JPH02503696A - Stabilized non-electrolytic bath for wear-resistant metal coatings - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Background of the development of stabilized non-electrolytic bath for wear-resistant metal coatings The present invention provides a metal coating that exhibits high hardness and outstanding corrosion and wear resistance. It relates to an improved method for. In particular, the present invention provides nickel and/or Electroless metal coating consisting of balt and new stabilizing coating bath The present invention relates more particularly to a method for reductively fixing said coating on the surface of a substrate object.

Preferred coatings fixed in accordance with the present invention include nickel-boron coatings known in the art. Hardness and wear resistance incomparable to bare or nickel/cobalt/boron coatings It is a nickel-boron coating with

Plating or plating a metal alloy on the surface of an object by chemically or electrochemically reducing metal ions. It is not possible to modify the surface characteristics for the purpose of decoration or functional improvement by fixing the , is a well-known technique. Of particular commercial importance are metals and activated non-metallic metals. This is a case where a metal alloy is fixed on a metal substrate to enhance surface hardness, corrosion resistance, and wear resistance. Ru. Coating electroless nickel and cobalt alloys using hypophosphite or boron reducing agents The method of fixing the coating depends on its functional properties such as hardness and its wear resistance. It is recognized as a technique for improvement. Looking at patent documents, it shows even higher hardness and wear resistance. electroless nickel/cobalt coating with the goal of creating a coating with high It can be seen that research and development efforts are progressing in the field of research and development. For example, US patent specifications Sho section No. 3,738,849; No. 3,045,334; No. 3.674.447 and No. 2,726,710.

One problem with so-called electroless coating baths is that the plating rate fluctuates and the solution It is said that the metal ions inside undergo early irregular reduction and produce a black metal precipitate. The problem is the instability of the bus. By using inorganic and Mt bath additives, There are reports that it can alleviate the instability of electrolytic coating baths. For example, Patent Specification Sections 2,762,723, 3.062,666, 3,234,0 Bath stabilizers are reported in No. 31 and No. 3°753.667. non-electrolytic It is also known to use low concentrations of lead ions to increase the stability of the coating bath. It's technology.

Using a combination of lead ions and tungsten-containing ions in a non-electrolytic coating bath The stability of the bath is greatly improved due to the improved metal alloy coating. It was recently discovered that it can be obtained. Stable due to combination of lead and tungsten containing ions Metal alloy coatings deposited by electroless plating baths were previously It was found that the coating had higher hardness and better wear resistance than the coating with the same composition as described above. It is.

A non-electrolytic coating bath for fixing nickel and cobalt has been described. There is something. For example, U.S. Patent Specification Section 3.378.400, No. 3,562.0 No. 00, No. 3,715.793, No. 3,234,031, No. 3,674゜4 See No. 47 and No. 3,342.338. U.S. Patent Specification Section 3,56 No. 2,000 and No. 3,715,793 use sodium hypophosphite and chloride. Metal coatings with baths containing rut and nickel chloride alone or in combination An example is shown. U.S. Pat. No. 3,062,666 discloses that nickel, copper Non-electrolytic metal coatings containing iron and boron absorb both nickel and cobalt salts. It is disclosed that the solution is fixed by a boron reducing agent from a bath containing the boron.

Contains nickel chloride and cobalt chloride, uses complexing agent and sodium borohydride Regarding non-electrolytic coating baths, Lang (author) J (Metalloberflache) Volume 19. PP, 257-262 (1965), footnote 4 of P, 259, and “Electroplating and Finishing of Metals J. (Electroplating and Metal ) March 1966 issue, PP, 86-96. However, the present invention improved coatings obtained with new baths stabilized according to the law. Nothing described in this paper is found in the prior literature.

It is therefore a general object of the present invention to provide improved metal coatings by non-electrolytic fixing. The objective is to provide a stabilized aqueous solution bath for obtaining

A further object of the invention is to stabilize a non-electrolytic bath using salts containing lead and tungsten. Non-electrolytic nickel and/or copper, which is hard and has excellent wear resistance and corrosion resistance, is fixed from Provides a method for manufacturing a product having at least a portion of its surface coated with a root coating. That's true.

In addition to the above, it is an object of the present invention to Provides a non-electrolytic metal alloy coating with a wear-resistant surface consisting of granular deposits It is to be.

