DE2164050C3 - Electroplating bath of conventional composition for the joint deposition of metal and a permanently lubricating solid lubricant - Google Patents

Description

8. Bath according to one of the preceding · contain anfluoride.

Claims, characterized in that there are additional, as these self-lubricating metal coatings are leveling means known per se and / or shown sliding property with low friction Contains brightener. they can show on the inner walls of

Cylinders, the inner walls of machines, piston rings, piston rods, bearings and sliding

Parts are used by other machines,

45 whereby they are operationally reliable with regard to their functions during their service life.

That used in the bath according to the invention

The invention relates to an electroplating bath graphite fluoride can be produced by using carbon Composition to the common waste material or graphite with fluorine or a fluorine separator of metal and a permanently lubricating bond react at a temperature below 550 ° C Solid lubricants. is left. It represents a powder of an inorganic

It is known that fine molybdenum disulphide powder can be seen to deposit a fluoride polymer with a structure! Together with metal in order to obtain metal coatings which lubricate between carbon layers, see e.g. B. or layers forming a lattice structure - "Co-Deposited Nickel Molybdenum Disulfide Metal 55 leads, with the fluofatoms between them on-pinishing" by CE Vest & DF Baggarre, pointing layers through covalent conditions Nov. 1967, in particular p. 52 to 58. Molybdenum - with the valence electron of a free, special sulfide - was used as a solid lubricant, since atoms of carbon atoms bonded to one another, molybdenum disulfide has a layered structure in which each of the molybdenum atoms between sulfur and 60 can be represented _{by the molecular formula (CF) n} . In the above-described graphite atoms is stored, where the molybdenum atoms are fluoride, the molar ratio of fluorine to carbon, the surfaces of the sulfur atoms glide so 1: 1, and it usually represents one and the molybdenum or a low shear strength gray solid that sits a specific. However, molybdenum disulfide is known to have a weight of 2.45.

is a hydrophilic compound and in terms of its 65 In addition, the graphite fluoride stands out Properties of chemical resistance and the fact that the compound has high elek-lubricating properties at elevated temperatures shows fresh insulation value, has defects due to chemicals, so that molybdenum is not satisfied - not attacked, not by water and oil

(Contact angle of 145 °) is wetted and is water and oil repellent and at elevated temperature Has pliability. In addition, it is graphite fluoride in both acidic and basic galvanic baths without affecting it Properties as a solid lubricant are stable.

Graphite fluoride is further characterized by that the compound's lubricity at elevated temperatures is on the order of Maintains 500 ° C at which other solid lubricants their lubricity and their stability against frictional heat and environmental conditions lose at boundary friction. It has been found that the adhesion of the connections is the lower, the greater the volume percentage of the connection in Metal plating is. Therefore, it is preferable to reduce the amount of graphite fluoride to be cut off together in the metal coating to a volume fraction of up to a maximum of 80%.

If a metal coating deposited by means of the bath according to the invention must have high mechanical strength, ζ. B. on a piston line or bearing, the joint deposition of graphite fluoride is preferably limited to a value of at most 10%. , ₅

The graphite fluoride particles to be added in the bath of the present invention are preferably in finely divided powder form, so that the particles adhere well to the deposited metal coating to have. The diameter of such particles is usually less than 10 [µm, and it is preferred that the powder contains about 80% of fine particles with a diameter of less than 0.5 μm. The amount of graphite fluoride is in particular less than 50 g / l, the preferred concentration in one Range from 0.1 to 10 g / l.

The preferred surface-active fluorocarbon compounds are perfluorinated, quaternary ammonium compounds, perfluorinated polyoxyethylene compounds or perfluorinated betaine compounds are used. However, if nonionic surfactants with a C-F bond are used, the graphite fluoride particles are only positively charged electrically if the galvanic Bath is an acidic bath.

