Encontrados 9 documentos, a visualizar página 1 de 1
Deformation Induced Martensite in an AISI 301LN Stainless Steel: Characterizati...
Abreu, Hamilton Ferreira Gomes de; Carvalho, Sheyla Santana de; Lima Neto, Pedro de; Santos, Ricardo Pires dos; Freire, Válder NogueiraIn austenitic stainless steels, plastic deformation can induce martensite formation. The induced martensite is related to the austenite (γ) instability at temperatures close or below room temperature. The metastability of austenite stainless steels increases with the decreasing of stacking fault energy (SFE). In this work, the deformation induced martensite was analyzed by X ray diffraction, electron back scatt...
Estudo estrutural e dielétrico da matriz cerâmicas Na2Nb4O11 adicionada de TIO2
Romeu, Mairton Cavalcante; Oliveira, Ronaldo Glauber Maia de; Sales, Antônio Jefferson Mangueira; Silva Filho, José Miranda da; Sales, Juscelino ChavesA fase Na2Nb4O11 tem se mostrado com grande potencial para aplicações em componentes eletromagnéticos. Na literatura encontramos estudos nos quais suas propriedades ferroelétricas são examinadas. O objetivo deste trabalho foi realizar uma analise estrutural e dielétrica da matriz cerâmica Na2Nb4O11 com a adição de TiO2, nas proporções ( 0, 2% em massa) em uma faixa de frequência (100 Hz - 1 MHz) em temperatura ...
Estudo das propriedades diéletricas do SrBi4Ti4O15 (SBTi) dopado com V2O5
Rodrigues Junior, Cauby Amorim; Silva Filho, José Miranda da; Freitas, Daniel Barros de; Oliveira, Ronaldo Glauber Maia deThe SrBi4Ti4O15 (SBTI) is a typical cation-deficient perovskite. This work aims to study the electrical and dielectric properties of the material SBTI doped vanadium oxide (V2O5). The SBTI was prepared by the ceramic method. The powders of bismuth oxide (Bi2O3), titanium oxide (TiO2) and strontium carbonate (SrCO3) were weighed stoichiometrically and mixed. The powders were mixed and milled calcined and then si...
SÍntese e caracterização da cerâmica BNO (BiNbO4) adicionada com 10% de CuO
Sales, Antônio Jefferson Mangueira; Silva, Paulo Maria de Oliveira; Rodrigues Junior, Cauby Amorim; Sales, Juscelino ChavesThe study of the synthesis and structural characterization of ceramic BiNbO4 and behavior of density when added 10% by weight of CuO, with a view to applications in ceramic capacitors, are presented in this work. The BiNbO4 was prepared by conventional ceramic method. The milled powders were calcined for 2 hours at 850 °C for 3 hours and characterized by using a diffractometer Rigaku DMAXB of Co- radiation. A ...
Síntese e refinamento da cerâmica ferroelétrica BaBi4TI4O15 (BBT) utilizando o ...
Silva, Paulo Maria de Oliveira; Sancho, Emmanuelle de Oliveira; Sales, Antônio Jefferson Mangueira; Carneiro, José Carlos de SouzaThe lead zirconate titanate (PZT) has potential application in nonvolatile ferroelectric memory and capacitors, however this material is linked to environmental pollution. In order to remedy this problem, we propose the synthesis of the compound, BaBi4TI4O15 (BBT) because of similarity to PZT. The phase of the BBT has been prepared by the method of solid state. Reagents (BaCO3, Bi2O3 and TiO2) were ground for 6...
Estudo e caracterização da cerâmica BBT (BaBi4TI4O15) dopada com 1% de Nb2O5
Silva, Paulo Maria de Oliveira; Sales, Antônio Jefferson Mangueira; Freitas, Daniel Barros de; Oliveira, Ronaldo Glauber Maia deThis study aims to synthesize and characterize the ceramic BBT (BaBi4TI4O15) doped with 1% by mass of the densification Nb2O5 to improve the products. The phase of the BBT has been found by solid state reaction. The mixed oxides starting processed by high-energy milling in planetary mill reactor polymer and spheres of zirconia and calcined at 850°C/3h. Later, "bulks" prepared with the calcined powder were sinte...
Estudo das propriedades dielétricas e estruturais das matrizes cerâmicas Na2Nb4...
Oliveira, Ronaldo Glauber Maia de; Romeu, Mairton Cavalcante; Sombra, Antônio Sérgio Bezerra; Silva, Paulo Maria de OliveiraThe ferroelectric phase Na2Nb4O11has shown a great potential forY applications: in electromagnetic components.In literature we findstudies where their ferroelectric properties are examined.This workaims to characterize the electrical and structural properties (inregion of 10Hz to 110MHz) of Na2Nb4O11: Y, in which additions were madeBi2O3 in proportions = 0%, 1%, 2% and 10%.As for conductivity, we find thatthis ...
Estudo dos efeitos da adição de ZnO e Nb2O5 nas propriedades dielétricas da mat...
Silva, Paulo Maria de OliveiraWith the rapid growth of the telecommunications industry created a strong need for ceramic materials for applications in microwave. These materials should exhibit high dielectric permittivity (εr), high quality factor (Q), good thermal stability (τf ±10 ppm/ºC) and low cost. With the invention of mobile phones, the field of wireless communication has undergone a revolutionary growth in recent decades. The succe...
Influência da deformação a frio na microestrutura, propriedades mecânicas e mag...
Silva, Paulo Maria de OliveiraAustenitic stainless steels (ASS) are widely used in food, transportation, nuclear and petrochemical industries because of their excellent combination of mechanical strength, formability and corrosion resistance. Among these grades, AISI 301 outstands due to its superior mechanical strength. However, this steel has the weakest corrosion resistance. The corrosion resistance of ASS is based on its passive film en...