Another object of the invention is to provide an improved and stabilized non-electrolytic coating bath. at least the surface of the metal or activated non-metallic substrate. A hard, wear-resistant and corrosion-resistant coating can be applied to some parts.

These and other objects of the invention are set forth in the Summary of the Invention and the Detailed Description of the Invention below. According to the invention, which will be clear to a person skilled in the art from the description, a non-electrolytic metal coating An improved method for bus stabilization, an improved method stabilized by that method. coated baths and improved metal alloy assemblies made of nickel or cobalt. products are provided.

Non-electrolytic metal coating baths include lead ions and tungsten containing ions in the bath. tungstate, preferably in a concentration sufficient to promote stabilization of the bath. This minimizes the random reduction of solute metal ions and improves metal fixation. It can be stabilized so that the efficiency is high and constant. said stabilization The alloy elements settled by the bath are brought into contact with other surfaces under abnormal friction and surface pressure. It is particularly advantageous for surfaces of products that slide or rub against each other.

The improved metal alloy coating according to the present invention has about 90 to about 99.5% It consists of nickel and/or cobalt and about 0.5 to about 10% boron or phosphorus.

In a preferred embodiment, the composition of the metal alloy coating according to the present invention is about 92% or less. from about 98 weight percent nickel and from about 2 to about 8 weight percent boron. Consists of. For example coatings that may be preferred depending on the composition of the plating bath: Traces may contain up to approximately 2% cobalt, lead and/or tungsten. Ru. These coatings when deposited from a plating bath in accordance with the present invention It has extremely high hardness and exhibits excellent corrosion resistance and wear resistance.

In a preferred method embodiment of the invention, the substrate is treated with nickel ions and/or cobalt. lead ions, lead ions and water-soluble forms of tungsten, preferably tungstic acid Contains anion, metal ion complexing agent and borohydride as reducing agent, pH about 12 with a coating bath whose temperature is adjusted to about 180 to about 210 @ F. By contacting the metal coating is applied non-electrolytically to the substrate.

Detailed description of the invention One of the main reasons for the present invention is that low concentrations of lead ions and low concentrations of tan are present in the non-electrolytic plating bath. The combination of stainless-containing ions improves bath stability and provides superior functional properties. It is assumed that the fixation of alloy coatings having a This is a great discovery.

A suitable substrate can be combined with nickel and/or cobalt salts, metal ion complexing agents, lead salts and A bath stabilizer consisting of a tungsten-containing salt and a plating bath consisting of an aqueous solution of a reducing agent. A metal coating is fixed on the surface of the substrate by contacting the substrate with the substrate.

In accordance with the present invention, at least a portion of the surface of the product is coated with a weight of about 90 to about 99.5. -cent nickel and/or cobalt and about 0.5 to about 10 percent by weight A hard, yet malleable, wear-resistant and corrosion-resistant metal piece made of boron or phosphorus. It can be coated with coating. Non-electrolytic coatings containing boron are borohydride It can be obtained using a reducing agent such as a compound or an amine-borane. Coatings containing phosphorus are Produced from a non-electrolytic bath by using phosphite as a reducing agent.

Preferred bath conditions, such as pH, temperature, metal ion complexing agents, etc. Although it varies somewhat depending on the specific reducing agent used in the , non-electrolytic buses are generally known to exhibit some degree of instability, and therefore The plating rate fluctuates and reduced metal is deposited. Approximately 5X10-' to approximately 5X10-5 lead ion at a concentration of mol/gal and at least 6X10-' mol/gal (preferably tungsten at a concentration of about 5 x 10-6 to 5 x 10-1' moles/gallon). Combinations of ion-containing ions can improve bath stability and efficiency. It was found that the properties of the coating were improved as well. Using borohydride as a reducing agent Particularly excellent results were observed in the case of a non-electrolytic nickel bath.

In the case of the present invention, the preferred bath stabilizer is lead tungstate, which has a range of concentrations in the bath. When used in a non-electrolytic coating bath at 5 to about 15 milligrams per gallon was the most effective. However, the practical tolerance for lead tungstate The concentration range in the gas is believed to be about 3 to about 25 milligrams per gallon. lead and tan Other materials that can be used to obtain gsten-containing ions include those described below. Ru.

