ABSTRACT
Magnesium-based biodegradable metal bone implants exhibit superior mechanical properties compared to biodegradable polymers for orthopedic and cardiovascular stents. In this study, MgZZC-x (x = 1, 1.2) alloys were screened by in vitro biocompatibility tests in three simulated body fluids under nontoxic conditions. The MgZZC-1 alloys with better biocompatibility were selected to predict the days required for complete degradation. The evolution of degradation products was analyzed, and the mechanism of formation of the product film was inferred. A degradation kinetic model was established to investigate the effect of MEM components on the degradation of the alloys. The results demonstrate that the proteins in MEM can greatly retard the degradation progress by attaching to the surface of MgZZC-1 alloys, which are predicted to degrade completely within 341 days. The carbonate and phosphate buffers were adjusted to pH in MEM solution, delaying the degradation of magnesium alloys. This process in MEM more accurately reflects the actual degradation in the body and is superior to that in Hanks and SBF solutions. This study will promote the application of biodegradable materials in clinical medicine.
Subject(s)
Alloys , Biocompatible Materials , Body Fluids , Magnesium , Alloys/chemistry , Body Fluids/chemistry , Magnesium/chemistry , Biocompatible Materials/chemistry , Hydrogen-Ion Concentration , Kinetics , HumansABSTRACT
Corrosion is an unavoidable issue that steel encounters during service; however, the generic methods employed for corrosion prevention often need high cost or preparation conditions. In this study, a facile chemical replacement deposition method was proposed to realize an anticorrosion superhydrophobic coating on a X80 steel surface. The growth mechanism of the rough structure and its impact on the wettability of the superhydrophobic coating were analyzed. The superhydrophobic coating, deposited for 50 s and modified for 30 min, achieved optimal electrochemical properties and a maximum water contact angle. The immersion test, in the saturated CO2 oilfield produced water, demonstrated the better corrosion resistance of superhydrophobic coating than X80 steel. Correspondingly, a kinetic corrosion model was established to analyze the anticorrosion mechanism. In summary, this method significantly improves the corrosion resistance of X80 steel and is attractive for other industrial fields.
ABSTRACT
To optimize the economic advantages and corrosion-resisting property of A572 Gr.65 steels, the inhibition effect of water-soluble imidazoline on the sample surface with rare earth was explored in a 3.5 wt % NaCl solution. In this paper, the mechanism of corrosion and the adsorptive behavior of water-soluble imidazoline inhibitors on A572 Gr.65 steels with 47 ppm of rare earth in saltwater solution were discussed, along with the establishment of the adsorption model. Achievements proposed that the inhibition efficiency of water-soluble imidazoline was as high as 95.73% at 80 mg L-1 dosage following an anodic-dominated mixed-type inhibition mechanism. Besides, the scanning electron microscopy and X-ray diffraction analysis revealed that the corrosion inhibitor resulted in a smoother and more stable rust layer with a significant reduction of the γ-FeOOH. Theoretical calculations confirmed that imidazoline formed a unimolecular layer adsorption film on the steel surface, exhibiting adherence to both Langmuir and Frumkin adsorption isotherms, involving physical and chemical adsorption.