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1

Metody badania odporności korozyjnej stopów magnezu do zastosowań w implantologii medycznej

Cesarz-Andraczke K., Nowosielski R., Sakiewicz P., Babilas R.

LAB Laboratoria, Aparatura, Badania

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2018

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R. 23, nr 5

34--38, 55

PL

W pracy przedstawiono obszar zastosowań stopów magnezu w implantologii medycznej. Opisano metody badania procesu korozji wybranych stopów magnezu, które są kluczowe do oceny przydatności badanego materiału w implantologii ortopedycznej. Różne metody badawcze odporności korozyjnej stopów magnezu mają swoje unikalne zalety, ale również ograniczenia. W pierwszej kolejności badania odporności korozyjnej ze względu na potencjalne zastosowanie stopów magnezu w implantologii medycznej należy wykonać tzw. badania in vitro. Są to badania przeprowadzane w warunkach laboratoryjnych, polegające na zbadaniu zachowania się ludzkich lub zwierzęcych komórek, tkanek albo symulowanych płynów ustrojowych w obecności badanego biomateriału. Niewłaściwa konfiguracja testu lub interpretacja wyników in vitro stwarza pole do błędnego uzasadnienia kolejnych eksperymentów in vivo, tj. badań wykonywanych na zwierzętach doświadczalnych, polegających na badaniu zachowania się żywego organizmu w kontakcie z biomateriałem (ciałem obcym). W pracy zawarto również wyniki badań własnych odporności korozyjnej amorficznych stopów magnezu.

2

Influence of Milling Time on Amorphization of Mg-Zn-Ca Powders Synthesized by Mechanical Alloying Technique

Lesz S., Kremzer M., Gołombek K., Nowosielski R.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

845--851

EN

Mg60 Zn35 Ca5 amorphous powder alloys were synthesized by mechanical alloying (MA) technique. The results of the influence of high-energy ball-milling time on amorphization of the Mg60 Zn35 Ca5 elemental blend (intended for biomedical application) were presented in the study. The amorphization process was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM). Initial elemental powders were mechanically alloyed in a Spex 8000 high-energy ball mill at different milling times (from 3 to 24 h). Observation of the powder morphology after various stages of milling leads to the conclusion that with the increase of the milling time the size of the powder particles as well as the degree of aggregation change. The partially amorphous powders were obtained in the Mg60 Zn35 Ca5 alloy after milling for 13-18h. The results indicate that this technique is a powerful process for preparing Mg60 Zn35 Ca5 alloys with amorphous and nanocrystalline structure.

3

Structure and compression strength characteristics of the sintered Mg–Zn–Ca–Gd alloy for medical applications

Lesz S., Kraczla J., Nowosielski R.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1288--1299

EN

Magnesium-based materials have promising mechanical properties and potential to serve as implants for loadbearing temporary applications. The main concern about such implants is their strength and resistance for the acting forces. In this investigation, magnesium-based biodegradable Mg65Zn30Ca4Gd1 alloy prepared by combination of innovative Mechanical Alloying (MA) and Spark Plasma Sintering (SPS) methods, was studied for the structure and mechanical properties. Structural studies were performed using X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). XRD studies were conducted to gain an overview of the phase composition in powdered and sintered samples. The energy dispersive spectroscopy (EDS) additionally determine the chemical composition of the samples. SEM observations were used to examine the morphology of the sinters on the fractured surface after the compressive tests. Mechanical properties of the Mg65Zn30Ca4Gd1 alloy were examined by compressive tests, to determine the compressive strength and Young's modulus of the samples at room temperature. The paper provides information about the density and porosity of the Mg-based alloy and additionally its corrosion resistance. Moreover the work shows advantages and possibilities of forming multi-compound, morphologically homogeneous alloys with high mechanical properties in the powder metallurgy processes.

