FI62144B - ARTICLE AV EN BASMETALL MED RELATIVT LITEN SLITSTYRKA OCH BELAGD MED ELDFAST METALL - Google Patents

Description

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UTLÄGGNINOSSKRIFT 62144 fte) Patent n-:! .Ί:. · Io n ^ (SI) K ».ik.3 / fcK.a.3 C 23 C 17/00 FINLAND —FINLAND (21) Λ **» «ΙΗΛ · Ι «ιι · - hMntmMuiMif 762973 (22) HtkamltpCiv * - AiwSfcnlnpdvg 19.10.76 (23) Alkvpaivt — GlWjhvttd · * 19.10.76 (41) Tulta fulktata - Wtvtt effvntllf 25.02.78 jjtaentti «I> o«) · kmiLNIluiwn pvm.— ratant · och registerutyrulMn '' AnaMca »uthfd och uti. * Krtft * n pubiicarad 30.07.82 (32) (33) (31) I'm *» tty vtuotkvu * —K «Tftnl priorttat pH. 08.76 USA 717391+ (71) Wamer-London, Inc., 2627 Grimsley Street, Greensboro, North Carolina, USA (72) Joshua B. Warner, Spartanburg, SC, James S. Wolf, Clemson, SC , USA (US) (7! +) Leitzinger 0y (5U) Article made of relatively wax-resistant base metal and coated with refractory metal - Artikel av en basmetall med relativt liten slitstyrka och belagd med eldfast metali

The invention relates to an article made of a relatively low-wear base metal and coated with a refractory metal and to a method for manufacturing the article.

U.S. Pat. No. 3,723,078 discloses a method of making metal-coated bodies in which a continuous layer completely covering the surface of metal particles is formed on the surface of the body, a similar continuous coating is obtained by the method of U.S. Pat. No. 2,990,293, in which a base metal with relatively low corrosion resistance properties is completely coated. corrosion resistant particles.

The hardness of such known products with a continuous coating roughly corresponds to the hardness of the surface materials. Since the coating completely covers the substrate and is thus a completely continuous coating, 2 62144 may, firstly, easily break and crack and, in addition, be relatively inelastic.

The object of the invention is therefore to provide a product in which the coating does not easily crack and in which the coating particles in wear are pressed into the base metal itself and thus do not wear as in known products.

The object of the invention is achieved in that it consists of a base metal having a relatively low abrasion resistance in the region of said base metal near the surface, a refractory metal having a melting point of at least 1490 ° C and deposited in said region near the surface and associated with the base metal, the refractory metal being deposited as discrete particles, many of said particles are adjacent to form a clay and the cords of the refractory metal particles are spaced apart to form an associated wear-resistant discontinuous coating on the base metal.

The figure schematically shows the various possible structural properties of the area close to the surface of the base metal.

The present invention consists in the unique finding that a refractory or protective metal having a melting point of at least 1490 ° C can be deposited on any metal, metal alloy or base metal-containing metal when combined with an electrolyte at least partially located between the refractory metal particle and the substrate. between.

Useful refractory or protective metals include e.g. the following metals in powder or particulate form and alloys containing them.

3 62144 boron rhodium chromium ruthenium cobalt tantalum iridium thorium molybdenum titanium niobium tungsten osmium vanadium palladium yttrium platinum zirconium renium The original shape of these metal particles is any of the following: iodomorphic or block-like or coaxial, or spherical or spherical preferably as small as practicable, usually between 0.01 microns and about 1 mm. The substrates on which the refractory material can be deposited can be any metal, such as: aluminum, iron, chromium, cobalt, copper, nickel, magnesium, tin, titanium, or any of these alloys, including: steels, cast irons, brasses, bronzes, solder metals etc., or any other suitable base metal.

In order for the refractory particulate metal to be deposited in an area near the surface of the substrate, it is also necessary to include a well-dispersed electrolyte material which should be located at least partially between the resinous refractory metal and the substrate metal.

Electrolytes found to be suitable include e.g. the following acids: mineral acids, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, perchloric acid, fluorosilicic acid, etc., and acid anhydrides such as arsenic trioxide and chromium trioxide, etc., organic acids, tartaric acid, malonic acid and the like. Useful basic electrolytes include: alkali and alkaline earth metal hydroxides such as sodium, potassium, lithium, calcium, magnesium, etc. Also useful are: alkali and alkaline earth metal salts of the above acids, such as alkali metal halide salts, especially chlorides, chlorates, fluorides, nitrates * / Vts, sulphates, phosphates, carbonates, etc., and metal salts, in which the metal now used as part of the electrolyte may be any of the metals mentioned above as a refractory metal or base metal, forming 4 62144 any salts such as sulphates, phosphates, nitrates, carbonates, chromates, molybdenates, tungstates, etc.

