CN204585986U - Nickel plating-chromium parts - Google Patents

Abstract

The nickel-chromium plating part disclosed by the utility model, wherein the nickel-chromium plating part comprises a substrate; a pretreatment coating, which is deposited on the entire substrate, and a copper plating layer and a functional layer are formed on the pretreatment coating, which are formed on On the copper plating layer, wherein the functional layer includes a low-potential nickel layer and a microporous nickel layer formed on the low-potential nickel layer; and a decoration layer, which is formed on the microporous nickel layer. The utility model increases the low-potential nickel coating on the basis of the micropores and chrome-plating process on the surface of the component, thereby improving the corrosion resistance of the product, especially the corrosion resistance of the trivalent chrome-plated product, which can promote a more environmentally friendly trivalent Larger-scale promotion and application of chromium products.

Description

Nickel-chrome plated parts

technical field

The utility model relates to a workpiece with a surface electroplating layer structure and its electroplating technology, in particular to a nickel-chromium plating part.

In this application, the potential difference is the difference between the standard potentials measured by taking each of the two adjacent layers as a whole.

Background technique

The European market has increasingly stringent environmental protection requirements, and automobile factories have higher and higher requirements for electroplating corrosion resistance. At present, chromium electroplating cannot meet the corrosion requirements of specific environments (at the same time, it can meet the salt spray resistance test of 80h and the Russian mud resistance test. 336h).

In the electroplating industry, the method of firstly plating double-layer nickel or triple-layer nickel and then chromium plating is generally used to improve the anti-corrosion ability of the workpiece. The layer nickel process includes: semi-bright nickel + light nickel + microporous nickel + crack-free chromium, or semi-bright nickel + light nickel + micro-crack nickel + crack-free chromium, but due to the high stress of the chromium layer itself, it is difficult to obtain in industry A chromium electroplating layer (including hexavalent chromium and trivalent chromium plating) without cracks or pores at all. After the chromium electroplating layer exposed to the air is passivated, its potential is more positive than that of nickel. When it encounters a corrosive medium, it will It forms a corrosion battery with the nickel layer, causing corrosion of the nickel layer. In extreme environments, excessive corrosion will occur, resulting in large-scale peeling off of the surface chromium layer, which will affect the quality of the product. In order to further improve the anti-corrosion ability of the coating, microporous nickel and microcracked nickel are applied to the light nickel coating. Its function is to promote a large number of microcracks or micropores on the surface of the product through different plating processes, forming a large number of tiny Corrosion channels, so as to separate the corrosion points into points that cannot be recognized by the naked eye, reduce the shedding of the chrome layer, and improve the appearance quality during use. Due to the use of microporous nickel or microcracked nickel alone, the improvement of corrosion resistance is limited; and the combination of microcracks and trivalent chromium has problems such as poor appearance, resulting in inapplicability for products with high corrosion resistance requirements. At the same time, in some existing technologies, it is disclosed to change the microporous nickel process to achieve noble potential characteristics, so as to meet the corrosion resistance requirements of trivalent chromium, but this process technology cannot achieve collinear production with hexavalent chromium and trivalent chromium. All components meet high-quality corrosion-resistant requirements.

In the prior art, for example, the Chinese patent application (publication number: CN 101988211 A) relates to a multi-layer nickel plating process on metal surfaces with excellent anti-corrosion performance. The electroplating process flow is: A. metallization of the surface of plastic parts, B. bright copper , C. semi-bright nickel, D. high-sulfur nickel E. bright nickel, F. microporous nickel, G. washing, H. bright chromium, I. washing, J. drying; although the four-layer nickel is used in this technical scheme The electroplating of nickel electroplating solution on the plastic surface improves the corrosion resistance of plastic parts to a certain extent, but the corrosion resistance of this process still cannot meet the requirements of the corrosive environment containing deicing salt (CaCl ₂ ). And about the technique of introducing micro-crack nickel, as Chinese patent application (publication number: CN101705508A) relates to a kind of electroplating solution and application thereof for micro-crack nickel electroplating, the main composition of this micro-crack nickel electroplating solution is as follows: nickel chloride: 180-260 g/L, acetic acid: 20-60 mL/L, ELPELYT MR: 80-120 mL/L, 62A: 1-5 mL/L, the evaluation of the examples described in the patent literature is actually limited to hexavalent chromium plating , did not talk about trivalent chromium plating, and at the same time, it was verified that there were phenomena such as poor corrosion resistance and inconsistent appearance.

Utility model content

In order to solve the above problems, the utility model discloses a nickel-chromium plated part, which not only ensures the bright appearance of the microporous nickel layer by organically utilizing the corrosion resistance and electrochemical properties of the multilayer nickel structure of the functional layer, It also has the dual corrosion resistance of the functional layer containing microporous nickel, which can make the product achieve ultra-high corrosion resistance and structural stability. Even after the low-potential nickel layer is corroded, the microporous nickel layer can also support and delay corrosion. The effect of corrosion.

The nickel-chrome plated part disclosed by the utility model comprises:

Substrate: Here, the substrate of the utility model can adopt metal, plastic and other parts that can be applied to electroplating.

Pretreatment coating (pretreatment coating can include any one or two layers of chemical nickel layer or primer nickel layer, and there is no such layer on the substrate. The specific choice depends on the material of the substrate. When the chemical nickel layer When existing simultaneously with the bottoming nickel layer, then the chemical nickel layer is formed on the substrate, and the bottoming nickel layer is formed on the chemical nickel layer), which is deposited on the entire substrate, and a copper plating layer is formed on the pretreatment coating; and

A functional layer formed on the copper plating layer, wherein the functional layer includes a low-potential nickel layer and a microporous nickel layer formed on the low-potential nickel layer; and

A decorative layer is formed on the microporous nickel layer.

An improvement of the nickel-chromium plating parts disclosed in the utility model, the decorative layer is any one of trivalent chromium coating or hexavalent chromium coating, wherein the trivalent chromium coating can be trivalent white chromium coating or trivalent black chromium coating or Other types of trivalent chromium coatings. Among them, a passivation film can also be formed on the trivalent chromium plating layer.

