Abstract: A prosthesis for treating ailments of the scaphoid consists of an implant shaped and sized to serve as a partial replacement of the scaphoid. The prosthesis consists of an element made of a material whose Young's modulus is approximately in the range 10-35 GPa, such as pyrolytic carbon, and having an external surface with a first curved portion having a small radius of curvature corresponding to the conjugated profile of the scaphoid between the head of the capitate and the radius, and a second curved portion having a large radius of curvature corresponding to the profile of the scaphoid facing the radius. Preferably, the partial scaphoid implant is elliptical in each of three mutually perpendicular planes. A method for treating ailments of the scaphoid consists in the surgical removal of a proximal portion of the scaphoid, while leaving the distal fragment thereof in place, and replacing the removed fragment by a prosthesis as described above.

Abstract: An activating system is provided for a heart valve having a seat (1) and at least one pivoting flap (2a, 2b) mounted on the seat (1). The activating system includes at least one mobile magnetic element (4) connected with said flap (2a, 2b) and at least one fixed magnetic element (3) on the seat (1), with the magnetic elements (3, 4) producing interacting fields that create a force which is exerted on said flap (2a, 2b) during its opening and/or closing movements.

Abstract: A composite abrasive product comprises a refractory carbide support and a ring-shaped compact having a rotational symmetry about an axis of the support. The compact has an axial thickness which is small as compared with the axial thickness of the support and a substantially triangular axial cross-section, said compact having a face metallurgically bonded to a chamfered circumferential part of the support and the two remaining faces joining at a cutting edge. A method for manufacturing such a product is also disclosed.

Abstract: An abrasive is provided having an active phase comprising a sintered product comprising diamond grains, each grain being linked directly to its neighbors by bridging to exhibit a polycrystalline structure, and a support consisting essentially of tungsten carbide. The tungsten carbide support comprises a chromium binder phase including 6 to 15% of carbide. The relative proportions by weight of nickel and chromium of the binder phase vary from 60 to 90% to 40 to 100%, respectively. The abrasive is made by placing a layer of diamond grains into a cupel, covering this layer with a tungsten carbide layer including a nickel-chromium mixture to provide the support, subjecting the stack thus produced to a temperature and a pressure sufficient to cause sintering in the plastic phase of the diamond grains and to assure the binding of the compact thus obtained on the support. Drilling and machine tools can be equipped with the abrasive product of the invention.

Abstract: The composite tool (1) comprises a sintered metal carbide support (2) and a polycrystalline diamond active part (3) having an inner surface (4) of metallurgical connection to the support (2) and an outwardly facing working surface (5). The working surface (5) comprises corrugations (7) which are substantially parallel to one another and form successive projecting zones (7) and hollow zone (8) on at leasst a part of the working surface (5). The composite tool is in particular intended for drilling to a great depth, such as drilling oil wells.

Abstract: The body (1) of the tool consists of a single-piece steel component. The housing (3) for the composite abrasive component (2) is provided in this steel component. The working surface (5) of the body (1) has, at least in its component-holder part (5a), and angle at the lower vertex of at least 20% with respect to the angle at the vertex of the corresponding part (8a) of a metallic carbide tool for working the same rock. The surface (5a) of the component holder (4) is at least partially covered by an erosion layer (10) of hard material.

Abstract: A cutting element of flat shape suitable for use as a drill tip comprises a central abrading blade containing more than 80% vol. CBN sandwiched between two lateral support layers. The lateral layers consist of a refractory metal or alloy selected from the group consisiting of tungsten, titanium and alloys thereof. The compact may particularly have a roof or pentagonal shape. An intermediate transition film may be located between the refractory metal or alloy and the CBN blade.

Abstract: For preparing a composite abrasive product having an active part, formed by a compact containing grains of ultra-hard product representing more than 80% per volume of the compact, each grain being bonded directly to its neighbors so that the compact has a polycrystalline structure, and by a hard and refractory support bonded to the compact, formed essentially of a refractory carbide such tungsten carbide, characterized in that: a layer of ultra-hard product grains (PCD or CBN) is placed in contact with components generating an ultra-hard ceramic binder phase in the cell. The powder layer is covered with a thin layer of tungsten coated with a carbide supplying material and, finally, with a tungsten carbide support. The cell containing the stack thus formed is brought to a temperature and a pressure sufficient to cause plastic phase sintering of the ultra-hard product grains with each other and bonding of the compact to the support.

Abstract: A thermostable abrasive diamond product includes a compact formed of diamond grains representing more than 80% by volume of the compact, each grain being bonded directly to its neighbors so as to form a polycrystalline structure. The empty spaces between diamond grains are occupied by a binder face containing silicon and/or titanium and nickel silicon (or titanium) and nickel being alloyed. The compact may be bonded by a metallurgical interface to a substrate of a refractory metal such as tungsten.

Abstract: The invention is a process for preparing a sintered polycrystalline compact of cubic boron nitride (CBN) with substantial intercrystalline bonding, together with the compact produced by the process. A carbon containing material, such as diamond or graphite, is added to a binder material which comprises elemental silicon. The carbon from the carbon containing material reacts with the silicon to form silicon carbide. Having silicon carbide as a constituent of the final product is preferable to having elemental silicon because the silicon carbide does not expand on cooling, and is also harder and more wear resistant than elemental silicon. In this way, the benefits of using elemental silicon in a binder system to enhance intercrystalline bonding of the CBN are realized while avoiding the disadvantages otherwise present. Another advantage is provided in the compact of this invention may be cut into precision shapes with a conventional Electric Discharge Machine (EDM).

Abstract: The invention is a process for preparing a sintered polycrystalline compact of cubic boron nitride, the compact produced by the process, and articles comprising the compact. A mixture is formed of cubic boron nitride grains and from 5 to 20 volume percent of binder material, or sintering aid, consisting essentially of silicon and an aluminum-containing material selected from the group consisting of aluminum, aluminum nitride, aluminum diboride, and mixtures thereof. The mixture is subjected to elevated pressure and temperature conditions sufficient to melt the binder material and at which the boron nitride is thermodynamically stable. The elevated pressure and temperature conditions are maintained for a time sufficient to sinter the compact. The compact is characterized by substantial intergranular CBN-CBN bonding, and has superior wear and impact resistance, thermal conductivity and stability.

Abstract: This invention relates to improved process and apparatus for producing reinforced composite light alloys. The improved apparatus comprises means for feeding a fluidized mixture of particulate additions, carried by a neutral gas, to a crucible in which a basic metal consisting preferably of nearly pure aluminium ingots is molten. Means are provided for stirring the contents of crucible during the feeding of said mixture thereto, in order to prevent the sedimentation or decantation of the dispersion formed therein. Means are further provided for transferring the mixture of basic metal and additions into another receptacle in which the desorption and degasing of said mixture take place.