4

Impact of Zn and Ca on dissolution rate, mechanical properties and GFA of resorbable Mg–Zn–Ca metallic glasses

Nowosielski R., Cesarz-Andraczke K.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 1

1--11

EN

This article presents investigations utility of Mg-based metallic glasses for resorbable orthopedic implants. Exploration of biocompatible Mg–Zn–Ca alloys in order to determine Zn and Ca optimum concentration were conducted, based on three criteria: sufficiently high GFA (glass forming ability), sufficiently high tensile strength, microhardness and the suitable dissolution rate (corrosion rate) in Ringer's solution. Fulfillment of these criteria should ensure bone union before implant dissolution. The optimatization of Ca and Zn concentration in the range of 4–6 at.% Ca and 28–32 at.% Zn was executed. The samples in form of ribbons (0.02–0.05 mm thickness) and rods (about diameter up to 4 mm) with amorphous structure were produced. These investigations allowed to determine the GFA. The optimal results for Mg66Zn30Ca4 and Mg64Zn32Ca4 alloys: tensile strength: 191–166 MPa, microhardness: 291–263 HV and volume of released hydrogen 0.04–0.12 ml/cm2/h. The corrosion studies - immersion and potentiodynamic methods were conducted (including measurement specific corrosion current density for Mg alloys). Finally, a comparative analysis was performed, which indicated the impact of Ca and Zn concentration on: GFA, mechanical properties and dissolution rate of studied metallic glasses.

5

Badania powierzchni i warstw produktów korozji amorficznych stopów magnezu w roztworze Ringera

Nowosielski R., Cesarz-Andraczke K., Nawrat G., Balin K.

Ochrona przed Korozją

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2017

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nr 6

186--192

PL

Celem pracy było zbadanie powierzchni i warstw produktów korozji pod względem budowy i składu chemicznego w zależności od czasu zanurzenia amorficznych stopów magnezu w środowisku chlorkowym w temperaturze 37˚C. W ramach pracy przeprowadzono badania struktury analizowanych próbek za pomocą badań rentgenowskich. Badania symulowały warunki odpowiadające ludzkiej krwi. Podczas badań mierzono ilość wydzielającego się wodoru, jako wskaźnika opisującego kinetykę procesu. Roztwór badawczy i temperaturę (37˚C) dobrano z uwagi na możliwość zastosowania masywnych szkieł metalicznych na osnowie magnezu na resorbowalne implanty medyczne. Stwierdzono, że stężenie cynku w stopach Mg68Zn28Ca4 oraz Mg64Zn32Ca4 ma decydujący wpływ na przebieg procesu korozyjnego, budowę oraz skład chemiczny produktów korozji w środowisku chlorkowym.

EN

The aim of the work was the surface and the layers of corrosion products investigation in terms of structure and chemical composition of the amorphous magnesium alloys according to immersion time in chloride environment at 37°C. The structure of the samples was analyzed by X-ray examinations. The study simulated conditions corresponding to human blood. During the tests the amount of evolved hydrogen was measured as an indicator describing the kinetics of the process. Testing solution and temperature (37°C) were selected due to the possibility of use Mg-based bulk metallic glasses for resorbable medical implants. It was found that the concentration of zinc in Mg68Zn28Ca4 and Mg64Zn32Ca4 alloys has very important influence on the corrosion process, structure and chemical composition of the corrosion products in chloride environment.

6

Deformation Mechanisms and Fracture of Ni-Based Metallic Glasses

Lesz S., Griner S., Nowosielski R.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

791--796

EN

The cracking of materials and fracture surface is of great practical and academic importance. Over the last few years the development of the fractography of crystalline alloys resulted in a useful tool for the prediction or failure analysis. Many attempts have been made to observe cracks using optical microscopy, X-ray topography and transmission electron microscopy (TEM). Of these techniques, the resolution of optical microscopy and X-ray topography is too poor. By contrast, the resolution of TEM is high enough for detailed information to be obtained. However, in order to apply TEM observations, a thin foil specimen must be prepared, and it is usually extremely difficult to prepare such a specimen from a pre-selected region containing a crack. In the present work, deformation mechanisms fracture surfaces of Ni-based metallic glass samples have been studied by specially designed experiments. In order to study the deformation mechanisms and fracture the Ni-based metallic glasses have been investigated in the tensile test. The structure and fracture surfaces after the decohesion process in tensile tests were observed using transmission electron microscope (TEM) and scanning electron microscope (SEM), respectively. The studies of structure were performed on thin foils. Moreover the investigated tape was subjected to a banding test. Then, the tape was straightened and the thin foil from the area of maximum strain was prepared. This thin foil sample was deformed before the TEM investigation to obtain local tears.