An improvement of the nickel-chromium plating part disclosed in the utility model, the potential difference between the microporous nickel layer and the low potential nickel layer is 10-120mV.

An improvement of the nickel-chrome plated parts disclosed in the utility model, the low-potential nickel layer includes a high-sulfur nickel layer and a composite of one layer or two layers of the micro-cracked nickel layer. Further preferably, the potential difference between the microporous nickel layer and the low potential nickel layer is 20-00mV.

When the low-potential nickel layer adopts the composite coating of the micro-cracked nickel layer and the high-sulfur nickel layer, the potential difference between the micro-cracked nickel layer and the high-sulfur nickel layer is within 10-80mV. Here, when the corrosion reaches the low-potential nickel layer, since the potential of the micro-cracked nickel layer is higher than that of the high-sulfur nickel layer, the high-sulfur nickel layer is preferentially corroded as an anodic coating, prolonging the corrosion of the micro-cracked nickel layer, thereby Further improved corrosion resistance.

The manufacturing method of the nickel-chromium plating part disclosed by the utility model comprises the following steps:

Pretreating the surface of the substrate;

depositing a pretreatment coating over the entire substrate, and forming a copper plating layer on the pretreatment coating; and

forming a low potential nickel layer in the functional layer on the copper plating layer; and

Forming the microporous nickel layer in the functional layer on the low potential nickel layer; the potential difference between the microporous nickel layer and the low potential nickel layer is in the range of 10-120mV;

A decorative layer is formed on the microporous nickel layer. Controlling the potential difference within this range will prevent bubbling during the electroplating process, and at the same time, the coating structure will be more stable and firm, and it will not be easy to separate and peel off. Here, the cooperation between the low-potential nickel layer and the copper-plated layer is to directly electroplate the low-potential nickel layer on the copper-plated layer without doping other plating layers in between.

An improvement of the manufacturing method of nickel-chromium plating parts disclosed in the utility model, the decorative layer is any one of trivalent chromium coating or hexavalent chromium coating, wherein the trivalent chromium coating can be trivalent white chromium coating or trivalent black Chrome plating or other types of trivalent chromium plating.

An improvement of the manufacturing method of nickel-chromium plating parts disclosed in the utility model, the decorative layer is a trivalent white chromium coating, and the trivalent white chromium coating is formed by electroplating with a trivalent white chromium plating solution, and the trivalent white chromium plating solution is electroplated. Including ingredients and concentration (addition amount per unit volume of plating solution): 90-150g/L of aqueous chromium chloride, 50-100g/L of potassium formate, 8-25g/L of ammonium bromide, 40-60g/L of ammonium chloride , potassium chloride 40-100g/L, sodium acetate 10-60g/L, boric acid 40-80g/L, wetting agent 0.5-2.5ml/L.

An improvement of the manufacturing method of the nickel-chromium plating parts disclosed in the utility model, the decorative layer is a trivalent black chromium coating, and the trivalent black chromium coating is formed by electroplating with a trivalent black chromium plating solution, and the trivalent black chromium plating solution Including ingredients and concentration (addition amount per unit volume of plating solution): 150-250g/L of aqueous chromium chloride, 2-5g/L of oxalic acid, 3-10g/L of ammonium acetate, 20-40g/L of ammonium chloride, boric acid 20-41g/L, additive 0.5-3g/L.

An improvement of the manufacturing method of nickel-chromium plating parts disclosed in the utility model, the decorative layer is a hexavalent chromium coating, and the hexavalent chromium coating is formed by electroplating with a hexavalent chromium plating solution, which includes components and concentrations For (addition amount per unit volume of plating solution): chromic anhydride 260-360g/L, sulfuric acid 0.5-3g/L, decorative chrome brightener 1-4g/L, chrome mist inhibitor 0.1-0.4ml/L.

The first aspect of the present utility model provides a nickel-plated part, which includes the following: a base material; a pretreatment coating (can include any one of the chemical nickel layer and the bottom nickel layer or a combination of the two), which is formed on the entire base material; The copper layer is formed on the pretreatment plating layer; the functional layer is formed on the copper layer, wherein the functional layer includes a low-potential nickel layer and a microporous nickel layer formed on the low-potential nickel layer. The low-potential nickel layer is formed on the copper-plated layer; and the microporous nickel layer in the functional layer is formed on the low-potential nickel layer; wherein the potential difference between the microporous nickel layer and the low-potential nickel layer is in the range of 10-120mV and a decorative layer (either of trivalent white chromium plating or trivalent black chromium plating or hexavalent chromium plating), which is formed on the microporous nickel plating and has at least any one of a microporous structure and a microcrack structure .

There are two ways to cooperate the low-potential nickel layer with the copper-plated layer. One is to directly electroplate the low-potential nickel layer on the copper-plated layer without doping other plating layers in the middle, and the other is to indirect electroplate the low-potential nickel layer. On the copper plating layer, that is to say, other plating layers can be electroplated between the low-potential nickel layer and the copper plating layer, which is generally called the basic plating layer. Here, the basic plating layer can be electroplated with full-gloss nickel, semi-gloss nickel, and satin nickel. Or high-sulfur nickel and other corresponding coatings.

A second aspect of the present invention provides a method for manufacturing a nickel-chrome plated part, which includes the following steps: pretreating the surface of the substrate; depositing a pretreated coating on the entire substrate, and forming a copper plating layer on the pretreated and the low-potential nickel layer in the functional layer is formed on the copper-plated layer; and the microporous nickel layer in the functional layer is formed on the low-potential nickel layer; the microporous nickel layer and the low-potential nickel layer The potential difference between them is in the range of 10-120mV; the decoration layer is formed on the microporous nickel layer.

An improvement of the manufacturing method of the nickel-chrome plated parts disclosed in the utility model, the low-potential nickel layer includes a high-sulfur nickel layer and a composite of one or two layers of the micro-cracked nickel layer.

