CN111394716A - Multi-coating stacked structure, preparation method and application thereof - Google Patents

Abstract

A multi-plating layer stack structure, its preparation method and application are disclosed. The multi-coating stacking structure comprises a nickel-phosphorus alloy combined coating, wherein the nickel-phosphorus alloy combined coating sequentially comprises the following components from bottom to top: a low-phosphorus nickel-phosphorus alloy plating layer with a phosphorus content of 0-4 wt%, a high-phosphorus nickel-phosphorus alloy plating layer with a phosphorus content of 9-20 wt%, and a low-medium-phosphorus nickel-phosphorus alloy plating layer with a phosphorus content of 3-9 wt%. According to the invention, through the special combination of the nickel-phosphorus alloy plating layers of low phosphorus, high phosphorus and low-medium phosphorus, a larger potential difference is generated among different nickel-phosphorus alloy plating layers, so that the corrosion can be prevented from developing in the depth direction, and more excellent corrosion resistance is provided.

Description

Multi-plating stack structure, its preparation method and application

technical field

The invention relates to the field of metal plating, in particular to a multi-plating stack structure, a preparation method and application thereof.

Background technique

In the electroplating production process, electroplating single-layer nickel and multi-layer nickel (sulfur-containing nickel) are widely used in various products to prevent corrosion, prevent the diffusion and migration of substrate atoms and increase the wear resistance of the surface coating. With the continuous improvement of application requirements for corrosion resistance and wear resistance, the above-mentioned electroplating of single-layer nickel or multi-layer nickel has limitations in application, and the comprehensive performance of the overall plating layer needs to be improved urgently.

SUMMARY OF THE INVENTION

The present invention aims to provide a multi-coating stack structure including nickel-phosphorus alloy composite coating, its preparation method and application, so as to solve the problem of corrosion resistance and corrosion resistance of electroplated multi-layer nickel in electroplating single-layer nickel and single-layer coating as bottom coating or intermediate coating. Insufficient wear resistance and other issues.

In order to achieve the above object of the present invention, one aspect of the present invention provides a multi-plating layer stack structure comprising a nickel-phosphorus alloy composite coating layer, wherein the nickel-phosphorus alloy composite coating layer sequentially includes from bottom to top: a low-phosphorus nickel-phosphorus alloy coating layer, High phosphorus nickel phosphorus alloy coating and low-medium phosphorus nickel phosphorus alloy coating, wherein the phosphorus content of the low phosphorus nickel phosphorus alloy coating is 0-4 wt %, and the phosphorus content of the high phosphorus nickel phosphorus alloy coating is is 9-20 wt%, and the phosphorus content of the low-medium phosphorus nickel-phosphorus alloy coating is 3-9 wt%.

In certain embodiments, the difference in phosphorus content between adjacent coatings in the nickel-phosphorus alloy composite coating is 5 wt% or more.

In certain embodiments, the multi-plating stack structure also includes other plating layers on the low-medium phosphorous plating layer of the nickel-phosphorus alloy combination plating.

In certain embodiments, other coatings include single-, double-, or multi-layer metal coatings, metal alloy coatings, or phosphorous-containing alloy coatings, or combinations thereof.

In certain embodiments, metal coatings include copper, nickel, gold, silver, tin, palladium, rhodium coatings, etc.; metal alloy coatings include silver-palladium, gold-silver, gold-nickel, gold-cobalt, palladium-nickel, palladium-cobalt, rhodium-ruthenium , rhodium-cobalt, rhodium-palladium, nickel-tungsten, nickel-cobalt coating, etc.; phosphorus-containing alloy coating includes nickel-phosphorus, nickel-cobalt-phosphorus coating, etc.

In certain embodiments, the multi-plating stack structure further includes a substrate, wherein the nickel-phosphorus alloy composite coating is formed directly on the substrate.

In certain embodiments, the multi-plating stack structure further includes an underplating layer on the substrate, wherein the nickel-phosphorus alloy combination plating layer is formed on the underplating layer.

In certain embodiments, the primer layer may be the same as or different from the other coatings, including single, double, or multi-layer combinations of metal coatings, metal alloy coatings, phosphorous-containing alloy coatings.