Anionic, surface-active substances with a C-F bond in the molecules or amphoteric surfactants that are used at the pH of the Bades show anionic properties, cause a negative electrical charge of the graphite fluoride particles, so that the co-deposition of the particles with the metal is prevented. Therefore, these two types of surfactant Agents are not used in the galvanic bath according to the invention.

The amount of surfactant to add to the base bath for co-deposition The fluorocarbon compound is preferably within a range of 5 mg / L to 5 g / L based on the Bath composition, with the range from 10 to 500 mg / l being particularly preferred.

The bath according to the invention can be used for all metals. Such metals are, for example, copper, nickel, chromium, zinc, cadmium, tin, iron, lead, Precious metals and alloys thereof.

The gloss-forming additives used in Examples 1, 2, 6 and 7 are electroplated Baths are added in such a way that the surfaces of the deposited coatings are not only smoothed (polished) but also the hardness of the coatings to sufficiently increase their abrasion resistance properties is increased.

example 1

An electroplating bath was made with the following composition:

Graphite fluoride fine powder (average particle diameter 0.2 µm) 5 g / l Water-soluble, cationic fluorocarbon surfactant compound (perfluorinated quaternary

Ammonium compound) 20 ppm

NiSO ₄ · 6 H..O 280 g / l

NiCI ₂ -6 H ~ O 45 g / l

H ₈ BO _n ... "40 g / l

Commercial brightener 1 20 ccm / 1

Commercial brightener 2 2 ccm / 1

The pH of the bath was adjusted to 4.2 using sulfuric acid. A steel specimen (30 mm outside diameter, 16 mm inside diameter and 8 mm thickness) for a Nishihara wear testing machine was nickel-plated under the following conditions: bath temperature 50 ° C and current density of 5 A / dm ² for about 50 minutes, until a coating with graphite fluoride in a Strength up to 50 μπι was deposited. For comparison purposes, a control sample of the same material was nickel-plated using the same bath but without graphite fluoride powder and surfactant under otherwise identical conditions. Wear tests were carried out on these test pieces. The results were as follows:

Wear and tear roles including

29.73% slip

Load 30 kg

Roll rate 613 rpm

Environment dry wear

in the atmosphere

Counter body hardened tool carbon steel SK 5

Test results Table I.

Test piece for measurement Specimen
with
stored
graphite
fluoride control Number of times for a wear and tear
up to 50 mg required
Rolling movements 15,000 3000

From this Table I it can be seen that the wear resistance of the metal coating deposited with the aid of an electroplating bath according to the invention is significantly larger than that of the metal coating which does not contain graphite fluoride.

Example 2

An electroplating bath was made with the following composition:

Fine graphite fluoride powder (average particle diameter 0.2 (im) 5 g / l Water-soluble, cationic, surfactant, fluorocarbon compound (perfluorinated quaternary am-

ionium compound) 20 ppm

NiSO ₄ -OHp 280 g / l

NiCl ₂ -OH ₂ O 45 g / l

H ₃ BO., .. '. 40 g / l

Brightener 1 20 ccm / 1

Brightener 2 2 ccm / 1

A coating of a copper-lead alloy, in which graphite fluoride was embedded, was deposited on brass bearing material with screw stirring under the following conditions in a thickness of up to 50 μm: pure copper as anode, bath temperature of 60 ° C. and current density of 5 A / dm ² for about 50 min. It was found that the torsional force of the bearing material treated in this way increased by 32%

■ was lower than that of a control part that ίο in the same bath, but without graphite fluoride and fluorocarbon surfactant had been treated.

Example 4

An electroplating bath was made with the following composition:

The pH of the bath was adjusted to 4.2 _{using H., SO 4.} Eight test pieces of SUJ-2 steel in ring shape (40 mm outer diameter and 8 mm thickness) for a roller-type friction testing machine were nickel-plated with screw stirring under the following conditions: bath temperature of 50 ° C and current density of 5 A / dm- 'for about 50 min until nickel coatings with graphite fluoride of 50 [im. For comparison purposes, the corresponding number of control test pieces were nickel-plated using the same nickel bath, but without the graphite fluoride and fluorocarbon compound.