An improvement of the manufacturing method of the nickel-chrome plated parts disclosed in the utility model, in the foregoing microporous nickel layer plating process, the microporous nickel layer is formed by electroplating with a microporous nickel plating solution, and the microporous nickel plating solution includes components And the concentration is: hydrated nickel sulfate 300-350g/L, hydrated nickel chloride 50-60g/L, boric acid 40-50g/L, nickel seal brightener 6-12ml/L (Konson Lesi Chemical Trading (Shanghai) Co., Ltd. Hereinafter referred to as Lesi, MacDermid Technology (Suzhou) Co., Ltd. hereinafter referred to as MacDermid, such as Lesi’s 63 and Macderma’s NIMAC 14 INDEX), nickel sealant main light agent 4-7.5ml/L (such as Lesi’s 610CFC and Macdermid’s NIMAC 33), nickel-sealed particles 0.2-1.5g/L (such as Lesi’s ENHANCER and Macdermid’s NiMac Hypore XL dispersant), nickel-sealed particle dispersant 0.5-3ml/L, wetting agent 1- 5ml/L. When the microporous nickel layer is plated, the operating temperature is controlled between 50-60°C, the pH value is controlled between 3.8-4.6, the current density is 2-5ASD, and the operating time is controlled between 2-8min, through direct current electrolysis. The nickel is deposited on the electroplated parts, and the thickness of the microporous nickel layer is not less than 1.5 microns.

An improvement of the manufacturing method of the nickel-chromium plating parts disclosed in the utility model, in the microcrack nickel layer plating process in the aforementioned low potential nickel layer plating process, the microcrack nickel layer is formed by electroplating with a microcrack nickel plating solution, Micro-crack nickel plating solution includes components and concentrations (addition per unit volume of the plating solution): aqueous nickel chloride 180-260g/L, acetic acid 20-60ml/L, PN-1A 40-90g/L, PN-2A 1~5ml/L, wetting agent 1~5ml/L. Wetting agents such as Lesi's 62A and MacDermid's NIMAC 32C WETTER. When the micro-cracked nickel layer is plated, the process temperature is controlled between 25-35°C, the pH is controlled between 3.6-4.6, the current density is 5-9ASD, and the operation time is controlled between 2-8min, through direct current electrolysis. The nickel is deposited on the surface of the electroplated part, and the thickness of the micro-cracked nickel layer is not less than 1.0 micron.

An improvement of the manufacturing method of nickel-chromium plating parts disclosed in the utility model, in the process of plating high-sulfur nickel layer in the process of plating low-potential nickel layer, the high-sulfur nickel layer is formed by electroplating with high-sulfur nickel plating solution, The high-sulfur nickel plating solution includes components and concentrations (addition amount per unit volume of the plating solution): hydrated nickel sulfate 250-350g/L, hydrated nickel chloride 35-60g/L, boric acid 35-65g/L, high-sulfur additives 3-10ml/L, wetting agent 0.5--3ml/L. Wetting agents such as Lesi's 62A and MacDermid's NIMAC 32C WETTER. When the high-sulfur nickel layer is plated, the temperature is controlled between 55-65°C, the pH is controlled between 2.0-3.5, the current density is 2-6ASD, and the operating time is controlled between 2-8min. Nickel is deposited on the surface of the electroplated part, and the thickness of the high-sulfur nickel layer is not less than 1.0 microns

In the above-mentioned manufacturing method, it also includes the pre-treatment process of the base material, wherein the pre-treatment process of the non-metal base material including ABS resin at least includes the surface oil treatment process, the surface hydrophilic, the surface roughening process, Surface neutralization treatment process, surface pre-dipping, surface activation treatment process and surface debonding treatment process; and metal substrates can be followed by subsequent plating after degreasing in the surface grease treatment process, and the non- The corresponding process in the pre-treatment process of the metal foundation.

In the above-mentioned manufacturing method, the pre-treatment process of the non-metallic substrate is specifically to wash the substrate blank in a mixed solution of sodium hydroxide, sodium carbonate and sodium silicate to remove grease, and then immerse it in a mixed solution of chromic anhydride and sulfuric acid surface roughening treatment in a hydrochloric acid solution, then surface neutralization in a hydrochloric acid solution, surface activation treatment with a colloidal palladium solution after neutralization, and surface degumming treatment in a sulfuric acid solution.

As preferably, composition and concentration are included in the mixed solution of surface grease treatment step: the concentration of sodium hydroxide is 20-50g/L, the concentration of sodium carbonate is 10-40g/L, the concentration of sodium silicate is 10-40g/L L, surfactant 1-3g/L.

Here, the surface degreasing step can remove oil and other impurities on the surface of the substrate, promote uniform surface roughening, and improve the bonding force of the coating.

Preferably, the concentration of the sulfuric acid solution in the surface hydrophilic step is 20-100g/L, and the finishing agent is 0.5-2ml/L.

Preferably, the components and concentrations included in the mixed liquid in the surface roughening treatment step are: the concentration of chromic anhydride is 330-480 g/L, and the concentration of sulfuric acid is 330-480 g/L.

Here, chromic anhydride is the main salt in the plating solution. Through the mechanism of oxidation-reduction reaction and electron gain and loss, metal chromium is deposited on the surface of the substrate and chromium trioxide hydrate is produced, which makes the coating black. The deep-plating ability has a great influence. If the content of chromic anhydride is high, the deep-plating ability will be strong and the crystallization will be fine. The surface of the substrate is to form a microscopic rough surface on the surface of the substrate to ensure the "locking effect" required for electroless plating, thereby improving the bonding force between the surface of the substrate and the coating. However, sulfate radicals will reduce the color properties of the coating and make the coating yellow. In order to corrode the surface of the substrate and reduce harmful effects at the same time, it is necessary to precisely configure the content of sulfuric acid.

Preferably, the concentration of the hydrochloric acid solution in the surface neutralization process is 30-100ml/L, and the concentration of hydrazine hydrate is 15-60ml/L.

Preferably, the concentration of the hydrochloric acid solution in the surface pre-soaking process is 40-120ml/L.