Another aspect of the present invention provides a method for preparing a multi-plating layer stack structure, comprising: using a low-phosphorus nickel-plating phosphorus solution, a high-phosphorus nickel-phosphorus solution, and The low-to-medium-phosphorus nickel-phosphorus plating solution sequentially forms a low-phosphorus nickel-phosphorus alloy coating with a phosphorus content of 0-4 wt%, a high-phosphorus nickel-phosphorus alloy coating with a phosphorus content of 9-20 wt%, and a phosphorus content of 3- 9 wt% low-medium phosphorus nickel-phosphorus alloy coating.

In certain embodiments, electroless plating methods are employed to form low phosphorus nickel phosphorus alloy coatings, high phosphorus nickel phosphorus alloy coatings, and low-medium phosphorus nickel phosphorus alloy coatings.

In certain embodiments, pulsed electroplating methods are used to form low phosphorus nickel phosphorus alloy coatings, high phosphorus nickel phosphorus alloy coatings, and low-medium phosphorus nickel phosphorus alloy coatings.

In certain embodiments, the conditions of pulse electroplating include: pulse current density 1-100 A/dm ² , duty cycle 0.1-0.5, frequency 1-100 KHz.

In certain embodiments, the step of forming a low phosphorus nickel phosphorus alloy coating may be replaced by electroplating nickel or electroless nickel plating.

Another aspect of the present invention provides applications of multi-plating stack structures, including applications in connectors and other industrial equipment, communication equipment, electronic equipment, household appliances, aerospace, automotive parts, hardware and sanitary products, and applications including continuous plating , application in the production of electroplating process of barrel plating and rack plating.

According to the present invention, a large potential difference is generated between different nickel-phosphorus alloy coatings through a special combination of low-phosphorus + high-phosphorus + low-medium phosphorus nickel-phosphorus alloy coatings, so that corrosion can be prevented from developing in the depth direction, providing More excellent corrosion resistance, and the highest hardness low-medium phosphorus nickel-phosphorus alloy coating is the top layer, so that the product has more excellent wear resistance.

Description of drawings

Embodiments of the present invention are described in detail in order to facilitate a more complete understanding of the present invention with reference to the following drawings, wherein:

FIG. 1 is a schematic structural diagram of the combined nickel-phosphorus coating in the multi-coating stack structure of the present invention.

Figure 2 shows the corresponding microhardness values of nickel-phosphorus alloy coatings with different phosphorus contents.

3 is a graph showing the abrasion test results of the plated product of the present invention and the comparative plated product 1 (A: the comparative plated product 1, B: the plated product of the present invention).

Detailed ways

The inventors of the present application found out when researching related stacked plating structures that the stacked plating structures, such as nickel+palladium-nickel+gold, copper+nickel+palladium-nickel+gold, etc., mostly use electroplating nickel, electroplating copper, etc. as the primer Or intermediate coating, but electroplating nickel, electroplating copper, etc. cannot meet the requirements of higher corrosion resistance and wear resistance. When electroplating nickel-tungsten or nickel-phosphorus alloy is used instead of nickel-plating or copper-plating, there are problems of unstable process and uneven coating of nickel-tungsten electroplating and nickel-phosphorus electroplating. There will be uneven coating thickness and nickel-phosphorus alloy ratio in the flat area, resulting in unstable product performance. Moreover, when a single coating (nickel, copper, nickel-tungsten, etc.) is used as the bottom coating or intermediate coating, once corrosion occurs, it is easy to cause the corrosion to develop rapidly in the depth direction, and the product quickly corrodes and fails.

In view of the above problems, the inventor has designed a new type of composite structure of multi-layer nickel-phosphorus alloy coating. In the multi-layer nickel-phosphorus alloy coating of this structure, due to the sufficient potential difference between different coatings, corrosion can be prevented in the depth direction. Rapid development; the inventor also designed a method for forming a nickel-phosphorus alloy coating by electroless plating or pulse electroplating to solve the problems of unstable nickel-phosphorus electroplating process and uneven coating, thus completing the present invention.