Chemical compounds found to be useful as an electrolyte also include ammonium thiocyanate, potassium thiocyanate, zinc sulfate, ammonium carbonate, ammonium sulfate, potassium sulfate, sodium sulfite, sodium carbonate, potassium cyanide, calcium nitrate, potassium chloride, and potassium chloride.

Although the electrolyte may generally be any acid, base or salt, it must dissociate in the presence of moisture, i. it must be able to conduct electric current and have a sufficient degree or percentage of dissociation or, more precisely, a sufficiently high equivalence conductance ratio.

For the purposes of this invention, the conductivity ratio is determined by diluting the equivalent conductivity at 1 g equivalent to 10 per liter of water and at the finite dilution of the equivalent conductivity at 25 ° C (see "The Physical Chemistry of Electrolytic Solutions", Harned and Owen). , Rheinhold Publishing Corp. 1958). The electrolytes useful in this invention are such that their conductivity ratios are in the range of about 0.13 to 0.93 and most preferably greater than 0.60.

The following are some of the acids, bases, and salts that meet the requirements of this invention, as well as their estimated equivalent equivalence ratios:

Acids Bases

Hydrochloric acid 0.90 Sodium hydroxide 0.88

Nitric acid 0.92 Potassium hydroxide 0.93

Sulfuric acid 0.60 Calcium hydroxide 0.80

Strontium hydroxide 0.86

Barium hydroxide 0.86 5 62144

salts

Silver nitrate 0/86 Sodium carbonate 0.61

Potassium chloride 0.86 Ammonium sulphate 0.59 ·

Sodium chloride 0.82 Barium nitrate 0.57

Potassium bromide 0.92 Strontium nitrate 0.62

Sodium nitrate 0.82 Lead nitrate 0.54

Sodium acetate 0.79 Copper (II) acetate 0.33

Potassium chlorate 0.83 Zinc sulphate 0.38

Calcium chloride 0.75 Copper sulphate 0.38

Since the electrolyte in this method is selected on the basis of dissociation, it can be concluded that the higher the dissociation capacity of the electrolyte, the more efficiently it causes the reaction of this method to take place. Thus, it is assumed that the more completely the electrolyte ionizes, the more efficiently it serves the purposes of this method.

As far as this method is concerned, no electric current needs to be used to deposit the refractory or protective metal on the surfaces *, however, because this method is believed to be essentially electrolytic in nature, the use of electric current has an effect and can help this event. The use of an electric current is not a prerequisite for the method, as the internally generated electrolytic currents are of sufficient magnitude on a microscopic scale to achieve the results of this invention.

In order to effect the electrochemical reaction required to deposit the refractory metal on the substrate material, it is believed that an effective interconnection takes place between the particulate refractory metal, the electrolyte and the substrate material. In this regard, for solid electrolytes, it has been found that the exact common particle size of the electrolyte and the refractory metal is not critical or important, as this size depends mainly on the dimensions of the harder refractory metal. The electrolyte particle - 3 is preferably finely divided and ranges in size from 10 microns to about 1 mm, preferably 10 to 100 times smaller than the refractory metal particle attachment to the substrate at the time of application.

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In order to initiate a reaction in which a portion of the parent metal is believed to be exchanged for the refractory metal, it is important that the refractory metal be partially ionized in order for the exchange reaction with the parent metal to occur. It has been found that the ion concentration should be between 1 and 60,000 mg of refractory metal ion per liter of solution. The range should preferably be 1000 to 15,000 mg of refractory metal ion per liter of solution.

The refractory metal ion, after being reacted with the base metal, is believed to form the site where the refractory metal particle is deposited. These reactions are believed to occur only on a microscopic scale. In order to produce refractory metal ions, at least in an amount sufficient to effect the desired reactions, it is important that the refractory metal have a bare surface on at least a portion of the surface of the refractory metal particle to be deposited. This fresh surface, for reasons which cannot be fully explained, makes it possible for the refractory metal in combination with the electrolyte and the moisture present to form the necessary concentration of refractory metal ions with sufficient speed. All refractory metals are insoluble in the ordinary sense of the term in the presence of moisture, but nevertheless the concentration of ions required in this invention consists of the exposed surfaces of the refractory particles in the presence of electrolyte and sufficient moisture. The required bare surface can be easily formed mechanically, such as by grinding, grinding in a mill or other means of mixing, grinding, or by the chemical action of an electrolyte or other reactive substance that forms a bare surface on a refractory metal particle.

The amount of mechanical or chemical action that forms the bare surface is not critical, as any such mixing forms some bare surface. Refractory metal ions are generated from the bare surface over a period of about 1 minute to 30 days, preferably 1 to 20 hours. The time depends on the amount of moisture, the temperature and the solubility of the refractory metal. Time is therefore not critical. All that matters is that the refractory metal ions are present in the required concentration and that a somewhat exposed surface is formed so that the particulate refractory metal can be deposited in an area near the surface of the base metal.