All of the test pieces thus treated were subjected to comparative tests for their coefficients of friction in additive turbine oil No. I (JIS K 2213) under a load of 60 kg / mm ² . The results are shown in Table II.

Table II

Test piece for measurement

Average coefficient of friction

Specimen

with

embedded graphite fluoride

0.0340

control

0.0530

From Table II it can be seen that the average coefficient of the nickel coatings has in common deposited graphite fluoride is smaller than that of the control nickel coatings which do not contain graphite fluoride contain.

Example 3

An electroplating bath was made with the following composition:

Fine graphite fluoride powder (average particle diameter 0.2 μm) 10 g / l Water-soluble, cationic surface-active fluorocarbon compound (perfluorinated quaternary ammonium compound) 20 ppm

Sodium cyanide 147 g / l

Copper cyanide 150 g / l

Sodium hydroxide 40 g / l

Potassium sodium tartrate 211 g / l

Lead acetate 75 g / 1

55

60

65 Fine graphite fluoride powder (average particle diameter 0.2 Lim) 10 g / l
Water soluble, cationic fluorocarbon surfactant (perfluorinated quaternary ammonium compound) 20 ppm

Lead boron fluoride 243 g / l

Fluoboric acid 23.3 g / l

Boric acid 23.3 g / l

Gelatin 0.2 g / l

The pH of the bath was adjusted to 1.5 using fluoboric acid. A lead coating, in which graphite fluoride was embedded, was deposited on brass bearing material with air stirring under the following conditions up to a coating thickness of 50 (im: lead as anode, bath temperature of 30 ° C and current density of 5 A / dm ² for about 20 min Control bearing material made of the same material was treated in the same bath, but without graphite fluoride and fluorocarbon compound. The two bearing materials were subjected to abrasion tests in which the time required for the material to wear down to a predetermined value was determined the time required for the coating produced with the aid of the bath according to the invention was about 4.5 times as long as in the control experiment.

Example 5

An electroplating bath was made with the following composition:

Fine graphite fluoride powder (average particle diameter 0.2 μm) 10 g / l
Water soluble, cationic fluorocarbon surfactant (perfluorinated quaternary ammonium compound) 20 ppm

Silver cyanide 38 g / l

Potassium cyanide 50 g / l

Potassium hydroxide 125 g / l

Potassium carbonate 44 g / l

The Mcssing bearing material was silver-plated with screw agitation under the following conditions:

Anode made of pure silver, bath temperature of 35 ° C and current density of 5 A / dm ² for about 16 min, in order to deposit a silver coating in which graphite fluoride was embedded up to a thickness of 50 μm. When used under light load conditions, the wear of the silver coating with incorporated graphite fluoride Vs was less than that of the control part, which had been silver-plated in the same bath, but without graphite fluoride and fluorocarbon compound.

Example 6

An electroplating bath was produced with the following composition: t5

Fine graphite fluoride powder (average particle diameter 0.2 μm) 5 g / l Water-soluble, nonionic fluorocarbon surfactant compound (perfluorinated polyoxyethylene compound - Product FC-170 from Minnesota Mining & Ma-

manufacturing Co., USA) 30 ppm

NiSO ₄ -OH ₂ O 280 g / l

NiCl ₂ -OH ₂ O 45 g / l

H ₃ BÖ _Ä 40 g / l

Brightener 1 20 ccm / 1

Brightener 2 2 ccm / 1

30th

The pH of the bath was adjusted to 4.2 _{using H 2} SO _4. The test piece used in this example was an identical piece to the steel piece used in Example 1, and nickel plating was carried out with agitation by liquid recirculation under the following conditions: bath temperature of 50 ° C and current density of 5 A / dm ² for about 50 minutes to produce a nickel coating with embedded graphite fluoride up to 50 μm thick. A control piece formed from the same type of material was treated in the same bath, but without graphite fluoride and fluorocarbon compounds. The two test pieces were subjected to abrasion resistance tests. It was found that the test part produced with the aid of the bath according to the invention had a wear resistance three times as high as the control part.

