WO1980000716A1

WO1980000716A1 - Method of corrosion-resistant plating

Info

Publication number: WO1980000716A1
Application number: PCT/JP1979/000251
Authority: WO
Inventors: H Uchida; T Uotani; K Deguchi; M Kubo
Original assignee: Uemura Kogyo Kk; H Uchida; T Uotani; K Deguchi; M Kubo
Priority date: 1978-10-05
Filing date: 1979-10-02
Publication date: 1980-04-17
Also published as: GB2043109A; JPS5550488A; JPS5817838B2; GB2043109B

Abstract

A method of providing a highly corrosion-resistant electroplated film, which comprises first nickel plating a material to be plated directly or after subjecting it to underplating, then subjecting it to high stress nickel plating and subsequently to final luster nickel plating, and finally conducting finish plating such as chromium plating. Unlike those formed according to a conventional microcracked chromium plating method wherein chromium plating is directly applied to form microcracks in the chromium film after high stress nickel plating, the thus formed highly corrosion-resistant plated film does not contain microcracks in the final film such as chromium film. Nevertheless, it exhibits excellent corrosion resistance.

Description

Specification '

Corrosion resistance method

'' Technology

The present invention relates to a method for corrosion resistance, in particular,

5 After that, high stress nickel plating is applied, and then chrome plating is performed, so that a so-called crack at the mouth plating film is generated. The present invention relates to a corrosion-resistant plating process that provides an excellent corrosion-resistant electroplated coating as compared to the ROM plating method.

0 Background technology

Traditionally, processes for corrosion resistance for automobile parts and the like include a two-layer nickel plating method in which nickel plating layers having mutually different sulfur contents are formed, and a three-layer nickel plating method. Known plating method 6 Also, after nickel plating, apply a thin plating in a nickel plating bath that suspends 5 inorganic fine particles, and then perform Chrome plating. And have fine pores

"" ■ * · "'" ■ — · ■ —- ——one · ..___ ...

Obtain a chrome-plated film. 'Polar Squeeze Method'; び-'後 After 、つ上. 、被膜被膜被膜高応力応力応力高応力応力高応力When the chrome plating is performed, the fine plating is formed on the chromium plating film, or the nickel plating is performed. There is a known method of plating micro-plates with a fine black chroma coating using a special bath on the plating film. Have been put to practical use as the corrosion-resistant plating method.

5 In particular, after high-stress nickel plating,

O PI • The method of generating cracks at the mouth of chrome is widely adopted because of its relatively good corrosion resistance, and various proposals for this method have been made (US U.S. Patent No. 3,388,049; U.S. Patent No. 3,471,27.1; U.S. Patent No. 3,563,864; Japanese Patent Publication No. 45'-187676; U.S. Patent No. 3,759,802, Japan JP-B-48-2183, JP-A-49-62334, JP-B-46 ^ -37 ': 645).

However, as the demand for corrosion resistance for plated coatings is becoming increasingly severe, there is a demand for a more advanced: high corrosion resistance, which provides IT corrosion resistance, and a mouth opening. Also general

Improve the corrosion resistance of the plating film 7¾'¾-¾, 'The more the coating, the thicker the film', the better, but the thicker the coating and the higher the cost of the plating Invite. Still 'thick'

"Make sure to increase the length of time. ^ Cf, there are 5 problems in terms of work efficiency. In particular, the conventional method has a problem in the corrosion resistance of the thin film part, which is relatively low in the current density. . For this reason, there is a demand for a plating process that provides sufficient corrosion resistance even at relatively thin film thicknesses. "-

-: 'Disclosure of the invention:

0 The object of the present invention is most important as a corrosion resistant process.

Compared to the conventional micro-mouth crack plating method, which is said to be one of the most popular methods, it is better than the conventional method.)) Excellent corrosion resistance Provide a method of attachment.

5 According to the present invention, the substrate can be directly or

¾ (, ..- ? : After the first nickel plating, high stress

:--Apply rf plating and then continue; Nickel plating with final gloss -I Fix: Apply and finish with chrome plating or other final plating- Such a method of corrosion resistance is provided.

