based alloys are widely used in dental skeletal structures and orthopedic implants such as screws, pins and plater. And recently they have been applied for making stents. The advantages of these alloys include low cost of casting, matching thermal expansion coefficient with the ceramics of metal-ceramic restorations, and acceptable mechanical and tribological properties in vivo. The microstructure of investigated alloys were studied by using optical microscopic observation, X-ray diffraction measurements and Scanning Electron Microscope with X-ray microanalyzer. The mechanical properties were characterized by microhardness tests.
Improvement of the Corrosion Resistance of Biomedical Magnesium Alloys in the Ringer’s Solution Using Protective Coatings
Authors: Kot Iwona , Krawiec Halina
Published: January 2015

The corrosion resistance of magnesium alloys depends on their microstructure, especially the presence of different intermetallic phases and precipitates. In this paper, the electrochemical behaviour of Mg1Ca and Mg1Ca1Si magnesium alloys has been investigated in the Ringer’s solution at 37 °C. In order to improve the corrosion resistance of these magnesium alloys composite coatings were fabricated by modification of a chitosan layer. The coatings were prepared by dip-coating in a chitosan solution and then modified by electrochemical deposition of a layer from a solution containing fluorine ions and water glass. The electrochemical performance of chitosan and chitosan modified coated alloys was evaluated by linear sweep voltamperometry and electrochemical impedance spectroscopy. The coated magnesium alloys possess suitable corrosion behaviour for the application as biodegradable implant material.
Influence of Ultrasound Bone Union Stimulation on Corrosion Resistance of Titanium Alloys
Authors: Szewczenko Janusz , Zabuga Anna , Kaczmarek Marcin , Basiaga Marcin , Kajzer Wojciech , Paszenda Zbigniew , Nowińska Katarzyna
Published: January 2015

The influence of bone union activation realized with the use of the low-intensity pulsed ultrasound (LIPUS) on degradation of titanium alloys was presented in the work. Ti6Al4V ELI and Ti6Al7Nb alloy samples of modified surface layer were used in the study. The preliminary surface treatments were: grinding, vibration machining, mechanical polishing, sandblasting and electrochemical polishing. The final procedures of the surface modification were anodization and steam sterilization.
The scope of the work included the study of pitting corrosion resistance and concentration of metal ions released to the Ringer’s solution. The study was performed for the undeformed and deformed samples subjected to the influence of ultrasound. The reference samples were the samples kept in the solution and not having the impact of ultrasound.
On the basis of the study it was found that the conditions for bone union stimulation by low intensity pulsed ultrasound do not initiate pitting corrosion of the titanium alloy samples, although they increase the mass of ions released from the surface to the solution.
Corrosion Properties of Anodically Oxidised and Alkaline Treated Titanium Nitride
Authors: Brojanowska Agnieszka , Kowalczyk Konrad , Sadłowska Dominika , Sobiecki Jerzy Robert
Published: January 2015

The article compares the corrosion properties of oxide layers formed on titanium nitride (obtained by means of glow-discharge nitriding) using anodic and plasma oxidation. The corrosion properties are analysed in relation to the surface morphology and microstructure of the layers. The oxidation processes were carried out in phosphoric acid (V) (25wt%) containing Ca2+ calcium ions. In this environment, oxide layers were produced using two anode oxidation potentials: 5 V and 9.5 V and two plasma oxidation potentials of 200 V and 600 V. The layers were then subjected to alkaline treatment in concentrated NaOH. The concentration of acid and calcium ions contained in the oxidation solution affected the surface morphology and corrosion properties of the oxide layers obtained after alkaline treatment.
The Properties of Refined Glasses with Aluminum Hydroxide Nano-Molecules
Authors: Drajewicz Marcin , Pytel Maciej , Rokicki Paweł , Góral Marek
Published: January 2015

New refining technology of soda – calcium – silicon glass surfaces with inorganic compounds nanomolecules has been presented in the study. In order to determine modification of the glass surface SEM observation and EDX analysis have been carried out. The glass samples were subjected to the UV-VIS, photo-elasticity and ellipsometry examinations. From obtained results follows, that refining of the glass surface by nanopowder aluminum hydroxide compounds provides forming of very thin surface layers. This type of modification improves physical glass properties. As the example results of microhardness refined glass are presented in the article.Keywords: glass, surface, nanoparticles, refining
Corrosion Properties of Plasma Oxidized Titanium Nitride for Biomedical Applications
Authors: Sobiecki Jerzy Robert , Brojanowska Agnieszka , Kowalczyk Konrad
Published: January 2015