The present invention will be described in further detail below with reference to specific embodiments. It will be understood that other embodiments are contemplated, which may be practiced without departing from the scope or spirit of the invention. Accordingly, the following detailed description is not limiting.

Unless otherwise indicated, all numbers used in this specification and claims for the dimensions, quantities, and physicochemical properties of features should be understood to be modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can be modified by those skilled in the art to obtain the desired properties sought to be obtained by the teachings disclosed herein. approximation. The use of numerical ranges by endpoints includes all numbers within that range and any range within that range, eg, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc. .

Multi-plating stack structure

The present invention provides a novel multi-coating stack structure comprising combined nickel-phosphorus coatings.

FIG. 1 is a schematic structural diagram of the combined nickel-phosphorus coating in the multi-coating stack structure of the present invention.

The combined nickel-phosphorus coating shown in FIG. 1 contains three layers, from bottom to top, low-phosphorus nickel-phosphorus alloy coating 1 , high-phosphorus nickel-phosphorus alloy coating 2 and low-medium phosphorus nickel-phosphorus alloy coating 3 .

In the above-mentioned low-phosphorus+high-phosphorus+low-middle-phosphorus three-layer coating structure, the phosphorus content of the low-phosphorus nickel-phosphorus alloy coating 1 may be 0-4 wt % (that is, when the phosphorus content is 0, the low-phosphorus nickel The phosphorus alloy coating can be pure nickel coating), and the thickness can be 0.01-0.5 μm, preferably 0.05-0.5 μm. The phosphorus content of the high-phosphorus nickel-phosphorus alloy coating 2 may be 9-20 wt %, and the phosphorus content of the low-medium phosphorus nickel-phosphorus alloy coating 3 may be 3-9 wt %. The thickness can be appropriately adjusted according to actual needs, for example, the thickness of the high-phosphorus coating can be 0.1-5 μm, the thickness of the low-medium phosphorus coating can be 0.1-1 μm, and so on.

Due to the special design of low phosphorus + high phosphorus + low-medium phosphorus, the phosphorus concentration between different nickel-phosphorus alloy coatings is quite different, and a large potential difference can be generated between different coatings, thereby preventing corrosion from deep. direction development, to provide more excellent corrosion resistance. In addition, the low-phosphorus nickel-phosphorus alloy coating is used as the bottom layer, which can exert the characteristics of fast plating and good bonding force on the low-phosphorus coating; the high-phosphorus nickel-phosphorus alloy coating is used as the middle layer, and the high-phosphorus coating has high corrosion resistance. (especially when the phosphorus content is higher than 10%, the nickel-phosphorus alloy has an amorphous structure, and the corrosion resistance is greatly improved); and the low-medium phosphorus coating with the highest hardness is used as the top layer, which can effectively exert the high performance of the medium phosphorus alloy. The hardness has a chopping block effect on the upper metal, so that the product has better wear resistance.

The phosphorus content range for each coating was determined based on the above considerations in conjunction with the properties of the nickel-phosphorus alloy. For example, the hardness of nickel-phosphorus alloy (coating) increases first and then decreases with the increase of phosphorus content. Figure 2 shows the corresponding microhardness values of nickel-phosphorus alloy coatings with different phosphorus contents. It can be seen that as the phosphorus content increases from 0, the hardness of the nickel-phosphorus alloy increases rapidly, reaching a peak when the phosphorus content is about 2-5 wt%, and then with the further increase of the phosphorus content, the hardness begins to decrease, at After the phosphorus content reached about 8% by weight, the decrease was significant. Therefore, in the present invention, as the uppermost low-medium phosphorus plating layer, the phosphorus content is set at 3-9 wt %, preferably 3-8 wt %, so as to exert the high hardness advantage of nickel-phosphorus alloy as effectively as possible. In addition, with the increase of phosphorus content in the nickel-phosphorus alloy, the corrosion resistance of the nickel-phosphorus alloy (coating) is improved, especially when the phosphorus content is higher than 10%, the crystal structure of the nickel-phosphorus alloy is amorphous, compared with pure nickel. (Crystalline) and low-phosphorus coatings are more detailed, resulting in better corrosion resistance. Therefore, the phosphorus content of the high-phosphorus plating layer of the present invention is set to 9-20 wt %, preferably 10-20 wt %.