Suitable substrates to which electroless coatings are applied using the stabilization bath of the present invention are: , a material with a so-called catalytically active surface, including nickel, cobalt, iron, #4. a Luminium, palladium, platinum, copper, brass, bronze, chrome, tungsten This includes carbon, titanium, tin, silver, carbon, graphite, and their alloys. These materials The material acts as a catalyst when the metal ions in the plating bath are reduced by the reducing agent. As a result, the metal alloy will settle on the substrate surface that is in contact with the plating bath. Ru. Non-metallic substrates such as glass, ceramics and plastics are generally non-catalytic. It is the material. However, by forming a thin film of catalytic material on its surface, these materials can be activated. There are various methods, but those familiar to those skilled in the art This is a technology that has been developed. A preferable example is glass, ceramic or plastic. The tick product is immersed in a tin chloride solution, which is then brought into contact with a palladium chloride solution. let This causes a thin film of palladium to be reduced and fixed on the treated surface. Then the product is According to the present invention, the metal composition is It is plated or coated with material. What you need to be careful about is the magnet In the case of sium, tungsten carbide and certain plastics, according to this publication. Coating may be difficult. Also, if the pH of non-electrolytic waste is high, The aluminum must be pretreated in a known manner.

The preferred coating bath configuration for carrying out the coating according to the invention is (1) Contains nickel ions, lead ions, and tungsten-containing ions in the amounts shown below. thing.

As a concentration in the bath in moles/gallon: about 0.4 to about 0.00 nickel ions. 9: about 5X10-' to 5X10-' each of lead and tungstate ions.

(2) Have a chemical means to adjust the pH of the bath to between about 12 and about 14:A Things.

(3) Apply a metal ion complexing agent (chelating agent) to an amount sufficient to prevent the precipitation of the ions. including the amount; and (4) About 0.01 to about 0.05 moles of borohydride per gallon of coating bath. Contains a chemical reducing agent.

It is also possible to use cobalt ions instead of nickel ions. It is also possible to use a combination of cobalt ion and cobalt ion. Both individually and in combination, Total concentrations in the solution can range from about 0.4 to 1.5 moles/gal. .

For baths stabilized according to the invention, cobalt has a slower fixation rate than nickel. . This was established from a bath containing nickel and cobalt ions in a 4:1 ratio. It is clear that the cobalt content in the coated coating is less than 1%. Ru.

Among the known borohydrides, one with good water solubility and stability in aqueous solution is selected and reduced. It can be used as an agent. Sodium or potassium borohydride is preferred.

In addition, there are substituted borohydrides in which 3 or less hydrogen atoms of the borohydride ion are substituted. Can be used. Examples of this type of compound include sodium trimethoxyborohydride C This is NaB (OCH3)sH:l. Other sodium cyanoborohydride It has been shown that non-electrolytic coating baths can be stabilized using borohydride reducing agents. (U.S. Pat. No. 3,738,849). Aminebo, a known reducing agent Ran also achieves reductive fixation of metal coatings with the improved bath of the present invention. and can be used.

Coating baths using sodium borohydride preferably have a pH of about 12 to about 14. Maintain the pH within the above range during the coating process. The best results were observed when More specifically, pH 13.5 is most preferred. bus To adjust the pH of: J8, add any of various alkali salts or their solutions. . The preferred chemical means of achieving and maintaining proper bath pH include alkali metals. hydroxides, especially sodium hydroxide and potassium hydroxide and ammonium hydroxide is recommended. Ammonium hydroxide also has other advantages.

Ammonium ions help complex metal ions in the coating bath. This is because that.

Due to the high alkalinity of the stabilized borohydride coating bath according to the present invention, hydroxide To prevent precipitation of nickel and/or cobalt hydroxide or other basic salts It is necessary to include a complexing agent, or sequestering agent, for the metal ions in the bath. Another heavy The important point is that metal ion complexing agents work to lower the reactivity of metal ions. be. Complex ions, or sequestered metal ions, form borohydride ions in a stabilized solution. It exhibits low reactivity towards The reaction progresses. The catalytically active surface here refers to the catalytically active material mentioned above. The surface of a product made of a material, even if it is itself a non-catalytic material. is activated with a thin film of the catalytically active material.