Example 7

An electroplating bath was made with the following composition:

Fine graphite fluoride powder (average particle diameter 0.5 μm) 10 g / l
Water-soluble, amphoteric fluorocarbon surfactant (perfluorinated betaine compound - product FC-172 of Minnesota Mining & Manufacturing Co.,

USA) 0.1 g / l

NiSO ₄ -6H ₂ O 280 g / l

NiCl ₂ -OH ₂ O 45 g / l

H ₃ BO ₃ 40 g / l

Brightener 1 20 ccm / 1

Brightener I 2 ccm / 1

The pH of the bath was adjusted to 4.2 _{using H 2} SO _4. The test part used in this example was a piece of steel identical to that used in Example 1. The nickel plating was carried out with liquid stirring under the following conditions: bath temperature of 50 ° C. and current density of 5 A / dm ² for about 50 min in order to deposit a nickel coating containing graphite fluoride up to a thickness of 50 μm. A control specimen made from the same type of material was treated in the same bath as in Example 7, but without graphite fluoride and fluorocarbon compound. The two coupons were subjected to an abrasion test as described in Example 1. The results of the investigations are given in Table III.

Table III

Test piece for measurement Specimen
with
stored
graphite
fluoride control Number of for one Ab
use until 50 mg he
necessary role movements
worked 17 500 3000

Table III clearly shows that the nickel coating with embedded graphite fluoride is a « Has higher wear resistance than the control part

Claims (7)

1 2 material for a common deposition Claims: represents. The object of the invention is to provide a 1. Galvanic bath of the usual composition - new galvanic bath of the usual composition for the common deposition of metal 5 tongue, through which a common deposition and a permanently lubricating solid lubricant of metal and graphite as a permanent lubricant, characterized in that it is possible for the solid lubricant. an inorganic polymer of graphite fluoride The bath is characterized by the fact that it is a and a cationic, nonionic or ampho-inorganic polymer of graphite fluoride and teres, at the pH value of the particular, an- io a cationic, nonionic or ainphoteric, applied galvanic bath cationic own- at the pH of the particular, applied Shafts exhibiting, water-soluble, boundary galvanic bath has static properties. surface-active agent, which is fluorocarbon-pointing, water-soluble, surface-active agent, has bonds in the molecule, contains. which fluorine-carbon bonds are in the molecule 2. Bath according to claim 1, characterized marked 15, contains. net that there is a graphite fluoride powder with an When dispersing fine powder of such an average particle diameter of we-inorganic polymer of graphite fluoride, what less than 10 μηι contains. with this material in the following simply as graphite 3. Bath according to one of claims 1 or 2, referred to as fluoride, in a conventional one characterized in that there is less than 50 g «galvanic bath - this bath in the following Contains graphite fluoride powder per 1. is referred to as a basic bath - with such a 4. Bath according to one of the preceding interface-active parts, the graphite fluoride, languages, characterized in that it has less flood-repellent properties, contains than 5 g of surfactant per liter. completely wetted and dispersed with stabilization 5. Bath according to one of the preceding An 25, wherein the fine particles of graphite say, characterized in that it can be electrically charged as a fluoride,
The cationic surfactant has been found experimentally that the elecfluorinated quaternary ammonium compound retains positively charged fine particles from fresh. Graphite fluoride electrophoretically uniform and 6. Bath according to one of claims 1 to 5, characterized by 30 simultaneously with the metal coating on the work that it is deposited as a nonionic piece. The deposition is a perfluorinated surfactant with mechanical agitation.
Contains polyoxyethylene compound. The coating obtained in this way shows 7. B «id according to one of claims 1 to 5, drawn electrical properties and above characterized in that it is amphoteric, 35 addition no brittleness, even if the bath surfactant contains a perfluorinated graphite fluoride in low concentration. Contains betaine compound. The coating can contain a large amount of graphite