Pretreatment process for secondary metallization of ceramic relay housing by electroplating nickel

Abstract

The application provides a ceramic relay shell secondary metallization electroplating nickel pretreatment process, which comprises the following steps: S1, pretreatment: a micro-etching solution is used to perform immersion micro-etching on the surface of the shell to form a metal rough surface; S2, activation: the shell treated in S1 is activated by immersion in an acid; S3, pre-plating nickel: the shell treated in S2 is pre-plated in a pre-plating nickel solution; and S4, soft nickel electroplating: nickel plating is performed in a nickel plating system. By performing pretreatment before conventional electroplating, a dense nickel layer with strong deep plating capacity is plated, and the subsequent welding blistering problem is effectively solved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of ceramic electroplating, and particularly relates to a pretreatment process for secondary metallization electroplating nickel of a ceramic relay shell. BACKGROUND

[0002] In modern industrial production, electroplating has been widely applied. After primary metallization of ceramics, it is generally difficult to directly use common solder for welding, and secondary metallization (electroplating nickel or coating nickel and sintering nickel) is needed. Most manufacturers choose the method of electroplating nickel to improve the flowability of solder on the metallized surface and prevent the erosion of solder to the metallized layer.

[0003] Now, two kinds of electroplating processes are commonly used for secondary metallization of ceramics. One is the ordinary electroplating process, such as the Watts dark nickel type of nickel sulfate-nickel chloride-boric acid, and the other is the nickel plating process of nickel sulfamate stress-free type. After nickelization or brazing of the ceramic relay shell, many raised small points appear on the metal surface. Especially after nickelization, these raised nickel points appear, and the raised points (also known as blisters) will flatten when gently pressed. It shows that the raised place is a hole. This situation is caused by: molybdenum-manganese sintering is to lay an organic paste and metal oxide mixture on the surface of the ceramic for wet hydrogen sintering. That is, the molybdenum wire furnace is reduced and sintered in a hydrogen atmosphere, the metal oxide is reduced to metal, and the organic matter is converted into carbon or CO, etc. Due to the generation of gas, the surface of the molybdenum-manganese sintered ceramic is loose and porous. In the subsequent brazing process of the ceramic relay shell, in order to avoid the presence of organic matter such as sulfur elements, a dark nickel electroplating process is adopted, but the process has poor deep plating capability, and it is impossible to plate nickel on the bottom layer from the air or micro-cracks in the loose and porous molybdenum-manganese layer, which is the nickel layer sealing the hole or forming a hole in the micro-crack. These holes have a serious impact on the air tightness and tensile strength of the shell, and are a great hidden danger to the quality of the shell.

[0004] With the development of new energy vehicles, the ceramic relay shell is an important link to form a battery. Air tightness and tensile strength are two important index parameters. Bubbling (holes) are easily produced on the secondary metallization welding surface of the ceramic, which seriously affects the air tightness and tensile strength.

[0005] The quality of the metalized surface layer of the porcelain piece plated with nickel directly affects the sealing quality of the metalized porcelain and the metal part. The existing plating methods include electroplating nickel and chemical plating nickel. The literature (Liu Huiqing, "Chemical plating nickel process for ceramic-metal sealing", Vacuum Electronics Technology, 2006, No. 2, pages 55-58) describes the conventional processes of the existing electroplating nickel and chemical plating nickel and their advantages and disadvantages. The literature discloses that the process flow of the existing electroplating nickel is: ① cleaning the metalized porcelain piece; ② soaking in dilute hydrochloric acid; ③ flushing; ④ immersing in plating solution; ⑤ adjusting the current for electroplating; ⑥ taking out from the plating solution; ⑦ flushing; ⑧ boiling in deionized water; and ⑨ drying. The plating nickel system is a nickel sulfate system. The prepared nickel layer has poor uniform plating and depth capacity, and the air tightness, wear resistance and corrosion resistance are general, which greatly limits the application of the electroplating nickel process.

[0006] For example, the patent CN104073850A discloses a method for electroplating nickel on a ceramic metal layer, which comprises pretreating the ceramic metal layer, activating the surface of the ceramic metal layer through acid and alkaline solutions, and then electroplating. The product obtained by controlling the alternating change of the current density has a uniform surface plating thickness, but the problem of welding blistering is not solved.

