Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D15/00—Electrolytic or electrophoretic production of coatings containing embedded materials, e.g. particles, whiskers, wires
  • C25D15/02—Combined electrolytic and electrophoretic processes with charged materials
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D7/00—Electroplating characterised by the article coated
  • C25D7/10—Bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/02—Parts of sliding-contact bearings
  • F16C33/04—Brasses; Bushes; Linings
  • F16C33/06—Sliding surface mainly made of metal
  • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
  • F16C33/121—Use of special materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/02—Parts of sliding-contact bearings
  • F16C33/04—Brasses; Bushes; Linings
  • F16C33/06—Sliding surface mainly made of metal
  • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
  • F16C33/122—Multilayer structures of sleeves, washers or liners
  • F16C33/124—Details of overlays
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/02—Parts of sliding-contact bearings
  • F16C33/04—Brasses; Bushes; Linings
  • F16C33/06—Sliding surface mainly made of metal
  • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
  • F16C33/122—Multilayer structures of sleeves, washers or liners
  • F16C33/127—Details of intermediate layers, e.g. nickel dams
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C2204/00—End product comprising different layers, coatings or parts of cermet

Definitions

• the invention relates to a layer material for sliding elements, which has at least one support body and a running layer with galvanically deposited matrix material, in particular made of SnCuNi, PbSnCu, PbSn, Sn, SnCu or CuSn, hard particles being embedded in the matrix material.
• the invention also relates to a method for producing such sliding elements.
• Fluoroborate baths have hitherto been used as the electrolyte, but they have the disadvantage that the particles are insufficiently wetted, with the result that even with a large supply of hard particles in the electrolyte, only a limited amount, generally up to a maximum of 2 vol.% , can be built into the matrix.
• the running layers produced with the known baths in particular ternary layers, sometimes show considerable fluctuations in thickness, which may make mechanical reworking of the sliding elements necessary.
• the tin is not evenly distributed in the overlay, so that there are accumulations and coarse crystalline deposits, so-called tin agglomerations.
• This inhomogeneous structure of the running layer favors the diffusion that occurs when the sliding element heats up during operation, so that such running layers can only be applied to an intermediate layer, such as a nickel dam, which prevents tin diffusion into the underlying lead bronze layer, such as in E. Romans. "Material and layer structure for plain bearings", special print from ZFW, Zeitschrift für Werkstofftechnik, Volume 4, Issue 7, Verlag Chemie Weinheim / Berg tile 1973. Only through this additional So far, the measure has improved the corrosion resistance and has prevented the running layer from detaching, which can lead to bearing damage. In addition, the hardness of these known running layers and therefore the wear resistance are unsatisfactory.
• This object is achieved with a layer material which has hard particles with a diameter of ⁇ 2 ⁇ m and with a proportion of 2 to 20% by volume in the matrix material, the hard particles being present as individual particles in a completely homogeneous distribution.
• the specification ⁇ 2 ⁇ m means that this diameter specification applies to at least 95% of the hard particles used.
• the hard particles are preferably carbides, oxides, borides, nitrides, silicides or silicon. An overview of the preferred hard particles is given in the table below:
• Solids to be stored (hard material particles)
• Carbides SiC, B 4 C, Cr 23 C b , TaC, TiC, WC, ZrC
• Oxides Al 2 O 3 , Cr 2 O 3 , Fe 2 O 3 , SiO 2 , TiO 2 , ZrO 2
• Nitrides BN (hexagonal), BN (cubic), Si 3 N 4 , A1N
• the tin is advantageously present as a fine crystalline deposit in a completely homogeneous distribution in the rest of the matrix material, if that Matrix material consists for example of SnCuNi, PbSn, SnCu, CuSn or PbSnCu.