7

Corrosion of Biocompatible Mg66+xZn30-xCa4 (x=0.2) Bulk Metallic Glasses

Nowosielski R., Cesarz-Andraczke K., Sakiewicz P., Maciej A., Jakóbik-Kolon A., Babilas R.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

807--810

EN

The aim of this paper was to investigate the corrosion resistance of Mg66Zn30Ca4 and Mg68Zn28Ca4 metallic glasses and evaluate the ability of this amorphous alloy use for medical applications as biodegradable medical implants. Taking into account the amount of Mg, Zn, Ca elements dissolved in multielectrolyte physiological fluid (MPF) from Mg66+xZn30-xCa4 (x=0.2) alloys the daily dose of evolved ions from alloys components was determined. Additional goal of the paper was determination of corrosion rate (Vcorr) and amount of hydrogen evolved from amorphous magnesium alloys in simulated environment of human body fluids during 24h immersion and during electrochemical tests. Corrosion studies were done in the multielectrolyte physiological fluid (MPF) at 37°C. The amount of hydrogen evolved [ml/cm2] and corrosion rate Vcorr [mm/year] of amorphous Mg66Zn30Ca4 and Mg68Zn28Ca4 alloys were compared. The work also presents characterization of Mg-based bulk metallic glasses structure in the form of 2 mm thickness plates. Samples structure was analyzed by means of X-ray diffraction. Fracture and surface morphology of magnesium alloy samples were identified using scanning electron microscopy.

8

Bulk metallic glasses based on magnesium to potential biomedical application

Kiljan A., Nowosielski R.

Selected Engineering Problems

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2015

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nr 6

41--44

EN

The paper presents some informations about materials for biomedical application. The study was performed on ternary Mg-based alloys. The Mg66Zn30Ca4 glassy alloy was prepared in the form of rods by pressure die casting method of molten alloy into water cooled copper mold. This alloy is potential material for biomedical application.

9

Cu47Ti34Zr11Ni8 amorphous alloy fabricated by the pressure die casting method

Nowosielski R., Guwer A., Gawlas-Mucha A.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 70, nr 1

5--12

EN

Purpose: The aim of present work is characterization of the pressure die casting, fabrication and testing of structure and properties Cu47Ti34Zr11Ni8 ingot and amorphous and crystalline alloys prepared in the form of rods. Design/methodology/approach: The preliminary ingot was prepared by using the method of arc melting. Rods were fabricated by the pressure die casting method. The melting point and liquidus temperatures of the ingot were determinated in the thermal analysis DTA. Analysis of the microstructure of a pre-alloy was carried out by using the EDS method. X-ray diffraction was used to study structure of fabricated ingot and rods. Hardness was measured by using the Vickers method and compression tests were also performed. Findings: Modernization of the pressure die casting station in the form of housing, which was made from the plexiglass, allowed to keep a protective atmosphere during casting, after that alloys did not oxidate. The X-ray diffraction investigations were indicated that the examined quaternary rods with 2 mm and 3 mm diameters had amorphous structure. The rod with diameter of 4 mm had crystalline structure. The phases occur in ingot and crystalline rods were identified by using X-ray card. Rod about 4mm diameter demonstrated the highest hardness. The rod with diameter of 3 mm demonstrated the highest compressive strength - 1798 MPa. Research limitations/implications: In the future, the research of mechanical properties of Cu47Ti34Zr11Ni8 amorphous rod will be performed. Moreover, further attempts of a fabrication of the Cu47Ti34Zr11Ni8 amorphous rod about diameter higher than 3 mm, will be prepared. Practical implications: A manufactured housing enables the production of bulk metallic glasses about different chemical compositions, by preventing possible oxidations of elements. Originality/value: Modernization of position for the pressure die casting into copper mould. A comparison of properties of Cu47Ti34Zr11Ni8 amorphous and crystalline rods.

10

Application of micro- and nanostructural multifunctional halloysite-based sorbents from DUNINO deposit in selected biotechnological processes

Sakiewicz P., Cebula J., Piotrowski K., Nowosielski R., Wilk R., Nowicki M.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 69, nr 2

