Estudo por espectroscopia Mossbauer e otica da formação de camadas de nitretos de ferro em pos-descarga

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciencias Fisicas e Matematicas2012-10-16T07:23:03

Dépôt de composés inorganiques du Si par plasma CVD sur substrats polymériques : caractérisation structurale et fonctionnelle

Perméation gazeuse -- Méthodologie expérimentale -- Étude de l'interphase couche-poymère -- Caractérisation de couches barrière transparentes su PET -- Étude des défauts dans des couches barrière déposées sur polymères -- Modélisation de la perméation gazeuse à travers les polymères revêtus d'une couche barrière

Evaluation of Piezoresistivity Properties of Sputtered ZnO Thin Films

Zinc oxide (ZnO) thin films were deposited by RF reactive magnetron sputtering on silicon (100) substrates under different experimental conditions. ZnO films were studied before and after annealing treatment at 600 degrees C. the crystallinity, electrical resistivity, stoichiometry, thickness, and elastic modulus of the films were investigated. ZnO piezoresistors were produced using microelectronics processes, such as photolithography, lift-off, and reactive ion etching (RIE). Cantilever method was used to determine the gauge factor, and measurements of Temperature Coefficient of Resistance (TCR) were performed on a hotplate. the optimization of the deposition conditions produced ZnO thin films with controlled stoichiometry (ZnO), crystalline microstructure (phase wurzite, 002), high elastic modulus (156 GPa), and low electrical resistivity (0.072 ohm.cm), which are good properties for application as piezoresistive pressure microsensor. in addition, the ZnO piezoresistors had a GF of 2.6 on the deformation in the plane (100) and TCR of -1610 ppm/K up to 250 degrees C.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Inst Tecnol Aeronaut ITA, Sao Jose Dos Campos, SP, BrazilFac Tecnol São Paulo FATEC SP, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo UNIFESP, Sao Jose Dos Campos, SP, BrazilWeb of Scienc

Characterization of SiC Thin Films Deposited by HiPIMS

In this work thin films of silicon carbide (SiC) were deposited on silicon wafers by High Power Impulse Magnetron Sputtering (HiPIMS) technique varying the average power of the discharge on a stoichiometric SiC target. X-ray diffraction, Raman spectroscopy, scanning electron microscopy and profilometry were used to analyze the films. It was observed that high values of the average electric power favors the formation of C-C bonds, while low values of the power promote the formation of Si-C bonds. At high power, we have also observed higher deposition rates, but the samples present surface imperfections, causing increase in the roughness and decrease in the film uniformity.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Inst Tecnol Aeronaut ITA, Ctr Tecn Aeroespacial CTA, BR-12228900 Sao Jose Dos Campos, SP, BrazilUniv Vale Paraiba, UNIVAP, BR-12244390 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, BR-12231280 Sao Jose Dos Campos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, BR-12231280 Sao Jose Dos Campos, SP, BrazilWeb of Scienc

Abutment coating with diamond-like-carbon films to reduce implant-abutment bacterial leakage

Backgroud: The influence of diamond-like-carbon (DLC) films on bacterial leakage through the interface between abutments and dental implants of external hexagon (EH) and internal hexagon (IH) was evaluated. Film deposition was performed by PECVD (Plasma Enhanced Chemical Vapor Deposition). Sets of implants and abutments (N=180, n=30) were divided according to the connection design and the treatment of the abutment base: (1) no treatment (control); (2) DLC film deposition, and (3) Ag-DLC film deposition. Under sterile conditions, 1 µL of Enterococcus faecalis was inoculated inside the implants, and abutments were tightened. The sets were tested for immediate external contamination, suspended in test tubes containing sterile culture broth, and followed-up for five days. Turbidity of the broth indicated bacterial leakage. At the end of the period, the abutments were removed and the internal content of the implants was collected with paper points and plated in Petri dishes. They were incubated for 24 h for bacterial viability assessment and colony-forming unit (CFU) counting. Bacterial leakage was analyzed by Chi-square and Fisher exact tests (α=5%). The percentage of bacterial leakage was 16.09% for EH implants and 80.71% for IH implants (P<0.0001). The bacterial load was higher inside these implants (P=0.000). The type of implant significantly influenced the results (P=0.000), whereas the films did not (P=0.487). We concluded that: (1) IH implants showed a higher frequency of bacterial leakage and (2) the DLC and Ag-DLC films did not significantly reduce the frequency of bacterial leakage and bacteria load inside the implants

Si-based thin film coating on Y-TZP: Influence of deposition parameters on adhesion of resin cement

This study evaluated the influence of deposition parameters for Si-based thin films using magnetron sputtering for coating zirconia and subsequent adhesion of resin cement. Zirconia ceramic blocks were randomly divided into 8 groups and specimens were either ground finished and polished or conditioned using air-abrasion with alumina particles coated with silica. in the remaining groups, the polished specimens were coated with Si-based film coating with argon/oxygen magnetron discharge at 8:1 or 20:1 flux. in one group, Si-based film coating was performed on air-abraded surfaces. After application of bonding agent, resin cement was bonded. Profilometry, goniometry, Energy Dispersive X-ray Spectroscopy and Rutherford Backscattering Spectroscopy analysis were performed on the conditioned zirconia surfaces. Adhesion of resin cement to zirconia was tested using shear bond test and debonded surfaces were examined using Scanning Electron Microscopy. Si-based film coating applied on air-abraded rough zirconia surfaces increased the adhesion of the resin cement (22.78 +/- 5.2 MPa) compared to those of other methods (0-14.62 MPa) (p = 0.05). Mixed type of failures were more frequent in Si film coated groups on either polished or air-abraded groups. Si-based thin films increased wettability compared to the control group but did not change the roughness, considering the parameters evaluated. Deposition parameters of Si-based thin film and after application of air-abrasion influenced the initial adhesion of resin cement to zirconia. (C) 2013 Elsevier B. V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ Potiguar, Dept Biotechnol, BR-59020280 Natal, RN, BrazilSão Paulo State Univ, Dept Prosthodont & Dent Mat, Sao Jose Dos Campos, BrazilUniversidade Federal de São Paulo, Inst Sci & Technol, Sao Jose Dos Campos, BrazilTechnol Inst Aeronaut, Dept Phys, Sao Jose Dos Campos, BrazilUniv Zurich, Dent Mat Unit, Ctr Dent & Oral Med, Clin Fixed & Removable Prosthodont & Dent Mat Sci, Zurich, SwitzerlandUniversidade Federal de São Paulo, Inst Sci & Technol, Sao Jose Dos Campos, BrazilFAPESP: 09/53584-4Web of Scienc

Corrosion performance of the biocompatible β-Ti12Mo6Zr2Fe alloy submitted to laser and plasma-nitriding surface modifications

International audienc