[0007] Therefore, how to solve the welding blistering is an urgent problem for the manufacturers of ceramic relay housings. SUMMARY

[0008] To solve the above technical problems, the present application provides a kind of ceramic relay housing secondary metallization electroplating nickel pretreatment process, by being carried out before conventional electroplating pretreatment, plating a layer of dense nickel layer with strong deep plating capacity, effectively solve the subsequent welding blistering problem.

[0009] To achieve the above object, the present application provides the following technical solutions:

[0010] On the one hand, the present application provides a kind of ceramic relay housing secondary metallization electroplating nickel pretreatment process, comprising the following steps:

[0011] S1 pretreatment: the shell surface is immersed in micro-etching solution for micro-etching to form a metal rough surface;

[0012] S2 activation: the shell treated by S1 is activated by soaking in acid;

[0013] S3 pre-plating nickel: the shell treated by S2 is pre-plated in a pre-plating nickel solution;

[0014] S4 soft nickel plating: nickel plating is carried out in a nickel plating system.

[0015] Further, the micro-etching solution comprises concentrated sulfuric acid and hydrogen peroxide.

[0016] Further, the micro-etching solution comprises concentrated sulfuric acid, hydrogen peroxide, thiourea, polyethylene glycol, EDTA-2Na salt and phytic acid.

[0017] Further, in the micro-etching solution, the concentration of the concentrated sulfuric acid is 50-65 ml / L; the hydrogen peroxide is 200-300 ml / L; the thiourea is 2-3 g / L; the polyethylene glycol is 0.5-2 g / L; the EDTA-2Na salt is 0.5-2 g / L; and the phytic acid is 0.2-1.0 ml / L.

[0018] Further, in the micro-etching solution, the concentration of the concentrated sulfuric acid is 60 ml / L; the hydrogen peroxide is 250 ml / L; the thiourea is 2 g / L; the polyethylene glycol is 1 g / L; the EDTA-2Na salt is 1 g / L; and the phytic acid is 0.5 ml / L. Further, the concentrated sulfuric acid is 98% sulfuric acid. Further, the polyethylene glycol is selected from polyethylene glycol 2000, polyethylene glycol 4000 or polyethylene glycol 6000.

[0019] In the micro-etching solution adopted by the present application, the sulfuric acid and the hydrogen peroxide are main components, which are used to remove the oxide film and corrode the metal surface; the thiourea and the polyethylene glycol are used in combination, which are mainly used to prevent over-corrosion of the uniform metal surface; the EDTA-2Na salt and the phytic acid are hydrogen peroxide stabilizers, which prevent the concentration of the hydrogen peroxide from changing too much, thereby affecting the corrosion effect.

[0020] Further, the temperature of the micro-etching is 20-30℃. Further, the time for the immersion micro-etching is 30-60 s.

[0021] Further, the acid is hydrochloric acid, and the concentration is 100-150 ml / L.

[0022] Further, in S2, the activation temperature is 15-25℃, and the activation time is 1-5 minutes. Further, in S2, the activation temperature is 20-25℃, and the activation time is 3-5 minutes.

[0023] Further, the pre-plating nickel solution comprises nickel sulfate, dimethylamino borane (DMAB), sodium citrate trihydrate, citric acid monohydrate, sodium acetate, boric acid, polyethylene glycol, KI and KIO3.

[0024] Further, in the pre-plating nickel solution, the concentration of the nickel sulfate is 20-30 ml / L; the concentration of the dimethylamino borane is 1-5 ml / L; the concentration of the sodium citrate trihydrate is 15-30 ml / L; the concentration of the citric acid monohydrate is 7-15 ml / L; the concentration of the sodium acetate is 10-20 ml / L; the concentration of the boric acid is 10-15 ml / L; the concentration of the polyethylene glycol is 0.5-1 ml / L; the concentration of the KI is 0.5-1.5 ml / L; and the concentration of the KIO3 is 2-5 ml / L.

[0025] Further, the concentration of nickel sulfate in the pre-plating nickel solution is 25ml / L; the concentration of dimethylamino borane is 2ml / L; the concentration of sodium citrate trihydrate is 20ml / L; the concentration of citric acid monohydrate is 10ml / L; the concentration of sodium acetate is 15ml / L; the concentration of boric acid is 12ml / L; the concentration of polyethylene glycol is 0.5ml / L; the concentration of KI is 1ml / L; and the concentration of KIO3 is 3ml / L.

[0026] Further, the pH of the pre-plating nickel solution is 7.8-8.8, preferably 8.5, and ammonia is used to adjust the pH of the solution.

