Browsing by Subject "Laser floating zone"

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    Generation of a porous scaffold with a starting composition in the CaO-SiO2-MgO-P2O5 system in a simulated physiological environment
    (MDPI, 2019-12-31) Grima, Lorena; Díaz-Pérez, María; Gil, Javier; Sola, Daniel; Peña, José Ignacio; Física
    Magnesium-based ceramics are involved in orthopedic applications such as bone scaffolds or implant coatings. They provide structural support to cells for bone ingrowth, but highly porous matrices cannot resist severe mechanical stress during implantation. In this study, the laser floating zone (LFZ) technique is used to prepare a dense crystalline material with composition in the CaO–SiO2–MgO–P2O5 system. This material, under physiological conditions, is able to generate a porous scaffold controlled by the dissolution of the MgO phase, meeting the mechanical advantages of a dense material and the biological features of a porous scaffold. FESEM (Field emission scanning electron microscopy), XRD (X-ray Diffraction), EDS (Energy Dispersive X-rays spectroscopy), and ICP ((Inductively Coupled Plasma) analysis were carried out in order to characterize the samples before and after immersion in simulated body fluid (SBF).
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    Laser-induced surface modification on Wollastonite-Tricalcium Phosphate and Magnesium Oxide-Magnesium stabilized Zirconia Eutectics for bone restoring applications
    (MDPI, 2022-11-28) Wang, Shunheng; Sola Martínez, Daniel; Peña, Jose I.; Física
    An adaptation of the laser floating zone technique is used to modify the surface properties of ceramics with interest for biomedical applications. This new method is based upon the surface remelting of ceramic rods by using laser radiation, and its versatility is demonstrated in the surface structuring of two different eutectic composites with potential application as bone substitutes. Firstly, directionally eutectic rods of wollastonite (W)–tricalcium phosphate (TCP) and magnesium oxide (MgO)–magnesium stabilized zirconia (MgSZ) were grown by the laser floating zone technique. In the case of W-TCP eutectics, materials with crystalline, glass–ceramic, or vitreous microstructure could be obtained as the growth rate was increased. In the other case, a material made up of magnesium oxide and magnesium stabilized zirconia phases arranged in fibrillar or lamellar geometry was obtained. At higher solidification rates, the rupture of the growth front gave rise to the organization of the phases in the form of colonies or cells. The laser zone remelting technique was used to remove defects and to refine the microstructure of the directionally solidified eutectic surfaces as well as to cover MgO–MgSZ rods with W–TCP glass in the eutectic composition. The study provides a promising technique that can tailor the surface properties and functionality of bone repair materials. The products’ properties and challenges in preparation procedures are discussed.