In order to ensure that there is a large potential difference between different nickel-phosphorus alloy coatings, preferably, the phosphorus content difference between adjacent coatings in the combined nickel-phosphorus coating can be more than 5 wt %, or even more than 6 wt % or 8 wt %.

The multi-plating stack structure of the present invention may also include other coatings on the low-medium phosphorus coating combined with the nickel phosphorus coating.

Here, the other coating may be any metal coating known in the art or a combination thereof, including metal coating, metal alloy coating, single-layer, double-layer or multi-layer combination of phosphorus-containing alloy coating, and the like. For example, metal coatings may include coatings of copper, nickel, gold, silver, tin, palladium, rhodium, etc., and combinations thereof; metal alloy coatings may include silver-palladium, gold-silver, gold-nickel, gold-cobalt, palladium-nickel, palladium-cobalt, rhodium Coatings of ruthenium, rhodium-cobalt, rhodium-palladium, nickel-tungsten, nickel-cobalt, etc., and combinations thereof; phosphorus-containing alloy coatings may include nickel-phosphorus, nickel-cobalt-phosphorus coatings, and the like. The other coating may also be a combination of the above-mentioned metal coating, metal alloy coating and phosphorus-containing alloy coating.

Therefore, the multi-plating stack structure may have one of the following structures: combined nickel phosphorus coating; combined nickel phosphorus coating + outer layer; combined nickel phosphorus coating + intermediate layer + outer layer; combined nickel phosphorus coating + intermediate layer 1 + intermediate layer 2+ Outer layer; combined nickel phosphorus coating + intermediate layer 1 + intermediate layer 2 + intermediate layer 3 + outer layer; combined nickel phosphorus coating + intermediate layer 1 + intermediate layer 2 + intermediate layer 3 + intermediate layer 4 + outer layer; combined nickel phosphorus coating Coating layer + intermediate layer 1 + intermediate layer 2 + intermediate layer 3 + intermediate layer 4 + intermediate layer 5 + outer layer, wherein the outer layer and the intermediate layer can be any one of metal coating, metal alloy coating and phosphorus-containing alloy coating .

The multi-plating layer stack structure of the present invention is formed on the substrate, wherein the combined nickel-phosphorus coating layer can be directly formed on the substrate, or the combined nickel-phosphorus coating layer can be formed on the bottom coating layer of the substrate.

The substrates described herein can be substrates commonly used in the art, such as metal or alloy substrates. In order to form a good coating, the surface of the substrate can be pretreated, such as degreasing and surface oxide treatment.

An undercoating layer can be formed on the base material first, and then a combined nickel-phosphorus plating layer and other plating layers can be formed on the undercoating layer. Here, the undercoating layer may include single-layer, double-layer or multi-layer combination of the above-mentioned metal plating layer, metal alloy plating layer and phosphorus-containing alloy plating layer, which may be the same as or different from other plating layers.

Method for preparing multi-layer stack structure

The present invention also provides a method for preparing a multi-plating layer stack structure, comprising using a low-phosphorus nickel-phosphorus-plating solution, a high-phosphorus nickel-phosphorus solution, and a low-medium phosphorus solution on the substrate or on the bottom coating layer on the surface of the substrate. The nickel-phosphorus plating solution forms a low-phosphorus nickel-phosphorus alloy coating layer, a high-phosphorus nickel-phosphorus alloy coating layer, and a low-medium phosphorus nickel-phosphorus alloy coating layer in turn.

Here, the low-phosphorus nickel-phosphorus alloy coating, the high-phosphorus nickel-phosphorus alloy coating, the low-medium phosphorus nickel-phosphorus alloy coating, and the substrate and undercoating layers are the same as described in the "Multi-Plating Stacked Structure" section above.

Low-phosphorus nickel-plated phosphorus potions, high-phosphorus nickel-plated phosphorus potions, and low-medium-phosphorus nickel-plated phosphorus potions are commercially available. Corresponding low-phosphorus, high-phosphorus, and low-medium-phosphorus nickel-phosphorus plating solutions can be selected according to the method used to form the nickel-phosphorus alloy coating.