Preferably, the colloidal palladium solution for surface activation treatment includes components and concentrations: the concentration of palladium chloride is 20-60ppm, the concentration of stannous chloride is 1-6g/L, and hydrochloric acid is 180-280ml/L.

Here, in the colloidal palladium solution, palladium chloride covers the surface of the substrate to provide a catalytic center for the subsequent chemical nickel, while the tin ions of stannous chloride can be deposited around the palladium ion as a compound group to prevent the palladium ion from Oxidation and shedding in water or air can increase the service life of the colloidal palladium solution.

Preferably, the concentration of the sulfuric acid solution in the surface degumming treatment process is 40-100 g/L.

Surface degelling treatment refers to the use of sulfuric acid to remove the stannous chloride coated around the palladium oxide in the colloidal palladium solution, exposing the metal palladium particles, making the subsequent chemical nickel deposition process smoother.

As preferably, include composition and concentration in the electroless nickel layer plating solution of chemical nickel layer process: the concentration of nickel sulfate is 15-40g/L, and the concentration of sodium hypophosphite is 20-50g/L, and the concentration of sodium citrate is 10 -4g/L, ammonium chloride 10-50g/L, ammonia water, for pH adjustment, PH=8.6-9.2.

Electroless nickel deposition here refers to the deposition of a thin conductive layer on the metal palladium with catalytic activity on the surface of the substrate, which is convenient for subsequent electroplating of various metals. In the electroless nickel deposition process, nickel sulfate provides nickel elements; sodium hypophosphite is strong A reducing agent, which reduces the nickel element in the nickel sulfate to metallic nickel; sodium citrate is a buffer, which makes the reaction of sodium hypophosphite reduce the nickel element more gentle. In the utility model, sodium citrate is used as the buffer .

As preferably, include composition and concentration in the bottoming nickel plating solution of laying nickel plating step: the concentration of aqueous nickel sulfate is 180-280g/L, the concentration of aqueous nickel chloride is 35-60g/L, the concentration of boric acid is 35-60g/L, wetting agent 1-3ml/L.

When the chemical nickel layer and the bottoming nickel layer exist on the substrate at the same time, the substrate has been covered with a thin conductive nickel layer through the oxidation-reduction reaction in the chemical nickel deposition; In nickel, a layer of nickel is plated on the chemical nickel by electrochemical method to further enhance the conductivity of the coating. In this step, the hydrated nickel sulfate and hydrated nickel chloride provide the nickel ions required for the electrochemical reaction.

As preferably, each component and concentration are in the copper plating layer bath of copper plating layer process: the concentration of copper sulfate is 160-260g/L, the concentration of sulfuric acid is 50-100g/L, and chloride ion is 40-100ppm, the whole Leveling agent 0.2-1ml/L, moving agent 0.2-1ml/L, cylinder opening agent 2-10ml/L.

The purpose of the copper plating layer here is to use the characteristics of copper sulfate to improve the brightness and smoothness of the substrate surface, and also to improve the overall toughness of the plating layer. This is because copper plating has better ductility than nickel plating and other metal plating, so after the acid copper layer is plated, the toughness and leveling of the overall plating are improved.

Micro-crack nickel plating refers to plating a layer of uniform coating containing countless cracks on the surface of the substrate, which can disperse the corrosion current and reduce the corrosion current density. Microporous nickel plating refers to plating a layer of uniform coating containing countless cracks on the surface of the substrate. A coating of non-conductive particles can further disperse the corrosion current, reduce the corrosion current density, and comprehensively improve the corrosion resistance of the coating.

In the steps of electroless nickel plating and primer nickel plating, the pre-plating nickel layer mainly plays an auxiliary role, during which boric acid can not only act as a stabilizer but also the main blackening agent of the plating solution, which can improve the covering ability and deep plating ability of the plating solution , improve the density of the coating.

Wherein, when the low-potential nickel layer adopts a single micro-cracked nickel layer or a composite nickel layer composed of a high-sulfur nickel layer and a micro-cracked nickel layer, the utility model can achieve the best corrosion resistance effect. Here, the micro-cracked nickel layer in the functional layer The reason why the microporous nickel layer or the combination of the two can prevent corrosion and protect the substrate is that the plating metal/base metal on the workpiece is extremely easy to form a corrosion cell, and the corrosion rate is determined by the plating layer The metal (cathode) surface is controlled by the ratio of the substrate metal (anode) exposed area. When there is only one corrosion point, the cathode/anode ratio is the largest at this time, the corrosion current is concentrated at this point, the corrosion rate becomes very large, and it is easy to form pitting corrosion inward, but when there are more potential corrosion points on the surface of the metal coating At the corrosion point, the cathode/anode ratio is small, the corrosion current is distributed everywhere, the current on the original corrosion point is significantly reduced, and the corrosion rate is also greatly reduced. At the same time, due to the division between micropores or cracks, the cathode of the coating is discontinuous, and the divided coating changes from a large area to a small area, which further limits the cathode/anode ratio. However, as time goes on, when the coating surface is affected by external factors and large cracks begin to appear, the potential corrosion cells of micro-cracks and micro-porous structures will be triggered, thereby protecting the corrosion points, so that it can be It plays the role of dual core to reduce the corrosion current density, thus greatly improving the corrosion resistance.

Anticorrosion Mechanism of Low Potential Nickel

Step 1: When removing the corrosive medium on the surface of the part, due to the presence of a highly corrosion-resistant passivation layer on the decorative layer (such as the chromium layer), micropores on the surface of the chromium layer exist, which guide the corrosion of the nickel layer at the micropores to expand. The discontinuity of the pores leads to the fact that the corrosion is divided into many areas when the total amount of corrosion remains unchanged, so the corrosion proceeds without affecting the appearance. .

Step 2: When the corrosion reaches the low-potential nickel layer, since the potential of the microporous nickel is higher than that of the low-potential nickel, the low-potential nickel is preferentially corroded as an anodic coating (that is, the low-potential nickel layer is preferentially used as a sacrificial layer), and the micro Corrosion in the porous nickel is stopped. Under the action of a large number of discontinuous micro-cracks, the corrosion is guided to develop simultaneously in the depth and lateral direction of the cracks, and the area of the corroded nickel layer will be greatly increased and discontinuous. Under the condition of a certain corrosion current, these "micro-pores" are greatly dispersed. The corrosion current reduces the single point corrosion rate again, delays the corrosion rate, and protects the chromium layer on the appearance surface and the microporous nickel layer attached to it, further improving the corrosion resistance of the product surface.

