In-situ studie rozkladu hořčíkových slitin v SBF roztocích pomocí AFM

In-situ study of magnesium alloys degradation in SBF solutions using AFM

abstrakt

en

Magnesium and magnesium alloys based materials find, due to their specific properties, huge application possibilities mainly in automotive, engineering, transport and space industry. Their usage for biomedical engineering applications such as biodegradable tissue and cardiovascular implants is also an important field of application. Important properties of magnesium alloys are biocompatibility and/or biodegradability, high specific strength and high internal dumping values. Main fields of magnesium alloys study, in the last decade, are development of new biodegradable alloys, investigation of new production and processing technologies and evaluation of magnesium alloys electrochemical and degradation properties in SBF solutions. From the point of view of interaction of magnesium alloys with biological systems, cytotoxicity, viability and biodegradability based experimental in vitro tests were proposed. Magnesium alloys degradation is strongly dependent on their chemical composition and production and processing of the alloy, which influence the reached microstructure, chemical and phase composition of the material. Corrosion mechanisms studies and analysis performed on magnesium alloys are nowadays focused on degradation analysis in SBF solutions. Within the cooperation of the Institute of Biophysics AS CR, v. v. i. and the Faculty of Mechanical Engineering BUT new methodology for in-situ evaluation of selected magnesium alloys degradation in SBF solutions by Atomic force microscopy (AFM) was developed and proposed. Veeco Multimode VIII AFM was used for the studies performed in water cell by continual SBF solution exchange/replacement. Selected magnesium alloys degradation was examined in chemically different corrosion solutions (different SBF – Hanks solutions), simulated body fluids. AZ31 and AZ61 magnesium alloy processed by advanced squeeze casting method were used for initial experiments. Degradation properties of examined alloys were influenced by different microstructure, chemical and phase composition. In-situ methodology developed and proposed for magnesium alloys degradation evaluation by AFM contributed in a significant way to understanding of magnesium alloys degradation mechanism and rate. From the methodology point of view, exist a strong expectation of developed in-situ tests

Materiály na bázi hořčíku a hořčíkové slitiny, vzhledem ke svým specifickým vlastnostem, nachází rozsáhlé uplatnění především v automobilovém, strojírenském, leteckém a kosmickém průmyslu a v neposlední řadě pro aplikace v biomedicínském inženýrství, jako biodegradabilní tkáňové i kardiovaskulární implantáty. Významnou vlastností hořčíkových slitin je biokompatibilita a/nebo biodegradabilita, vysoká specifická pevnost slitin a vysoké hodnoty vnitřního tlumení. V poslední době je výzkum hořčíkových slitin zaměřen na návrh nových biodegradabilních slitin, nové technologie výroby a zpracování, hodnocení degradace slitin v SBF roztocích a z pohledu interakce s biologickými systémy s využitím in vitro testů na bázi cytotoxicity, viability a jejich schopnosti biodegradace. Degradace hořčíkových slitin je přitom výrazně závislá na chemickém složení, způsobu výroby a zpracování slitin, což ovlivňuje strukturu, chemické a fázové složení materiálů. Studium mechanismů koroze a analýza degradace u hořčíkových slitin v SBF roztocích je současným trendem v oblasti výzkumu hořčíkových slitin. V rámci spolupráce BFÚ AVČR v.v.i. a FSI VUT v Brně byla navržena metodika in-situ hodnocení degradace u vybraných hořčíkových slitin pomocí AFM v SBF roztocích. Studium bylo prováděno pomocí AFM mikroskopu Veeco Multimode VIII. Vlastní měření probíhalo ve vodní cele za kontinuální výměny SBF roztoků. Degradace hořčíkových slitin byla studována v chemicky rozdílném korozním prostředí simulující tělní tekutiny (SBF – Hankovy roztoky). Pro pilotní studie byly použity hořčíkové slitiny AZ31 a AZ61, vyrobené pokročilou metodou squeeze casting. Degradační vlastnosti těchto slitin jsou ovlivněny různým chemickým a fázovým složení a strukturou. Návrh a vypracování metodiky in-situ hodnocení degradace hořčíkových slitin pomocí AFM významnou měrou přispělo k pochopení mechanismu a rychlosti degradace slitin. Z hlediska metodiky lze předpokládat využití i v případě nově navržených biodegradabilních hořčíkových slitin.

Magnesium and magnesium alloys based materials find, due to their specific properties, huge application possibilities mainly in automotive, engineering, transport and space industry. Their usage for biomedical engineering applications such as biodegradable tissue and cardiovascular implants is also an important field of application. Important properties of magnesium alloys are biocompatibility and/or biodegradability, high specific strength and high internal dumping values. Main fields of magnesium alloys study, in the last decade, are development of new biodegradable alloys, investigation of new production and processing technologies and evaluation of magnesium alloys electrochemical and degradation properties in SBF solutions. From the point of view of interaction of magnesium alloys with biological systems, cytotoxicity, viability and biodegradability based experimental in vitro tests were proposed. Magnesium alloys degradation is strongly dependent on their chemical composition and production and processing of the alloy, which influence the reached microstructure, chemical and phase composition of the material. Corrosion mechanisms studies and analysis performed on magnesium alloys are nowadays focused on degradation analysis in SBF solutions. Within the cooperation of the Institute of Biophysics AS CR, v. v. i. and the Faculty of Mechanical Engineering BUT new methodology for in-situ evaluation of selected magnesium alloys degradation in SBF solutions by Atomic force microscopy (AFM) was developed and proposed. Veeco Multimode VIII AFM was used for the studies performed in water cell by continual SBF solution exchange/replacement. Selected magnesium alloys degradation was examined in chemically different corrosion solutions (different SBF – Hanks solutions), simulated body fluids. AZ31 and AZ61 magnesium alloy processed by advanced squeeze casting method were used for initial experiments. Degradation properties of examined alloys were influenced by different microstructure, chemical and phase composition. In-situ methodology developed and proposed for magnesium alloys degradation evaluation by AFM contributed in a significant way to understanding of magnesium alloys degradation mechanism and rate. From the methodology point of view, exist a strong expectation of developed in-situ tests

Magnesium and magnesium alloys, degradation, SBF

25.03.2015

SPM workshop 2015 seminář o metodách blízkého pole

6–7

20