The methods of the present invention for forming low-phosphorus, high-phosphorus, and low-medium-phosphorus nickel-phosphorus alloy coatings may include electroless plating and pulse electroplating methods. The inventor found that the nickel-phosphorus electroplating process has the following problems: due to the inconsistent current distribution during the electroplating process, there is an obvious edge effect or tip discharge effect on the plated part, so that the thickness of the nickel-phosphorus coating at the edge and tip is much higher than the flat area. , which will make products with high size requirements fail to meet the requirements for use. At the same time, the phosphorus content of the plated alloy layer in the edge and tip regions is lower than that in the flat region, and different nickel-phosphorus alloy ratios will cause inconsistencies in product performance. To this end, the present invention adopts electroless nickel-phosphorus plating, so that consistent thickness and nickel-phosphorus alloy ratio can be obtained at different positions of the product. Further, in view of the problems of uneven distribution of the coating layer, high porosity, and imprecise crystallization in direct current electroplating of nickel and phosphorus, as well as the problems of low production efficiency of electroless nickel and phosphorus plating, the present invention can also adopt the pulse electroplating nickel phosphorus process to make the nickel phosphorus coating layer. The crystals are more detailed and uniform, and the electroplating efficiency is higher, extending the service life of the potion.

The electroless nickel-phosphorus plating of the present invention can be selected from commercially available electroless nickel-phosphorus syrups, including low-phosphorus, high-phosphorus and low-medium-phosphorus electroless nickel-phosphorus syrups, and is carried out according to a general electroless plating process. Of course, the thickness of each nickel-phosphorus alloy plating layer can be controlled by adjusting the process conditions (eg, temperature) and time of electroless plating.

The pulsed nickel-phosphorus electroplating of the present invention can be carried out by using commercially available electroplating nickel-phosphorus syrup under the following pulse conditions: pulse current density 1-100A/dm ² , duty ratio 0.1-0.5, frequency 1-100KHz. For example, the pulse condition may be 10-30A/dm ² , duty cycle 0.1-0.3, frequency 5-50KHz.

Although low-phosphorus, high-phosphorus, and low-medium phosphorus three-layer nickel-phosphorus alloy coatings can all be formed by electroless plating and pulse plating methods, the step of forming a low-phosphorus nickel-phosphorus alloy coating can be performed with electroplated nickel (such as electroplating shock Nickel) or electroless nickel plating, ie, a nickel plating layer with 0 phosphorus content is formed.

The method for preparing the multi-plating layer stack structure of the present invention may further include the step of forming other plating layers on the low-medium phosphorus nickel-phosphorus alloy plating layer.

For the "other plating layers", please refer to the relevant descriptions in the "Multiple Plating Layer Stacked Structure" above. For example, other coatings may include copper, nickel, gold, silver, tin, palladium, rhodium, silver palladium, gold silver, gold nickel, gold cobalt, palladium nickel, palladium cobalt, rhodium ruthenium, rhodium cobalt, rhodium palladium, nickel tungsten, Single-layer, double-layer, multi-layer plating of nickel-cobalt, nickel-cobalt-phosphorus, nickel-phosphorus, etc., or a combination thereof.

The substrate may be subjected to surface pretreatment prior to forming the nickel-phosphorus alloy coating, or prior to forming the undercoating. For metal or alloy substrates, surface pretreatment may include degreasing (eg, electrolytic degreasing) and surface oxide removal (eg, treatment with acid).

Application of Multiple Plating Stacks

According to actual needs, the nickel-phosphorus alloy composite coating of the present invention can be applied to any substrate or coating, and can be applied to different electroplating production processes such as continuous plating, barrel plating, and rack plating.

Therefore, the multi-plating stack structure of the present invention can be used for but not limited to the following applications: connectors and other industrial equipment, communication equipment, electronic equipment, household appliances, aerospace, auto parts, hardware and sanitary products, especially for connectors, Anti-corrosion, corrosion resistance, wear resistance, temperature resistance, welding, magnetic conductivity and other functions in electronic equipment, automobile and other industries.