The plated product obtained according to the corrosion-resistant plating method of the present invention is `` high-stress nickel plating, and then subjected to a final bright nickel plating, '' whereby a chrome-plated film or other final plating is obtained. Micro-cracks occur on the membrane. High stress nickel plating-direct chrome plating afterwards

10 A conventional micro-clock plating method that generates a clock.; ^ The micro-clock generated on the plating film The idea is to disperse the corrosion current and thereby improve the corrosion resistance (note that the micro-porous plating method, which produces many micropores in the chrome plating film).

15 is also based on the same concept.) Compared with the method of the present invention, the method for corrosion resistance of the present invention is performed after performing high-nickel plating and then performing bright nickel plating. In the case of chromium plating, the microplate (or micropore) is not formed on the chromium plating film. It is surprising that a coating with superior corrosion resistance can be formed compared to i2f.

: '.

^¾;;. In the present invention, after the high-stress two Tsu Ke Le plated cormorants this good, the final gloss two-Tsu Ke Le plating and line cormorant this important! ), Bright nickel plating coating on high stress nickel plating coating.

25 After film formation, final chrome plating and other final Plating and interposing a bright nickel plating film between the high-stress nickel plating film and the final plating film. ??, a conventional micro crack It has achieved the formation of a corrosion-resistant coating that dramatically surpasses the corrosion resistance achieved by the ROM plating method.

According to the present invention, as described above, the corrosion resistance of the plating film is good, and the same level of corrosion resistance as that obtained by the conventional plating method can be maintained. ) It is possible to make the entire coating film thinner]), and to reduce the plating film thickness.] 3 It is possible to reduce the plating cost and shorten the plating time. Thus, the work efficiency can be improved. According to the method of corrosion resistance of the present invention, the coating of the high current density portion (thick plating portion) and the low current density portion (thin plating portion) can be significantly improved. The method of the present invention can be suitably applied to a component in which the generation of heat is easily observed from a low current density portion in the conventional method, such as a component having a complicated shape, a component having a deep depression, or the like.

Furthermore, according to the present invention, as a final bright nickel plating performed after high stress nickel plating, a normal bright nickel plating bath can be used under normal working conditions, In addition, in the conventional micro-chroming process, it is sufficient to simply add the final gloss nickel plating process after the high stress nickel plating. Therefore, there is also a feature that the corrosion resistance method of the present invention can be easily adopted. Brief explanation of the drawing

PIG. I is a plan view showing the corrosion resistance evaluation section of the fitted test piece.

From FIG. 2 to FIG. 9, plating specimens according to the corrosion-resistant plating method of the present invention and the conventional micro-black σ-mu plating method or the corrosion-resistant plating method of the present invention, respectively. The corrosion resistance of the comparative plating test piece according to the plating method different from the plating method is determined by the cast test method.] Relationship between the number of cycles and the rating number in the test In the drawings from FIG. 2 to PIG. 6, the figures marked with A show the degree of corrosion resistance of the high-current-density portion of the plated test piece. The drawings marked with R and B are the graphs showing the degree of corrosion resistance at the current density portion during the plating of the test piece, respectively, and the drawings marked with C are the cross-sections of the test piece, respectively. This is a graph showing the degree of corrosion resistance in the low current density area.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the material of the covering object is not particularly limited, and may be iron, steel, zinc, aluminum, copper, copper-zinc alloy, other metal base materials, ABS resin, or other plastic. After performing a predetermined pre-treatment on the metal substrate by a normal method according to the material, the method of the present invention can be carried out on this. For example, in the case of a metal substrate as the pretreatment, a method of generally degreased the metal surface by a dipping method and Z or electrolytic method and then neutralizing with an acid can be adopted. In the case of aluminum

OMPI-ichi WIPO—

, After activation, a method of performing zinc substitution can be adopted. -In the case of plastic substrates, the plastic surface is roughened by chemical etching with a mixture of chromic acid and sulfuric acid or by mechanical roughening. After that, an activation process is performed to attach catalytic metal nuclei such as palladium to the roughened plastic surface, and then electroless copper plating and electroless nickel plating Metallization of plastic surface by electroless plating such as

