Plasma electrolytic oxidation is a well-known technique for surface modification of biomedical magnesium alloys,with good corrosion protection and the ability to produce biocompatible and bioactive coatings.In this st...Plasma electrolytic oxidation is a well-known technique for surface modification of biomedical magnesium alloys,with good corrosion protection and the ability to produce biocompatible and bioactive coatings.In this study,calcium-phosphate coatings were produced on WE43 magnesium alloy for use,as orthopedic implants.Coating formation was prepared using different oxidation parameters with various duty ratios(DR)of 15,25 and 50%and current ratios(R)-2 or 1.6.Application of R with excess cathodic current(R>1)in processes with DR≥25%allowed attaining the soft-sparking regime(SSR)that resulted in thicker oxide coatings with higher degree of crystallinity compared to the films obtained without SSR.The results of the corrosion tests contributed to a noticeable improvement in the corrosion resistance of the magnesium alloy.Optimization of the oxidation parameters allowed the selection of the variants with the most favorable degradation behavior over the tested immersion period,indicating a successful modification of the magnesium alloy surface to obtain an implant biomaterial capable of providing controlled degradation.Furthermore,biological evaluation of the produced coatings showed that the proposed surface modifications significantly reduced the cytotoxic effects observed in direct contact with the material while still maintaining the cell proliferation-promoting effects of the material eluents.展开更多
A chemical method was used to deposit dicalcium phosphate dehydrate coatings on AZ91 magnesium alloy. The aim was to improve the biodegradation behavior of magnesium alloy in a simulated body fluid. The microstructure...A chemical method was used to deposit dicalcium phosphate dehydrate coatings on AZ91 magnesium alloy. The aim was to improve the biodegradation behavior of magnesium alloy in a simulated body fluid. The microstructures of the coating before and after immersion in the simulated body fluid were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD） The results indicated that the dicalcium phosphate dehydrate coatings exhibited two morphologies during the pre-calcification process. The titration speed of the pre-calcification process had great influence on the morphologies of the pre-calcification coatings. As the soaking time increased, the diffraction peaks of dicalcium phosphate dehydrate disappeared and hydroxyapatite precipitated on the coated substrate surfaces. This indicates the dissolution of dicalcium phosphate dehydrate during the immersion process. The structures of the dicalcium phosphate dehydrate coatings and the formation mechanisms of the hydroxyapatite coatings were investigated in detail.展开更多
Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties.Mg and its alloys are of poor co...Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties.Mg and its alloys are of poor corrosion resistance.Its high corrosion rate leads to its quick decomposition in the corrosive ambiance and as a result weakening its mechanical properties and before it is repaired,it will vanish.The corrosion and degradation rate must be controlled in the body to advance the usage of Mg and its alloys as implants.Different techniques have been utilized to boost biological properties.Plasma electrolytic oxidation(PEO)can provide porous and biocompatible coatings for implants among various techniques.Biodegradable implants are generally supposed to show enough corrosion resistance and mechanical integrity in the body environment.Much research has been carried out in order to produce PEO coatings containing calcium phosphate compounds.Calcium phosphates are really similar to bone mineral composition and present great biocompatibility.The present study deals with the usage of calcium phosphates as biocompatible coatings applied on Mg and its alloys to study the properties and control the corrosion rate.展开更多
基金funded by Silesian University of Technology,no.07/020/BKM24/0104.
文摘Plasma electrolytic oxidation is a well-known technique for surface modification of biomedical magnesium alloys,with good corrosion protection and the ability to produce biocompatible and bioactive coatings.In this study,calcium-phosphate coatings were produced on WE43 magnesium alloy for use,as orthopedic implants.Coating formation was prepared using different oxidation parameters with various duty ratios(DR)of 15,25 and 50%and current ratios(R)-2 or 1.6.Application of R with excess cathodic current(R>1)in processes with DR≥25%allowed attaining the soft-sparking regime(SSR)that resulted in thicker oxide coatings with higher degree of crystallinity compared to the films obtained without SSR.The results of the corrosion tests contributed to a noticeable improvement in the corrosion resistance of the magnesium alloy.Optimization of the oxidation parameters allowed the selection of the variants with the most favorable degradation behavior over the tested immersion period,indicating a successful modification of the magnesium alloy surface to obtain an implant biomaterial capable of providing controlled degradation.Furthermore,biological evaluation of the produced coatings showed that the proposed surface modifications significantly reduced the cytotoxic effects observed in direct contact with the material while still maintaining the cell proliferation-promoting effects of the material eluents.
基金Project(51272055) supported by the National Natural Science Foundation of China
文摘A chemical method was used to deposit dicalcium phosphate dehydrate coatings on AZ91 magnesium alloy. The aim was to improve the biodegradation behavior of magnesium alloy in a simulated body fluid. The microstructures of the coating before and after immersion in the simulated body fluid were characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD） The results indicated that the dicalcium phosphate dehydrate coatings exhibited two morphologies during the pre-calcification process. The titration speed of the pre-calcification process had great influence on the morphologies of the pre-calcification coatings. As the soaking time increased, the diffraction peaks of dicalcium phosphate dehydrate disappeared and hydroxyapatite precipitated on the coated substrate surfaces. This indicates the dissolution of dicalcium phosphate dehydrate during the immersion process. The structures of the dicalcium phosphate dehydrate coatings and the formation mechanisms of the hydroxyapatite coatings were investigated in detail.
文摘Magnesium has been known as an appropriate biological material on account of its good biocompatibility and biodegradability properties in addition to advantageous mechanical properties.Mg and its alloys are of poor corrosion resistance.Its high corrosion rate leads to its quick decomposition in the corrosive ambiance and as a result weakening its mechanical properties and before it is repaired,it will vanish.The corrosion and degradation rate must be controlled in the body to advance the usage of Mg and its alloys as implants.Different techniques have been utilized to boost biological properties.Plasma electrolytic oxidation(PEO)can provide porous and biocompatible coatings for implants among various techniques.Biodegradable implants are generally supposed to show enough corrosion resistance and mechanical integrity in the body environment.Much research has been carried out in order to produce PEO coatings containing calcium phosphate compounds.Calcium phosphates are really similar to bone mineral composition and present great biocompatibility.The present study deals with the usage of calcium phosphates as biocompatible coatings applied on Mg and its alloys to study the properties and control the corrosion rate.