Example

Several specific embodiments are shown below by way of illustration. It is to be understood that other embodiments are contemplated and modifications may be made without departing from the scope or spirit of the invention. Therefore, the following specific examples are not intended to be limiting.

Unless otherwise indicated, "%" mentioned below is "% by weight".

Example 1

A sample of a copper alloy substrate was selected, first electrolyzed to remove oil, and then activated with 5% sulfuric acid to remove the surface oxide layer.

Put the sample into the low phosphorus electroless nickel plating phosphorus solution (nickel sulfate 35g/L, sodium hypophosphite 20g/L, sodium acetate 6g/L, lactic acid 20ml/L, propionic acid 8ml/L, sodium dodecylbenzenesulfonate 0.04g/L, pH5.5, temperature 75°C), control pH=9.5, temperature 40°C, make the sample quickly plated, and deposit about 0.1 μm low-phosphorus nickel (phosphorus content 1%) on the surface.

Put the sample into high phosphorus electroless nickel plating phosphorus solution (nickel sulfate 20g/L, sodium hypophosphite 45g/L, sodium acetate 6g/L, lactic acid 20ml/L, propionic acid 8ml/L, sodium dodecylbenzenesulfonate 0.04g/L, pH 4.5, temperature 75°C), control pH=9.5, temperature 40°C, so that the sample is deposited on an amorphous high phosphorus alloy (phosphorus content 12%) with a thickness of 1 μm.

Put the sample into the low-medium phosphorus electroless nickel plating phosphorus solution (nickel sulfate 30g/L, sodium hypophosphite 40g/L, sodium acetate 6g/L, lactic acid 20ml/L, propionic acid 8ml/L, dodecylbenzenesulfonic acid Sodium 0.04g/L, pH 5.0, temperature 75°C), control pH=9.5, temperature 40°C, and deposit 0.2 μm-thick low-medium phosphorus nickel (phosphorus content 4%) on the surface of the sample.

Then, the sample was placed in a cobalt-plated gold solution and electroplated with a 0.76 μm gold-cobalt alloy.

In this way, a plating product 1 with three layers of chemical nickel-phosphorus as a combined bottom plating layer is obtained.

Example 2

The same procedure as in Example 1 was repeated, but in the steps of forming the low-phosphorus nickel coating, the high-phosphorus alloy coating, and the low-medium phosphorus nickel coating, respectively, a low-phosphorus nickel coating (thickness about 0.1 μm) with a phosphorus content of 4% was formed, A high-phosphorus alloy coating (thickness 1 μm) with a phosphorus content of 15% and a low-medium phosphorus nickel coating (thickness 0.2 μm) with a phosphorus content of 8% were obtained as a coating product 2.

Example 3

A plated product 3 was obtained by repeating the same procedure as in Example 1, except that electroplating impact nickel was used instead of the step of forming the low-phosphorus nickel plated layer.

Example 4

A sample of a copper alloy substrate was selected, first electrolyzed to remove oil, and then activated with 5% sulfuric acid to remove the surface oxide layer.

Put the sample into the low-phosphorus electroplating nickel-phosphorus solution (495g/L of nickel sulfamate, 10g/L of nickel chloride, 30g/L of sodium hypophosphite, 35g/L of boric acid, 40g/L of sulfamic acid), and control the temperature to 65 g/L. ℃, pH=1.2, under the conditions of pulse current density 20A/dm ² , duty cycle 0.2, frequency 10KHz, low phosphorus nickel (phosphorus content 1%) of about 0.1 μm was deposited on the surface by pulse electroplating.

Put the sample into high-phosphorus electroplating nickel-phosphorus syrup (nickel sulfamate 380g/L, nickel chloride 10g/L, sodium hypophosphite 70g/L, boric acid 35g/L, sulfamic acid 60g/L), control the temperature 65g/L ℃, pH=1.2, pulse current density 20A/dm ² , duty cycle 0.2, frequency 10KHz, high-phosphorus alloy with amorphous structure (phosphorus content 12%) was pulse-plated on the surface of the just-deposited low-phosphorus nickel coating, thickness 1μm .