The article compares the corrosion properties of oxide layers formed on titanium nitride (obtained in glow-discharge nitriding) using electrolytic plasma oxidation. The corrosion properties are analysed in correlation with the surface morphology, microstructure and chemical composition of the layers. The oxidation processes were carried out in 10% and 25% phosphoric acid (V) solutions containing Ca2+ calcium ions. In each of these environments, oxide layers were formed using three oxidation potentials: 200V, 400V and 600 V. The oxidation potential and the concentration of acid and calcium ions in the oxidation solution was shown to affect the morphology of the surface and the corrosion properties of the oxide layers obtained.
Corrosion Properties of Oxide Layers Produced on Titanium Nitride by Means of Plasma Electrolytic Oxidation of Various Duration
Authors: Kowalczyk Konrad , Brojanowska Agnieszka , Sobiecki Jerzy Robert
Published: January 2015

The corrosion resistance of oxide layers produced on titanium nitride (obtained in glow-discharge nitriding) by means of electrolytic oxidation at different potentials and durations is presented in the paper. The oxidation processes were carried out in phosphoric acid (V) (25wt.%) containing Ca2+ calcium ions. Two plasma oxidation potentials of 40 V and 100 V were applied. Treatment was carried out at two different process durations, i.e. 30 minutes and 120 minutes. The impact of oxidation potential and process time on the morphology of the surface and corrosion properties of the oxide layers obtained was examined.
Effect of the High Voltage Anodic Oxidation on the Titanium Corrosion Resistance
Authors: Koper Jeremiasz Krzysztof , Jakubowicz Jarosław
Published: January 2015

The paper describes anodic oxidation of titanium surface in a potential range from 30 to 240 V in a 2M H3PO4 electrolyte with the addition of 0÷2 % HF. The aim of the treatment was to form titanium oxide with a developed, rough morphology, useful for biomedical application. The morphology of the anodically oxidized samples was examined using SEM and AFM. The phase structure of the oxides was determined by XRD. One of the main parameters determining the suitability of that material for biomedical application is the corrosion resistance in an environment comparable to human body (Ringer’s solution). It has been observed that corrosion resistance of the anodized surfaces increases with the increase of the anodizing voltage for the samples oxidized in an electrolyte containing 0 % and 0.2 % HF. In electrolytes with the addition of 1 % and 2 % HF an inverse relationship was observed. The corrosion resistance of all tested surfaces was sufficiently high for the application as a biomaterial. The most promising anodizing treatment, providing best surface morphology and corrosion resistance was performed at 210 V in a 2M H3PO4 + 1 % HF electrolyte.
Impact of Surface Modification of Ti-6Al-7Nb Alloy on Electrochemical Properties in the Environment of Artificial Blood Plasma
Authors: Basiaga Marcin , Paszenda Zbigniew , Walke Witold , Karasiński Paweł , Marciniak Jan
Published: January 2015

In order to improve the hemocompatibility of the Ti-6Al-7Nb alloy the study authors have proposed the modification of surface by the creation of surface layer with the application of anodic oxidation as well as sol-gel method. To verify the usefulness of the two methods and properties of created layers electrochemical testing has been proposed. Those tests have been meant to determine electrical properties that influence corrosion resistance of the alloy before and after the surface modification. Tests have been conducted with the use of measuring device equipped with PGSTAT 302n potentiostat with FRA2 attachment for impedance tests. Measurements have been taken in human blood environment simulating – artificial serum at temperature of 37 degrees Centigrade. To identify phenomenon proceeding at phases border the alloy has been additionally tested in artificial serum for 28 days. It has been found that higher voltage value (90 V) in the case of anodic oxidation has a favourable influence for electrochemical properties of the modified surface. In the case of sol-gel method, thin layer of SiO2 (some 150 nm) baked at the temperature T = 430 degrees Centigrade has the most advantageous set of electrochemical properties. Proper selection of parameters of the surface layer deposition process has a direct influence on the success of implant implantation surgery.
Influence of Electrolytic Polishing and Anodic Passivation on Corrosion Resistance of Ti-15Mo Alloy
Authors: Babilas Dorota , Michalska Joanna , Pamuła Elżbieta , Simka Wojciech
Published: January 2015

