the diamond particles are bonded to the metallic matrix by a combination of chemical and mechanical interactions. The present work reports the results obtained on the This is a process that needs a close control of processing evaluation of both the response of commercially availparameters to avoid diamond dissolution, attack, and/or able Cu-Fe-Co pre-alloyed powders during prographitisation that could deteriorate the final cutting cessing for the consolidation of diamond tools under performance.2,3 several fabrication routes, and the performance of the For a specific application, the optimisation of a diamond tools during in field cutting operations. The new tool performance requires finding the right combination of metallic binders look attractive since they combine diamond grits (concentration, particle size, quality, and good sinterability with adequate values of hardness shape) and metal matrix. In general, the metallic binder and wear resistance, as observed from the cutting tests must be tailored to wear at the same rate that the diamond carried out on granite and marble. The consolidation grits, so that when a set of diamonds is worn, a new set is routes under research were conventional hot pressing, exposed to continue cutting.2 pressureless sintering, and hipping after sintering. The Cobalt is the main component of the binder phase of amount of copper contained in these alloys leads to most diamond tools. It combines acceptable chemical fully dense parts by hot pressing at temperatures compatibility with diamond at the processing temperatures, approximately 150°C lower than those used for adequate diamond retention and good wear resistance after cobalt. Pressureless sintering experiments showed a number of cutting operations.2,4,5 However, cobalt is that full densification requires the application of hipsubjected to price fluctuations in the market, is a strategic ping post-sintering treatments. During processing material, and does not seem to be the best choice for every under non-reducing atmospheres, the presence of type of application. Therefore, recently, research has focused metallic oxides contained in the powder was observed on widening the choice of alloys that could be alternatively to exert a direct influence on the degradation of the used or at least reduce the cobalt content in diamond diamond grits.PM/0902 tools.6-8 The search for novel metallic binders to be used for the fabrication of diamond cutting tools has produced Dr Castro, Dr Iturriza, and Dr Sa ´nchez are at the an intensification of research activities in this field thus Centro de Estudios e Investigaciones Te ´cnicas de widening the choice of metal powders for this purpose. On Guipu ´zcoa (CEIT), Department of Materials, Paseo this basis, commercially available powders containing Cu, de Manuel Lardiza ´bal, 15, 20018, San Sebastian, Fe, and Co in predetermined ratios have been produced Spain, Dr del Villar and P. Muro are in the Escuela and launched by a powder producer under the name Superior de Ingenieros, University of Navarr...

International audienceSelective diamond growth on etched diamond substrates allows the developement of 3D-type device geometries, which can make possible higher capacity, higher surface for contacts and benefits from better properties versus growth orientation. Such structures need the control of lateral growth and lateral etching that garantee the best epitaxial growth, with a well-faceted surface, with a minimum density of emerging defects in order to limit the current leakage and to improve the breakdown voltage. Previous works used 111-oriented selective growth on etched diamond for lateral p-n junctions or bipolar junction transistors. The behavior of homepitaxial overgrowth on etched diamond substrates depends directly on growth parameters such as temperature, gas concentration or microwave power that can favor the growth in one specific direction. The present contribution considers the effect of methane concentration during the overgrowth of the mesa pattern. The presence of highly doped intermediate layers allowed following the growth plane orientation in a stratigraphic approach. Faceting and growth velocities were analyzed using scanning and transmission electron microscopes (SEM and TEM)

A transmission electron microscopy (TEM) study of superconducting nanocrystalline diamond (NCD) 12 continuous layers is reported. The high resolution transmission electron microscopy (HREM) and the

No abstract

No abstract