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Several alternative methods can be used to achieve a close relationship between the electrolyte and the particulate refractory metal and to obtain the electrolyte base metal surface and the refractory metal ¥ 7 62144, as well as to expose more exposed surfaces in the refractory metal particles. When the physical state of the refractory metal under ambient conditions is a dry powder, and the electrolyte is also in a substantially dry granular form, a good mixture can be obtained by thoroughly mixing the two powders together. The amount of refractory metal is between 99 and 50%, preferably 96 to 66% by weight of the dry mixture of refractory metal and electrolyte. The amount of electrolyte may be between 1 and 50% and preferably 4-34% by weight of the dry mixture of refractory metal electrolyte.

In order to enhance the electrochemical effect of the present invention, it has been found that if desired, it is possible to add an element or compound acting as an electrochemical polarization inhibitor along with the particulate refractory metal and electrolyte in an amount of 1 to 10% by weight of the total refractory metal and electrolyte mixture. »Platinum metal powder, CuO, HgO, ionizable iron or tin salts such as their halides, sulphates, nitrates, etc. and activated carbon.

The thickness of the electrolyte coating * on top of the refractory particle should be as continuous and uniform as possible, and may be from the thickness of the molecular films to 25 microns or thicker up to 1 mm. Most of the surface of the refractory metal is best coated, although a smaller portion is acceptable, up to about 10%.

It has been found that mixing or grinding to either provide fresh surfaces to the refractory metal particles or to coat the refractory particle with electrolyte powder or both can be performed when both the electrolyte powder and the refractory metal powder are somewhat dry with little or no detection. moisture. This mixing period usually takes about 30 minutes to 30 days. However, sufficient moisture must be present to produce refractory metal ions, or otherwise no ions will be formed.

Whether either the refractory metal or the electrolyte or both are dry at ambient conditions, the refractory metal and electrolyte mixture should contain about 0.5 to 60 weight percent water of the total mixture before the base metal is treated with the 4,822,144 mixture. The amount of moisture is preferably 1-40% by weight.

The advantages of this invention can also be realized by making the electrolytic and refractory metal a moist mixture such as a paste, slurry or solution in a liquid medium such as water.

The amount of water in the mixture is sufficient when the specific electrical resistance of the electrolyte is less than about 10 ohm-centimeters. If the electrolyte is a liquid, it may not be necessary to add any liquid medium, although this is recommended, especially when using strong mineral acids.

The fact that some water is present in the mixture of refractory metal and electrolyte is important because the protective metal will provide the necessary ion concentration and make the electrolyte so reactive that it is likely to participate in ion exchange with the parent metal.

This single mixing or combined mixing and aging step, performed over a period of 10 minutes to 30 days, can replace the time required to provide the required concentration of bare surfaces and refractory metal ions, although if a refractory metal ion concentration is found to be insufficient, a remixing time may be required. and / or increase the aging time usually from 1 to 30 days. The actual concentration of refractory metal ions determines whether additional mixing or aging time is required.

The highly mixed powder, paste, liquid, etc. of the electrolyte and the refractory metal can then be applied by spraying the base metal, dipping, brushing, mixing, spraying or any other suitable method of applying or coating the combined refractory metal and the electrolyte so as to obtain thin layer.

A refractory metal having a bare surface and a finished mixture of electrolyte having the required moisture content and the required .N ^ concentration of refractory metal ions can be mixed together with the parts to be treated in a ball mill without balls to adequately coat the refractory metal and electrolyte. the next step of the invention, the deposition of refractory metal. As for the wet mixture, the electrolyte is between the surface of the base metal and the refractory metal and works in exactly the same way as if the refractory metal particles had been coated with the electrolyte.

The temperature at which the base metal is replaced or exchanged for the refractory metal may be ambient temperature or any suitable temperature. Although temperature is not critical to the performance and functionality of the present invention, raising the temperature increases the reaction rate. At ambient temperatures, it has been found that about 1 to 168 hours, and preferably 6 to 72 hours, is sufficient to cause saturation or exchange of the parent metal with the refractory metal. Longer times are not critical and do not adversely affect the method. Shorter times are possible if the reaction is sufficient. The temperature range can be 0 to 200 ° C, preferably 10 to 100 ° C and especially 15 to 40 ° C. The lower limit of the temperature is not critical and may be lower than 0 ° C, but this involves a longer reaction time.