Suitable complexing or sequestering agents (chelating agents) for use in the present invention include ammonia; Examples include organic complexing agents containing one or more of the following functional groups: primary amino, 27th amino, tertiary amino, imino, carboxy and hydroxy. metal ion complexation Many agents are known. A preferred complexing agent is ethylenedia Min, diethylenetriamine, triethylenetetramine, organic acids, oxalic acid, lactic acid , citric acid, tartaric acid and ethylenediaminetetraacetic acid and nitrilotri These include acetic acid and their water-soluble salts. Preferred coatings of the invention Also suitable for use in gum baths are ethylene diamine, water-soluble tartarates, and ethylene diamine. diaminetetraacetic acid, nitrilotriacetic acid, and ammonia. Combinations of these may be mentioned.

Ethylenediamine tetraacetate alone or in combination with ethylenediamine Particularly beneficial when used together.

These solubilize poorly soluble stabilizers such as lead tungstate and lead ions. Dissolves these ions, which are generated from soluble salts containing ions and tungstate ions. This is because it has the function of keeping it in the liquid.

From about 2 to about 5 moles of complexing agent per gallon of coating bath is used. Ko With approximately 3 to 5 moles of complexing or sequestering agent per gallon of bathing bath. The best results were obtained.

Nickel, cobalt, lead and tungsten or tungsten in the coating bath To contain each ion of the nickel salts, add each water-soluble nickel salt and cobalt salt to the bath. Ruto salt, lead salt and tungsten-containing salt may be added. reduction coating process Any salts of these metals with ionic components may be used as long as they do not interfere. example Salts of oxidizing acids, such as chlorates, are preferred because they react with the borohydride reducing agent in the bath. Not good. cobalt, nickel and lead chlorides, sulfates, formates, acetates and Other salts whose resulting anions are present in the alkaline coating bath There is no problem as long as it is inert to other ingredients. soluble tungsten The raw material is a compound containing tungsten, especially tungsten, an alkali metal. States or ammonium tungstate are good, other tungstates Lead tungstate and tungstic acid can also be used. lead tungstate is a source of both lead and tungsten as stabilizing components of the bath according to the present invention. is the preferred choice.

The preferred concentration of lead ions and tungsten-containing ions to stabilize the bath is , each ion between about 1X10-' and about 3.5X10-' moles/gal. . In stabilized non-electrolytic nickel baths using borohydride reducing agents, lead ions and tan Preferably, stenate ions are used at a concentration of about 2.3 x 10-' moles/gallon. stomach. Periodically add stabilizers and reducing agents to maintain a constant coating fixation rate. , for example, every 1/2 hour. At the time of addition, the concentration of these components is close to zero. It is added as if the amount has been reduced to .

Reducing agents, stabilizer ions, and nickel and/or cobalt ions in solution If it is desired to monitor the concentration of the compound, a known quantitative analysis method may be used. However, the Experiments have shown that baths have satisfactory performance as long as stabilizers and reducing agents are added at regular intervals. Demonstrate one's abilities.

The fixing speed can be controlled to some extent by the concentration of the reducing agent. Therefore, the above-mentioned advantages of the present invention In a preferred bath embodiment, a uniform fusing speed of 1 m1J2 per hour is maintained. To achieve this, add approximately 1 gram/gallon of sodium borohydride every 30 minutes. Also add about 2.3 x 10-5 moles/gal of lead tungstate. 0.5 To maintain plating rate of m1J/hr, 0.6 g/gal sodium borohydride Add 2.3 x 10 moles/gal of lead tungstate every 30 minutes. Bye. The ratio of bus volume (ctj) to plate surface area (cd) is typically is greater than about 2.5.

Lead and tan are present in the coating established by the preferred stabilization bath of the present invention. Sten is found in very small amounts (less than 1-2% of the total). in spite of, According to the experimental results, stabilizing salts should be used together with the reducing agent to ensure the stability of the bath. I realized that I needed to add it.

Preferred coating baths typically contain appropriate amounts of nickel salts and/or cobalt. Create an aqueous solution of salt and a salt as a stabilizer, add a complexing agent to this, and adjust the pH. and finally, just before immersing the substrate in the bath. by adding the required amount of sodium borohydride (usually as an alkaline aqueous solution) to Created from

Products to be coated or plated using a bath according to the invention 11° Cleaned by mechanical methods After cleaning, degreasing and anodic alkaline cleaning, in an acid bath according to metal plating method standards. Perform pink ring with.