This paper presents the results of investigations on electrolytic polishing and anodic passivation of Ti-15Mo alloy. The influence of chemical composition of the bath used in electrolytic polishing and anodic passivation process on the morphology, wettability and corrosion resistance of the electrochemically modified vanadium-free Ti-15Mo alloy was presented. The electropolishing process was carried out in a solution containing: sulphuric acid, ethylene glycol, ammonium fluoride and oxalic acid. Moreover, the anodic oxidation process was carried out in a 1.0 M H2SO4, 1.0 M H3PO4 and 0.5 M solution of K2SiO3 and 5 g/dm3 KOH. It was found that the electrolytic polishing and anodic passivation led to significant improvement of the surface morphology. The electrolytic polishing and anodic passivation of Ti-15Mo improved corrosion resistance of the alloy in contact with of Ringer's physiological solution. The samples anodised at 100 V in 1.0 M H3PO4 presented the highest corrosion resistance.
Corrosion Behavior of a Novel Hybrid Co/UHMWPE Composite Biocoating with Potential Application as a Biomaterial
Authors: Danaila Eliza , Benea Lidia , Bounegru Iulian
Published: January 2015

In the present paper we report the acquisition of a composite coating based on cobalt and ultra high molecular weight polyethylene (Co/UHMWPE) as a novel hybrid biocoating with potential application as a biomaterial, using the electrochemical deposition technique at room temperature. Three different concentrations of UHMWPE, namely 20 gL-1, 30 gL-1 and 50 gL-1, were used in a cobalt sulphate bath. The corrosion behaviour of the Co/UHMWPE hybrid biocoating was studied in comparison with pure cobalt coating at different exposure times in Hanks’ solution as simulated body fluid (SBF), using the electrochemical impedance spectroscopy method. The polarisation resistance of the Co/UHMWPE hybrid biocoating increased during immersion time in the SBF medium in comparison to the pure cobalt coating. An easy way to prepare Co/UHMWPE hybrid biocoatings was identified: namely, by properly incorporating UHMWPE microparticles into a Co matrix using electrocodeposition from a cobalt electrolyte plating bath with increasing corrosion resistance in a solution simulating body fluid.
Corrosion Resistance of Sinters CNT-Cu/Cu
Authors: Zygoń Patrycja , Gwoździk Monika , Nitkiewicz Zygmunt , Jagielska-Wiaderek Karina
Published: January 2015

Copper and its alloys are used in many industrial and marine applications due to their good heat transfer and electrical properties. Copper is, however, susceptible to many forms of corrosion, including localized corrosion, such as crevice corrosion. The paper presents the preliminary results of studies on obtaining copper-based composite materials strengthened with carbon nanotubes modified with copper nanoparticles. The nanotubes modification was carried out by chemically attaching copper nanopaticles originating from copper acetate. Electrolytically obtained copper powders were used as the matrix. The materials were consolidated by one-sides pressing followed by sintering. One of the important property of these materials is its resistance to corrosion. Potentiokinetic investigations in a 3.5% NaCl solution were performed on specimens of different CNTs content. Determined what influence on the corrosive changes has the addition of nanotubes to copper.
Corrosion Properties of Ti Scaffolds Prepared with Sucrose as a Space Holder
Authors: Adamek Grzegorz , Pałka Krzysztof , Jakubowicz Jarosław
Published: January 2015

In this work we shows procedure for new biomaterial - void metal composite (VMC) formation. We used a quasi-spherical sucrose crystals as a space holder material. In the process, titanium powder (different particle sizes) and sucrose were mixed together and uniaxially pressed to make a green compacts. In the next step the sucrose crystals were dissolved in water, leaving open spaces surrounded by metallic scaffold with different porosity (50 – 70%). Such prepared titanium scaffold was dried and sintered in vacuum. The foams morphology was investigated by SEM and CT. The corrosion tests of the as prepared materials were performed in Ringer`s solution using cyclic polarization measurements. We shows that Ti scaffolds prepared by using sucrose as a space holder have corrosion resistance comparable to bulk microcrystalline titanium.
Corrosion Resistance of Hip Endoprosthesis Cups in the Initial State and after Implantation
Authors: Kajzer Anita , Kajzer Wojciech , Semenowicz Jacek , Mroczka Adam
Published: January 2015

The aim of the paper was to compare physicochemical features of hip joint cups coated with hydroxyapatite in the initial state and after period of 36 months of implantation. The cups we produced from stainless steel Cr-Ni-Mo with increased content of azote dedicated to implants which chemical composition is compatible with recommended ISO 5832-9 standards. On the basis of obtained results it can be stated that hydroxyapatite resorption did not affect equally the entire surface of the cup. It was also stated that tested biomaterial of the cup was well wetted (hydrophilic). For all the tested samples prepared from cups in the initial state and cups after the implantation the presence of transpassivation potential Etr was stated, which proves not only good corrosion resistance but also biocompatibility of analyzed cups.
Application of Research Methods in Expert Opinions
Authors: Zubielewicz Małgorzata , Królikowska Agnieszka
Published: January 2015

