1000 resultados para Queijo - Tratamento térmico


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As they have excellent mechanical properties, corrosion resistance and biocompatibility, much research has been conducted with respect to biomedical applications of titanium alloys. This work aims to study the experimental system binary alloy Ti-15Mo, in the raw state of fusion and heat treatment after homogenization, solubilization and calcination (simulating conditions employed for nanotube growth) targeting biomedical applications. Samples were obtained by casting the components in an electric arc furnace with inert atmosphere of argon. After obtaining the alloy, it was heat treated at three different heat treatments, namely homogenizing, calcining and simulation solubilization. The phases present were analyzed by X-ray diffraction, optical microscopy and microhardness testing

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Odontologia Restauradora - ICT

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The ceramic pigments are colored inorganic substances that during the process of dispersion in the ceramic glazes and subsequent calcination, are stable against physical and chemical attack. Therefore, they are crystalline compounds applied in the ceramic industry for coloring vitreous base. In this study, the Pechini method was used for obtaining the pigment CuCr2O4 with heat treatment at the temperatures of 800, 900 and 1000 ° C. The powder pigments were characterized on their structural, morphological and colorimetric aspects. The thermal analysis conducted on an amorphous precursor in a TG / DTA indicates the weight loss in the entire temperature range investigated, with characteristic exothermic peak of the elimination of the organic composition of the precursor around 300°C. The development of the crystalline phases were investigated by XRD, using a diffractometer with Cu Ka radiation and graphite monochromator, where it was observed the presence of crystalline phases corresponding to Cr2O3 and CuCr2O4.The measurements of the specific surface area of the powders pigments were carried out in an equipment Micromeritcs, model ASAP 2000, using N2 as gas of adsorption/desorption. The colorimetric measurements of the pigments were made in a colorimeter Gretac Macbeth Color-eye spectrophotometer 2180 / 2180UV in CIELAB standards. Based on the obtained results, it can be verified the thermal stability of the powder pigments of green coloration, which enables it as an alternative to the materials currently used in the manufacture of ceramic tiles.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Ciência dos Materiais - FEIS

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In the seeds of pioneer plants, the application of treatments for breaking dormancy, and selection by colour and size, are strategies for obtaining seeds of less dormancy and better germination performance. The aim of this study was to evaluate the effect of the physical and physiological aspects of seeds of the tall fringe-rush (Fimbristylis dichotoma) on germination and dormancy. To do this, the seeds were submitted to the following treatments in three studies: (i) control, immersion in H2SO4 (98%, 36N) for 1 minute, immersion in KNO3 (1, 2 and 3%) for 15 minutes, seeding on a substrate moistened with KNO3 (0.2%) and exposure for 5 and 10 hours in a forced air circulation oven at 40 and 70 degrees C; (ii) classification of the seeds by colour (light and dark) and application of the following treatments: control, immersion of the seeds in H2SO4 (98%, 36N) for 1 and 2 minutes, immersion in KNO3 (5% and 10%) for 15 and 30 minutes and seeding on a substrate moistened with KNO3 (0.2%); (iii) classification by size (0.60, 0.50 and 0.40 mm) and germination on a substrate moistened with KNO3 (0.2%) or distilled H2O. The seeds were evaluated by germination test, first count and germination speed index. Moistening the substrate with KNO3 (0.2%), and heat treatment at 40 degrees C for 10 hours improve performance in seeds of the tall fringe-rush. Light-coloured seeds do not display dormancy. Medium-sized seeds of the tall fringe-rush show better performance in terms of percentage and speed of germination.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This study evaluated the influence of different forms of heat treatment on a pre-hydrolyzed silane to improve the adhesion of phosphate monomer-based (MDP) resin cement to glass ceramic. Resin and feldspathic ceramic blocks (n=48, n=6 for bond test, n=2 for microscopy) were randomly divided into 6 groups and subject to surface treatments: G1: Hydrofluoric acid (HF) 9.6% for 20 s + Silane + MDP resin cement (Panavia F); G2: HF 9.6% for 20 s + Silane + Heat Treatment (oven) + Panavia F; G3: Silane + Heat Treatment (oven) + Panavia F; G4: HF 9.6% for 20 s + Silane + Heat Treatment (hot air) + Panavia F; G5: Silane + Heat Treatment (hot air) + Panavia F; G6: Silane + Panavia F. Microtensile bond strength (MTBS) test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using stereomicroscope and scanning electron microscope (SEM) to categorize the failure types. Data were analyzed statistically using two-way test ANOVA and Tukey's test (=0.05). Heat treatment of the silane containing MDP, with prior etching with HF (G2: 13.15 ± 0.89a; G4: 12.58 ± 1.03a) presented significantly higher bond strength values than the control group (G1: 9.16 ± 0.64b). The groups without prior etching (G3: 10.47 ± 0.70b; G5: 9.47 ± 0.32b) showed statistically similar bond strength values between them and the control group (G1). The silane application without prior etching and heat treatment resulted in the lowest mean bond strength (G6: 8.05 ± 0.37c). SEM analysis showed predominantly adhesive failures and EDS analysis showed common elements of spectra (Si, Na, Al, K, O, C) characterizing the microstructure of the glass-ceramic studied. Heat treatment of the pre-hydrolyzed silane containing MDP in an oven at 100 °C for 2 min or with hot air application at 50 ± 5 ºC for 1 min, was effective in increasing the bond strength values between the ceramic and resin cement containing MDP.