Necessary before nickel plating, which is the first process of the corrosion-resistant plating method of the present invention.]? A desired undercoating can be performed. In this case, the type of the undercoating is not particularly limited, and is selected according to the material, use, and the like of the covering object. For example, bright copper plating can be performed before nickel plating, which is the first process. For the bright copper plating, use a normal copper sulfate plating bath, a copper chlorophosphate plating bath, a copper plating bath, and other copper plating baths with the usual bath composition and plating conditions. In the present invention which can be carried out by this, the nickel plating (first nickel plating) as the first process is thus covered. This is performed directly or after forming a predetermined undercoating film on the surface of the attachment. The bath used for the first-nickel plating may be any of a normal ordinary nickel bath, a semi-gloss nickel bath, and a gloss-nickel bath. As for the bath composition, a watt bath mainly containing nickel sulfate, nickel chloride and boric acid is usually used, but is not necessarily limited to this. However,

RE

O PI

/, WIPO Usually, a nickel bath or a glossy nickel bath is preferably used from the viewpoint of improving the appearance of the plating and improving the repelling. In this case, it is necessary. ?? A conventionally known multi-layer nickel plating method can be adopted, for example, by performing gloss-nickel plating after semi-bright nickel plating.めっき. As the plating conditions for the first nickel plating, ordinary conditions according to the type of bath and the like are employed.

Specifically, a bath having the following composition is preferably used as the first nickel plating bath under the following conditions. Tori: Holiday

Ni S0 ₄ 6¾0 00 ~ 400 ^ 280 280

Ni C ₂ 6H ₂₀ 30〜60 ^ ¾ 45

H ₃ B0 ₃ 20-60 ^ 40 /

Semi brightener or brightener τΜ. Straight PH 3.5 5.5 4, 2

Plating temperature 40-65 ° C 55 ° C

Cathode current density 1 to 10

Stirring air, machine air, machine In addition, as a semi-brightening agent and a brightening agent, known ones which are usually used can be used in a usual addition amount, for example, a semi-brightening agent As such, coumarin, formalin, -zatin-1,4-diol and derivatives thereof can be used alone or in combination. 1,5-, 1,6-or 2,5-naphthalene sulfone as primary brightener

Α

OMPI crane Sodium phosphate, 1,3,6-Naphthalene trisulfonate Sodium phosphate Pensence Sulfonates such as sodium phosphate Snorrenone amides such as sensnorehone amide, norat noren hen norenhon amide, etc., sulphone imids such as saccharin, Sulfuric acids, sulfones, etc. can be used alone or in combination, and as a secondary brightener, 2-tin-1,4-diol and its derivatives, pronogyl Alcohol and its derivatives, water-sealable chloral and its derivatives, ethylene hydrin and its derivatives, thiocyanate urea and its derivatives azo, dyes and bears Lin, formalin, etc. can be used alone or in combination.

The bath may contain a humectant for preventing pitting and other desired components.

The thickness of the coating by the first nickel plating is determined by the method of the present invention.]), Because a coating having excellent corrosion resistance can be obtained as compared with a conventional corrosion-resistant coating process. ) Although it may be thin, for example, about 2 is acceptable, but from the viewpoint of providing high corrosion resistance, when the first nickel plating is applied directly to the object to be covered, about 5 μm or more is required. 3] Desirably 6 or more. After applying the undercoating to the object to be plated, and then applying the first nickel plating, the plating between the undercoating and the first nickel plating should be performed. The total film thickness is about 5 or more, and more preferably about 6 or more. That is, it is preferable that the total plating thickness before high-stress nickel plating to be described later is set to be about or more, preferably j or more. In particular, When the copper plating is applied, the thickness of the copper plating is 6 to 8 mm or more, preferably 1 to 2 if the coating thickness of the first nickel plating is 1 to 2. At least 10 (that is, about twice or more the thickness of nickel plating alone); more preferred. Also, the corrosion resistance improves as the thickness of the first nickel plating or the total thickness of the first nickel plating and the undercoating increases, but from the economical point of view. Considering that the upper limit is about 50]), the thickness is usually about 30 or less. Next, in the present invention, high stress nickel plating is performed on the first nickel plating film. As the high-stress nickel plating bath, known baths can be used. For example, when the high-stress nickel plating is applied directly to the chrome plating, the plating film is formed on the plating film. On the other hand, a nickel electrodeposit having a high stress that is about the same as or higher than that of a bath that generates micro cracks or nickel electrodeposition obtained from this bath A bath or the like that gives a bath can be used under the usual plating conditions. More specifically, nickel chloride, nickel sulfamate or nickel sulfofinate disclosed in U.S. Pat. No. 3,388,049, and sulfuric acid, ammonium acetate Bath containing monium or nickel acetate; aminocarboxyl acrylates disclosed in U.S. Pat. No. 3,471,271; aminosulphonic ash And high chloride baths containing amino acids selected from the group consisting of aminophosphonic acid, described in US Pat. No. 3,563,864 and Japanese Patent Publication No. 45-18766. Nicky

