Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
  • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
  • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
  • C23C4/06—Metallic material
  • C23C4/067—Metallic material containing free particles of non-metal elements, e.g. carbon, silicon, boron, phosphorus or arsenic

Definitions

• the invention relates to a metallic powder for the production of wear-resistant surface layers by means of a thermal spraying method, which consists of one or more transition metals, in particular predominantly nickel or iron, and each chromium as an alloying element and which also has at least one metalloid, in particular boron, carbon, silicon or phosphorus, as well as a manufacturing method and a spraying method therefor.
• a thermal spraying method which consists of one or more transition metals, in particular predominantly nickel or iron, and each chromium as an alloying element and which also has at least one metalloid, in particular boron, carbon, silicon or phosphorus, as well as a manufacturing method and a spraying method therefor.
• nickel or iron alloy wear protection layers produced using thermal spraying methods (flame spraying, high-speed flame spraying, arc spraying, plasma and, more recently, laser spraying, etc.) are known, which can be produced by the fact that a corresponding spray powder, for example a NiCrFeBSi powder or a FeCrCB powder, is sprayed onto the substrate to be coated while melting or melting the individual particles.
• a corresponding spray powder for example a NiCrFeBSi powder or a FeCrCB powder
• the desired, firmly adhering, dense and wear-resistant surface layer is only obtained with the layer materials mentioned in a second working step - the so-called melting - in which changes, in particular improvements, are made in this by a second heating and melting of the layer material already on the workpiece Layer can be reached.
• a spray powder is used as spray material which, on the one hand - as described in the introductory paragraph - is composed, which, however, already has deposits in the powder grains, which consist of hard particles derived from the respective metalloid.
• hard deposits for example made of borides, carbides, silicides or phosphides, are already contained in the wettable powder granules.
• a wettable powder of this type taking into account the fact that during the spraying process itself a sufficient but as short as possible heat input to the powder particles is carried out, leads to the result that the spraying process alone contains one which contains the advantageous hard particles to a suitable extent and at a favorable design , Material layer is obtained.
• the spraying of such powders which can be produced particularly cheaply on the basis of nickel or iron, has two advantages: on the one hand there are economic advantages because the melting step is omitted, on the other hand layers of these materials - or alloys thereof - can also on thermally sensitive base materials, e.g. Aluminum materials are sprayed on, the structure and properties of which would be adversely affected by the heat of the otherwise necessary melting step.
• a powder according to the invention is particularly advantageous in which the embedded hard particles are present in a “relatively coarse distribution” - as defined in claim 2.
• the pulverization of the remelted master alloy is accomplished particularly advantageously by atomizing a melt strand of the master alloy with a gas stream. This can be done in detail, for example, according to DE-PS 35 29 217 or DE-PS 39 13 649.
• a particularly advantageous application of the wettable powder according to the invention is that it is processed in particular by high-speed flame spraying, spray particle speeds of more than 250 m / s, preferably more than 300 m / s, being used with advantage.
• a melting step is no longer necessary.
• the important boundary conditions such as the energy input to the spray particles and the particle speed, can be regulated particularly well, because it is closed
• flame, arc, laser or plasma spraying can also be used with restrictions in conjunction with the wettable powders according to the invention, the method described is the cheapest.
• a spray powder according to the invention is first to be produced by means of the powder production process described above. To do this, a melt with the appropriate composition must first be produced, for example one Ni 70.5 Cr 17 Fe 4 B 3.5 Si 4.0 C 1.0 melt or one Fe 59.3 Cr 21 Ni 8 Mn6.5 Si 5.0 C 0.7 melt.
• melt compositions with 50 to 80% by weight of nickel or iron are suitable as a starting point. These melts are to be cooled appropriately in order to separate out the desired metalloid hard particles and then to be melted again, largely avoiding the hard parts being re-dissolved. (see again EP-B1 0 326 785). Furthermore, a metallic powder is obtained from the pre-alloy melt thus prepared by atomizing an outflowing melt strand with one or more gas jets, the desired hard particles now being contained in the individual powder grains. These hard particles can be composed of a number of different metalloid compounds, for example they can consist of CrB, CrB4, Cr7BC4, ..., NiB, Ni3B, Ni5Si2, ..., FeB, Fe2B, ... exist.
• a particularly advantageous application of wettable powders according to the invention for forming wear-resistant layers now consists in processing them with high-speed flame spraying.
• a Ni spray powder formed approximately as described above with a grain size of 15 to 50 micrometers and hard particle inclusions of approximately 7 to 11 micrometers can, for example, with propane fuel gas and particle speeds of preferably over 300 m / s to a high-quality wear-resistant surface layer, in which an advantageous number of hard particles is present. This can be done in one operation.
• the present invention and in relation to the surface layers mentioned, i.e. in particular with regard to nickel or iron surface layers containing hard particles a considerable advantage compared to the prior art achieved.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Plasma & Fusion (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Powder Metallurgy (AREA)
• Coating By Spraying Or Casting (AREA)
• Manufacture Of Metal Powder And Suspensions Thereof (AREA)
• Chemically Coating (AREA)

Applications Claiming Priority (2)

Publications (2)

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Citations (4)

• 1993
  • 1993-01-29 DE DE4302521A patent/DE4302521A1/de not_active Withdrawn
  • 1993-05-14 EP EP93107907A patent/EP0608468B1/fr not_active Expired - Lifetime
  • 1993-05-14 AT AT93107907T patent/ATE141340T1/de not_active IP Right Cessation
  • 1993-05-14 ES ES93107907T patent/ES2090768T3/es not_active Expired - Lifetime
  • 1993-05-14 DE DE59303439T patent/DE59303439D1/de not_active Expired - Fee Related

Patent Citations (4)

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