Navegando por Palavras-chave "Fibras cristalinas"

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    Adaptação e otimização de um sistema micropulling-down para o crescimento de fibras monocristalinas
    (Universidade Federal de São Paulo, 2015-01-29) Silva, Marcus Vinicius de Siqueira [UNIFESP]; Santo, Ana Maria do Espírito [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The advances in Science has led to a technological progress in the last few decades. This has motivated the interest in the development of materials with applicable characteristics for miniaturized systems. It is known that monocrystalline fibers show distinct properties when compared to the corresponding bulk crystals, especially in terms of the crystallization kinetic, defects and mechanical behavior. The main characteristic of the Micro-Pulling-Down (?-PD) technique consists in the optimization of the obtained fibers that are long, homogeneous and showing good crystalline quality. In this issue, the development of single crystalline fibers for optical applications and piezoelectric sensors plays an important role in materials science. The subject of this work is the implementation of a ?-PD system for the pulling of single crystalline fibers for the investigation and development of new materials. It was modified a previous ?-PD equipment constructed and donated by the Crystal Growth Laboratory (CLA-IPEN-USP). The behavior of the liquid in the capillary, the geometry of the meniscus and the proper adjustment of the temperature gradient near the solid-liquid interface are essential to the growth success by this technique. For this, a vertical translation system to control the fiber pulling rate was installed. the operational test of the system was performed by exploratory pulling of lithium niobium oxide (LiNbO3). The system was successfully adapted and is appropriate for the growth of oxide fibers with a melting point until 1300°C.