Magnesium(Mg) and its alloys have emerged as a favored candidate for bio-regenerative medical implants due to their superior biocompatibility, biodegradability and the elastic modulus close to that of human bone. Unfo...Magnesium(Mg) and its alloys have emerged as a favored candidate for bio-regenerative medical implants due to their superior biocompatibility, biodegradability and the elastic modulus close to that of human bone. Unfortunately, the rapid and uncontrollable degradation rate of Mg alloys in chloride-rich body microenvironments limits their clinical orthopedic applications. Recently, Calcium Phosphate(Ca-P)biomaterials, especially Hydroxyapatite(HA), have been broadly applied in the surface functional modification of metal-based biomaterials attributed to their excellent bioactivity and biocompatibility. Hydrothermal modification of Ca-P coatings on Mg alloys has been extensively exploited by researchers for its significant superiorities in controlling coating structure and improving interfacial bonding strength for better osseointegration and corrosion resistance. This work focuses on the up-to-the-minute advances in Ca-P coatings on the surface of Mg and its alloys via hydrothermal methods, including the strategies and mechanisms of hydrothermal modification. Herein, we are inclined to share some feasible and attractive hydrothermal surface modification strategies. From the perspectives of hydrothermal manufacturing technique innovation and coating structure optimization, we evaluate how to foster the corrosion resistance, coating bonding strength, osseointegration and antibacterial properties of Mg alloys with Ca-P coatings synthesized by hydrothermal method. The challenges and future perspectives on the follow-up exploration of Mg alloys for orthopedic applications are also elaborately proposed.展开更多
Three different kinds of coatings were coated on the concrete surface, and the changes in appearance, surface roughness, microstructure and components of coatings in artificial sewage were investigated. In addition, t...Three different kinds of coatings were coated on the concrete surface, and the changes in appearance, surface roughness, microstructure and components of coatings in artificial sewage were investigated. In addition, the strength, micrograph, mineral compositions and pore structure of concrete specimens after removing coatings were also studied. The results show that epoxy coal tar pitch coating(ECTPC) has the best effect of protecting concrete from the sewage corrosion. After being immersed in sewage for 90 days, the compressive strength of concrete coated with ECTPC is still as high as that of specimen immersed in water, and the cement paste has a high CH content and dense structure with low porosity, which mainly accounts for its excellent barrier property and certain antibacterial function. Cement-based bactericidal coating(CBC) also has good effectiveness to sewage corrosion of concrete. The strength and microstructure of concrete coated with CBC in sewage are still significantly superior to those of uncoated concrete. Although cement-based capillary crystalline waterproofing coating(CCCWC) is a good waterproof material, it is not suitable for the corrosion resistance of concrete in sewage. After 2 months corrosion, almost all of the CH crystals in coating reacted with the metabolic acid substance by microbes. Therefore, the strength and pore structure of concrete coated with CCCWC are only slightly superior to those of uncoated concrete. Overall, the protective effect of cement-based inorganic coatings is relatively poor.展开更多
Magnesium(Mg)and its alloys have become a hot research topic in various industries owing to the specific physical and chemical properties.However,high corrosion rate is considered the key lifetime-limiting.Plasma elec...Magnesium(Mg)and its alloys have become a hot research topic in various industries owing to the specific physical and chemical properties.However,high corrosion rate is considered the key lifetime-limiting.Plasma electrolytic oxidation(PEO)method is a simple strategy to deposit an oxide layer on the surface of light metals such as magnesium alloys,to control corrosion rate and promote some other properties,depending on their performances.Nevertheless,their features including their micropore size,distribution,and interconnectivity,and microcracks have not been improved to an acceptable level to support long-term performances of the magnesium-based substrates.Studies have introduced micro/nano-enabled approaches to enhance various properties of PEO coatings such as corrosion resistance,tribological properties,self-healing ability,bioactivity,biocompatibility,antibacterial properties,or catalytic performances.These strategies consist of incorporating of micro and nanoparticles into the PEO layers to produce multi-functional surfaces or the formation of multi-layered coatings to cover the defects of PEO coatings.In this perspective,the present paper aims to overview various nano/micro-enabled strategies to promote the properties of PEO coatings on magnesium alloys.The main focus is given to the functional changes that occurred in response to the incorporation of various types of nano/micro-structures into the PEO coatings on magnesium alloys.展开更多