Put the sample into the low-medium phosphorus electroplating nickel phosphorus solution (430g/L of nickel sulfamate, 10g/L of nickel chloride, 50g/L of sodium hypophosphite, 35g/L of boric acid, 55g/L of sulfamic acid), control The temperature is 65°C, pH=1.2, pulse current density is 20A/dm ² , duty cycle is 0.2, and frequency is 10KHz. Low-medium phosphorus nickel (4% phosphorus content) was pulse plated on the surface of the freshly deposited high phosphorus nickel coating with a thickness of 0.2 μm.

Put the sample into the electroplating gold-cobalt potion, and direct-current electroplating on 0.76μm gold-cobalt alloy.

In this way, a coating product 4 with three layers of chemical nickel phosphorus as the combined bottom coating layer is obtained.

Example 5

The same procedure as in Example 4 was repeated, but the pulse plating conditions were changed to: pulse current density of 10A/dm ² , duty cycle of 0.5, frequency of 20KHz, and the formation of low-phosphorus nickel plating, high-phosphorus alloy plating and low-medium phosphorus In the nickel plating step, a low-phosphorus nickel coating (thickness of about 0.1 μm) with a phosphorus content of 4%, a high-phosphorus alloy coating (thickness 1 μm) with a phosphorus content of 15%, and a low-medium phosphorus nickel layer with a phosphorus content of 8% are respectively formed Plating (thickness 0.2 μm), plating product 5 was obtained.

Example 6

A plated product 6 was obtained by repeating the same procedure as in Example 4, except that electroless nickel plating was used instead of the step of forming the pulse electroplating low-phosphorus nickel plated layer.

Comparative Example 1

A sample of a copper alloy substrate was selected, first electrolyzed to remove oil, and then activated with 5% sulfuric acid to remove the surface oxide layer.

Using the DC electroplating process, a single layer of nickel with a thickness of 1.27 μm was electroplated on the sample as the bottom coating, and then, it was placed in a cobalt-plated gold solution and electroplated with a gold-cobalt alloy of 0.76 μm to obtain a comparative coating product 1.

Comparative Example 2

A sample of a copper alloy substrate was selected, first electrolyzed to remove oil, and then activated with 5% sulfuric acid to remove the surface oxide layer.

Electroplating nickel-plated phosphorus solution (nickel sulfate 35g/L, sodium hypophosphite 20g/L, sodium acetate 6g/L, lactic acid 20ml/L, propionic acid 8ml/L, sodium dodecylbenzenesulfonate 0.04g/L, pH 5.5, temperature 75°C), a single-layer nickel-phosphorus alloy coating with a thickness of about 1.2 μm was electroplated on the sample through the DC electroplating process as the bottom coating, and then, put into the cobalt-plating gold solution, and electroplated with 0.76 μm of gold-cobalt alloy, Comparative Coated Product 2 was obtained.

Corrosion resistance test (salt spray test) and abrasion test were performed on the resultant coated products 1-6 and comparative coated products 1-2.

Corrosion resistance test conditions: Pour 500ml of nitric acid solution into a clean desiccator, seal it and let it stand for 30 minutes. Place the plated sample in a desiccator at a position 5cm above the liquid surface, so that the sample is fully exposed to the sealed nitric acid vapor. After 30 minutes, take out the sample and put it in a drying box at 125 degrees Celsius to dry for 30 minutes, and then put it under a microscope. The corrosion state of the sample surface was observed.

Abrasion test experimental conditions: apply a positive pressure of 50N on the top of the sample (flat plate) with a hemisphere of the same material, reciprocate back and forth 5cm, and observe the scratches on the surface of the sample under a microscope after 50 cycles.

The results show that on the surface of the comparative coating products 1-2, there are 15 corrosion points per square centimeter on average, and the surface of the coating products 1-6 has only 1 or 2 corrosion points. In addition, as shown in Fig. 3, the comparison coating product 1 has deeper scratches and wider scratch areas, while the coating products 1-6 have very shallow and slight scratches.

It should be understood that the present invention is not intended to be unduly limited by the exemplary embodiments and examples presented herein, which are provided by way of example only, and that the scope of the present invention is intended to be limited only by the appended claims.

