Solid State Processing of BCZT Piezoceramics Using Ultra Low Synthesis and Sintering Temperatures.

Lead-free (BaCa) (Ti Zr) O (BCZT) ceramics were prepared by a solid-state route (SSR) using ultra-low synthesis (700 °C/30 min and 700 °C/2 h) and sintering temperatures (from 1150 °C to 1280 °C), due to prior activation and homogenization by attrition milling of the starting high purity raw materials for 6 h before the synthesis and of the calcined powders for 3 h before the sintering. The comparison of the thermal analysis of the mixture of the starting raw materials and the same mixture after 6 h attrition milling allowed to evidence the mechanisms of activation, resulting in a significant decrease of the perovskite formation temperature (from 854 °C down to 582 °C). The secondary phases that limit the functional properties of the ceramic and their evolution with the sintering conditions were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which allowed the design of a two-step sintering method to eliminate them.

Peptide-functionalized zirconia and new zirconia/titanium biocermets for dental applications.

Objective: Titanium materials have been functionalized with biomolecules as a modern strategy to incorporate bioactive motifs that will expand and improve their biomedical applications. Here, we have biofunctionalized biomaterials based on zirconia of much interest for dentistry: the widely used bioceramic 3Y-TZP and a newly developed 3Y-TZP/Ti biocermet.

Methods: The biosurfaces were activated, silanized, and functionalized with coatings made of oligopeptides.

Biocompatibility assessment of spark plasma-sintered alumina-titanium cermets.

Alumina-titanium materials (cermets) of enhanced mechanical properties have been lately developed. In this work, physical properties such as electrical conductivity and the crystalline phases in the bulk material are evaluated. As these new cermets manufactured by spark plasma sintering may have potential application for hard tissue replacements, their biocompatibility needs to be evaluated.

Osteoblastic cell response to spark plasma-sintered zirconia/titanium cermets.

Ceramic/metal composites, cermets, arise from the idea to combine the dissimilar properties in the pure materials. This work aims to study the biocompatibility of new micro-nanostructured 3 Y-TZP/Ti materials with 25, 50 and 75 vol.% Ti, which have been successfully obtained by spark slasma sintering technology, as well as to correlate their surface properties (roughness, wettability and chemical composition) with the osteoblastic cell response.

Ceramic/metal biocidal nanocomposites for bone-related applications.

Hydroxyapatite/silver nanocomposites have been designed and synthesized as an engineering material for biomedical applications. The hydroxyapatite matrix was synthesized by a sol-gel method and, subsequently, the Ag nanoparticles were deposited by heterogeneous precipitation followed by two different reduction routes: thermal or chemical. Both sets were studied and compared and, in all cases, the metal nanoparticles appear perfectly isolated and attached to the surface of the hydroxyapatite.

Nanotechnology in joint replacement.

This paper reviews the most relevant achievements and new developments in the field of nanomaterials and their possible impact on the fabrication of a new generation of reliable and longer lasting implants for joint replacement. Special emphasis is given to the role of nanocomposites with different microstructural designs: micro-nano composites, nano-nano composites, macro-micro-nano composites as well as bioinspired hierarchical composite materials. These nanostructured materials have opened up an exciting avenue in the design of non-metallic biocompatible, crack growth resistant, tough, and mechanically resistant implants with a lifespan close to the life expectancy of the patients.

Spreading of viscous liquids at high temperature: silicate glasses on molybdenum.

The spreading of Si-Ca-Al-Ti-O glasses on molybdenum has been investigated. By controlling the oxygen activity in the furnace, spreading can take place under reactive or nonreactive conditions. As the nucleation of the reaction product under reactive conditions is slow in comparison to the spreading kinetics, in both cases the glass front moves on the metal surface with similar spreading velocities.