O PI And an internal stress-forming additive selected from an aluminum compound, a pyridinium compound, a quinoline compound, and an isoquinoline compound. Nickel chloride, nickel nickel sulfamate, or nickel sulfide, described in U.S. Pat. No. 3,759,820 Bath containing sodium chloride, luconic acid, formic acid, malic acid, lactic acid, citric acid, succinic acid or its salt, Japanese Patent Publication 48-27 183 Nickel chloride and sodium, potassium or ammonium chloride and acetic acid, dalconic acid, tartaric acid, and] taronic acid described in No. A bath containing lactic acid, formic acid, citric acid, citric acid, succinic acid or its alkali and nickel salts, and further disclosed in Japanese Patent Publication No. 46-37645. To Includes additives such as xamethylene tetramin, piperazine, razin, and 2,6-dimethinolepyrazine, and has a high tensile stress of about 8400 ^ or more. Nickel plating baths to be given can be used.

Further, as a high stress nickel plating bath, a bath having the following composition and plating conditions is also preferably used.

Optimum range Nickel chloride (hexahydrate) 70-4 QQS ^ / i 50-300 / ¾ Boric acid 3-45 I '7-30 "Al-chlorite earth metal chloride 5-200 I' 10-100 "

(Especially barium chloride)

Ammonium chloride 0 ~ 50 "30 / ^ or less Primary brightener Weekly

Secondary brightener

ΓΙ ΓΙ AT pH 3 ~ 5 3 ~ 5

Plating temperature-room temperature ~ 60 at 50

In this bath, stirring may or may not be performed. In particular, if this bath is plated with this bath and then subjected to direct chrome plating, even in low current density areas, compared to the conventional bath, the number of fine cracks may increase. That is, (For example, a crack of 400 cm or more Z cm is generated in the portion where the current density is 2 A / d or more, and 100-400 cracks are generated in the portion of OS SAZC ² .

The thickness of the high stress nickel plating is preferably about 0.5 or more, particularly about 0.5 to 3, and usually about 1 is sufficient.

In the present invention, after performing high stress nickel plating, final gloss nickel plating is performed. As the bath for the final gloss nickel, a known bath can be used, and a known brightener can also be used.

Specifically, baths and brighteners (primary brighteners, secondary brighteners) of the composition and conditions described in the description of the first nickel plating are preferably used.

The thickness of the final glossy nickel after high stress nickel plating is preferably about 0.5 ^ or more. The upper limit is not particularly limited, but is generally 10. Particularly preferably, the film thickness is about 0.5 to 5 and usually 1 to 2 mm is sufficient. After the final gloss-to-kernel plating, the chrome plating is usually applied, but the chrome alloy plating (eg chrome-to-kernel) or tin-to-cobalt A desired final plating such as alloy plating can also be performed. For these final platings, a bath having a normal composition according to the type of plating can be employed under normal plating conditions. For example, the chrome plating bath includes a surge bath, a fluoride-containing bath such as fluorinated fluoride, a bath made of trivalent chromium containing chromic acid, and other appropriate baths. A bath is used, and the film thickness is 0.05 or more, usually 0.1 to 0.3. The usual method can be used for post-processing after final plating. Generally, it is sufficient to wash with water and dry after final fixation.

