Fluoride conversion coatings for magnesium and its alloys for the biological environment

Fluoride Coatings on Magnesium Alloy Implants

“…The desired properties can be obtained by modifying the composition of the deposited layer. The traditional method of immersion fluorination involves immersing magnesium in a certain concentration of HF solution at a specific temperature for a certain amount of time before removing it [ 42 ]. Table 1 shows the characteristics of different HF-coated magnesium alloys prepared under various parameters.…”

“…Currently, there is only one review of immersed fluoride conversion coatings for medical magnesium alloys [ 28 ]; however, no review for fluoride coatings is available. Therefore, this paper reviews the advances in fluoride coatings for medical magnesium alloys, with the aim of discussing the pros and cons of existing fluoride coatings from the perspectives of preparation methods, coating structures and properties, and challenges and suggestions for further research.…”

Extrusion-based 3D printed magnesium scaffolds with multifunctional MgF2and MgF2–CaP coatings

“…We found that without this pre-treatment, MgF 2 coating does not significantly improve the corrosion resistance of Mg. That is because alkali-heat pre-treatment removes inclusions and impurities at the surface [59], such as oxides or carbon residue, and forms a homogenous, dense, and well-bonded Mg(OH) 2 film (even on the struts of the Mg scaffolds, Fig. S2), which is helpful to form a more protective MgF 2 coating layer on the top [36]. This coating strategy has been also employed by other researchers to achieve effective protection for Mg alloys [37,41,60,61].…”

“…Among various conversion coatings, fluoride conversion coating is one of the most effective methods for porous Mg-based materials, since it has been found that a MgF 2 coating layer can, indeed, form on the entire surface of the struts of porous Mg [26,34,35], although the pore sizes of the scaffolds used in those studies (150-400 µm) are much larger than the sizes of the micropores that were present in the struts of the scaffolds fabricated earlier (10-100 µm) [24]. In addition to improving the corrosion resistance, MgF 2 coating has the other advantages of strongly adhering to the Mg substrate and demonstrating good biocompatibility [36,37]. However, MgF 2 coating has a limited osteogenic ability [26].…”

Fire Resistance and Mechanical Properties of Intumescent Coating Using Novel BioAsh for Steel

“…These mineral compounds were predicted from EDX and FTIR analysis of BioAsh of those most likely to undergo thermal decomposition in coating when heattreated in TGA. The potential thermal decompositions of compounds that might take place caused a mass loss of samples, as shown in Table 3 [32][33][34][35][36]. These mineral compounds were predicted from EDX and FTIR analysis of BioAsh of those most likely to undergo thermal decomposition in coating when heat-treated in TGA.…”