To apply a metal alloy coating to only selected surfaces, apply the coating as needed. Mask the parts that will not be monitored. If the surface of the substrate is properly pretreated, it will be true to its true nature. Coating 1 exhibits superior adhesion, but is particularly useful in cases where strong adhesion is important. If there is a risk of problems with adhesion or adhesion, use a coating that is By electrochemically applying a two-sokel strike to the substrate surface prior to It can improve the adhesive strength of coatings.

Products that have been cleaned or otherwise surface treated should be heated to a high temperature (approximately 180 to 210'F). Start the coating process by dipping into the coating bath. The work process is Continue until the thickness of the tinging force is obtained or until there are no more metal ions in the solution. It will be done. Of course, the fixing speed varies depending on the process conditions, and is approximately 0.1 m1 J per hour ( 1 miJ = 1/1000th of an inch) Force ranges from 1 to approximately 1 m1J2.

Certain stabilizing salts, such as thallium salts, can be used in non-electrolytic coating baths. It is a notable component of electrolytic coatings. Adding such salt to the bath of the present invention, When used in addition to the lead and tungsten salts mentioned above, the stability of the It also further improves the functionality and performance characteristics of the coating.

Maintain uniform quality of coating when using plateable stabilizing salts Therefore, it is necessary to systematically add such stabilizers along with stabilizing salts and reducing agents. Ru.

The timing for replenishing the coating bath with reducing agent and stabilizer depends on the volume of the bath. It depends on the ratio of the surfaces to be coated. Thus, for example, preferred coating baths include Replenishing hydride may not be necessary if the target is a small surface.

For a one gallon bath made in accordance with a preferred embodiment of the invention, the bath includes According to If the coating is made as follows, approximately 700 square inches can be covered with a thickness of 1 mm and 1 J. Cotin The concentration of borohydride in the bath is determined as a function of the plating rate of the bath, or as a function of the plating rate of the bath. Can be monitored using appropriate methods.

Of course, the concentration of cobalt ions and nickel ions in the plating bath also affects the plating speed. and the composition of the coating. Nickel ions and cobalt ions are depleted Add nickel salt and cobalt salt to the coated bath in a timely or measured manner, respectively. It can be replenished on a continuous basis. The frequency of replenishment of both components depends on the surface area to be treated and the is a function of the ratio of space volumes. The smaller the ratio of bath volume to plated surface, the easier it is to refill. The frequency must be increased or, in the case of continuous replenishment, the speed must be increased.

The practical aspects of implementing electroless coatings are well known. So U.S. Pat. No. 3,338, dated August 19, 1967, for methods such as No. 726 (inventor Virgins), No. 3,096,182 dated July 2, 1963 (Inventor Virgins), No. 3.045.334 dated October 1, 1958 (Inventor No. 3.378.400 dated April 16, 1968 (inventor No. 2,658,841 dated November 10, 1953 (inventor Guto Zeit and Cleve).

The preferred non-electrolytic metal alloy coatings of the present invention exhibit unprecedented hardness and associated Demonstrates wear resistance. At the same time, they have amazing malleability and when the substrate is bent after coating, As a result, the coating layer maintains strong adhesion even when bent. Also, the coating is actually It is essentially non-porous and therefore has good corrosion resistance.

The non-electrolytic metal alloy coating of the present invention is a hard, wear-resistant coating consisting of a granular deposit of metal alloy. Provides an abrasion resistant surface. The hardness of this coating can be determined by heat treating the coated product. This can be further improved. Heat treatment from about 375 to about 750'F This is accomplished by heating at a temperature of from about 1 hour to about 24 hours. Approximately 550- For high temperatures of 750'F, a short time (about 1-2 hours) is desirable; For lower temperatures, from about 450°F, longer heat treatment times may be more effective. I understood.

A metal alloy coating made in accordance with a preferred embodiment and containing nickel and boron. ) is in the form of hard granular deposits. Granular deposits are removed from the non-electrolytic coating bath. When established, it is considered to be amorphous. When the above heat treatment is performed, boronization The crystalline region of metal boride selected from nickel and cobalt boride is amorphous. dispersed within the metal alloy matrix of the base. Coating composition by washing with water is a precedent The reason for the lack of hardness is still unknown. However, other nickel/cobalt Similar to boron coatings, hard crystalline regions of metal boride form inside the grain structure. What generally contributes to the high hardness of the coating after heat treatment it is conceivable that.

