Le Carbone Lorraine

Pechiney Recherche

Pechiney

Christophe Bommier

Philippe Gimenez

Jean-Louis Chareire

Jacques Rabiet

Jean-Claude Kucza

Gerard Laslaz

Jean Salem

A carbon-carbon composite material formed from a fibrous substrate and a matrix. The fibrous substrate has a carbon fiber base which acts as a reinforcement, a coarse texture and large sized cavities. The matrix includes pyrocarbon layers coating the fibrous substrate and a carbon based cellular structure dividing the large sized cavities of the substrate into small cavities having open porosity.

Carbon-carbon composite friction material with divided porosity

A process for manufacturing porous tubes made from carbon-carbon composite material by winding over a mandrel a non-woven sheet, made from a carbon fiber precursor, followed by compression and hot stabilisation of the assembly, with impregnation of the compressed sheet by a resin, followed by a thermal carbonisation treatment of the resin. Tubes are obtained having high permeability, small pore diameter and an inner surface of low rugosity. The tubes produced ar particularly suitable for the manufacture of filtration elements and of filtering membrane supports.

Process for manufacturing porous tubes of high permeability made from

A multi-layer friction element is disclosed consisting of carbon-carbon composite material comprising a structure layer of so-called 'coarse' texture comprising segments of rovings and at least one friction layer of so-called 'fine' texture comprising fibre segments. A method also is disclosed for producing the friction element by preparation of a fibrous substrate by introducing segments of roving and/or fibers into a mould preferably by means of a distribution apparatus. Further disclosed is an apparatus for automatically obtaining a fibrous substrate of predetermined texture.

Friction elements of composite carbon-carbon material and of

An apparatus for the anodic treatment of aluminum alloy pistons used in internal combustion engines. The apparatus comprises at least two members applied symmetrically to the lateral cylindrical surface of the piston which are connected to a source of positive direct current. An electrode connected to a source of negative direct current and having at least one aperture therein is positioned adjacent the head portion of the piston which is to be treated. A deflector of electrically insulating material disposed generally parallel to and spaced from the electrode and having a circumference curved toward the electrode is provided with a central passage therethrough which receives the head portion of the piston, with the head portion being disposed opposite the electrode. The deflector surface facing the electrode is provided with a flexible means for sealing the deflector to the head portion and a regulated flow of anodizing electrolyte is provided through the aperture in the electrode, in the direction of the deflector and the head portion. This apparatus can be applied to the high speed production of barrier coatings which are confined to the piston heads and which can prevent development of heat stresses which could adversely affect the satisfactory functioning of the piston. The coatings are produced without the use of masks or treatments other than the anodic treatment.

Anodic treatment apparatus for aluminium alloy pistons

This invention relates to a process for identifying the external surface or surfaces of an Al alloy of a homogeneous or composite material by electrochemical means. This method involves forming an anodic layer, in situ, on the products to be identified, by electrolysis under predetermined conditions and following or plotting the development of the voltage U at the terminals of the electrolyzer as a function of time t during an intentiostatic test. The shape and relative position of curves U=f(t), thus obtained, allows the various alloys tested to be identified from a comparison of the derived curve from a curve U=f(t) derived from a known sample. The present method has advantages over the earlier methods of marking in that it provides: non-destructive method employable in situ on products which may have large dimensions (coils, plates, sheets, etc.); almost instantaneous identification; high reliability; and is simple and economic to use.

Growing community of inventors

Paris, France

Christophe Bommier