Use of Niobium Oxide as a Binder in the Production of Diamond Nanostructured Composites

Ana Lúcia Diegues Skury; Guerold Sergueevitch Bobrovinitchii; Marcia G. de Azevedo; Sérgio Neves Monteiro

doi:10.4028/www.scientific.net/MSF.727-728.924

Paper Titles

Synthesis and Characterization of Strontium and Calcium Titanate Polycrystalline Powders by a Modified Polymeric Precursor Technique
p.904

Ceramic Processing of NBC Nanometric Powders Obtained by High Energy Milling and by Reactive Milling
p.909

Ceramic Compacts Based on Sintered ZrO₂ Nanopowder
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Performance of Nanostructured Diamond Composites in Wear Tests
p.919

Use of Niobium Oxide as a Binder in the Production of Diamond Nanostructured Composites
p.924

Purification of a Brazilian Smectite Clay
p.929

Effect of Glassy Phase Additions to Zirconia on its Sintering Behavior and Microstructure
p.935

Effect of Glassy Phase Additions to Zirconia on its Mechanical Properties
p.940

Mechanical Characterization of Zirconia Synthesized by the Sol-Gel Process
p.945

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Use of Niobium Oxide as a Binder in the Production of Diamond Nanostructured Composites

Abstract:

The sintering of nanodiamond powders is of interest for both applied engineering of tool materials and fundamental materials science of nanodisperse covalent-type ceramic materials. It is a accept as a general notion that the driving force for sintering of monophase particles is determined by the level of the surface energy. In the case of diamond nanopowder, this level must be significantly higher which makes sintering a difficult process. This difficulty of sintering is connected with the low diffusive mobility of carbon causing the formation of a graphite structure onto surface of the diamond crystals. From this point of view the use of niobium oxide as a binder could be a solution. In an attempt to inhibit the diamonds graphitization process, Nb2O5 and small amounts of amorphous carbon were introduced in the reaction zone. Sintering process was conducted at 6.0 GPa of pressure and 1100-1400oC for a processing time of 30 seconds. At the end of the process, the samples were cleaned, and prepared to be characterized by X-ray diffraction, scanning electron microscopy, density and porosity. From these results it was proposed a densification mechanism based on the consolidation of the particle by diffusion and coalescence of clusters.