As plated, the preferred coating of the present invention has a Knoop hardness (100 gm load). weight) is between about 850 and about 950. Heat-treated coating according to the invention The rope hardness value is between about 1330 and about 1375. These values are for nickel-boron non- 15-20% higher than the highest values previously reported for electrolytic coatings It's expensive.

As one skilled in the art will appreciate, the coating has wide applications. these are Especially for applications that are subject to extreme wear such as constant sliding and rubbing under high temperature and high pressure. Can be used as a coating on product surfaces. These high wear conditions are Internal combustion engines including gas turbine engines, transmissions and many types of heavy duty Found in various parts of machines.

The following examples provide details of bath composition, process conditions, and coating composition. The details and representative characteristics of the invention will be understood. The examples are also meant to illustrate the invention. This should not be considered as limiting the scope of the invention. do not have.

Example 1 The plating bath was prepared as follows: 4:1 nickel chloride and cobalt chloride. 160 mJ2 of a solution containing the mixture at a concentration of 6 bonds salt/gallon was Ethylenediamine (EDA) and 60gm ethylenediamine tetraacetic combined with a mixture of acids (EDTA). Add sodium hydroxide (160gm) to this. The resulting solution was diluted to a volume of 1 gallon with deionized water.

Lead tungstate stabilizing solution: Add 10 gm of lead tungstate to about 10 gm of lead tungstate. ethylenediaminetetraacetic acid disodium salt in 1 gallon of deionized water dissolved in.

Sodium borohydride solution: 0.8 lb (363 gm) of sodium borohydride , 21/2 bond (1135 gm) of sodium hydroxide to 1 gallon of deionized water. Dissolved in 1 gallon of solution made by dissolving.

Heat the plating bath to 192'F and add 6 liters of sodium borohydride solution while stirring. r+J and 4 mJ of lead tungstate solution were added. 12 metal plating coupons and two 1 inch x 3 inch measuring plates were suspended in the bath and the plating speed was increased to 4 hours. I monitored it over and over. During that time, add 6 mA of borohydride solution and tungsten every 30 minutes. 4 mJ of acid lead solution was added to the bath. During the 4-hour experiment, the bus received 0.5 mJ! /One of the time Plating was performed at a constant speed.

The measurement plate was heat treated at 725'F for 90 minutes and the hardness was measured using a testing machine with a 100gm load. As a result, the average Knoop hardness (average of 8 readings) was 1365.75.

Example 2 Filter the bath of Example 1 and nickel/cobalt chloride solution.

EDA and EDTA were added at 25%. Using the same procedure, i.e. every 30 minutes N a 6 mJ of B Ha solution and 4 mJ of P b W O4 solution were added. The plating speed is 0 for 4112 hours. 5rr+j! / It was constant with time.

Hardness as plated - average Noob value: 897.25, hardness after heat treatment - average Noob value Value: 1373.9° Example 3 (A) The same procedure as in Example 1 was followed. However, 10 mj of NaBH4 solution every 30 minutes! and pbwo4 solution 4m solution 4bf2 were added.

The plating rate was 1 mJ/hour, and the plating was continued for 4 hours, but there was no change.

(B) Filter the bath of (A) on the cobalt/nickel chloride solution, EDA and E The bus was regenerated by adding 50% DTA.

Following the same dosing schedule as in (A), the plating rate was set at one time during the 5-hour plating run. Fixed 1.0m1j! / kept at the time.

Example 4 Using the same proportions as mentioned in Example 3, while constantly filtering/stirring the plating solution. A 75 gallon plating tank was heated and prepared. pbwo, solution 220 mJ and N Start plating by adding aBH solution first, and then every 30 minutes during plating. Added the same amount to. The plating speed was 1.0 mi/hour and did not change during the 5-hour plating process. won. Falex ring and block alphaware test (Falex Rlngand Block Alpha WearTest) (ASTMG7 7) was performed in an independent testing facility on coatings after heat treatment at 725°F for 90 minutes. The mass change of the ring (10,800 cycles) was -o,oo.

The mass change (10,800 cycles) of 4gm5 block is -0,0037gm there were.

Example 5 (A) According to the procedure of Example 1, salt was substituted for the combination of nickel chloride and cobalt chloride. When a stabilizing bath was prepared using nickel chloride at 0.7 mol/gal, uniform The nickel-boron coating was able to adhere at a reasonable plating speed. The coating is excellent It showed excellent hardness and wear resistance.