Step 3: When the corrosion extends further downward in the low-potential nickel layer, since the potential of the plating layer (such as copper plating layer) under the low-potential nickel layer is also higher than that of low-potential nickel, the low-potential nickel is also regarded as an anodic coating. At this time, the corrosion extending downward is terminated, and the corrosion direction is carried out horizontally in the low-potential nickel, which further delays the time for corrosion to the substrate and greatly reduces the corrosion speed.

Compared with the prior art, the utility model has the advantages of:

1. The utility model lays the foundation for the subsequent electroplating of the low-potential nickel layer and the microporous nickel layer after the pre-treatment process of the substrate workpiece, and the process is stable and the compatibility is reasonable;

2. The microporous nickel layer and low-potential nickel layer obtained by electroplating the surface of the base material of the utility model have the advantages of high corrosion resistance, high hardness, high wear resistance, good bonding force of the coating, and high brightness; at the same time, it has the advantages of high potential characteristic microporous nickel layer and multilayer nickel with low potential characteristics - the low potential nickel layer is the functional layer, and the low potential nickel layer is used as the sacrificial layer, and the microporous nickel layer with microporous structure can disperse electrochemical corrosion The micro-current can delay the occurrence of corrosion, and at the same time, it can also support the formation of oxides after oxidation through the microporous structure, which can form a support for the low-potential nickel layer as a sacrificial layer after it is corroded more severely, reducing parts Coating damage rate. The low-potential nickel layer set as a sacrificial layer has a lower potential. When electrochemical corrosion occurs on the surface coating of the part, the low-potential nickel layer corrodes preferentially, and when there is a microporous nickel layer or a microcracked nickel layer, its micropores Or the micro-crack structure can also disperse the corrosion micro-current, and at the same time, when there is an outer layer structure outside the low-potential nickel layer (such as a decorative layer or a protective layer), the outer structure can also be supported by the micro-pore or micro-crack structure. Enhance the stability of the material structure. In addition, the utility model scheme utilizes the pore structure of microporous nickel and microcracked nickel, which can reduce the quality of the coating and reduce the consumption of raw materials while enhancing the structural support performance of the material. At the same time, its microporous structure can also form a large-area oxide film structure when oxidation and corrosion occur, thereby greatly delaying the occurrence of corrosion.

3. In addition, the utility model chooses the plating solution that has little impact on the environment as much as possible when selecting the formula, so that the electroplating process is more environmentally friendly. Further, the plating layer is firmly bonded, evenly distributed, and has a longer service life, so that the final product can be used both in appearance and The performance can meet the requirements of users, so that the technology obtained by the utility model has higher market competitiveness.

Description of drawings

Fig. 1 is the coating structure schematic diagram of the embodiment of nickel-chromium plating part of the present invention.

Fig. 2 potential difference picture of the single low-potential nickel layer of the utility model (the low-potential nickel layer is either a high-sulfur nickel layer or a micro-crack nickel layer).

Fig. 3 potential difference picture of composite low-potential nickel layer of the utility model (low-potential nickel layer is a composite layer of high-sulfur nickel layer and micro-crack nickel layer).

Fig. 4 multilayer nickel corrosion schematic diagram of the utility model (using ABS as the part base material).

List of reference signs:

1. Substrate; 2. Pretreatment coating;

4. Functional layer; 141. Low potential nickel layer; 142. Microporous nickel layer;

801. Corrosion medium; 802. Decorative layer; 805. Corrosion surface;

808. Primer nickel layer; 809. Chemical nickel layer; 810. ABS substrate.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, further illustrate the utility model, it should be understood that following specific embodiment is only for illustrating the utility model and is not used for limiting the scope of the utility model, and the substrate of the utility model can adopt metal, plastics here And other parts that can be applied to electroplating.

As shown in Figure 1, the coating structure of the nickel-chromium-plated part of the present invention will be described below.

Structural Example 1

The nickel-chromium plating part of the present embodiment, this part comprises: base material 1 (ABS material); Pretreatment plating layer 2 comprises chemical nickel layer 809, makes a bottom nickel layer 808 and copper-plated layer 3, and chemical nickel layer deposits 809 to deposit on On the whole substrate 1, a bottoming nickel layer 808 is deposited on the chemical nickel layer 809, and a copper plating layer 3 is formed on the bottoming nickel layer 808; and a functional layer 4, which is formed on the copper plating layer 3, wherein the functional layer 4 comprising a low-potential nickel layer 141 and a microporous nickel layer 142, wherein the low-potential nickel layer 141 is a high-sulfur nickel layer, the microporous nickel layer 142 formed on the high-sulfur nickel layer; and the microporous nickel layer 142 formed on the microporous nickel layer 142 Decorative layer 802 (trivalent white chrome plating).

Structural Example 2

The nickel-chromium plating part of the present embodiment, this part comprises: base material 1 (ABS material); Pretreatment plating layer 2 comprises chemical nickel layer 809, makes a bottom nickel layer 808 and copper-plated layer 3, and chemical nickel layer deposits 809 to deposit on On the whole base material 1, a bottoming nickel layer 808 is deposited on the chemical nickel layer 809, and a copper plating layer 3 is formed on the bottoming nickel layer 808; and a functional layer 4, which is formed on the copper plating layer 3, wherein the function Layer 4 comprises a low-potential nickel layer 141 and a microporous nickel layer 142, wherein the low-potential nickel layer 141 is a microcracked nickel layer, formed on the microporous nickel layer 142 on the microcracked nickel layer; and formed on the microporous nickel layer 142 The decorative layer 802 (trivalent black chromium plating).