[0027] Further, the temperature of the pre-plating treatment is 40-60℃, preferably 45℃. Further, the current of the pre-plating is 0.5-1A, and the time is 5-10s.

[0028] Further, the loading amount of nickel on the surface of the shell obtained after the pre-plating treatment is 0.5-2.0dm 2 / L, preferably 1.5dm 2 / L. Further, the deposition rate of nickel on the surface of the shell obtained after the pre-plating treatment is 1-10um / h, preferably 4.0um / h. Further, the thickness of the nickel layer on the surface of the shell obtained after the pre-plating treatment is controlled to be 0.5-1.0um.

[0029] The main salt of the pre-plating nickel solution of the present application is nickel sulfate; using DMAB as a reducing agent can avoid the problem of nickel layer melting caused by soldering temperature fluctuation in the subsequent soldering process, thereby affecting the problem of the airtightness of the nickel layer; sodium citrate trihydrate, citric acid monohydrate and sodium acetate are combined complexing agents, which can on the one hand avoid the deposition of nickel ions, thereby reducing the pre-plating nickel efficiency, and on the other hand effectively ensure the efficiency of nickel plating with nickel sulfate, and minimize the cost consumption of the pre-plating nickel solution; boric acid is a pH buffer and preservative, which can prevent the chemical nickel from causing bacterial proliferation due to the complexing agent citrate during shutdown, and can cause quality problems to the plated layer. The addition of boric acid can kill bacteria and inhibit the generation of bacteria, thereby maintaining the stability of the pre-plating nickel solution. Polyethylene glycol is a surfactant that reduces the generation of pinholes in the nickel layer. Potassium iodide and potassium iodate are combined stabilizers that are harmless to the physical and chemical properties of the plated layer, and can effectively slow down the autocatalytic speed of the pre-plating nickel solution. The pre-plating nickel solution of the present application is a phosphorus-free solution, which solves the defect of containing phosphorus in the chemical nickel plating solution (pre-plating nickel solution), can prevent the influence of the presence of phosphorus in the nickel layer on the subsequent soldering effect, and can also avoid the air leakage phenomenon in the subsequent soldering. The pre-plating nickel solution of the present application is a chemical nickel system, which does not contain phosphorus, and can induce chemical nickel after forcibly plating a layer of nickel on the shell.

[0030] Further, the nickel plating system includes nickel, nickel chloride, and boric acid. Further, the nickel plating system comprises a nickel concentration of 25–35 g / L; a nickel chloride concentration of 3–7 g / L; and a boric acid concentration of 35–50 g / L. Further, the nickel plating system comprises a nickel concentration of 30 g / L; a nickel chloride concentration of 5 g / L; and a boric acid concentration of 40 g / L.

[0031] Furthermore, the pH of the nickel plating system is 3.8 to 4.5, preferably 4.

[0032] Further, the temperature of the soft nickel plating is 40-50°C, preferably 45°C. Further, the shell D of the soft nickel plating... K The value is 0.5–1.0 dm. 2 Preferably 0.5dm 2 Furthermore, the current density of the soft nickel plating is 1–40 A / dm². 3 .

[0033] Furthermore, the nickel layer thickness on the shell is controlled at 1.5–2.0 μm after the soft nickel electroplating step, and the nickel layer thickness of the final product is controlled at 2–3.5 μm.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] ① The micro-etching step removes the deep oxide film on the surface, forming a uniform and fresh rough metal surface, creating a good metal surface layer for subsequent nickel plating. The activation step removes a small amount or slight oxide film from the metal surface layer. During pre-plating, alkaline electroless nickel plating provides a ductile and deep-plating-capable electroless nickel layer. Because phosphorus is a solder-incompatible element, easily forming secondary crystal phases and other harmful components with iron, the pre-plating solution uses nickel-boron electroless nickel plating, which is phosphorus-free. During soft nickel plating, a nickel sulfamate process is used to thicken the nickel layer. The nickel plating system primarily obtains a nickel layer plated with nickel sulfamate, which achieves stress-free or low-stress performance, significantly preventing cracking during subsequent brazing.

[0036] ② Compared with conventional electroplating processes, after pretreatment by the method described in this invention, almost no blistering was found in the products obtained by subsequent nickel plating or brazing, with a blistering rate of less than 0.1%. This effectively solves the problem of welding blistering in conventional electroplating processes. This method has also been applied to actual production and has achieved good economic results.