Claims (15)

1. The utility model provides a many cladding material stack structure, it includes nickel phosphorus alloy combination cladding material, nickel phosphorus alloy combination cladding material includes from bottom to top in proper order: a low-phosphorus nickel-phosphorus alloy plating layer, a high-phosphorus nickel-phosphorus alloy plating layer, and a low-medium phosphorus nickel-phosphorus alloy plating layer, wherein the phosphorus content of the low-phosphorus nickel-phosphorus alloy plating layer is 0-4 wt%, the phosphorus content of the high-phosphorus nickel-phosphorus alloy plating layer is 9-20 wt%, and the phosphorus content of the low-medium phosphorus nickel-phosphorus alloy plating layer is 3-9 wt%.

2. The multiple plating layer stack structure of claim 1, wherein the difference in phosphorous content between adjacent plating layers in the nickel phosphorous alloy combination plating layer is 5 wt.% or more.

3. The multi-plating layer stack of claim 1, wherein the multi-plating layer stack further comprises an additional plating layer on the low-mid-phosphorous plating layer of the nickel phosphorous alloy combination plating layer.

4. The multiple plating stack structure of claim 3, wherein the additional plating layer comprises a single, double, or multiple layer metal plating, metal alloy plating, or phosphorous alloy plating, or a combination thereof.

5. The multi-plating stack structure of claim 4, wherein the metal plating comprises copper, nickel, gold, silver, tin, palladium, rhodium plating; the metal alloy plating layer comprises silver palladium, gold and silver, gold nickel, gold cobalt, palladium nickel, palladium cobalt, rhodium ruthenium, rhodium cobalt, rhodium palladium, nickel tungsten and nickel cobalt plating layers; the phosphorus-containing alloy coating comprises a nickel-phosphorus coating and a nickel-cobalt-phosphorus coating.

6. The multi-plating layer stack structure of claim 1, wherein the multi-plating layer stack structure further comprises a substrate, wherein the nickel phosphorous alloy combination plating layer is formed directly on the substrate.

7. The multi-plating layer stack structure of claim 1, wherein the multi-plating layer stack structure further comprises a substrate having an undercoat layer formed thereon, wherein a nickel-phosphorus alloy composite plating layer is formed on the undercoat layer.

8. The multiple plating stack structure of claim 7, wherein the base plating layer may be the same or different from the other plating layers, including a single layer, a double layer, or a multi-layer combination of metal plating, metal alloy plating, phosphorous alloy plating.

9. A method of making the multi-plating stack structure of any of claims 1-8, comprising: on the base material or on the bottom plating layer of the surface of the base material, a low-phosphorus nickel-phosphorus alloy plating layer with the phosphorus content of 0-4 wt%, a high-phosphorus nickel-phosphorus alloy plating layer with the phosphorus content of 9-20 wt% and a low-medium-phosphorus nickel-phosphorus alloy plating layer with the phosphorus content of 3-9 wt% are formed in sequence by using low-phosphorus nickel-phosphorus liquid medicine, high-phosphorus nickel-phosphorus liquid medicine and low-medium-phosphorus nickel-phosphorus liquid medicine.

10. The method of claim 9, wherein the low-phosphorous, high-phosphorous, and low-intermediate phosphorous nickel phosphorous alloy plating is formed using an electroless plating process.

11. The method of claim 9, wherein the low-phosphorous, high-phosphorous, and low-intermediate phosphorous nickel-phosphorous alloy plating is formed using a pulse plating process.

12. The method of claim 11, wherein the conditions of the pulse plating comprise: pulse current density of 1-100A/dm²Duty ratio of 0.1-0.5, and frequency of 1-100 KHz.

13. The method of claim 9, wherein the step of forming the low-phosphorous nickel-phosphorous alloy plating is replaced with electro-or electroless nickel plating.

14. Use of the multi-coating stack according to any of claims 1-8 in connectors and other industrial equipment, communication equipment, electronic equipment, household appliances, aerospace, automotive parts, sanitary and bathroom hardware products.

15. Use of a multi-layer stack according to any of claims 1-8 in the production of an electroplating process, including continuous plating, barrel plating and rack plating.

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