Structural Example 3

The nickel-chromium plating part of the present embodiment, this part comprises: base material 1 (ABS material); Pretreatment plating layer 2 comprises chemical nickel layer 809, makes a bottom nickel layer 808 and copper-plated layer 3, and chemical nickel layer deposits 809 to deposit on On the whole substrate 1, a bottoming nickel layer 808 is deposited on the chemical nickel layer 809, and a copper plating layer 3 is formed on the bottoming nickel layer 808; and a functional layer 4, which is formed on the copper plating layer 3, wherein the functional layer 4 includes a low-potential nickel layer 141 and a microporous nickel layer 142, wherein the low-potential nickel layer 141 is a high-sulfur nickel layer and a micro-crack nickel layer (it may be that the high-sulfur nickel layer is formed on the copper plating layer 3, and the micro-crack nickel layer is formed On the high-sulfur nickel layer; it can also be that the micro-crack nickel layer is formed on the copper-plated layer 3, the high-sulfur nickel layer is formed on the micro-crack nickel layer), and the micro-porous nickel layer 142 formed on the low-potential nickel layer 141; And a decorative layer 802 (hexavalent chromium plating) formed on the microporous nickel layer 142 .

Structural Example 4

The nickel-chromium plating part of the present embodiment, this part comprises: base material 1 (ABS material); Copper-plated layer 3 is formed on the chemical nickel layer 809; And functional layer 4, it is formed on the copper-plated layer 3, wherein functional layer 4 comprises low-potential nickel layer 141 and microporous nickel layer 142, wherein low-potential nickel layer 141 is A high-sulfur nickel layer, a microporous nickel layer 142 formed on the high-sulfur nickel layer; and a decorative layer 802 (hexavalent chromium plating layer) formed on the microporous nickel layer 142 .

Structural Example 5

The nickel-chrome plated part of the present embodiment, this part comprises: base material 1 (ABS material); , a copper-plated layer 3 is formed on the underlying nickel layer 808; and a functional layer 4 is formed on the copper-plated layer 3, wherein the functional layer 4 includes a low-potential nickel layer 141 and a microporous nickel layer 142, wherein the low-potential nickel Layer 141 is a microcracked nickel layer, a microporous nickel layer 142 formed on the microcracked nickel layer; and a decorative layer 802 (trivalent white chrome plating) formed on the microporous nickel layer 142 .

Structural Example 6

The nickel-chromium plating part of the present embodiment, this part comprises: base material 1 (ABS material); Pretreatment plating layer 2 comprises copper plating layer 3, is directly formed with copper plating layer 3 on base material 1; And functional layer 4, It is formed on the copper plating layer 3, wherein the functional layer 4 includes a low-potential nickel layer 141 and a microporous nickel layer 142, wherein the low-potential nickel layer 141 is a high-sulfur nickel layer and a micro-crack nickel layer (which can be formed by a high-sulfur nickel layer On the copper-plated layer 3, the micro-cracked nickel layer is formed on the high-sulfur nickel layer; it may also be that the micro-cracked nickel layer is formed on the copper-plated layer 3, and the high-sulfur nickel layer is formed on the micro-cracked nickel layer), formed on the function The microporous nickel layer 142 on the layer 4; and the decorative layer 802 (trivalent black chromium plating layer) formed on the microporous nickel layer 142 .

The only difference between structural examples 7-12 and structural examples 1-6 is that the base material 1 is made of pp material;

The only difference between Structural Examples 13-18 and Structural Examples 1-6 is that the substrate 1 is made of nylon nylon;

The only difference between structural examples 19-24 and structural examples 1-6 is that the base material 1 is made of pc;

The only difference between structural examples 25-30 and structural examples 1-6 is: the base material 1 is made of pet material;

The only difference between Structural Examples 31-36 and Structural Examples 1-6 is that the substrate 1 is bakelite;

The only difference between structural examples 37-42 and structural examples 1-6 is that the base material 1 is cast iron (including but not limited to gray cast iron, white cast iron, nodular cast iron, vermicular cast iron, malleable cast iron and alloy cast iron, etc.) material;

The only difference between Structural Examples 43-48 and Structural Examples 1-6 is that the substrate 1 is made of steel (including various common steels, stainless steel, etc.), aluminum alloy, and magnesium alloy;

The material of the base material 1 adopted in the technical solution of the utility model can also be other materials that can be used for plating copper, nickel, and chrome coatings on its surface.

The solvent of the solution in the embodiment of the utility model is water (including but not limited to distilled water, deionized water, low hardness water, etc.) unless otherwise specified, and the concentration is measured by the solution per unit volume or mass.

The base material of the parts in the following examples is preferably made of ABS.

Preparation Examples 1-5

The manufacturing method of the nickel-chrome plated part of an embodiment of the present invention is as follows, the surface of the substrate is pretreated (the pretreatment includes the following steps in sequence: surface degreasing, surface hydrophilic treatment, surface roughening treatment, surface middle and treatment, pre-dipping, surface activation treatment, surface debonding treatment); the pre-treatment coating (including electroless nickel and primer nickel, in addition to whether the pre-treatment coating is retained and the selection of the composition of the pre-treatment coating depends on the material of the substrate and Flexible selection of process product requirements) deposited on the entire substrate, the chemical nickel layer and the bottom nickel layer formed from the surface of the substrate in sequence, and the copper plating layer is formed on the pretreatment coating (outside the bottom nickel layer) and the low-potential nickel layer in the functional layer is formed on the copper-plated layer, where the low-potential nickel layer is a high-sulfur nickel layer; and the microporous nickel layer in the functional layer is formed on the high-sulfur nickel layer; and The decoration layer is formed on the microporous nickel layer, wherein the decoration layer is a trivalent white chromium plating layer.

The potential difference between the microporous nickel layer and the high-sulfur nickel layer (low-potential nickel layer) is any of 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120mV or 10 Other arbitrary values in the range of -120 (embodiments 1-5 can select different numerical values in 10-120 respectively to be the potential difference between the microporous nickel layer and the low-potential nickel layer in the corresponding embodiment, the microporous nickel layer in each embodiment The potential difference with the low-potential nickel layer may also be the same). The microporous nickel layer is a nickel layer that is uniformly plated on the surface of the product and contains countless non-conductive particles and conductive particles, so that the surface of the ABS substrate workpiece has high corrosion resistance, high hardness, high wear resistance, and the coating is combined Good strength, high brightness and other advantages.

