Search results for "cemented"
showing 6 items of 6 documents
Influence of Biologically Oriented Preparation Technique on Peri-Implant Tissues; Prospective Randomized Clinical Trial with Three-Year Follow-Up. Pa…
2019
Purpose: The objective of this prospective randomized clinical trial (RCT) was to analyze and compare the clinical behavior of three types of prosthesis supported by single implants in the posterior region after three years of functional loading. Materials and methods: Seventy-five implants were divided into three groups according to the type of prosthetic restoration: screw-retained crown (group GS); cemented crown without finishing line (biologically oriented preparation technique) (group GBOPT); and conventional cemented crown with finishing line (group GCC). After three years in function, clinical parameters (presence of keratinized mucosa, probing depths, bleeding on probing, and radio…
Influence of Biologically Oriented Preparation Technique on Peri-Implant Tissues; Prospective Randomized Clinical Trial with Three-Year Follow-Up. Pa…
2019
Purpose: The objective of this prospective randomized clinical trial (RCT) was to analyze and compare the clinical behavior of three types of prosthesis supported by single implants in the posterior region after three years functional loading. Materials and Methods: Seventy-five implants were divided into three groups according to the type of prosthetic restoration: screw-retained crown (Group GS); cemented crown without finishing line (biologically oriented preparation technique) (Group GBOPT); and conventional cemented crown with finishing line (Group GCC). The clinical behavior of each restoration type was analyzed after 3 years functional loading by analyzing radiographic peri-implant b…
Grinding Tungsten Carbide Used for Manufacturing Gun Drills
2015
This paper presents a study of grinding cemented carbide DK460UF (91 % WC and 9 % Co), a material used to produce cutting tools with solid cutting edges. The aim is to establish the manufacturing conditions that lead to high surface quality. A model of the main factors that influence the grinding process is presented first. Following that, grinding wheel wear and surface roughness are analysed. Grinding wheel wear is studied in experimental conditions under which small diameter gun drills were sharpened with two diamond grinding wheels of different grain sizes. Finally, the wear curve can be made. The "G ratio" is used to characterise the performance of the grinding process. Next, the exper…
Synthesis and processing of nanocrystalline tungsten carbide: Towards cemented carbides with optimal mechanical properties
2011
Abstract Nanocrystalline tungsten carbide has been obtained by reduction/carburization at low temperature from precursors obtained by freeze-drying of aqueous solutions. Nanocrystalline WC powders with a adequate content of carbon were mixed with submicrometric Cobalt powder (12 wt.%), obtained by same synthesis method, and sintered in vacuum furnace. The cemented carbides fabricated from experimental powders were compared with both commercial ultrafine and nanocrystalline WC-12Co mixtures consolidated by the same route. The synthesised powders were characterized by X-ray powder diffraction, elemental analysis and scanning and high resolution transmission electron microscopy. On the other h…
Cutting performance and indentation behaviour of diamond films on Co-cemented tungsten carbide
2000
Abstract Diamond films were grown by Hot Filament Chemical Vapour Deposition (HFCVD) on differently pretreated ISO-grade K10 cemented carbide (WC-5.8 wt.%Co) cutting inserts. Etching with diluted HNO3 and surface roughening by Murakami's reagent were used as substrate pretreatments. The adhesion of the films was evaluated by indentation tests. In order to obtain a reliable estimation of the adhesion by the slope of the crack radius–indentation load curves, a careful SEM measurement of the crack lengths was performed. Bare and diamond-coated cutting inserts were used for turning tests of Al2O3-reinforced aluminum alloy. The adhesion levels obtained from the indentation curves correlated well…
On the optimization of the cutting conditions for an improved corrosion resistance of OFHC copper
2018
International audience; Machining has a particular impact on the surface integrity and on corrosion resistance of components. In fact, material removal induces geometrical, mechanical and micro-structural modifications in the machined surface and sub-surface that alter the electrochemical behavior of the material, and so the aging process. In this study, oxygen free high conductivity copper (OFHC) has machined under orthogonal cutting conditions using uncoated cemented carbide tools. Then, the corrosion resistance in 0.1 M NaCl salt fog atmosphere of the machined samples is analyzed. Finally, the optimal cutting conditions, including the tool geometry, for an improved corrosion resistance a…