(B) According to the procedure of Example 1, salt was substituted for the combination of nickel chloride and cobalt chloride. When using 0.9 mol/gal of cobalt chloride, the plating rate decreased; However, the cobalt-boron coating has excellent hardness and wear resistance at a uniform speed. A 1 gallon plating bath was prepared with the following composition.

Nickel sulfate: 0.50 mol/gal Sodium hypophosphite: 1.0 mol/gal Lactic acid: 2.0 mol/gal Propionic acid: 0.1 mole/gallon Lead chloride: 2.3X10-'mol/gal Sodium tungstate: 4.0X10-'mol/gal This bath was used to plate clean steel products at a bath temperature of 200@F. bath products After 30 minutes of soaking, the product was coated with a uniform nickel-phosphorus alloy. .

Example 7 The procedure of Example 1 was followed, except that two separate stabilizer solutions were prepared. those in concentrated sodium hydroxide solution, one in lead acetate at 6 x 10-' mol/liter, and the other in concentrated sodium hydroxide solution. One contains tungsten iodide at a concentration of 1×10-” mol/liter. there were. Each stabilizer was added in an amount corresponding to the amount of lead tungstate solution used in Example 1. Solutions were added to the bath in equal amounts.

Example 8 Lead citrate and tungsten acid chloride (in 10% NaOH solution) as stabilizer solution ) at concentrations of 5X10-6 mol/liter and 6X10-6 mol/liter, respectively. A bus was created in the same manner as in Example 7, except that the following was used.

Although preferred embodiments of the present invention have been described above, many modifications are possible. will be understood. The appended claims shall include all such modifications. be.

international search report

Claims (1)

