Abstract: Manufacturing a porous component used as flow restrictor includes a metal injection molding process enhanced to obtain a component with open porosity homogeneously distributed. The flow restrictor includes at least one porous component having at least one restricting portion with some porosity dimensioned to regulate the flow of gas to an aerostatic bearing of a mechanical system, such as a hermetic compressor. Use and production of a porous component obtained by powder injection molding or powder injection molding of multi-material parts is also described, the porous component being a flow restrictor with a layer of dense material, with no open pores, on the outer surface parallel to the flow direction in which the flow through the porous component occurs, allowing it to be inserted into the bearing system without interfering with the porous structure of the core (dual porosity). Sealing existing between the porous component and its housing is described.

Abstract: The plasma reactor defines a reaction chamber provided with a support for the metallic pieces and an anode-cathode system, and a heating means is mounted externally to said plasma reactor. The plasma process, for a cleaning operation, includes the steps of connecting the support to the grounded anode and the cathode to a negative potential of a power source; feeding an ionizable gaseous charge into the reaction chamber and heating the latter at vaporization temperatures of piece contaminants; applying an electrical discharge to the cathode; and providing the exhaustion of the gaseous charge and contaminants. A subsequent heat treatment includes the steps of: inverting the energization polarity of the anode-cathode system; feeding a new gaseous charge to the reaction chamber and maintaining it heated; applying an electrical discharge to the cathode; and exhausting the gaseous charge from the reaction chamber.

Abstract: The process comprises the steps of: mixing a load of oxide ceramic material particles (10) with a load of space holder particles (20), defined by graphite and/or amorphous carbon; compacting the mixture formed by ceramic material particles (10) and space holder particles (20), to form a compact body (E); and sintering said compact body (E), so that the ceramic material particles (10) form sintering contacts with each other, whereas the carbon of the space holder particles (20) is removed by the reaction with the oxygen in the sintering medium, to form open secondary pores (II), by eliminating the space holder particles (20). The metallurgic composition comprises the mixture of the ceramic material particles (10) with the space holder particles (20).

Abstract: The plasma reactor defines a reaction chamber provided with a support for the metallic pieces and an anode-cathode system, and a heating means is mounted externally to said plasma reactor. The plasma process, for a cleaning operation, includes the steps of connecting the support to the grounded anode and the cathode to a negative potential of a power source; feeding an ionizable gaseous charge into the reaction chamber and heating the latter at vaporization temperatures of piece contaminants; applying an electrical discharge to the cathode; and providing the exhaustion of the gaseous charge and contaminants. A subsequent heat treatment includes the steps of: inverting the energization polarity of the anode-cathode system; feeding a new gaseous charge to the reaction chamber and maintaining it heated; applying an electrical discharge to the cathode; and exhausting the gaseous charge from the reaction chamber.

Abstract: The process basically comprises: dissolving a lamellar disulphide, as a source of the solid lubricant, in an aqueous solvent, forming a first aqueous solution; dissolving a reducing agent, as hydroxylamine, sodium hypophosphite or sodium borohydride, in an aqueous solvent, forming a second aqueous solution; mixing the first and second aqueous solutions, forming a third aqueous solution; neutralizing the pH of the third aqueous solution; dissolving a sulphur source, in an aqueous solvent, forming a fourth aqueous solution; mixing the third and fourth aqueous solutions, forming a fifth aqueous solution, which is contained and heated in an autoclave; cooling the fifth aqueous solution to the room temperature; and removing, from the autoclave, the nanoparticles in powder form.

Abstract: The composition includes the iron as the main particulate metallic material; at least one particulate alloy element, with the function of hardening the ferrous structural matrix; and a precursor non-metallic particulate compound, generally a carbide or a carbonate, which is capable of generating, upon its dissociation during the sintering, graphite nodules, whose formation is facilitated: by the precursor compound itself when it includes a chemical element which stabilizes the iron alpha phase of the ferrous structural matrix; or by an additional alloy element included in the composition and which is defined by a chemical element that stabilizes the iron alpha phase during the sintering. The composition can be conformed by compaction or by powder injection molding. The process of the invention leads to obtaining products in self-lubricating sintered steel from said composition.

Abstract: The metallurgical composition includes a main particulate metallic material, for example iron or nickel, and at least one alloy element for hardening the main metallic material, which form a structural matrix; a particulate solid lubricant, such as graphite, hexagonal boron nitride or mixture thereof; and a particulate alloy element which is capable of forming, during the sintering of the composition conformed by compaction or by injection molding, a liquid phase, agglomerating the solid lubricant in discrete particles. The composition may include an alloy component to stabilize the alpha-iron matrix phase, during the sintering, in order to prevent the graphite solid lubricant from being solubilized in the iron. The invention further refers to a self-lubricating sintered product, obtained from the composition, and to the process for obtaining said product.

Abstract: The plasma reactor defines a reaction chamber provided with a support for the metallic pieces and an anode-cathode system, and a heating means is mounted externally to said plasma reactor. The plasma process, for a cleaning operation, includes the steps of connecting the support to the grounded anode and the cathode to a negative potential of a power source; feeding an ionizable gaseous charge into the reaction chamber and heating the latter at vaporization temperatures of piece contaminants; applying an electrical discharge to the cathode; and providing the exhaustion of the gaseous charge and contaminants. A subsequent heat treatment includes the steps of: inverting the energization polarity of the anode-cathode system; feeding a new gaseous charge to the reaction chamber and maintaining it heated; applying an electrical discharge to the cathode; and exhausting the gaseous charge from the reaction chamber.