The area density of the combined electrolyte and refractory metal used as the protective material, which can be applied to the base metal, is not critical and can range from about 0.5 refractory particles / mm of the protective coating to the case where the mixture completely and evenly covers the base metal surface. 2 about 10 particles / mm when the particle size is 1.0 micron. When the size of the particles is 1 to 5 microns, their concentration when the coverage is complete is about 4 x 10 to 10 particles / mm. When the particle size is about -325 mesh (maximum nominal diameter 44 microns), which includes commercially available metal powders and electrolyte in combination, the concentration of the particles 2 to be deposited on the base metal can range from about 10 to 10 particles / mm. The number and size of the refractory metal particles applied determines the proximity of the particles and then the size of the individual particles actually deposited on the substrate.

Product V3? .R- λ FThe drawing of Fig. 1 schematically shows in one figure the possible different structures that can be found on the base metal 10 and within the region 12 defined by the planes A-A near the surface.

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10,621 44

The quality of the individual refractory metal particles 14 deposited in the region of the base metal near the surface will depend to some extent on the manner in which the present invention is practiced. For example, the region near the surface of the substrate has refractory metal particles that are substantially the same shape and nominally the same size or somewhat smaller than the particles of refractory metal in powder or particulate form initially used in the process of this invention. This characteristic feature of the present invention is supported by microscopic observations of both the refractory metal powder and the particles used in the process and the deposited refractory metal particles in the treated metal substrates. Many of these such deposited particles are no larger than about 2 microns in size, and all such deposited refractory metal particles have been found to be in the entire range of 0.01 to 100 microns.

The proximal surface 12 of the base metal 10 may further be deposited with a plurality of refractory metal particles 14 that are both larger and smaller in size than the average nominal particle size of the refractory metal powder or particles initially used in the method of the present invention. Thus, for example, if the shapes of refractory metal particles used in the process of this invention are initially iodomorphic or block-shaped and have an average size of 1 micron, the deposited refractory metal particles may be of this quality and may contain both large spherical particles up to 10 microns in diameter. adjacent particles with an average size of less than 0.2 microns. Although the deposited refractory metal particles 10 may have such other forms, it has been found that such deposited particles range in size from 0.01 to 100 microns, and that the size of the plurality of deposited refractory particles is less than about 2 microns.

Separate deposited refractory metal particles are mostly found at grain interfaces, in microscopic pores or valleys in the region near the surface of the substrate, and / or BP 'a «i (i.e. as a result of any irregularities in the region near the surface of the substrate that may have formed in the past). such as 11 62144 in machining grooves 16, etc. Similarly, the distribution of refractory metal particles in substantially planar, single-phase microscopic regions of the substrate metal is seemingly spatially arbitrary.

As this procedure of the invention proceeds, a plurality of these discrete refractory metal particles are deposited in an adjacent pattern to form particle creams 18 that are arbitrarily deposited on the substantially planar regions 20 of the substrate metal. These particle creams are spaced apart and are mostly located in irregularities in the region near the surface of the parent metal, such as in the machining grooves 16.

When the reactions of the process of this invention are carried out to later stages of development by increasing the processing time or raising the processing temperature or the like, the clumps of discrete particles 14 deposited at a certain location and arbitrarily deposited come close to other nearby clusters and thus form a layered refractory small) areas to an area near the surface of the 22 base metals. Such microscopic regions of the deposited refractory metal appear to be continuous because the base metal is not visible in these regions. These microscopic regions 22 of refractory metal are separated from each other in an arbitrary manner, but are formed primarily by irregularities in the region near the surface of the base metal, such as machining grooves 16 and the like.

As the reactions of the process of this invention are subjected to more and more advanced steps, and especially as the number of reacting regions is increased by increasing the surface density of the discrete particles on the substrate, more and more mutual bonds of refractory metal occur. Both the fixed and arbitrarily positioned refractory microscopic regions 22 come adjacent to other nearby microscopic * Xf regions of the refractory metal, such as at 24, forming macroscopic (large areas) of the deposited refractory metal 26 in the near-surface region of the base metal. The macroscopic regions 26 of the deposited refractory metal appear continuous to the naked eye because the base metal is not visible in such regions. These macroscopic regions of the deposited refractory metal are separated from each other and seemingly arbitrarily deposited in the region near the surface of the base metal.

Thereafter, as the refractory metal continues to grow laterally through the events described above, the entire base metal 10 is covered under the deposited refractory metal, as in step 28. Further, the refractory metal grows in the normal direction of the substrate surface, thickening the refractory metal layer, point 30, and forming a refractory metal cohesive and a pseudo-uniform layer 32 that adheres to the base metal 10 as an integral part thereof.

The described distribution and subsequent incorporation of the deposited discrete refractory metal particles forms a deposition pattern that is different from any other metal deposition method, including in particular electrochemical methods. For example, a cast steel sheet when treated with the present invention appears to have a continuous coating to the naked eye, but still withstands bending at a radius of 140 ° to about 0.95 mm without visible cracks or fracture at up to three diameters. The structure of this coating, although seemingly uniform, is in fact discontinuous.

