Caracterización mecánica de discos de hidroxiapatita nanoporosos obtenidos por sinterización//Mechanical characterization ofnanoporous hydroxyapatite disks obtained by sintering

El objetivo de este trabajo es la caracterizacion mecanica de discos fabricados a partir de polvos de hidroxiapatita (HA) sintetica cubana y de la StremChemicals – USA, con tamanos de particulas diferentes y de forma semiesfericas con superficies porosas, sin aditivos formadores de poros, por compactacion uniaxial y sinterizacion en horno electrico a diferentes regimenes de sinterizacion, Se obtuvieron porosidades aparente entre 3 y 40 % con tamanos de poros entre 18 y 100nm, dimensiones menores a 20 mm de diametro y 2 mm de espesor. Se evaluo la dureza mediante el ensayo de microdureza Vickers y la tenacidad a la fractura a travesdel ensayo de compresion diametral. Muestras con polvos de mayor tamano de particulas presentaron comportamiento no lineal con la porosidad en los valores de dureza y de tenacidad a la fractura. Las muestras con menor tamano medio de polvos presentaron resultados superiores.  Palabras claves: hidroxiapatita, sinterizacion, porosidad. ______________________________________________________________________ Abstract The objective of this work is the mechanical characterization of disks made from Cuban synthetic hydroxyapatite (HA) and Strem Chemicals - USA powders. With different particle sizes and semi-spherical shape with porous surfaces. Without pore-forming additives, by uniaxial compaction and sintering in electric furnace at different sintering regimes. Obtaining ranges of apparent porosities between 3 and 40%, with pore sizes between 18 and 100 nm and their dimensions smaller than 20 mm in diameter and 2 mm thick. The hardness, fracture toughness and diametrical compression of the discs were evaluated. To determine the hardness, the Vickers microhardness test and fracture toughness were used for the radial cracking and palmqvist analysis method produced by Vickers prints. Samples with larger particle size powders presented behavior in the values of hardness and toughness to nonlinear fracture with porosity. In general, the samples with lower mean powder size presented higher results. Key words: hydroxyapatite, sintering, porosity.