69--78

EN

Purpose: The aim of this paper was to present some research data from real industrial tests of halloysite-based sorbents in simultaneous removal of various groups of gaseous hazardous substances produced in selected industrial-scale biotechnological processes. Special attention was paid on effectiveness of original, newly developed micro- and nanostructural, universal “Dunino” halloysite-based sorbents in simultaneous removal of odors, ammonia, hydrogen sulphide, silanes, siloxanes and VOCs. Design/methodology/approach: Numerous studies including SEM, analytical method of continuous flame-ion detection (FID), identification of outlet gas stream composition with spectrophotometric methods, olfactometry tests and practical verification in real industrial-scale biotechnological processes were made to examine sorption properties of the halloysite-based filters. Findings: Newly invented nanostructural multifunctional halloysite-based sorbents show high capabilities in respect to simultaneous removal of unwanted substances from biotechnological processes penetrating into natural environment, e.g. odors, ammonia, hydrogen sulphide, silanes, siloxanes, VOCs. Research limitations/implications: Experimental studies described in this work should contribute to improvement of halloysite-based sorbents composition and optimal selection of their work parameters. Practical implications: Enhanced research results in the discussed problem area will make appropriate, rational composition of filtration bed possible – sorbent mixture (halloysite with other sorbents admixtures, natural or synthetic), disintegration degree (granulated form, powder, dust), activation method (physical, chemical) and optimal conditions for interphase contact between sorbent of a given size distribution and purified gas stream to reach the possibly maximal efficiency in unwanted components removal. Originality/value: Newly invented nanostructural halloysite-based sorbents demonstrate higher sorption capabilities in relation to known conventional solutions, moreover simultaneous sorption of many hazardous species is possible.

11

Structure and Properties of Mg-Cu-(Y,Ca) Bulk Metallic Glasses

Babilas R., Cesarz-Andraczke K., Nowosielski R.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 4

2645--2650

EN

The work presents preparation methods, structure characterization and mechanical properties analysis of Mg-based bulk metallic glasses in as-cast state and after crystallization process. The studies were performed on Mg60Cu30Y10 and Mg37Cu36Ca27 glassy alloys in the form of plates and rods. The X-ray diffraction investigations revealed that the tested samples with different thicknesses and shapes were amorphous. The characteristics of the fractured surfaces showed mixed fractures with the “river” and “mirror” patterns, which are characteristic for the glassy materials and some “smooth” areas. The samples of Mg37Cu36Ca27 alloy presented a two-stage crystallization process, but addition of Y caused a single stage crystallization behavior. Qualitative phase analysis from the X-ray data of examined alloys annealed at 473 K enabled the identification of Mg, Mg2Cu, Cu2Mg and CaCu crystalline phases. The changes of compressive strength as a function of annealing temperature for studied rods were stated. The best mechanical properties including microhardness and compressive strength were obtained for the alloy with the addition of Y in as-cast state.

PL

W pracy przedstawiono wyniki badań struktury i wybranych własności masywnych szkieł metalicznych na osnowie magnezu. Badania przeprowadzono na próbkach w stanie wyjściowym oraz po procesie wygrzewania. Do badań wybrano dwa trójskładnikowe stopy magnezu z dodatkiem itru lub wapnia o następującym składzie chemicznym:Mg60Cu30Y10 oraz Mg37Cu36Ca27. Badania rentgenowskie potwierdziły, że analizowane próbki w postaci płytek i prętów posiadają strukturę amorficzną. Obserwacje mikroskopowe wybranych obszarów powierzchni przełomów płytek i prętów pozwoliły na wyodrębnienie stref o morfologii przełomów „gładkich” i „łuskowych”. Analiza procesu krystalizacji wykazała występowanie pojedynczego etapu krystalizacji dla szkła metalicznego Mg60Cu30Y10 związanego z wydzielaniem się fazy Mg2Cu oraz dwuetapowego procesu krystalizacji dla stopu Mg37Cu36Ca27, w którym zidentyfikowano fazę Cu2Mg i CaCu. Największą wytrzymałość na ściskanie oraz mikrotwardość uzyskano dla próbek szkła metalicznego z dodatkiem itru w stanie bezpośrednio po odlaniu.

12

Weeecontainingnanowaste –riskforenvironment and health&safety

Sakiewicz P., Nowosielski R., Babilas R., Pilarczyk W., Cesarz-Andraczke K.

Selected Engineering Problems

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2014

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nr 5

119--122

EN

The quantities of waste electrical and electronic equipment (WEEE) will increase in the near future and the importance of its recycling has become more evident. This waste are mixture of materials and components that because of their hazardous content, can cause major environmental and health problems. In order to minimize risks two legislation acts have been put in place; the Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment (RoHS Directive) and Directive on waste electrical and electronic equipment (WEEE Directive). It has led to a reduction of hazardous substances which often are replaced by new ones for example nanomaterials. Actually, existing processes for the recycling of used electronic equipment focuses on separation of metals but there is not procedures taking into account the presence of nanowaste. It is significant subject not only from the point of waste treatment and the recovery of valuable materials but also from the risk for environment and health.

13

The influence of milling and interval time on the amorphizationprocess of Cu-Ti alloys

Guwer A., Nowosielski R., Gawlas-Mucha A., Kiljan A., Babilas R.

