Showing papers by "Alexandre Zirpoli Simões published in 2010"
TL;DR: In this paper, the authors used the hydrothermal-microwave method (HTMW) to synthesize barium strontium titanate (BST) nanoparticles in the temperature range of 100-130°C.
61 citations
TL;DR: In this paper, the mechanical and adhesive properties of epoxy formulations based on diglycidyl ether of bisphenol A cured with various aliphatic amines were evaluated in the glass state.
Abstract: The mechanical and adhesive properties of epoxy formulations based on diglycidyl ether of bisphenol A cured with various aliphatic amines were evaluated in the glass state. Impact and uniaxial compression tests were used to determine the impact energy, elastic modulus and yield stress, respectively. The adhesion tests were carried out in steel–steel joints using single-lap shear, T-peel, and impact adhesive joints geometry. The better mechanical and adhesive behavior of the networks is obtained when exists high flexibility of chain between crosslink and/or high elastic modulus. The 1-(2-aminoethyl)piperazine epoxy network presents the best adhesive properties, high flexibility, and the largest impact energy. However, it possesses low elastic modulus and yield stress. Also, exhibits increases in peel strength and impact energy while reductions in lap shear strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
25 citations
TL;DR: In this paper, the piezoresponse characteristics at room temperature in niobium modified bismuth ferrite thin films (BFN) deposited on Pt/TiO2/SiO 2/Si substrates by the soft chemical method were investigated.
22 citations
TL;DR: In this paper, calcium bismuth niobate (CaBi2Nb2O9, CBNO) thin films were evaluated for use as lead-free piezoelectric in microelectromechanical systems.
18 citations
TL;DR: In this article, the effect of temperature on the structural and electrical properties of BZT:2V ceramics was investigated and the fine-grained sample showed a relaxor-like ferroelectric behavior.
13 citations
TL;DR: In this paper, the adhesive properties have been investigated in blends of mono-carboxyl-terminated poly(2-ethylhexyl acrylate-co-methyl methacrylate) with diglycidyl ether of bisphenol A and three different aliphatic amine epoxy hardener.
Abstract: The adhesive properties have been investigated in blends of mono-carboxyl-terminated poly(2-ethylhexyl acrylate-co-methyl methacrylate) with diglycidyl ether of bisphenol A and three different aliphatic amine epoxy hardener. The adhesives properties are evaluated in steel alloy substrate using single-lap shear test. The copolymers are initially miscible in the stoichiometric blends of epoxy resin and hardener at room temperature. Phase separation is noted in the course of the polymerization reaction. Different morphologies are obtained according to the amine epoxy hardener. The most effective adhesive for steel–steel joints in single-lap shear test is the blends using 1-(2-aminoethyl)piperazine (AEP) as hardener. This system shows the biggest lap shear strength. However, the modified adhesives show a reduction in the mechanical resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
9 citations
TL;DR: In this paper, the authors have observed that the main source of retention-free characteristic of the capacitors is the oxygen environment in the CBTi144 lattice, which is a single phase of layered-structured perovskite with polar axis orient.
Abstract: (CBTi144) thin films were grown on Pt/Ti//Si substrates using a soft chemical solution and spin-coating method. Structure and morphology of the films were characterized by the X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman analysis, X-ray photoemission spectroscopy (XPS), and transmission electron microscopy (TEM). The films present a single phase of layered-structured perovskite with polar axis orient. The a/b-axis orientation of the ferroelectric film is considered to be associated with the preferred orientation of the Pt bottom electrode. XPS measurements were employed to understand the nature of defects on the retention behavior of CBTi144 films. We have observed that the main source of retention-free characteristic of the capacitors is the oxygen environment in the CBTi144 lattice.
2 citations
TL;DR: In this article, the authors present the results of a study conducted at the Instituto de Quimica Universidade Estadual Paulista (UEP) in Brazil.
Abstract: Laboratorio Interdisciplinar em Cerâmica Instituto de Quimica Universidade Estadual Paulista, P.O. Box 355, 14801-907, Araraquara, Sao Paulo
1 citations
TL;DR: In this article, the authors present the results of a study conducted at the Instituto de Quimica Universidade Estadual Paulista (UEP) in Brazil.
Abstract: Laboratorio Interdisciplinar em Cerâmica Instituto de Quimica Universidade Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, Sao Paulo
1 citations
TL;DR: In this article, the electrical response of Ba(Ti 0.90 Zr 0.10 )O 3 (BZT) ceramics obtained by the mixed oxide method as a function of tungsten content was investigated.
Abstract: The electrical response of Ba(Ti 0.90 Zr 0.10 )O 3 (BZT) ceramics obtained by the mixed oxide method as a function of tungsten content was investigated. According to X-ray diffraction analysis the single phase BZT1W (1 wt.% W doped BZT) and BZT2W (2 wt.% W doped BZT) ceramics, crystallized in a perovskite structure, were obtained. It is also shown that tungsten substituted ceramics can be sintered at a reduced temperature when compared to the undoped BZT. Electron paramagnetic resonance (EPR) analyses reveals that substitution of Ti 4+ by W 6+ causes distortion in the crystal structure changing lattice parameter. Substitution of W 6+ on B-site of ABO 3 perovskite BZT ceramics shifted the phase transition to lower temperatures up to a tungsten content of 2 wt.% leading to a relaxor-like behaviour.