As described above, the high corrosion resistance plating process according to the present invention is to apply the first nickel plating after directly or undercoating the object to be coated, and then perform the high stress plating. It is characterized by the application of a nickel plating, a final gloss-nickel plating, and finally a chrome plating or other final plating. (4) It was possible to form a coating with better corrosion resistance than the conventional micro black plating method.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the following Examples. [Example 1]

-In accordance with the following plating process, use a 10 _OT X 6.5 polished steel plate in the usual manner.]? Electrolytic degreasing and pickling to make the surface After cleaning and activating, plating was performed in a bright nickel plating bath of the following composition with the thickness shown in Table 1 (with the first bright nickel plating). Next, a high-strength nickel plating bath having the following composition is subjected to l 更に plating, and a plating having a predetermined thickness is performed in a bath having the same composition as the above-mentioned glossy nickel plating bath. Final gloss nickel plating) was applied. Next, using a normal Hall cell tester, the pi-membrane plating was performed under the conditions of 1 OA and 1 minute (using the chrome plating bath described below).

According to the above method]? As shown in Fig. 1, the obtained plated test piece was divided into three parts: A part on the high current density part, B part on the medium current density part, and C part on the low current density part. The sections were divided into sections, and the following cast tests (JIS D 201) were performed to examine the corrosion resistance of sections A, B, and C, respectively. Contact, middle L = 2 cm.

For comparison, bright nickel plating and high-stress nickel plating were sequentially performed, and then the final bright nickel plating was not performed, and the chrome plating was performed as it was. The corrosion resistance of the test specimen was examined in the same manner.

The results are shown in FIG. 2A, B, C and FIG. 3A, B, C. In the drawings from FIG. 2 to FIG. 6

The drawing with A shows the corrosion resistance test results on the high current density side A, the drawing with B shows the corrosion resistance test results on the medium current density side B, and the drawing with C shows the corrosion resistance test results on the low current density side C. Plating process

1.Cathode electrolytic degreasing.

WIPO Composition Sodium metasilicate 1 09 / &

Sodium ash 10 n sodium hydroxide 30 〃

Tripoly sodium phosphate 10 "Anionic activator 0.1 II Cathode current density 1 OAZd ^

Time 1-2 minutes

60-65. C

2. Water! Π

3.Pickling 10 weight sulfuric acid aqueous solution

'' Time 10 seconds

Temperature 20 ¾

4.Washing

5.First bright nickel plating

6.Washing

7.High stress nickel plating

8.Washing

9.Final gloss nickel plating

10.Washing

11.Cock mouth (with Hall cell test)

12.Washing

13.drying

Bright nickel plating bath

Nickel sulfate _{(Ni S0 4 - 6¾0) 280} i nickel chloride _{_{(Ni C ^ 2 · 6H 2}} 0) 45 "

〇 :: π ν,? 0 Boric acid 40 Ά saccharin 2 "

2-Sen-, 4-diol 0.2 "pH 4

Plating conditions

Stir air

High stress-nickel plating bath

Nickel chloride (NiC_ ^ ₂ · 6¾0) 250 /

Sodium acetate 50 〃 salt ^ ammonium 5

Saccharin '2 "

2-Chin-4-Jiichi 0.2

PH 4.0

30. C

8 A / d ^ Agitated air

Chrome bath

Chromic anhydride (Cr0 ₃₎ 250 ^ / & trivalent click π-time (C r ³⁺⁾ 2.0 "sulfuric acid 2-5 //

45 ° 0

Reader 0 Note that the following tests were conducted for the salt solution.

Sodium chloride 5.0 weight

Distilled water 9 5.0

Cupric chloride 0.2 6 ^ / &

CCnC £ ₂ · 2¾0) using adjusted to PH 3.1 with glacial acetic acid, was carried out good in the arc spraying at a pressure of 1.0 to have you in an ambient temperature of the salt solution at 4 9丄2. In the test, one cycle was sprayed for 16 hours continuously, and the cycle was carried out as prescribed. Specimens were taken out at regular intervals, and the occurrence of mirrors was evaluated using a rating tamper. The results shown in the drawing show the relationship between the number of cycles (horizontal axis) and the rating number (vertical axis).

