Sol-gel synthesis is used to obtain coatings that can modify the surfaces of metals to avoid corrosion or to enhance the biocompatibility and bioactivity of metals and their alloys that are of biomedical interest. Anticorrosion coatings composed of smart coatings and self-healing coatings will be described. TiO2, hydroxyapatite, bioglass, and hybrid coatings synthetized by sol-gel technology will be briefly introduced with regard to their role in surface-modifying metals for biomedical purposes. Finally, although there are other approaches to surface-modifying metals for either anticorrosion or biomedical purposes, sol-gel methods have several advantages in controlling surface chemistry composition and functionality.

Actualmente se tiene a disposición una gran variedad de materiales, muchos de los cuales empleamos para resolver las diversas necesidades del quehacer cotidiano. Usamos materiales tan comúnmente que, de manera empírica, hemos aprendido a identificar algunas de las propiedades generales que los caracterizan; así, se sabe que los llamados cerámicos son aislantes eléctricos y térmicos, son frágiles y muy duros. Sin embargo, probablemente no nos hemos detenido a cuestionar más a detalle sobre otros aspectos de estos materiales, tales como su origen, su composición o bien su trascendencia en el desarrollo de diversas tecnologías. Al ocurrir esto, pudiera no percibirse la amplia gama de materiales cerámicos que hoy en día existen y que se usan de manera intensiva en aplicaciones que van más allá de las tradicionales. Este artículo tiene por objetivo ofrecer al lector no especializado en el área de ciencia de materiales una visión general de la presencia e importancia de los cerámicos como materiales tradicionales y de ingeniería, cuyas propiedades únicas permiten aplicaciones diversas, entre las que se incluyen los materiales más modernos diseñados para tecnologías de última generación.

This study proposes a new dense membrane for selectively separating CO₂ and O₂ at high temperatures and simultaneously producing syngas. The membrane consists of a cermet-type material infiltrated with a ternary carbonate phase. Initially, the co-doped ceria of composition Ce_0.9Zr_0.05Y_0.05O_2−δ (CZY) was synthesized by using the conventional solid-state reaction method. Then, the ceramic was mixed with commercial silver powders using a ball milling process and subsequently uniaxially pressed and sintered to form the disk-shaped cermet. The dense membrane was finally formed via the infiltration of molten salts into the porous cermet supports. At high temperatures (700–850 °C), the membranes exhibit CO₂/N₂ and O₂/N₂ permselectivity and a high permeation flux under different CO₂ concentrations in the feed and sweeping gas flow rates. The observed permeation properties make its use viable for CO₂ valorization via the oxy-CO₂ reforming of methane, wherein both CO₂ and O₂ permeated gases were effectively utilized to produce hydrogen-rich syngas (H₂ + CO) through a catalytic membrane reactor arrangement at different temperatures ranging from 700 to 850 °C. The effect of the ceramic filler in the cermet is discussed, and continuous permeation testing, up to 115 h, demonstrated the membrane’s superior chemical and thermal stability by confirming the absence of any chemical interaction between the material and the carbonates as well as the absence of significant sintering concerns with the pure silver.