[0037] ③ The method described in this invention obtains a nickel layer thickness of 2-3.5 μm on the shell surface, which has high tensile strength, good airtightness and fineness, and high yield. It is significantly better than the electroplating process in the prior art and has broad application prospects. It also produces almost no bubbles. Attached Figure Description

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from the structures shown in these drawings without creative effort.

[0039] Figure 1 Sample nickelized according to the prior art that foamed;

[0040] Figure 2 Sample nickelized according to the method provided in Example 1 of the present application. DETAILED DESCRIPTION

[0041] As used herein the terms:

[0042] "Made by" is synonymous with "comprising". The terms "comprising", "including", "having" "with" or any other similar forms are intended to cover non-exclusive inclusions. For example, a composition, step, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0043] The conjunction "consisting of is exclusive of any element, step, or ingredient not specified. If used in a claim, this phrase will close the claim to the addition of any element not specified. When the phrase "consisting of appears in the body of a claim, it should be construed in accordance with the definition found in the Manual of Patent Examining Procedure, Section 2111.03.

[0044] When numerical ranges are disclosed, the endpoints of the ranges are included. Also, the endpoints of the ranges are not inclusive of the endpoints themselves. For example, a range of "1-5" is inclusive of 1 and 5, but not 1 and 5. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1-5" is intended to include a range of 1-4, 1-3, 1-2, 1-2 and 4-5, 1-3 and 5, etc.

[0045] "and / or" is used to indicate one or both of the stated situations can occur, for example, A and / or B includes (A and B) and (A or B).

[0046] The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the embodiments are provided so that the disclosure of the present application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. In an embodiment, where not otherwise indicated, conventional conditions or manufacturer's recommendations are used. Where a reagent or instrument is used without a manufacturer's name specified, a conventional product available commercially is used.

[0048] The technical solutions of the present application are described in further detail below in conjunction with the specific embodiments.

[0049] Example 1:

[0050] A ceramic relay housing secondary metallization electroplating nickel pretreatment process, comprising the following steps:

[0051] S1 pretreatment: 25℃, using a micro-etching solution to immerse the housing surface for micro-etching 40s to form a metal rough surface, and then taking out and rinsing with water;

[0052] S2 activation: the housing treated by S1 is immersed in hydrochloric acid with a concentration of 120ml / L at 25℃ for 5 minutes, and then taking out and rinsing with water;

[0053] S3 pre-plating nickel: the housing treated by S2 is pre-plated in a pre-plating nickel solution with a pH of 8.5 at 45℃, and then taking out and rinsing with water, the pre-plating current is 0.8A and the time is 10s; the load of nickel on the housing surface after the pre-plating treatment is 1.5dm 2 / L; the deposition rate of nickel on the housing surface is 4.0um / h; the thickness of the nickel layer on the housing surface is controlled to be 0.5-1.0um;

[0054] S4 soft nickel plating: 45℃, plating nickel in a nickel plating system, and then taking out and rinsing with water, the D K of the housing after the soft nickel plating is 0.5dm 2 , the current density of the soft nickel plating is 20A / dm 3 ; the thickness of the nickel layer on the housing after the soft nickel plating is controlled to be 1.5um, and the thickness of the nickel layer of the final product is controlled to be 2um.

[0055] The micro-etching solution contains 60ml / L of concentrated sulfuric acid, 250ml / L of hydrogen peroxide, 2g / L of thiourea, 1g / L of polyethylene glycol 6000, 1g / L of EDTA-2Na salt, and 0.5ml / L of phytic acid. Further, the concentrated sulfuric acid is 98% sulfuric acid.

[0056] The pre-plating nickel solution contains 25ml / L of nickel sulfate, 2ml / L of dimethylaminoborane, 20ml / L of sodium citrate trihydrate, 10ml / L of citric acid monohydrate, 15ml / L of sodium acetate, 12ml / L of boric acid, 0.5ml / L of polyethylene glycol, 1ml / L of KI, and 3ml / L of KIO3.

[0057] The nickel plating system has a pH of 4 and contains 30g / L of nickel, 5g / L of nickel chloride, and 40g / L of boric acid.