When the tool steel substrate is treated by the method of the present invention, a deposit is formed formed of discrete refractory metal particles arbitrarily located as spaced apart particle creams. These particle clusters are deposited in an area near the surface of the base metal and primarily between the carbide particles of this steel on the substantially planar metal matrix present. When SÄE 1018 steel is treated by the method of the present invention, a similar but more complex pattern of refractory metal particles is obtained in the area near the surface of the substrate. In this case, the refractory metal particles are separately arbitrarily deposited as discrete particle creams on a substantially planar ferrite microcomponent of the substrate, and 13 62144 were further distributed primarily on the ferrite portion between the carbide particles of the ferrite microcomponent of the parent metal. For both types of steels, the unitary metal matrix phase was found to be the primary deposition site for refractory metal particles, and in both cases, arbitrarily spaced discrete particle creams were found to be deposited on substantially planar portions of the unitary metal matrix phase of the substrate.

The thickness of the particle deposit that forms the applicable adhesive coating varies depending on time, temperature, and ion concentration. The coating properties can also be affected by the current conducted during the time the electrolyte and refractory metal are in contact with the substrate material. A layer with a thickness starting from molecular films, which may be selectively continuous or discontinuous, up to a thickness of 0.5 mm can be deposited in the region close to the surface of the substrate.

It is to be understood that one of the unique features of the present invention is that the refractory metal is applied to the substrate and partially replaces or replaces a portion of the substrate, and thus there is usually no change in the size of the substrate that could be detected by standard workshop techniques. Only in the most advanced deposition step can a significant change in size be observed.

According to a particular embodiment of the present invention, there may be microscopic amounts of at least one corrosion product 24 in the region near the surface of the parent metal. These corrosion products are solid chemical compounds substantially insoluble in the electrolyte formed as a result of a corrosion reaction in which the electrolyte has chemically affected the parent metal. consist essentially of base metal cations and electrolyte anions. The corrosion products may thus exist as parent metal hydroxides, chlorides, nitrates, sulfates, cyanates, carbonates, acetates, and the like, or may alternatively be more complex parent metal compounds such as oxyhydrates, oxychlorides, thiocyanates, and the like.

When corrosion products are present, they tend to nucleate and grow in the region 12 near the surface of the substrate 10 and in those areas; ». * ·> X '4 14 62144 in areas where the electrolyte can enter * especially in areas other than those where the refractory metal is in direct physical contact. in contact with the substrate. The growth of corrosion products, which occurs substantially laterally, tends to at least partially surround, as at 36, immerse, as at 38, partially immerse, as at 39, or retain, as at 40, the deposited refractory metal in the form of particles 14, shingles 18, microscopic as well as macroscopic regions 26. Since all of these corrosion products are attached to the base metal, they are believed to improve the adhesion of the refractory metal particles to the substrate, in particular by surrounding or retaining the refractory metal particles.

The alloy structure of the coating thus obtained consists of refractory metal particles attached to the base metal, refractory metal particles surrounded or retained by the corrosion product or better attached to the substrate, and further some refractory metal particles completely encapsulated by the corrosion product. Such an alloy structure increases the likelihood that certain refractory metal particles, especially those fully encapsulated by a corrosion product, will be mechanically submerged or welded by friction or naturally as a result of forces generated in the base metal near the surface of the coated portion. In this sense, the alloy coating acts as a reservoir that ensures a continuous supply of refractory metal particles attached to the area of the base metal near the surface. In addition, in some cases, the corrosion product itself acts as a lubricant, reducing friction and / or consumption, either due to its own properties or as a porous store for common lubricants such as oils, greases, graphite, molybdenum disulfide, and the like.

The last step in the treatment of the parent metals according to the present invention is preferably a rapid washing with hot water and then a rapid drying with air. This operation terminates the microelectrolytic activity and removes almost all ionized products and salts in the vicinity of the base metal substrate. The effluent wash solution, usually water, contains valuable non-deposited refractory metallic particles which it is desirable to recover and use in subsequent applications of the present invention. 99% of the total weight of the refractory metal particles can be recovered by normal operations, decantation, sedimentation, centrifugation and the like when treating the effluent wash water. However, not all refractory metal particles can be recovered in this way.