Most of the modern instrumental methods are mainly applicable only in R&D work. It is shown that some of them could be also used in the field, proving very useful in solving practical corrosion problems. The use of the following methods for testing coatings and substrates are discussed: scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), optical microscopy, Fourier transformation infrared analysis (FTIR), electrochemical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC).
Detection of the Corrosion of Axisymmetric Elements by Means of the Eddy Current Testing Method
Authors: Zbrowski Andrzej , Jóźwik Wojciech
Published: January 2015

The article describes the influence the operating frequency of the transducer on the possibility to detect corrosion using the eddy current method. A bearing ring with two artificially made corrosion defects was used as a test object. The authors determined the characteristics of the defect’s signal value in the function of frequency. The results obtained were then compared to the peak-to-peak value of the signal for a model ring. The tests confirmed the possibility of automatic detection of corrosion on the surface of bearing rings using the eddy current method.
Application of the Electrochemical Microcell Technique in Solid State Surface Analysis
Authors: Krawiec Halina
Published: January 2015

In the two last decades, the Electrochemical Microcell Technique (EMT) was used in various electrochemical surface investigations. The diameter of microcapillaries was in the range between few and few hundred microns. This technique was commonly used in corrosion research. Indeed, metallic alloys exhibit a complex microstructure consisting of different metallic and intermetallic phases, inclusions, precipitates... The use of microcapillaries based techniques like EMT makes possible to perform local electrochemical measurements in individual phases. Therefore, it was possible to get information about the behavior of a single grain, inclusion, precipitate... From these information, precursor sites can be identified and criteria leading to corrosion can be proposed.
A Study on the Inhibition of J55 and P110SS Steel in 3.5% NaCl Solution Saturated with CO2 by Seed Extract of Momordica charantia (Karela)
Authors: Singh Ambrish , Lin Yuan Hua , Liu Wan Ying , Zhou Lu Jiang , Deng Kuan Hai , Huang Bo
Published: January 2015

Seed extract of Momordica charantia (MC) was used to investigate the inhibition efficiency on corrosion of J55 and P110SS steel in 3.5% NaCl solution saturated with CO2 through AC impedance, polarization curves, and SEM techniques. The Nyquist diagrams showed increase in Rct values in the presence of inhibitor, thus increasing inhibition efficiency. Potentiodynamic curves suggested that the inhibitor is mixed type in nature. The adsorbed film on J55 and P110SS steel surface containing inhibitor was confirmed by the SEM results.Keywords: Momordica charantia, P110SS steel, J55 steel, SEM
The Concept of Using Model Gas Turbine for Burner Rig Corrosion Test
Authors: Góral Marek , Filip Ryszard , Dyrda Jakub
Published: January 2015

The paper presents a proposed application of the Gunt ET794 turbine model and subsequent tests carried out in order to determine its usability in sample testing under erosive and corrosive conditions. The most important parameter measured during the tests was temperature before the T3 turbine as well as fuel consumption (propane-butane). Following measurement taking and determining conditions, an optimum place for sample attaching was established. CATIA and Autocad software was used to elaborate the sample attachment model. It has been assumed that the tested sample had 14mm in diameter and thickness of 4mm, while the protective coat will be 500μm max. The summary presents additional research and works, whose aim would be to improve the application of the Gunt ET794 as the test stand.
Machine Vision System for Corrosion Detection as an Additional Tool beside EIS for Evaluation of Protective Properties of Electrolessly Deposited Ni-P Coatings
Authors: Stankiewicz Alicja , Stankiewicz Maciej , Winiarski Juliusz , Szczygieł Irena , Szczygieł Bogdan
Published: January 2015

The electroless deposition technique was used to obtain Ni-P coatings with various phosphorus content. Machine vision method was applied as a tool for the analysis and interpretation of the data provided by electrochemical impedance spectroscopy (EIS) corrosion studies. The degree of corrosion of the coating surface could be determined by this method. The combination of both methods allows a more complete evaluation of the protective properties of the obtained coatings.
Investigation of Some Mannich Bases Corrosion Inhibitors for Carbon Steel
Authors: Manciulea Ileana , Bogatu Cristina , Cazan Cristina , Dumitrescu Lucia , Duta Anca
Published: January 2015

The paper presents the results obtained when using two ketonic Mannich bases (BM1 and BM2) as corrosion inhibitors in saline (standard sea water-3.5% NaCl) for different types of steel, with various alloying elements. The corrosion experiments were performed by potentiodynamic polarization studies. Based on the polarization curves, the corrosion current density and rate were calculated. The inhibitors efficiencies were evalued and the protection mechanisms were discussed.