[Claims] 1. Metal ions selected from nickel and cobalt and metal ion chelating agents. , a heated aqueous bath comprising a reducing agent capable of reducing said metal ions to the surface of the substrate; In the method of fixing a non-electrolytic metal alloy coating to a substrate in the aqueous solution bath, from about 5 x 10-6 to about 5 x 10-5 moles of lead ions and tungsten per gallon. It is prepared to contain ten-containing ions, which increases the stability of the bath and also improves the gold content. An improved method for increasing the hardness and wear resistance of metal alloy coatings. 2. The reducing agent is a borohydride reducing agent selected from borohydride and amine borane. The method according to claim 1. 3. The bath contains about 1× each of the lead ions and tungstate ions per gallon. 10-5 to about 3.5 x 10-5. . 4. The bath contains about 0.4 to about 0.9 moles of nickel ions per gallon. 4. The method according to claim 3, wherein the method is prepared as follows. 5. 2. The method of claim 1, wherein the reducing agent is a hypophosphite. 6. Lead ions and tungsten by adding lead tungstate to the bath 4. The method according to claim 3, wherein acid ions are obtained. 7. The lead tungstate is added to the bath as an aqueous solution containing a lead chelating agent. , the method according to claim 6. 8. A claim in which the metal chelating agent consists of a salt of ethylenediaminetetraacetic acid. The method described in Section 7. 9. A non-electrolytic metal coating deposited according to the method of claim 1. Ng. 10. A non-electrolytic metal coating deposited according to the method of claim 2. 11. 7. A non-electrolytic metal coating deposited according to the method of claim 6. 12. A metal ion selected from the group consisting of nickel ions and cobalt ions. aqueous solution of ion, reducing agent, metal ion complexing agent, about 5 x 10-6 to about 5 x 10-5 lead ions at a concentration of moles/gal; and a concentration of at least about 5 x 1-6 moles/gal. A stabilized non-electrolytic metal bath consisting of tungsten-containing ions. 13. 13. The non-reducing agent according to claim 12, wherein the reducing agent is a borohydride or an amine borane. Electrolytic metal bath. 14. The borohydride reducing agent may be sodium borohydride, potassium borohydride, or Glue consisting of sodium methoxyborohydride and potassium trimethoxyborohydride 14. The coating pass of claim 13, wherein the coating pass is selected from the group consisting of: 15. The metal ion complexing agent may be water-soluble salts of tartaric acid, citric acid, and oxalic acid, or ethylene. diamine, diethylenetriamine, triethylenetriamine, ethylenediamine selected from tetraacetic acid, nitrilotriacetic acid and ammonia. 13. The coating bath according to claim 12, wherein the coating bath is a compound comprising: 16. The metal ion complexing agent is ethylenediamine and ethylenediaminetetraamine. 16. The method of claim 15, wherein the method is cetic acid. 17. The metal ion is a nickel ion, and the tungsten-containing ion is 15. The non-electrolytic metal bath of claim 14, which is tungstate ion. 18. Said Claim 17, wherein the raw material for the lead ions and tungsten ions is lead tungstate. Non-electrolytic nickel bath as described. 19. The concentrations of the lead ions and tungstate ions are each about 1 x 10-5. 18. The non-electrolytic nickel of claim 17, wherein the non-electrolytic nickel is about 3.5 x 10-5 moles/gal from Lubas. 20. Metal chelating agents are ethylenediamine and ethylenediamine tetraacetic 20. The non-electrolytic nickel bath of claim 19 consisting of an acid. 21. The lead tungstate is contained at a concentration of about 2.3 x 10-5 moles/gal. 21. The non-electrolytic nickel bath of claim 20. 22. It also contains about 0.05 to about 0.4 moles of cobalt ions per gallon of bath. 22. The non-electrolytic nickel bath of claim 21. 23. a substrate; and a wear-resistant metal alloy coating applied to at least a portion of the surface of the substrate. coating, said coating comprising a coating bath according to claim 12. Thus, the product is affixed to the surface of the substrate. 24. a substrate and a wear-resistant nickel-boron coating applied to at least a portion of the surface of said substrate; coating bath according to claim 17, wherein said coating is according to claim 17. the product affixed to the surface of the substrate by. 25. a substrate and a wear-resistant nickel-boron coating applied to at least a portion of the surface of said substrate; a coating bath according to claim 22, wherein said coating is according to claim 22. The product is affixed to the surface of the substrate by. 26. Defining a hard wear and corrosion resistant non-electrolytic metal coating on the substrate including the following steps: How to wear it. (1) Nickel ions at a concentration of about 0.4 to 0.9 moles per gallon of bath, about lead ions at a concentration of from 5 x 10-6 to about 5 x 10-5 molar, and at least about 5 x 1 tungsten-containing ions at a concentration of 0-6 molar; Complexing the ions to prevent them from precipitating out of the bath during coating operations from about 2 to about 8 moles of metal ion complexing agent per gallon of bath; chemical means to adjust between 12 and about 14; and from about 0.01 to about 0.05 moles per gallon of bath of borohydride reducing agent; (2) preparing an aqueous coating bath consisting of heating to a temperature of about 210°F; (3) Place the substrate in the heated coating bath and apply approximately 0.2 mil to the surface of the substrate. contact for a sufficient time to establish the coating to a thickness of about 10 mils; Process. 27. The pH of the bath is selected from alkali metal hydroxide and ammonium hydroxide. 27. The method of claim 26, wherein the method is adjusted to about 13.5 using the compound defined above. 28. The temperature of the coating bath was maintained at about 18 ℃ while the coating was being deposited on the substrate. 27. The method of claim 26, wherein the temperature is maintained at 5 to about 195 degrees Fahrenheit. 29. The lead ions and tungsten-containing ions in the bath are approximately 1×10 −5 formed by the addition of about 3.5 x 10-5 moles of lead tungstate from The method according to claim 26. 30. The metal ion complexing agent is ethylenediamine and ethylenediaminetetraacetate. 30. The method of claim 29, comprising tic acid. 31. The reducing agent is sodium borohydride and fixes the coating to the substrate. Periodically add approximately 0.0 ml per gallon to the coating bath to maintain a suitable fixing rate. 5 to about 1.5 grams of sodium borohydride as an alkaline aqueous solution and about 4 31. The method of claim 30, wherein about 15 mg of lead tungstate is added. 32. About 5 x 10-6 to about 5 Non-electrolytic metal coating bath containing a concentration of x10-5 moles/gal. 33. Lead tungstate from about 3 milligrams/gallon to about 25 milligrams/gallon 33. A non-electrolytic metal coating pass according to claim 32, comprising a concentration of . 34. Contains lead tungstate at a concentration of about 5 to about 15 milligrams per gallon , Ingbas. Detailed description of the non-electrolytic metal coach invention according to claim 32