Selected Engineering Problems

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2014

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nr 5

47--52

EN

The aim of this paper is describing a preparation, investigation and comparison of the structure size and shape of the Cu50Ti50 amorphous and nanocrystalline powders depending of the milling and interval time in cycle. The Cu50Ti50 alloy was obtained by mechanical alloying (MA) in a high energy ball mill SPEX 8000. The structure of Cu50Ti50 powders was examined by X-ray diffraction (XRD). Chemical composition, particle size and shape of the prepared powders was investigated by scanning electron microscopy (SEM). Amorphous Cu50Ti50 alloy can be prepared by a high energy ball milling. Milling and interval time determined an amorphization process of starting elements. The SEM analysis showed that the increase of milling time caused the increasing of powder particle size. The shape changing of the particles was also observed.

14

Selected aspects of magnesium alloys melting technology

Gawlas-Mucha A., Nowosielski R., Babilas R., Guwer A.

Selected Engineering Problems

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2014

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nr 5

33--36

EN

Magnesium alloys are new class of biodegradable materials usually called as bioresorbable biomaterials for orthopedic applications. The potential benefits of Mg alloys are the nearer modulus of elasticity to the bone than stainless steel or titanium, biocompatibility and bone-active properties and the elimination of necessity of a second operation to remove the implant body. Two- component Mg-Ca alloy is characterized by a solid solution limit, and creates a stable intermetallic phase Mg2Ca. Studied samples were prepared by melting starting material in an induction furnace in a quartz crucible.The micro chemical analysis of samples using a scanning electron microscope with EDS was performed. Values of the microhardness of materials were compared before and after remelting.

15

Characterization of selected Mg-based amorphous alloy

Nowosielski R., Kiljan A., Guwer A., Babilas R.

Selected Engineering Problems

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2014

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nr 5

103--108

EN

This paper describes results of chosen investigations of Mg-based amorphous alloy. The amorphous structure has been verified by X-ray diffraction method, SEM observations and thermal analysis. The investigations have been done on the glassy alloy Mg65Cu25Y10 in the form of plate which was obtained by copper mould pressure casting

16

Technology development of magnesium-based bulk amorphous alloys

Babilas R., Lebuda A., Cesarz-Andraczke K., Sakiewicz P., Nowosielski R.

Selected Engineering Problems

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2013

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nr 4

9--12

EN

The paper presents some methods for producing bulk metallic glasses. The study was performed on ternary Mg-based alloys. The Mg65Cu25Y10 glassy alloy was prepared in the form of rods by pressure die casting method of molten alloy into water cooled copper mold. The X-ray diffraction investigations revealed that the examined samples obtained in the bulk form were amorphous.

17

Nanotechnology - unpredictable risk for environment, health and safety

Sakiewicz P., Nowosielski R., Babilas R., Lebuda A., Cesarz-Andraczke K.

Selected Engineering Problems

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2013

|

nr 4

153--157

EN

Rapid development of nanotechnology requires from scientists, manufacturers, politicians and users comprehension of all nanomaterials properties. They should pay attention not only to production but also to other phases of product environmental lifecycle as the processes of its exploitation, utilization and recycling. We are not able to predict all longterm hazards of current nanomaterials application posing threats and unpredictable risks for ecology and health and safety. This means that we will need completely new habits for safe use and technologies for recycling and utilization of those materials and products.

18

Badania korozyjne amorficznego i krystalicznego stopu Mg36,6Cu36,2Ca27,2 w płynie fizjologicznym

Nowosielski R., Cesarz K., Nawrat G., Maciej A., Babilas R.

Ochrona przed Korozją

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2013

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nr 4

144--151

PL

Celem pracy jest zbadanie odporności na korozję elektrochemiczną szkła metalicznego Mg36,6Cu36,2Ca27,2 w stanie bezpośrednio po odlaniu oraz po wygrzewaniu. W ramach pracy przeprowadzono badania struktury analizowanych próbek za pomocą badań rentgenowskich i mikroskopowych. W celu określenia szybkości roztwarzania badanego stopu Mg36,6Cu36,2Ca27,2 oraz jego przydatności do potencjalnych zastosowań biomedycznych przeprowadzono badania immersyjne i potencjodynamiczne odporności na korozję elektrochemiczną w płynie fizjologicznym (wieloelektrolitowym). Stwierdzono, że stop Mg36,6Cu36,2Ca27,2 o strukturze amorficznej charakteryzuje się znacznie wyższą odpornością korozyjną od stopu Mg36,6Cu36,2Ca27,2 o strukturze krystalicznej.

