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AssigneeAgence Nationale de Valorisation de la Recherche (ANVAR)
InventorsPierre Guiraldenq, Daniel Treheux, Daniel Marchive
Estimating the term…
A steel part, and more particularly a stainless steel part, is coated with a varnish containing particles of an additional metal such as tin or aluminium, and it is heated at a temperature situated above the melting point of the said additional metal, but outside a zone comprised between 700.degree. C and 970.degree. C. The treated part may be annealed at about 500.degree. C. The varnish may besides contain particles of a substance having a melting point situated above the melting point of the additional metal, but which may dissolve in the liquid phase of the latter. This substance may be chromium, molybdenum, cobalt, titanium, vanadium, nickel or copper.
A method for the treatment of steel surfaces to form thereon an intermediate layer of ferrites and an outer layer on tin-iron compound of the type FeSn to improve their resistance to corrosion and their frictional properties which consists essentially:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Coating with metallic material, i.e. metals or metal alloys, optionally comprising hard particles, e.g. oxides, carbides or nitrides: coating with…
Sn-base component: next to Group VIII metal-base component
Coating metallic material
Technical subjects covered by former us classification
Term ended 30 Aug 1994 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to the superficial treatment of steel in order to increase its resistance against corrosion or to improve its properties concerning frictional effects.
It has been proposed to coat a steel article with an organic varnish containing an appropriate powdered additional metal, such as tin or aluminium, and then to heat the surface to destroy the varnish and to cause the powder particles to migrate into the steel where they realize a layer of complex compounds which protects the underlying metal against corrosion. But these methods have not given very satisfactory results. Moreover the steel parts thus treated afford quite poor frictional properties.
It is an object of the present invention to provide a method for the superficial treatment of steel parts, which permits of obtaining an improved protection against corrosion and also excellent frictional characteristics.
FIG. 1 is a graphic representation of the results of the friction test effected on an untreated sample.
FIG. 2 illustrates the result of a friction test concerning a sample treated with tin at a relatively low temperature.
FIG. 3 shows a micrographic section of this sample.
In the following examples, the steel to be treated was a stainless steel of the type 18-10 (18% Cr, 10% Ni). The additional metal was tin under finely divided form (average diameter of the particles 10.mu.). The organic varnish was made of nitrocellulose. The tin particles were uniformly dispersed in this varnish by prolonged stirring. The suspension obtained was applied onto the parts by means of a brush. The coating was dried in open air at a relatively moderate temperature to obtain a uniform and smooth layer of dried varnish in which the metallic particles were embedded.
The heating step was effected in an atmosphere formed of argon gas.
The friction tests were performed on a Faville machine, the sample to be tested being the rotating member, while the stationary member was made of quenched and annealed steel. The rotational speed was 88 r.p.m. and the load applied 14 kg.