[0058] Example 2:

[0059] 1. A ceramic relay housing secondary metalization electroplating nickel pre-treatment process, the detailed steps are as follows:

[0060] S1 pre-treatment: immerse the housing surface in a micro-etching solution to form a rough metal surface, and then remove and rinse with water; the experimental conditions are as follows:

[0061] The micro-etching solution contains 50-65ml / L of concentrated sulfuric acid, 200-300ml / L of hydrogen peroxide, 2-3g / L of thiourea, 0.5-2g / L of polyethylene glycol, 0.5-2g / L of EDTA-2Na salt, and 0.2-1.0ml / L of phytic acid; the micro-etching temperature is 20-30°C, and the immersion time is 30-60S.

[0062] S2 activation: immerse the housing treated in S1 in an acid for activation, remove, and rinse with water; the experimental conditions are as follows:

[0063] The acid is hydrochloric acid with a concentration of 100-150ml / L, the activation temperature is 20-25°C, and the activation time is 3-5 minutes.

[0064] S3 pre-plating nickel: the shell treated in S2 is pre-plated in a pre-plating nickel solution, and then taken out and washed with water; the experimental conditions are as follows: in the pre-plating nickel solution, the concentration of nickel sulfate is 20-30 ml / L; the concentration of dimethylaminoborane is 1-5 ml / L; the concentration of sodium citrate trihydrate is 15-30 ml / L; the concentration of citric acid monohydrate is 7-15 ml / L; the concentration of sodium acetate is 10-20 ml / L; the concentration of boric acid is 10-15 ml / L; the concentration of polyethylene glycol is 0.5-1 ml / L; the concentration of KI is 0.5-1.5 ml / L; and the concentration of KIO3 is 2-5 ml / L; the pH of the pre-plating nickel solution is 7.8-8.8, and the pH of the solution is adjusted by ammonia water; the temperature of the pre-plating is 40-60°C; the current of the pre-plating is 0.8 A, and the time is 10 s; the loading amount of nickel on the surface of the shell obtained after the pre-plating is 0.5-2.0 dm 2 / L; the deposition rate of nickel on the surface of the shell obtained after the pre-plating is 1-10 um / h; and the thickness of the nickel layer on the surface of the shell obtained after the pre-plating is controlled to be 0.5-1.0 um,

[0065] S4 soft nickel plating: nickel plating is carried out in a nickel plating system, and then the shell is taken out and washed with water. The experimental conditions are as follows:

[0066] In the nickel plating system, the concentration of nickel is 25-35 g / L; the concentration of nickel chloride is 3-7 g / L; and the concentration of boric acid is 35-50 g / L; the pH of the nickel plating system is 3.8-4.5; the temperature of the soft nickel plating is 40-50°C; and the current density of the soft nickel plating is 1-40 A / dm 3 .

[0067] The shell D K after the soft nickel plating is 0.5-1.0 dm 2 The thickness of the nickel layer on the shell after the soft nickel plating is controlled to be 1.5-2.0 um, and the thickness of the nickel layer of the final product is controlled to be 2-3.5 um.

[0068] 2. Parameter selection experiment

[0069] (1) Each component in the micro-etching solution is screened, and the results are shown in Table 1 as follows:

[0070] Table 1 Screening results of the concentration of each component in the micro-etching solution

[0071]

[0072]

[0073] (1) The concentration of the activating hydrochloric acid is screened, and the specific results are shown in Table 2

[0074] Table 2 Screening concentration of the activating hydrochloric acid

[0075]

[0076]

[0077] (2) The activation step was missing. The results showed that there was a residual oxide film on the surface of the shell. After subsequent pre-plating of nickel and soft nickel electroplating, the surface of the ceramic shell had about 3% blistering.

[0078] (3) Screening of each component of the pre-plating nickel solution. The results are shown in Table 3.

[0079] Table 3. Screening of components in the pre-plating nickel solution (unit: ml / L)

[0080]

[0081]

[0082] (4) After using phosphorus-containing chemical nickel for pre-plating, the resulting ceramic shell leaks during brazing.

[0083] (5) Comparison of blistering in nickel plating

[0084] As attached Figure 1 and attached Figure 2 It can be seen that the existing traditional electroplating method results in a lot of blistering on the surface of the sample; the sample prepared by the method in Example 1 of this invention has a smooth surface, no blistering, and good air tightness and fineness.

[0085] (6) Thermal shock test

[0086] The metallized component prepared according to this invention was sealed with a metal part to form a test specimen. The test specimen was kept at room temperature to 600°C for 30 minutes, followed by room temperature thermal shock. After 6 thermal shocks, a leak test was performed, and no leakage was found in any of them. The test results were all qualified. The yield rate of the whole pipe sealing reached 99%, and the thermal shock qualification rate reached 100%.

