Navegando por Palavras-chave "Lead-Free"

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    Investigação Da Cinética De Sinterização De Cerâmicas De (K0,48na0,52)Nbo3 (Knn) Densificadas Por Spark Plasma Sintering
    (Universidade Federal de São Paulo (UNIFESP), 2018-03-29) Souza, Camila Alves De [UNIFESP]; Lente, Manuel Henrique [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    In This Work, It Was Proposed The Study Of The Densification Of Lead-Free Piezoelectric Ceramics Based On (Kx,Na1-X)Nbo3 Via Spark Plasma Sintering And The Study Of Sintering Kinetics Through The Determination Of The Master Sintering Curve. In Addition, The Effect Of The Cuo Doping On Knn Properties And The Effect Of A Lower Pressure Applied During The Sintering Process Were Analyzed In A Complementary Manner. Thus, For The Initial Study, Ceramic Samples Of Knn Were Sintered At Different Heating Rates Using The Same Sintering Temperature And Applying The Maximum Allowable Pressure. Then, This Same Criterion Was Applied For Knn Samples Differing Only In The Magnitude Of The Pressure Applied During The Sintering, Whose Value Became The Minimum Allowed. Subsequently, Using The Initial Sintering Parameters, Knn Ceramics Doped With 1.5 %Mol Cuo Were Produced. The Results Were Correlated With Microstructural, Structural And Electrical Properties In Order To Analyze The Influence Of The Sintering Rate, Doping And Di
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    Propriedades físicas de fibras monocristalinas de niobato de sódio e potássio puras e dopadas com cobre obtidas por Micro-Pulling-Down
    (Universidade Federal de São Paulo (UNIFESP), 2020-02-28) Silva, Marcus Vinicius De Siqueira [UNIFESP]; Lente, Manuel Henrique [UNIFESP]; Universidade Federal de São Paulo
    Due to the toxicity of lead and its large application in electronic devices, the current work aimed to study the matrix ((Na0.52,K0.48) NbO3 and (Na0.52,K0.48) (Nb0.985,Cu0.015)O3 in single crystal fibers as an alternative to replace lead-based ferroelectric (Pb) materials, such as lead zirconate titanate. Additionally, single crystal ferroelectric materials, in general, show enhanced electromechanical properties compared to polycrystalline ceramics of same composition. The experimental growth proccess of pure and copper-doped single crystal fibers was carried out evaluating the effect of the atmosphere (argon, synthetic air and oxygen) on the dielectric properties of the grown fibers. The influence of the growth atmosphere on the microstructural, structural, chemical and dilatometric properties was also evaluated. The results reveled that synthetic air is the best atmosphere to grow single crystal fibers.