The method for electroplating on the above-mentioned parts comprises the steps:

(1) Surface degreasing: cleaning treatment in a mixed solution of sodium hydroxide NaOH, sodium carbonate Na ₂ CO ₃ , sodium silicate Na ₂ SiO ₃ and surfactant. In this step, the concentration ratio of each component in different embodiments in the mixed solution is shown in Table 1: the surfactant is a common surfactant such as sodium dodecylsulfonate, sodium octadecylsulfonate, etc.

Table I

(2) Surface hydrophilic treatment: carried out in a mixed solution of sulfuric acid and finishing agent. In this step, the concentration ratio of sulfuric acid and surface finishing agent in different embodiments is shown in Table 2:

Table II

(3) Surface roughening treatment: carried out in a mixed solution of chromic anhydride CrO ₃ and sulfuric acid H ₂ SO ₄ . In this step, the concentration ratios of chromic anhydride CrO3 and sulfuric _{acid H2SO4} in different embodiments are shown in Table ₃ :

Table three

(4) Surface neutralization treatment: put the roughened substrate into a mixed solution of hydrochloric acid and hydrazine hydrate. In this step, the concentration ratios of hydrochloric acid and hydrazine hydrate solutions in different embodiments are shown in Table 4:

Table four

(5) Surface pre-soaking: the base material after surface neutralization treatment is carried out in hydrochloric acid solution. In this step, the concentration ratio of hydrochloric acid solution in different embodiments is shown in Table 5:

Table five

(6) Surface activation treatment: surface activation treatment adopts colloidal palladium solution, and the concentration ratios of palladium chloride PdCl ₂ , stannous chloride SnCl ₂ and hydrochloric acid in different embodiments in the colloidal palladium solution are shown in Table 6:

Table six

(7) Surface degumming treatment: carried out in sulfuric acid H ₂ SO ₄ solution. In this step, the concentration ratio of sulfuric acid solution in different embodiments is shown in Table 7:

Table seven

(8) Chemical nickel precipitation: in a mixed solution containing nickel sulfate hydrate, sodium hypophosphite hydrate, sodium citrate C ₆ H ₅ Na ₃ O ₇ , ammonium chloride and ammonia water (ammonia water is used to adjust the pH of the solution to 8.6-9.2) in progress. In this step, the concentration ratio of each component in the mixed solution in different embodiments is shown in Table 8:

table eight

(9) Primer nickel plating: carried out in a mixed solution containing aqueous nickel sulfate Ni ₂ SO ₄ -6H ₂ O, aqueous nickel chloride NiCl ₂ -6H ₂ O, boric acid H ₃ BO ₃ and a wetting agent. In this step, the concentration ratio of each component in the mixed solution in different embodiments is shown in Table 9: the wetting agents in Table 9 are 62A from Rustica and NIMAC 32C WETTER from MacDermid.

Table nine

(10) Copper plating layer: carried out in a mixed solution of copper sulfate CuSO ₄ , sulfuric acid H ₂ SO ₄ , chloride ions, leveling agent, positioning agent and cylinder opener. See Table 10 for the concentration ratio of the various components of the solution in different embodiments: Among them, the leveling agent, positioning agent, and cylinder opening agent can be selected from the 1560 acid copper additive series of Schleich.

table ten

(11) A high-sulfur nickel layer (low-potential nickel layer) and a microporous nickel layer are plated in sequence. Among them, in the process steps of microporous nickel plating and high-sulfur nickel plating, the main components of the plating solution are the same, which are aqueous nickel sulfate Ni ₂ SO ₄ -6H ₂ O, aqueous nickel chloride NiCl ₂ -6H ₂ O and boric acid H ₃ BO ₃ Mix the solution. The concentration ratios of microporous nickel plating and high-sulfur plating in different examples are shown in Table 11 and Table 12 respectively. The particle carrier is ENHANCER from Schleich. The wetting agents in Table 11 and Box 12 are Rosuria's 62A and MacDermid's NIMAC 32C WETTER.

Table 11 (microporous nickel plating)

Table 12 (high sulfur nickel plating)

(12), plating decorative layer, electroplating in the trivalent white chromium plating solution, each composition of solution is shown in Table 13 in the concentration ratio of different embodiments:

Table 13 (trivalent white chromium plating)

The CASS test of the above examples reaches 96-120 hours or more, and the corrosion paste test reaches a stability of more than 336 hours.

The only difference between Embodiments 6-10 and Embodiments 1-5 is that the low-potential nickel layer includes a nickel layer with microcracks, and the decorative layer is a trivalent black chromium plating layer. And corresponding micro-crack nickel layer plating solution adopts the plating solution shown in Table 14, and the corresponding trivalent black chromium plating solution adopts the plating solution shown in Table 15, wherein the wetting agent is a common surfactant, such as 10 Sodium dialkylsulfonate, sodium octadecylsulfonate, etc. The wetting agents in Table 14 are 62A from Rosuria and NIMAC 32C WETTER from MacDermid.

Table 14 (Microcrack Nickel Plating)

Table 15 (trivalent black chromium plating)

The only difference between Preparation Examples 11-15 and Preparation Examples 1-5 is that the low-potential nickel layer includes a high-sulfur nickel layer (each embodiment plating solution is correspondingly shown in Table 12 in sequence), micro-cracked nickel layer (each embodiment plating solution is correspondingly referring to shown in Table 14 successively) the composite between two layers, and this moment, potential difference is 10,20,30,40,50 between the microcrack nickel layer and the high-sulfur nickel layer , any one of 60, 70, 80 or any value in the range of 10-80 mV; the decorative layer is hexavalent chromium plating, and the corresponding plating solution of hexavalent chromium plating adopts the plating solution shown in Table 16 below, in which the decorative chromium is bright The agent can be 1120F of Rosuria and 7000C of Nippon Metal Chemical Industry.