Here, the relationship between the rating number and the 鐳 occurrence rate (corrosion area rate) is shown below. ). .

Latency, 'Nanno' Corrosion area rate ()

1 0 0

9 Less than 0.10

8 0.10 or more and less than 0.25

7 0.2 5 or more and less than 0.5 0

6 0.5 0 or more and less than 1.0

5 1.0 or more 2.5 Not yet

4 2.5 or more 5.0 Not yet

3 5.0 or more 1 0

2 1 0 or more 2 5

25 or more and less than 50

0 5 0 or more

V> i? 〇 »1 ¾

From the results of and 3, the nickel plating is higher than that of the conventional micro-clock plating method in which the plating is performed immediately after the high stress nickel plating. According to the method of the present invention in which the final nickel plating is further performed on the 'stress nickel plated' and then the chrome plating is performed, the corrosion resistance can be dramatically increased. Was found.

The corrosion resistance when a steel plate is subjected to direct nickel plating after 7 glossy nickel platings was applied, and the corrosion resistance was evaluated in one cycle (16 hours) of the cast test. The average number was 6-8.

[Example 2]

In Example 1, a semi-bright nickel plating having the following composition was replaced by the first nickel plating instead of the first bright nickel plating. In the same manner as in Example 1 except that the film thickness was as shown in Table 2] ?, a semi-gloss-nickel-high-stress nickel-gloss nickel was applied on a polished steel plate. — Cup plating (Halsell test was performed, and in the same way, a corrosion test was performed by performing a gas test. The results are shown in PIG. 4).

Semi-gloss-nickel plating bath

Nickel sulfate _{_{(NiS0 4 · 6Η 2 0)}} 280 ^ / &

Shio-Dai-Kel (NiC ₂ 6Η ₂₀ ) 45

Boric acid 40 "

Kumarin 0.1 "

PH 4.0

Plating conditions

50 ° C stirring air Table 2

According to the results of FI G.4, in the corrosion resistance method of the present invention, when nickel plating is directly applied to the material to be coated, the first nickel as a base for high stress nickel plating is applied.めの / ΟΜΡΪ Even if the thickness is about 5 mm or less, corrosion resistance can be sufficiently provided as compared with the conventional micro-chrome chromium plating method, but the thickness of the first nickel plating is about 5 or more

D, It was found that very good corrosion resistance could be given.

[Example 3]

After pre-treating a polished steel plate (10c7 «X 6.5 _OT ) in the same manner as in Example 1, a solidified copper strike having the following composition was performed. Plating. Next, in the same manner as in Example 1, the first gloss nickel plating, the high stress nickel plating, the final gloss nickel plating, and the chrome plating (Hall cell test) were sequentially performed. 5) Fig. 5 and Fig. 6 show the 01 trees.

For comparison, after copper plating, high-stress nickel plating was performed directly without first nickel plating, followed by gloss nickel plating and chrome plating. The results of the corrosion resistance test in the case where the corrosion was performed are shown.

Copper bronze strike bath

Cuprous material 25 Ά

Free blue soup 12. //

Mouth salt 10 //

PH 12.0

inn ¾. 40 ° C

¾ΕΛ Γ

ΟΙνΙΡΙ _ Time 1 minute

Copper plating bath

Cuprous blue 800 0 Ά

Free realization soda 10

Pissel salt 30

Rodin Power 15

PH 0.5

Temperature 60 ° 0

Stir air

P R ㊉ 3: Θι 0 Table 3

5 and 6], excellent corrosion resistance when the thickness of the underlayer before high stress nickel plating is about 5 or more.

-one

C.:FI o In addition to the effect, it was recognized that it was necessary to perform -nickel plating as a base plating immediately before high-stress nickel 'plating.

[Example 4]

Polished steel sheet which had been subjected to the same pretreatment as in Example 1 was subjected to No. 6 first gloss nickel plating using a gloss-nickel plating bath having the same composition as in Example 1, and then the following composition was obtained.