There are certain combinations of refractory metal and electrolyte which, unfortunately, cement with each other after the washing cycle. This cementation is undesirable because the product mass thus formed is substantially unsuitable for recycling and cannot be easily re-particles. In such cases, it has been found that the wash water can be treated with mineral acid, keeping the acid concentration in the wash water between 1 and 10% by volume of the total volume to avoid cementation. For example, when treating a mixture of tungsten metal powder used as a refractory metal and calcium chloride used as an electrolyte, it has been found that cementation can be avoided by adding hydrochloric acid up to about 5% by volume of the total wash water, after which the effluent can be washed again and decanted or centrifuged. to recover the powder. The concentration of hydrochloric acid used to provide a suitable wash water concentration is not critical.

The following are examples of the method of the present invention.

Example 1

In order to apply tungsten metal as a wear-resistant refractory material to the near-surface area of the sliding mechanisms of a textile machine made of high-carbon steel, pure tungsten powder is used, although purity is not particularly critical. The size of this powder is -325 mesh, which means that the largest dimension of the tungsten metal particles is 45 micrometers, and that many of the particles are much smaller than this size, up to a maximum size of about 1 micrometer. This dry tungsten powder is mixed with a commercial dry anhydrous calcium chloride powder of a particle size in a weight ratio of 1 part by weight of calcium chloride and 10 parts by weight of tungsten powder. The two powders are then mixed or ground together for about 24 hours in a cup-type ball mill '' 'O' * using 0.64 to 1.27 mm porcelain balls in a porcelain bowl, although good results are also obtained by using a mortar and pestle for the same time.

w 62144 During this co-grinding, bare surfaces are believed to form on the refractory tungsten particles # the particle size of the calcium chloride decreases and the calcium chloride deposits or remains on the surfaces of the tungsten powder particles.

The co-ground mixture of dry powders is then allowed to stand for about 20 hours in contact with moist air having a relative humidity of about 60% because calcium chloride is hygroscopic, this mixture absorbing water in an amount corresponding to about 10-20% of the total weight of the moistened mixture. At this point, most of the calcium chloride has dissociated into ions, and also a small amount of the tungsten metal powder has also dissolved in ionic form so that the ionic concentration of the refractory metal is about 3,000 to 10,000 mg / L in the liquid phase of the mixture. The moistened and aged mixture is then applied as a slurry by inverting the mixture and the sliding mechanisms together. Said parts have previously been cleaned in a CCl 4 bath to remove grease, oil or other foreign matter, exposing the area near the surface of the steel base of the sliding mechanisms so that it is exposed to and in contact with the mixture of electrolyte and refractory metal. Within 24 hours at room temperature, the refractory metal powder particles and the refractory metal traces, which interact with the electrolyte and the steel substrate, form a deposit of metallic tungsten particles in the area of the sliding mechanism near the surface of the steel substrate. The final step in handling steel sliding mechanisms is rapid washing with hot (80-100 ° C) water followed by rapid drying with air. This operation ceases microelectrolytic activity and removes ionized products and salts from the vicinity of the steel substrate.

The product obtained is a steel part in which, in the area close to the surface, the tungsten metal is deposited arbitrarily as separate particles of discrete particles. Between this spatially discontinuous layer of tungsten particles is a solid corrosion product, believed to consist of substantially hydrated ferric oxides, deposited as a side mass near the surface of the steel substrate, λ t attached to it. This corrosion product surrounds and retains the deposited tungsten particles and is partially on top of them, forming a multicomponent, attached layer of corrosion product on the steel substrate.

17 62144 Coated steel surfaces appear inconsistently coated and dark to the naked eye compared to an uncoated substrate. They have a macroscopic gray color and absorb predominantly visible electromagnetic radiation at wavelengths of 580 to 610 nanometers. This quality of the treated surfaces means both higher absorption and emission of electromagnetic radiation. The latter is particularly important for the evaporation of radiant heat.

Example 2

To apply tungsten as a wear and refractory metal to the surfaces of heat treated bevel gears made of low alloy steel, a wetted and aged mixture of tungsten and calcium chloride is prepared in exactly the same manner as in Example 1. This mixture is then applied as a slurry by painting the surface density of the refractory metal particles becomes about 10 pieces / 2 mm on the surface of the cleaned steel gears. Within 24 hours at room temperature, the refractory metal ions, which interact with the electrolyte and the low-alloy steel substrate, form a deposit of tungsten particles in the area of the steel gear near the surface. The portion is then washed and dried as in Example 1.

Sliding wear tests performed in the laboratory on similarly treated SÄE 1018 high carbon steel plates showed that at a load of 0.5 kg and a speed of 120 cm / second, the treated material withstood about 250 times more wear than similar untreated samples in terms of weight loss. The macroscopic appearance of the treated material used in these 1-hour accelerated wear experiments was similar to that of the treated low-alloy bevel gears described above.

Example 3

For coating tungsten as a refractory and abrasion resistant material. tungsten powder with a size of -325 mesh is used on the surfaces of the metal parts. The dry tungsten powder is mixed with dry anhydrous calcium chloride of commercial size and the powders are mixed and ground in one mill as described in Example 1.