Table 16 (hexavalent chromium plating)

The only difference between Preparation Examples 16-30 and Preparation Examples 1-15 is that the nickel sealing brightener is Macdermid’s NIMAC 14 INDEX; the nickel sealing main brightening agent is Macdermid’s NIMAC 33; Midea NiMac Hypore XL dispersant.

The only difference between Preparation Example 31-60 and Preparation Example 1-30 is that the microporous nickel plating solution also includes microporous powder particles 0.3-0.8ml/L (in this embodiment about microporous powder particles The dosage can choose any value: 0.3, 0.32, 0.33, 0.34, 0.37, 0.39, 0.4, 0.42, 0.43, 0.44, 0.47, 0.49, 0.5, 0.52, 0.53, 0.54, 0.57, 0.59, 0.6, 0.62, 0.63, 0.64 , 0.67, 0.69, 0.7, 0.72, 0.73, 0.74, 0.77, 0.79, 0.8), Lesi's 618; wetting agent 1.0-3.0ml/L (you can choose any value for the amount of wetting agent in the examples here : 1, 1.2, 1.3, 1.4, 1.7, 1.9, 2, 2.2, 2.3, 2.4, 2.7, 2.9, 3.0), Lesi’s 62A.

The only difference between Preparation Examples 61-90 and Preparation Examples 31-60 is that the microporous powder particles in the microporous nickel plating solution are NiMac Hypore XL powder from MacDermid; the wetting agent is NIMAC 32C WETTER from MacDermid.

The only difference between Preparation Examples 91-180 and Preparation Examples 1-90 is that the pretreatment coating is an electroless nickel layer.

The only difference between Preparation Examples 181-270 and Preparation Examples 1-90 is that the pretreatment coating is a primer nickel layer.

The only difference between Preparation Examples 271-360 and Preparation Examples 1-90 is that the pretreatment plating layer on the surface of the substrate is empty, and the copper plating layer is directly formed on the surface of the substrate.

In the above preparation examples, PN-1A and PN-2A are commercially available products from Atotech (China) Chemical Co., Ltd.

In the technical solution of the utility model, the base material can also be made of materials including but not limited to PC, PP, nylon, PET, bakelite and metal materials. When selecting other substrates except ABS, the pretreatment coating can be selected according to the actual material performance and process requirements with pretreatment coating or without pretreatment coating.

Then it can be seen from the coating potential diagrams of Fig. 2 and Fig. 3 that in the utility model scheme, no matter whether the low-potential nickel layer is a single layer or a composite layer structure, it is the sacrificial layer with the low-potential nickel layer when being corroded, and the low-potential nickel layer is low. When the potential nickel layer is a composite layer of a high-sulfur nickel layer and a micro-cracked nickel layer, the potential of the high-sulfur nickel layer and the micro-cracked nickel layer is adjusted with the actual production process. It can be that the potential of the high-sulfur nickel layer is slightly higher, or it can be The potential of the micro-cracked nickel layer is slightly higher.

As shown in Figure 4, the mechanism when the nickel-chromium plating parts obtained by the utility model scheme is corroded is: in the figure, an chemical nickel layer 809, a bottoming nickel layer 808, a copper plating layer are formed layer by layer on the ABS base material 810 Layer 3, low potential nickel layer 141, microporous nickel layer 142 and decorative layer 802, corrosion medium 801 is on the surface of decorative layer 802 (i.e. trivalent chromium coating or hexavalent chromium coating) and in the microporous structure of microporous nickel layer 142 To disperse the corrosion current and enter the low-potential nickel layer 141 (based on the reason that the corrosion rate in electrochemical corrosion is directly related to the area of the participating electrode, that is, the size of the corrosion current, the actual area participating in the corrosion is reduced here, thereby having a smaller corrosion area and forming Multiple independent corrosion points, thereby dispersing the corrosion current and delaying the corrosion speed), after corrosion forms the corrosion surface 805, when the corrosion surface 805 penetrates the low-potential nickel layer 141 and encounters the high-potential copper plating layer 3, the longitudinal corrosion is stopped For lateral etching, the next step of etching will not be performed until the entire low-potential nickel layer 141 is etched until the coating structure is destroyed as a whole.

The embodiment here does not exhaust the mid-point value of the technical scope claimed by the utility model, and all of them are also within the scope of the utility model.

The technical means disclosed in the solution of the utility model are not limited to the technical means disclosed in the above technical means, but also include technical solutions composed of any combination of the above technical features. The above are the specific embodiments of the present utility model, and it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present utility model, some improvements and modifications can also be made, and these improvements and modifications are also considered It is the protection scope of the utility model.

Claims (7)

1. A nickel-chromium plated part comprising: a substrate; a pretreatment coating deposited on the entire substrate, on which a copper coating is formed; and a functional layer formed on the copper coating, The functional layer includes a low potential nickel layer and a microporous nickel layer formed on the low potential nickel layer; and a decoration layer formed on the microporous nickel layer. 2. The nickel-chrome plated part according to claim 1, characterized in that: the decorative layer is any one of trivalent chromium plating or hexavalent chromium plating. 3. The nickel-chrome plated part according to claim 1, characterized in that: the potential difference between the microporous nickel layer and the low potential nickel layer is in the range of 10-120mV. 4. The nickel-chromium-plated part according to claim 1 or 3, characterized in that: the low-potential nickel layer includes a high-sulfur nickel layer, a layer of micro-cracked nickel layer or a composite between the two layers. 5. The nickel-chrome plated part according to claim 1 or 3, characterized in that: the potential difference between the microporous nickel layer and the low potential nickel layer is in the range of 20-100 mV. 6 . The nickel-chrome plated part according to claim 4 , wherein the potential difference between the microporous nickel layer and the low potential nickel layer is in the range of 20-100 mV. 7. nickel-chromium plating part according to claim 4, is characterized in that: when low-potential nickel layer adopts the composite coating of microcrack nickel layer and high-sulfur nickel layer, between microcrack nickel layer and high-sulfur nickel layer The potential difference is within 10-80mV.