• Matrix material consists for example of SnCuNi, PbSn, SnCu, CuSn or PbSnCu.
• the fine crystalline deposition of the tin in a completely homogeneous distribution means that there are no more localizable tin agglomerations.
• the finely divided tin cannot be identified as particles with a defined diameter in electron micrographs with a magnification of up to 1000 times. As a result, there are fewer lattice defects in the running layer and no incorporation of interfering foreign atoms, so that the packing density is much higher than in known running layers. This also results in greater hardness of the overlay.
• the diffusion of the tin which usually occurs during operation of the plain bearings made from such layer materials due to the increase in temperature, can be observed far less or not at all.
• This advantageous effect is also due to the fine crystalline deposition of the tin and to the hard particles which are present as individual particles in a completely homogeneous distribution and which obviously restrict the mobility of the tin to such an extent that little or no diffusion effects can occur. It can thus be applied to an intermediate layer, e.g. a so-called nickel dam can be dispensed with.
• the running layer forms the ternary layer of a multilayer material, it can preferably be applied directly to the sintered layer, in particular a lead-bronze layer.
• the production process is characterized in that a ternary, fluoroborate-free electroplating bath without a brightener with addition of non-ionic wetting agents and free alkyl sulfonic acid, as well as a grain refining agent containing carboxylic acid and a fatty acid polyglycol ester used and that the hard particles are kept in a constant concentration in the electroplating process during the electroplating process
• the hard particles in the electroplating bath must be kept in a correspondingly high and, in particular, constant concentration during the electroplating process. This makes it possible to increase the proportion of hard particles in the matrix material up to 20% by volume
• Hard particles exist not only in that they reduce wear, but in particular also in that the diffusion of tin is hindered.
• the particles act as a barrier for the tin, in particular if they are present as individual particles in a fine distribution in the matrix material
• Hard particles speak of a kind of diffusion barrier agent which, as foreign bodies in the sliding layer, prevents the tin particles from moving
• the fatty acid polyglycol ester has a positive effect on the uniformity of the deposition. In the known processes, this is done in the edge areas of the grooves. Holes or significant increases occurred, so these are now not detectable. Obviously, the fatty acid polyglycol ester has an influence on the ion distribution in the electroplating bath, which ultimately also leads to a more uniform deposition. It has been shown that not only the thickness fluctuations can be avoided, but also that the surface roughness decreases significantly
• the electroplating bath preferably has a methanesulfonic acid.
• a preferred bath composition contains, in addition to the metals and hard particles to be deposited, 30 to 200 g / 1 free methanesulfonic acid, 5 to 125 ml / 1 non-ionic wetting agent, 5 to 25 ml / 1 grain refining agent and 0.01 to 1 g / 1 fatty acid polyglycol ester.
• the grain refining agent preferably has an ⁇ - / 3-unsaturated carboxylic acid with the general formula
• R and R 2 are the same or different and represents hydrogen or lower alkyl groups having 1 to 3 C atoms and R 3 is hydrogen or lower alkyl having 1 to 5 C atoms.
• the electroplating baths according to the invention are notable for high stability, since the alkyl sulfonic acid does not decompose during the electrolysis. This gives a uniform, almost 100% current efficiency both at the cathode and at the anode.
• Current densities of 2 to 20 A / cnr can preferably be used during the galvanization. No changes in the composition of the coating could be determined.
• the advantage of rapid deposition is achieved by using such high current densities. It is therefore possible to reduce the process time by almost a factor of 10.