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In a mill of dry powders, the co-ground mixture is then applied by screening to the cleaned surfaces subjected to wear in such a way that the surface density of the refractory metal particles on the surfaces is about 3 x 10 pieces / mm. Such treads are then kept exposed to air at a temperature of 40 ° C and a relative humidity of 40-50% for 20 hours. Within this 20 hours, the refractory metal powder particles and the refractory metal ions, which interact with the electrolyte and the treads, form a deposit of tungsten metal particles in the region near these surfaces.

Example 4

In order to apply tungsten to the surfaces of metal parts as a wear and refractory metal, a wetted and aged mixture of tungsten and calcium chloride is prepared exactly as outlined in Example 1.

This mixture is then placed in a relatively large amount in a stainless steel vessel which acts as a positive terminal for the electrolysis cell. The wetted mixture in this case acts as an "electrolyte" of the electrolytic cell. Using the given polarities across the cell, a DC voltage of about 1 volt (a stainless steel "electrolyte" coated substrate) is applied. The electric current is then allowed to run for about 6 hours, after which it is observed that the substrate has acquired a typical blue tinge associated with the surfaces prepared according to Examples 1-3, in which no current was used. The current conduction in this case is found to accelerate the deposition of discrete particles.

Example 5

Hooks and needles of various types and shapes made of hardened carbon steel and partly chromium steel, and chrome steel knives are treated with a mixture of 1 1/2 cm of hydrochloric acid and 20 g of powdered tungsten, -325 mesh in size. Hydrochloric acid forms an electrolyte and is mixed with 1 part to 5 parts of water. Before the mixture of hydrochloric acid and tungsten is brought into contact with the parts to be treated, it is triturated to a homogeneous mixture over a period of 24 hours, finally yielding a wetted powder.

19 621 44:

The moisture content is adjusted to 9% by weight of the total mixture. After a second aging period of 24 hours, the tungsten ion concentration should be at least 15 mg / l of solution. The mixed product is then screened at 25 ° C at 200 particles / mm 4 evenly on the surfaces of the hooks, knives and needles and allowed to stand for 12 hours in open boxes. At the end of this episode, all the pieces are found to be somewhat darker in hue. At the end of the reaction period, the surfaces of the bodies are found to withstand longer abrasion wear than similar untreated bodies.

Various terms have been used in the descriptions and claims of the present invention. Three concepts are defined below. Terms not defined in this context have the same meaning as normal.

Deposition: includes the chemical, mechanical, or physical attachment of a material to another material, and in particular includes coating, bonding, attachment, and embedding.

Refractory metal ion concentration: means the concentration of refractory * metal ions in aqueous solution, calculated by weight and with the metal itself being ionized in a monovalent or multivalent state. We are aware that this simple concept of ionization may not correspond to the real case, for example, tungsten in solution may be a tungstate ion in which tungsten is attached to oxygen.

Area close to the surface: the base metal and its immediate environment are considered to be the system in question. Parallel to the actual interface of the metal vessel and the environment could think of two surfaces, as the actual interface on each side being located so far from the interface between them that is included in their entirety the ship metal surface irregularities and inhomogeneities. The volume between these two surfaces is the "near-surface area" of the parent metal. The definition of this definition is based on the definition of J. Willard Gibbs (see CE Reid, "Principles of Chemical Thermodynamics", Reinhold Publishing Company, New York, 1960). The 'near-surface area' depends on the structural details of the method used to make the surface, but all such surfaces generally have openings or cracks or pores of irregular size and shape: width 4 20 621 4 4, ie between 0,02 microns and 1 mm and a depth of about 0.02 microns to 200 microns, irregularly spaced apart over the entire surface of the body to be treated, between these openings being substantially planar surfaces of the substrate material, which may have or appear to have internal parts and thus a surface-dependent portion All such geometrical structural details are defined in this context belongs to the area close to the surface.

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Claims (27)

