Abstract: Process for the reduction of breakdown risks with respect to the solid dielectric insulant of transmission cables and lines operating under high voltages. The insulant normally separates the conductors of a multi-conductor line or the central conductor and the outer metal envelope of a coaxial line. Small amounts of metal particles with dimensions below 1 micron are added to the dielectric insulant mass.

Abstract: Process for the reduction of breakdown risks with respect to the solid dielectric insulant of transmission cables and lines operating under high voltages. The insulant normally separates the conductors of a multi-conductor line or the central conductor and the outer metal envelope of a coaxial line. Small amounts of metal particles with dimensions below 1 micron are added to the dielectric insulant mass.

Abstract: A method of verifying that a given insulative element conforms with a reference insulative element, comprising the steps of: emitting a primary beam of electrons impinging on the given insulative element, receiving a secondary beam of electrons returned by the given insulative element in response to emission of the primary beam of electrons, and comparing a curve as a function of time of the electrical current of the secondary beam received with a curve as a function of time of a reference electrical current to establish whether or not the given insulative element conforms to a reference insulative element.

Abstract: Process and apparatus for the characterization of an insulator (5) at breakdown with the aid of an electron microscope (1), in which the electron flow rate of the beam (3) is adjusted as a function of in particular backscattered, lost, secondary or absorbed electrons. An automatic controller (9) sensitive to certain sensors (10,12) is provided for this purpose. The electron flow rate is proportional to the voltage to be simulated in the insulator.

Abstract: Process for the preparation of ceramic materials for parts having friction surfaces subject to friction and free from auto/self-adhesion under stress or during aging. A precursor of the ceramic undergoes successive operations of pressing, sintering, polishing the surface obtained, cleaning the solid gangue resulting from the polishing, roasting in the presence of oxygen, and a doping treatment for increasing the dielectric susceptibility and homogeneity of the ceramic material adjacent the friction surfaces and to increase the mobility of the charges.

Abstract: Process for the preparation of ceramic materials for parts having friction surfaces subject to friction and free from auto/self-adhesion under stress or during aging. A precursor of the ceramic undergoes successive operations of pressing, sintering, polishing the surface obtained, cleaning the solid gangue resulting from the polishing, roasting in the presence of oxygen, and a treatment aimed at increasing the dielectric susceptibility and homogeneity of the ceramic material adjacent the friction surfaces and to increase the mobility of charges.

Abstract: Process for the production of an electrical insulant (5) placed in an intense electrical field, particularly between two electrodes (1, 2) of an electron tube. The insulant (5) is a crystalline material, whose free surfaces (7) in vacuo (6) have been treated so as to reduce or eliminate crystallization defects. The treatment is checked by measurements of a particular optical or mechanical property of the free surfaces. The breakdown voltage can be multiplied by three or four compared with conventional insulants and can approach the breakdown voltage of the vacuum.