目的研究不同粗糙度的氧化锆涂层对氧化锆生物活性的影响。方法将氧化锆试件随机分三组:实验组T_(1)、T_(2)组分别浸入1M ZrOCl_(2)溶液和0.5 M ZrO_(2)的混合液、1M ZrOCl_(2)溶液和1 M ZrO_(2)的混合液处理,然后进行致密烧结。对照组...目的研究不同粗糙度的氧化锆涂层对氧化锆生物活性的影响。方法将氧化锆试件随机分三组:实验组T_(1)、T_(2)组分别浸入1M ZrOCl_(2)溶液和0.5 M ZrO_(2)的混合液、1M ZrOCl_(2)溶液和1 M ZrO_(2)的混合液处理,然后进行致密烧结。对照组C组放入去离子水中清洗后干燥保存。通过扫描电镜及表面元素分析表征样本。测量表面粗糙度(Ra)、三点弯曲强度以及涂层结合强度。将MC3T3-E1细胞接种在试件表面以检测各组样本对细胞增殖、黏附以及成骨分化的影响。结果氧化锆表面制备了不同粗糙度的氧化锆涂层,未影响氧化锆基底的机械性能,涂层结合强度足够。接种在实验组试件表面的细胞表现出良好的增殖特性及成骨分化效果。结论氧化锆表面粗糙涂层的制备是改善其生物活性的一种有效方式。展开更多
基金supported by National Natural Science Foundation of China(Grant No.51872197,81772363 and 81972076)Shanghai Committee of Science and Technology,China(Grant No.15411951000)。
文摘Magnesium(Mg) and its alloys have emerged as a favored candidate for bio-regenerative medical implants due to their superior biocompatibility, biodegradability and the elastic modulus close to that of human bone. Unfortunately, the rapid and uncontrollable degradation rate of Mg alloys in chloride-rich body microenvironments limits their clinical orthopedic applications. Recently, Calcium Phosphate(Ca-P)biomaterials, especially Hydroxyapatite(HA), have been broadly applied in the surface functional modification of metal-based biomaterials attributed to their excellent bioactivity and biocompatibility. Hydrothermal modification of Ca-P coatings on Mg alloys has been extensively exploited by researchers for its significant superiorities in controlling coating structure and improving interfacial bonding strength for better osseointegration and corrosion resistance. This work focuses on the up-to-the-minute advances in Ca-P coatings on the surface of Mg and its alloys via hydrothermal methods, including the strategies and mechanisms of hydrothermal modification. Herein, we are inclined to share some feasible and attractive hydrothermal surface modification strategies. From the perspectives of hydrothermal manufacturing technique innovation and coating structure optimization, we evaluate how to foster the corrosion resistance, coating bonding strength, osseointegration and antibacterial properties of Mg alloys with Ca-P coatings synthesized by hydrothermal method. The challenges and future perspectives on the follow-up exploration of Mg alloys for orthopedic applications are also elaborately proposed.
基金Funded by National Natural Science Foundation of China(No.51878421)Hebei Key Discipline Construction Project
文摘Three different kinds of coatings were coated on the concrete surface, and the changes in appearance, surface roughness, microstructure and components of coatings in artificial sewage were investigated. In addition, the strength, micrograph, mineral compositions and pore structure of concrete specimens after removing coatings were also studied. The results show that epoxy coal tar pitch coating(ECTPC) has the best effect of protecting concrete from the sewage corrosion. After being immersed in sewage for 90 days, the compressive strength of concrete coated with ECTPC is still as high as that of specimen immersed in water, and the cement paste has a high CH content and dense structure with low porosity, which mainly accounts for its excellent barrier property and certain antibacterial function. Cement-based bactericidal coating(CBC) also has good effectiveness to sewage corrosion of concrete. The strength and microstructure of concrete coated with CBC in sewage are still significantly superior to those of uncoated concrete. Although cement-based capillary crystalline waterproofing coating(CCCWC) is a good waterproof material, it is not suitable for the corrosion resistance of concrete in sewage. After 2 months corrosion, almost all of the CH crystals in coating reacted with the metabolic acid substance by microbes. Therefore, the strength and pore structure of concrete coated with CCCWC are only slightly superior to those of uncoated concrete. Overall, the protective effect of cement-based inorganic coatings is relatively poor.
文摘Magnesium(Mg)and its alloys have become a hot research topic in various industries owing to the specific physical and chemical properties.However,high corrosion rate is considered the key lifetime-limiting.Plasma electrolytic oxidation(PEO)method is a simple strategy to deposit an oxide layer on the surface of light metals such as magnesium alloys,to control corrosion rate and promote some other properties,depending on their performances.Nevertheless,their features including their micropore size,distribution,and interconnectivity,and microcracks have not been improved to an acceptable level to support long-term performances of the magnesium-based substrates.Studies have introduced micro/nano-enabled approaches to enhance various properties of PEO coatings such as corrosion resistance,tribological properties,self-healing ability,bioactivity,biocompatibility,antibacterial properties,or catalytic performances.These strategies consist of incorporating of micro and nanoparticles into the PEO layers to produce multi-functional surfaces or the formation of multi-layered coatings to cover the defects of PEO coatings.In this perspective,the present paper aims to overview various nano/micro-enabled strategies to promote the properties of PEO coatings on magnesium alloys.The main focus is given to the functional changes that occurred in response to the incorporation of various types of nano/micro-structures into the PEO coatings on magnesium alloys.
文摘目的研究不同粗糙度的氧化锆涂层对氧化锆生物活性的影响。方法将氧化锆试件随机分三组:实验组T_(1)、T_(2)组分别浸入1M ZrOCl_(2)溶液和0.5 M ZrO_(2)的混合液、1M ZrOCl_(2)溶液和1 M ZrO_(2)的混合液处理,然后进行致密烧结。对照组C组放入去离子水中清洗后干燥保存。通过扫描电镜及表面元素分析表征样本。测量表面粗糙度(Ra)、三点弯曲强度以及涂层结合强度。将MC3T3-E1细胞接种在试件表面以检测各组样本对细胞增殖、黏附以及成骨分化的影响。结果氧化锆表面制备了不同粗糙度的氧化锆涂层,未影响氧化锆基底的机械性能,涂层结合强度足够。接种在实验组试件表面的细胞表现出良好的增殖特性及成骨分化效果。结论氧化锆表面粗糙涂层的制备是改善其生物活性的一种有效方式。