1. An article of a base metal having a relatively low abrasion resistance and coated with refractory metal, characterized in that it consists of a base metal, whose wear resistance is relatively low, of said base metal near the surface, a refractory metal whose melting point is at least 1490 ° C and coated on said portion adjacent to the surface and adjoining to the base metal, the refractory metal being coated as separate particles, many of said particles adjoining and forming accumulations and the refractory metal particle accumulations being separated from each other forming on the base metal a to the adjacent wear-resistant discontinuous coating. 2. An article as claimed in claim 1, characterized in that the refractory metal is formed a) of iodomorphic particles, the dimensions of which are smaller are 2 micrometers, b) of coaxial particles, of which the dimensions are smaller are 10 microns, or of iodomorphic or gel-shaped. particles. 3. An article according to claim 1, characterized in that it contains the solid corrosion product of the base metal formed in said portion near the surface and adheres to the base metal, the corrosion product at least partially surrounding other refractory particles at places where these other particles do not join. to the base metal, with the aid of which said other refractory particles form an extra durable coating. 4. An article according to claim 1 or 3, characterized in that many of the aforementioned accumulations further adhere to the formation of many microscopic areas of refractory metal, and that at least some of these areas are separated from each other. Article according to claim 4, characterized in that it contains the solid corrosion product of the base metal formed in said portion near the surface and adheres to the base metal p in the areas which do not belong to said microscopic regions 621 44 27 or to said refractory particles. , and said corrosion product, which at least partially surrounds the microscopic regions and retains the other refractory particles which do not adhere to said base metal, tightly in their places to form an extra durable coating. An article according to claim 1 or 3 or 5, characterized in that it contains several of said accumulations which adhere to refractory microscopic regions of refractory metal and several said microscopic regions which adjoin forming macroscopic regions of refractory metal to the base metal. . 7. An article as claimed in claims 1, 3, 4, 5 or 6, characterized in that the portion of the base metal near the surface is characteristic of the size and shape of irregular irregularities, openings, cracks or hollows, it occupies numerous accumulations which adhere to forming microscopic areas of refractory metal, and multiply said microscopic areas of the portion near the surface of the characteristic irregularities, said microscopic regions being partially and clearly affixed to cover said portion near the surface. 8. An article according to claims 1, 3, 5, 6 or 7, characterized in that the macroscopic areas are adjacent and form a macroscopically uniform coating of the refractory metal on the base metal. 9. An article as claimed in claims 1, 3, 5, 6, 7 or 8, wherein the metal of the base material is iron or steel. 10. An article as claimed in claims 1, 3, 5, 6, 7 or 9, wherein the refractory metal is molybdenum or tungsten. 11. An article as claimed in claims 1, 3, 5, 7 or 8, wherein the excipient is chloride. 00 62144 28 12. An article as claimed in claims 1, 3, 5, 7 or 8, characterized in that said excipient forms layers for outer particles of the elastomeric metal, which are not the same as those in contact with the base metal, wherein said additional refractory metal particles give the base metal better abrasion resistance. 13. A process whereby refractory metal is stored on a base metal of relatively poor abrasion, characterized in that electrolyte material is used, which dissociates itself into ions and whose conductance ratio lies between 0.13 - 0.93 calculated in 0.1 standard solution. a portion of non-refractory metal is used, which is to be stored in the portion near the surface of the base material, the melting point of the refractory metal being at least 1490 ° C, 99-50% by weight of refractory metal and 1-50% by weight of electrolyte so long as each surface of each refractory metal to be stored is at least partially exposed, and at least partially the particles of the refractory metal are surrounded with said electrolyte, the moisture content of said mixture is poured so that the specific resistance of the electrolyte is less about 10 µm-cm in said the mixture, wherein to the ionic concentration of the refractory metal is 1 - 60 g / l solution, the surface of the base material is calibrated and at least partially coated with the particulate refractory metal and with said electrolyte mixture, said composition is reacted with the base material at temperatures between 0 - 200 ° C, and the refractory metal is stored ρέ the base of the base material near the surface as separate particles, the base material providing a protective surface a. 14. A process according to claim 13, characterized in that the refractory metal is stored as separate particles. 15. A process according to claim 13 or 14, characterized in that the reaction is carried out at a temperature between 15 and 40 ° C. 16. A method according to claim 13 or 14, characterized in that the refractory metal is stored at least up to a thickness of 0. 5 mm in the portion of the base metal near the surface. 17. A process according to any one of claims 13-16, characterized in that the dissociation ratio of the electrolyte is 0.60 - 0.93. 18. A process according to any one of claims 13 to 17, wherein the electrolyte is hydrochloric acid or chloride. 19. A process according to any of claims 13-18, wherein the refractory metal is molybdenum or tungsten. 20. A method according to any of claims 13-19, characterized in that the particle size of the refractory metal is 0.01 micron - about 1.0 mm. 21. A process according to any one of claims 13-20, characterized in that the base metal is iron or steel. 22. A process according to any one of claims 13 to 21, characterized in that the mixture of the refractory metal and the electrolyte is stirred for about 30 minutes. - 30 days to form the aforementioned exposed surfaces. 23. A method according to claims 13 to 22, characterized in that the ionic concentration of the refractory metal is formed by pouring refractory metal particles having exposed surfaces into contact with the electrolyte for 10 minutes. - 60 days. Process according to claims 13-23, characterized in that said reaction time is between 1 - 168 hours. 25. A method according to claims 13 to 24, characterized in that the moisture content of the electrolyte bond is 0.5 - 60%.