[0087] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A ceramic relay housing secondary metallization electroplated nickel pretreatment process characterized by, The method comprises the following steps: S1: pre-treatment: the shell is immersed in a micro-etching solution to form a rough metal surface; S2: activation: the shell treated in S1 is activated by immersion in an acid; S3: pre-plating of nickel: the shell treated in S2 is pre-plated in a pre-plating solution of nickel; In the pre-plating solution of nickel, the concentration of nickel sulfate is 20-30 ml / L; the concentration of dimethylaminoborane is 1-5 ml / L; the concentration of sodium citrate trihydrate is 15-30 ml / L; the concentration of citric acid monohydrate is 7-15 ml / L; the concentration of sodium acetate is 10-20 ml / L; the concentration of boric acid is 10-15 ml / L; the concentration of polyethylene glycol is 0.5-1 ml / L; the concentration of KI is 0.5-1.5 ml / L; and the concentration of KIO3 is 2-5 ml / L; The pH of the pre-plating solution of nickel is 7.8-8.8, and the pH of the solution is adjusted by using ammonia water; The temperature of the pre-plating treatment is 40-60°C; the current of the pre-plating is 0.5-1 A, and the time is 5-10 s; The load of nickel on the surface of the shell obtained after the pre-plating treatment is 0.5-2.0dm 2 The deposition rate of nickel on the surface of the shell obtained after the pre-plating treatment is 1-10um / h, and the thickness of the nickel layer on the surface of the shell obtained after the pre-plating treatment is controlled to be 0.5-1.0um. S4: soft nickel plating: nickel plating is performed in a nickel plating system.

2. The ceramic relay housing secondary metalization electroplated nickel pretreatment process of claim 1 wherein, The micro-etching solution comprises concentrated sulfuric acid, hydrogen peroxide, thiourea, polyethylene glycol, EDTA-2Na salt, and phytic acid.

3. The ceramic relay housing secondary metalization electroplated nickel pretreatment process of claim 2 wherein, In the micro-etching solution, the concentration of concentrated sulfuric acid is 50-65 ml / L; the concentration of hydrogen peroxide is 200-300 ml / L; the concentration of thiourea is 2-3 g / L; the concentration of polyethylene glycol is 0.5-2 g / L; the concentration of EDTA-2Na salt is 0.5-2 g / L; and the concentration of phytic acid is 0.2-1.0 ml / L; the temperature of the micro-etching is 20-30°C; and the time of the immersion micro-etching is 30-60 s.

4. The ceramic relay housing secondary metalization electroplated nickel pretreatment process of claim 3 wherein, In the micro-etching solution, the concentration of concentrated sulfuric acid is 60 ml / L; the concentration of hydrogen peroxide is 250 ml / L; the concentration of thiourea is 2 g / L; the concentration of polyethylene glycol is 1 g / L; the concentration of EDTA-2Na salt is 1 g / L; and the concentration of phytic acid is 0.5 ml / L; the concentrated sulfuric acid is 98% sulfuric acid; and the polyethylene glycol is selected from polyethylene glycol 2000, polyethylene glycol 4000, or polyethylene glycol 6000.

5. The ceramic relay housing secondary metalization electroplated nickel pretreatment process of claim 1 wherein, The acid is hydrochloric acid, and the concentration is 100-150 ml / L; In S2, the activation temperature is 15-25°C, and the activation time is 1-5 minutes.

6. The ceramic relay housing secondary metalization electroplated nickel pretreatment process of claim 1 wherein, In the nickel plating system, the concentration of nickel is 25-35 g / L; the concentration of nickel chloride is 3-7 g / L; and the concentration of boric acid is 35-50 g / L; The pH of the nickel plating system is 3.8-4.

5.

7. The ceramic relay housing secondary metalization electroplated nickel pretreatment process of claim 1 wherein, The temperature of the soft nickel electroplating is 40-50℃, the shell D of the soft nickel electroplating K is 0.5-1.0 dm 2 , the current density of the soft nickel electroplating is 1-40 A / dm 3 ; The thickness of the nickel layer on the shell after the soft nickel plating step is controlled to be 1.5-2.0 um, and the thickness of the nickel layer of the final product is controlled to be 2-3.5 um.

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