• the new process is therefore also suitable for high-speed deposition and thus for strip galvanizing. It is therefore possible to set up large-scale production with high throughput.
• the electroplating bath is preferably kept at a temperature below 25 ° C., because otherwise controlled deposition is no longer possible. Since the bath heats up during the electroplating process, it must be cooled accordingly.
• Figures 2a. b two diagrams showing the surface roughness of one
• FIGS. 1 a and 1 b show two micrographs, FIG. 1 a showing a layer material according to the prior art and FIG. 1 b one according to the invention.
• a layer material la which consists of a steel back 2a, a lead-bronze layer 3a. there is a nickel dam 4a and a ternary layer 5a.
• the ternary layer has the composition PbSnl4Cu8 with inclusions of ⁇ -Al 2 O r dispersoids 8a, which are present in the ternary layer 5a essentially in the form of agglomerates 7a.
• This ternary layer was produced using a plating bath containing fluoroborate. Furthermore, tin accumulations 6a can clearly be seen in the ternary layer. Overall, the ternary layer 5a has an inhomogeneous structure and a rough surface.
• FIG. 1b shows a layer material 1b according to the invention.
• a lead-bronze layer 3b on the steel back 2b. on which the ternary layer 5b is applied directly, ie without a nickel dam, the matrix material of which consists of PbSnCu corresponding to the matrix material of the ternary layer 5a in FIG. 1a.
• the tin can clearly be seen as a fine crystalline deposit in a homogeneous distribution, and the hard particles 8b, which have a diameter of ⁇ 2 ⁇ m, are no longer in the form of agglomerates but as individual particles in a homogeneous distribution in the ternary layer 5b .
• the ternary layer 5b shows a good bond and no tin diffusion was found even after heat treatment at 170 ° C. for 1000 hours.
• the hardness of this ternary layer 5b is 38 HV.
• the surface roughness of the layered materials shown in FIGS. 1a and 1b is plotted in FIGS. 2a and 2b. It can be clearly seen that the surface roughness shown in FIG. 2a, which relates to the layer material according to FIG. 1a, is far greater than that in FIG. 2b.
• the average roughness was RZ 4.375 ⁇ m in the curve shown in FIG. 2a and RZ 3.225 ⁇ m in the curve shown in FIG. 2b.
• An exemplary bath composition for the PbSnCu- ⁇ -Al 2 0 3 system looks as follows: Total quantity 250 1
• Wetting agent N denotes a wetting agent based on alkylaryl polyglycol ether and wetting agent L an additive which, in addition to the 30% carboxylic acid, has up to a third of arylpolyglycol ester and / or alkylarylpolyglycol ether, the rest consisting of water.
• These wetting agents are sold, for example, under the trade names BN 160308 Stannosar HMB or BN 160309 Stannosar HMB from Blasberg / Solingen.
• the solids content of ⁇ -Al 2 0 3 in the electrolyte was increased in several steps from 20 to 100 g / 1, the respective concentration in the electroplating bath being kept constant during the electroplating process. The result is shown in the table below.
• the diameter of the hard particles used was less than 2 ⁇ m.
• Hardness measurements and wear tests were carried out on the PbSnl4Cu8 system. Without hard particles, the hardness of the ternary layer was 22 HV. With a share of 4.8% by volume A1 2 0 3 , the hardness could be increased to 37 HV.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Electroplating Methods And Accessories (AREA)
• Electroplating And Plating Baths Therefor (AREA)
• Sliding-Contact Bearings (AREA)

Applications Claiming Priority (3)

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• 1996
  • 1996-06-01 DE DE19654953A patent/DE19654953A1/de not_active Withdrawn
• 1997
  • 1997-05-24 US US09/000,433 patent/US6077815A/en not_active Expired - Fee Related
  • 1997-05-24 KR KR1019980700679A patent/KR100528362B1/ko not_active Expired - Fee Related
  • 1997-05-24 CZ CZ1998310A patent/CZ294803B6/cs not_active IP Right Cessation
  • 1997-05-24 BR BR9702278A patent/BR9702278A/pt not_active IP Right Cessation
  • 1997-05-24 WO PCT/DE1997/001018 patent/WO1997046737A1/de not_active Ceased
  • 1997-05-24 EP EP97925855A patent/EP0846196A1/de not_active Withdrawn
  • 1997-05-24 JP JP10500079A patent/JPH11510859A/ja not_active Ceased

Non-Patent Citations (1)

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