EN

The aim of this paper is to investigate the electrochemical corrosion resistance of metallic glass Mg36,6Cu36,2Ca27,2 in as-cast state and after annealing. In the work was carried out studies of the structure of the analyzed samples using X-ray diffraction and microscopic observation. In order to determine the dissolution rate of the tested alloy Mg36,6Cu36,2Ca27,2 and potential suitability for biomedical applications were carried out immersion test and potentiodynamic test electrochemical corrosion in a physiological fluid (electrolyte solution). It was found that Mg36,6Cu36,2Ca27,2 alloy with amorphous structure has a much higher corrosion resistance than the same alloy with crystalline structure.

19

The amorphous structure of Fe72B20Si4Nb4 metallic glasses in the form of rods and rings

Babilas R., Nowosielski R., Czeppe T.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

150--155

EN

Purpose: The thermal and magnetic properties of Fe-based bulk amorphous materials in as-cast state in the form of rods and rings were studied. Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in the form of rods and rings. The amorphous structure of tested samples was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The thermal stability of the glassy samples was measured using differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained coercive force and magnetic permeability relaxation measurements. The crystallization temperature (Tp), supercooled liquid region (ΔTx), coercive force (Hc) and magnetic permeability relaxation (Δμ/μ) versus sample thickness of studied glassy samples were also examined. Findings: The X-ray diffraction and calorimetric investigations revealed that the studied Fe72B20Si4Nb4 bulk metallic glasses were amorphous. However, the differences of glass transition temperature and crystallization temperature between samples with selected thickness are probably caused by different amorphous structures. The changing of glass-forming ability and magnetic properties obtained for samples with different shape and thickness is a result of the non-homogenous amorphous structure of tested metallic glasses. The different states of amorphous phase could be caused by the free volume concentrations formed by different cooling rates in casting process. Practical implications: The soft magnetic properties of studied metallic glasses can be formed by different sample thickness which are strictly linked with different states of amorphous structure. Originality/value: The applied methods of materials investigations are suitable to determine the changes of structure and selected properties of studied samples cast in different forms and dimensions, especially in aspect of the soft magnetic properties improvement.

20

Structure and corrosion properties of Mg70-xZn30Cax(x=0.4) alloys for biomedical applications

Nowosielski R., Cesarz K., Babilas R.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 58, nr 1

7--15

EN

Purpose: The main objective of the paper was to investigate the structure and corrosion properties of amorphous and crystalline Mg-based alloys for biodegradable implants. This paper presents a preparation method and the structure, microhardness and corrosion properties characterization of Mg70Zn30and Mg66Zn30Ca4 alloys in the form of plates. Design/methodology/approach: The studied samples were prepared by the pressure die-casting to copper mould. The structure of the both alloys was examined by X-ray diffractometry (XRD) and a scanning electron microscope (SEM). The thermal properties of the samples were examined using a differential scanning calorimeter (DSC). In addition, corrosion properties research (immersion tests) were performed in a physiological fluid. Microhardness was measured using the Vickers microtester. Findings: The results of X-ray diffraction investigations confirmed that the sample of Mg66Zn30Ca4 alloy is amorphous and sample of Mg70Zn30 alloy has crystalline structure. Immersion tests of both samples have shown homogeneous progress of corrosion. The changes of a structure caused by calcium addition resulted in an increase of microhardness for sample Mg66Zn30Ca4 compared with the sample of Mg70Zn30 alloy. Research limitations/implications: Results of immersion tests are dependent of used fluid. In this paper used physiological (multielectrolyte) fluid to corrosion studies, which composition is similar to the electrolyte composition of the blood plasma. Chemical composition of fluid used in corrosion studies could be affected to results of studies. Therefore it is appropriate to carry out comparative studies such as electrochemical corrosion studies. Practical implications: Mg-based alloys can be applied as the medical implants. The chemical composition of the samples Mg66Zn30Ca4 and Mg70Zn30 was chosen, because they meet the requirements of a biodegradable material, that is, material, which after completing their stability function will dissolve in the body of the patient without the harmful effects on health. Originality/value: Crystalline and amorphous magnesium alloys are examined as a material for biodegradable medical implants. This new concept is an alternative to previously used conventional implant materials. New concept doesn’t require re-operation, and allows foreign object to remain in the human body.