Last. Lirio Schaeffer(UFRGS: Universidade Federal do Rio Grande do Sul)H-Index: 12
view all 0 authors...
Abstract This study aimed to analyze the wettability characteristics applied to the surface of heat-treated pure titanium grade 2. Titanium is widely used for applications in implants produced by incremental sheet forming (ISF), where the 3D model resulting from tomography was used to produce the part. Since the ISF process creates residual stresses in the sheet, heat treatments were applied to relieve them. Also analyzed were roughness, researching what the literature recommends to enable surfa...
Abstract Optical thermometry is a growing technological field which exploits the ability of certain materials to change their optical properties with temperature. In this work, poly(glycerol dendrimer) microspheres (PGLyD) encapsulating cobalt-doped hopeite (CoHo) was synthesized for its potential use as optical thermometer. The structure of the CoHo:PGLyD was studied using scanning electron microscopy (SEM), infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD) and thermogravimetric analysi...
In this paper, NiMoO4 powder was synthesized by the complexation method combining EDTA-Citrate. The behavior of the NiMoO4 material in the ethyl transesterification reaction was evaluated by analyzing the acidity index under specified reaction conditions. The results showed that NiMoO4 crystallized at 800 °C with a total mass loss of 85%, presenting a monoclinic structure, free of secondary phases, high degree of crystallinity and average crystallite size of 140 nm. The particles had heterogeneo...
In this study, the sliding wear of a DIN 18MnCrSiMo6-4 continuous cooling bainitic steel plasma nitrided with a nitrogen rich gas composition was investigated. To evaluate the influence of processing time and temperature on mechanical and microstructural characteristics of nitrided layer, the samples were nitrided at 400, 450, 500 and 550 °C for 3, 6 and 9 h. The produced nitrided layers were characterized concerning the microstructure, phase composition, microhardness and surface roughness. The...
In this study, tubular ceramic membranes were prepared from a mixture of ball clay, talc and alumina. The mixture was characterized by the following techniques: particle size analysis, X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD) and thermal analysis. Tubular membranes were produced by extrusion process and thermal treated at temperatures between 1025 °C and 1175 °C. The membranes were characterized by XRD, linear shrinkage, apparent porosity, flexural strength, mercury porosim...
Grain refinement in Al-Si alloys improves their mechanical properties. Research available in the literature shows the search for refinement efficiency through heterogeneous nucleation of the grain, involving the stoichiometric ratio between the alloy elements, the inoculant, and process parameters. In these surveys, there are divergences of information. However, this study does not aim to contradict this information but present an investigation made with the Al-4Nb-0.5B master alloy, where Nb >>...
This paper presents the study of the addition of the polyaniline polymer (PANI), at the junction of the cadmium telluride and cadmium sulfide (CdTe/CdS) layers in order to improve the contact between the layers, to decrease the air gap that limit the conversion photovoltaic. The morphology of CdS, CdTe and polyaniline (PANI) were characterized with multiple techniques including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and optical absorptio...
Abstract Wear resistance is a fundamental property which defines the lifetime of cutting tools, but the investigation of wear performance of alternative hard materials for traditional WC-Co composites are recent. The present work evaluated the pin-on-disk wear behavior and mechanical properties, i.e., hardness and fracture toughness of spark plasma sintered Al2O3 matrix composites with additions of 5, 15, 25 or 30%wt of niobium carbide NbC. The wear resistance was observed to increase as a funct...