Abstract: A coating for a part made of a nickel alloy of the following type: Cr: 15% to 20%, Co: 8% to 20%, Mo: 1.5% to 4%, Ti: 3% to 5%, Al: 3% to 3.5%, W: .ltoreq.3.8%, Fe: .ltoreq.1.2%, Nb: .ltoreq.0.9%, C: .ltoreq.0.1%, B: .ltoreq.0.01%, and Ta: .ltoreq.2.8%, the remainder being Ni, the coating having hardness of about 400 HV and including a plurality of layers (5', 5") of a wear-resistant cobalt-containing material of the following type: C: <1%, Cr: 26% to 30%, W: 18% to 21%, Ni: 4% to 6%, V: 0.75% to 1.15%, Fe: .ltoreq.3%, Mn .ltoreq.1%, Si: .ltoreq.1%, and B: .ltoreq.0.05%, the remainder being Co, said coating being characterized in that a buffer layer (5) is disposed between the part and the cobalt-containing layers (5', 5"), which buffer layer is made from a pre-alloyed powder having the following composition: Si: 0.7% to 2.9%, Cr: 11% to 26%, Fe: 0.5% to 3%, C: 0.35% to 0.85%, B: 0.3% to 1.35%, Ni: 20% to 69%, W: 3.6% to 16.8%, Mn .ltoreq.0.8%, and Co: 7% to 41.5%.

Abstract: A method of coating a notch in an "upsidedown Z-shape" part of nickel alloy, said notch being constituted by a rounded end wall in the hollow of the "upsidedown Z-shape" followed by a plane wall corresponding to the intermediate portion of the "upsidedown Z-shape" in which a plurality of layers of anti-wear metal material are deposited on said plane wall of the notch. Deposition is performed by a laser whose beam forms a constant angle with the jet of powder. While depositing the first layer the laser beam forms an angle .alpha..sub.1 of several tens of degrees with the normal to the plane wall. While depositing subsequent layers the laser beam initially forms an angle .alpha..sub.3 close to the normal to the rounded portion before being tilted up to the angle .alpha..sub.1, which it then retains throughout the remainder of the pass.

Abstract: A method for producing a prestressed fiber-optic sensor of two superposed metal strips (2,3) sheathing an optical fiber (1) with the strips being secured to each other along their lateral sides to provide a sheath exerting a prestress on the optical fiber includes a first step of superposing the lateral sides of the strips and aligning the edges of the strips. The superposition of the sides is carried out so as to produce a desired prestress on the optical fiber after the sides have been secured together. In a further step, the strips are continuously welded to each other to unite the adjacent edges after superposition of their lateral sides. The welding is performed simultaneously along both sides of the strips and with the same input of energy. The invention also relates to apparatus for carrying out the method and a prestressed fiber-optic sensor produced thereby.