In this exploratory work,micrometric radiopaque W-Fe-Mn-C coatings were produced by magnetron sputtering plasma deposition,for the first time,with the aim to make very thin Fe-Mn stents trackable by fluoroscopy.The po...In this exploratory work,micrometric radiopaque W-Fe-Mn-C coatings were produced by magnetron sputtering plasma deposition,for the first time,with the aim to make very thin Fe-Mn stents trackable by fluoroscopy.The power of Fe-13Mn-1.2C target was kept constant at 400 W while that of W target varied from 100 to 400 W producing three different coatings referred to as P100,P200,P400.The effect of the increased W power on coatings thickness,roughness,structure,corrosion behavior and radiopacity was investigated.The coatings showed a power-dependent thickness and W concentration,different roughness values while a similar and uniform columnar structure.An amorphous phase was detected for both P100 and P200 coatings while γ-Fe,bcc-W and W_(3)C phases found for P400.Moreover,P200 and P400 showed a significantly higher corrosion rate(CR)compared to P100.The presence of W,W_(3)C as well as the Fe amount variation determined two different micro-galvanic corrosion mechanisms significantly changing the CR of coatings,0.26±0.02,59.68±1.21 and 59.06±1.16μm/year for P100,P200 and P400,respectively.Sample P200 with its most uniform morphology,lowest roughness(RMS=3.9±0.4 nm)and good radiopacity(~6%)appeared the most suitable radiopaque biodegradable coating investigated in this study.展开更多
The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a...The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices.For biodegradable metals,acid pickling has already been reported as a preliminary surface preparation given further processes,such as electropolishing.Unfortunately,biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry(e.g.,non-uniform scale removal and rougher surface).Indeed,this translational knowledge lacks a detailed investigation on this process,deep characterization of treated surfaces properties,as well as a comprehensive discussion of the involved mechanisms.In this study,the effects of different acidic media(HCl,HNO_(3),H_(3)PO_(4),CH_(3)COOH,H_(2)SO_(4) and HF),maintained at different temperatures(21 and 60℃)for various exposition time(15-240 s),on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated.Changes in mass loss,morphology and wettability evidenced the combined effect of temperature and time for all conditions.Pickling in HCl and HF solutions favor mass loss(0.03-0.1 g/cm^(2))and effectively remove the initial scale.展开更多
基金partially funded by the Natural Science and Engineering Research Council of Canada(the Fonds de Recherche du Quebec sur les Natures et Technologie)the Canada Foundation for Innovationthe CHU de Quebec Research Center(through the Fonds de Recherche du Quebec sur la Sante).
文摘In this exploratory work,micrometric radiopaque W-Fe-Mn-C coatings were produced by magnetron sputtering plasma deposition,for the first time,with the aim to make very thin Fe-Mn stents trackable by fluoroscopy.The power of Fe-13Mn-1.2C target was kept constant at 400 W while that of W target varied from 100 to 400 W producing three different coatings referred to as P100,P200,P400.The effect of the increased W power on coatings thickness,roughness,structure,corrosion behavior and radiopacity was investigated.The coatings showed a power-dependent thickness and W concentration,different roughness values while a similar and uniform columnar structure.An amorphous phase was detected for both P100 and P200 coatings while γ-Fe,bcc-W and W_(3)C phases found for P400.Moreover,P200 and P400 showed a significantly higher corrosion rate(CR)compared to P100.The presence of W,W_(3)C as well as the Fe amount variation determined two different micro-galvanic corrosion mechanisms significantly changing the CR of coatings,0.26±0.02,59.68±1.21 and 59.06±1.16μm/year for P100,P200 and P400,respectively.Sample P200 with its most uniform morphology,lowest roughness(RMS=3.9±0.4 nm)and good radiopacity(~6%)appeared the most suitable radiopaque biodegradable coating investigated in this study.
文摘The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices.For biodegradable metals,acid pickling has already been reported as a preliminary surface preparation given further processes,such as electropolishing.Unfortunately,biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry(e.g.,non-uniform scale removal and rougher surface).Indeed,this translational knowledge lacks a detailed investigation on this process,deep characterization of treated surfaces properties,as well as a comprehensive discussion of the involved mechanisms.In this study,the effects of different acidic media(HCl,HNO_(3),H_(3)PO_(4),CH_(3)COOH,H_(2)SO_(4) and HF),maintained at different temperatures(21 and 60℃)for various exposition time(15-240 s),on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated.Changes in mass loss,morphology and wettability evidenced the combined effect of temperature and time for all conditions.Pickling in HCl and HF solutions favor mass loss(0.03-0.1 g/cm^(2))and effectively remove the initial scale.
