Estudo da signifcância de variáveis de compactaçã o e sinterização de pastilhas de β-TCP utilizando planejamento de experimentos

Abstract

Among the ceramic materials for biomedical applications, tricalcium phosphate type β (β-TCP) can be highlighted. Usually, ceramic powders are pressed and densifed at high temperatures in order to improve the mechanical strength. One way to optimize the densifcation of ceramic bodies is to analyze the signifcance of processing variables using an experimental design. The purpose of this work is to determine the signifcance of the following parameters: uniaxial pressure (28 and 111 MPa); previous thermal treatment of the powder (as-received-non-calcined and calcined at 650 °C); sintering temperature and time (900 and 1150 °C, 2 and 4 h, respectively). The produced tablets were characterized by scanning electron microscopy, X-ray diffraction and infrared spectroscopy, while linear shrinkage and microhardness results were considered as responses of the experimental design. It was observed that the uniaxial pressure and sintering temperature were the most important parameters for samples densifcation. The average grain size of the tablets sintered at 1150 °C was approximately 1-2 μm and maximum linear shrinkage of, approximately, 20%, well above the values found for the samples sintered at 900 °C, which did not present complete densifcation. Phases other than β-TCP were not present in the sintered samples and no cracking was observed.