Nickel chloride (Ni C ^ ₂ · 6¾0) 2 50 Ά

Boric acid 1 0 //

Parium chloride 20 〃

'' Ammonium chloride 10 //

ΡΗ 4.0 //

Using a high-stress nickel plating bath with a bath temperature of 50, a cathode current density of 5 A / d ^, and a 1-cm plating under air-turbulent conditions, then the same luster as above A final gloss nickel plating of 1 is performed in a nickel plating bath, and finally a chrome plating of about 0.2 in an Asahichrome NC bath (manufactured by Kamimitsu Kogyo Co., Ltd.) is selected. I went all the way.

The corrosion resistance was very good, and almost no occurrence of '鐯 was observed even after 5 cycles of the cathode test.

¾ The composition and plating conditions of the Asahichrome NC bath are as follows.

Asahichrome NC 1 8 09- / Ά

(Chromic anhydride 1 78 ")

Trivalent chromium (Cr ^3T ) Sulfuric acid 0.9

¾3 §C at 45

Since Again A non click port beam NC baths that are a mixture of full Tsu fluoride-based additive 2 parts by weight of anhydrous click port beam acid (Cr0 ₃₎ l 78 by weight part a]), the full Tsui匕浴It is a kind. It is different from a micro black plating bath.

[Example 5]

In the same manner as in Example 1, a polished steel plate (10 _OT X 5 cm) was subjected to electrolytic degreasing, followed by a pretreatment of pickling and washing. Next, the semi-bright nickel plating bath shown in Example 2, the bright nickel plating bath shown in Example 1, the high-stress nickel plating bath, and the chromium plating bath were used together. It was used under the following conditions and plating was performed in the following processes I and Π.

I. Semi-bright nickel plating One high stress-Nickel plating One final gloss nickel plating

Π. Semi-gloss nickel plating 1st gloss nickel plating

—High stress nickel plating-final gloss-nickel plating

For comparison, plating was performed in the step I [.

I. Semi-bright nickel plating-1st bright nickel plating-1 high stress nickel plating-1 hole plating

The chrome plating was performed in a 10 ^ beaker at a cathode current density of 15 A / d ^, a bath temperature of 45, and a plating time of 2 minutes and 30 seconds. The plating thickness is as shown in Table 4.

\ / v, 'Nii Oh, the total nickel plating thickness was 10 μm, 15 μm, and 20 μm. (It was confirmed by the electrolytic film thickness meter that the plating thickness was the same.) did ) . '

Next, the corrosion resistance of each of the plating specimens was determined by a cast test. The results are shown in FIGS. 7 to 9. .

Table 4

Or? As shown in Figs. 1 & 9, it is clear that the corrosion resistance plating method of the present invention significantly improves the corrosion resistance as compared with the conventional micro-chromic plating method. Was seen.

.. ·-": ι

¾ τΐο Copper sulfate CuSO ₄ · 5H ₂ 0 220

Sulfuric acid 60 //

And plated at a temperature of 20 at a cathode current density of 0.5 A / d ^ for 1 minute. The results show that, in the case of the test pieces of Experiment Nos. 19, 22 and 25 (conventional micro-black and chrome plating method), copper was deposited at the cracks, It was confirmed that micro cracks were generated on the chromium plating film. On the other hand, in the test pieces (experiment numbers 17, 18, 20, 21, 23, 24) obtained by the method of the present invention, copper was not deposited and cracks were not generated. Was recognized.

(Example 6 ')

Except that the baths (1) to (5) having the following composition were used as the high-stress nickel plating bath, the total nickel plating thickness was reduced in the same manner as in step (5) of Example 5. 15 μ (Semi-gloss nickel plating 7.5 to 9 ^, first gloss nickel plating 3.5, high stress nickel plating 0.5 to 2 μ ヽ final gloss nickel plating 2 Next, as a result of examining the corrosion resistance by a cast test, almost no 鐯 was observed even after the completion of 15 cycles. Rating, number 9 to 10).

Bath (1)

Nickel chloride (NiC_ ^ ₂ · 6¾0) 3 7 5

Nickel acetate 100 I '

2-Amino-Cial 10 /

PH 4.0

ΟΜΡΪ

0 10 A / d Temperature 25 ° G Stirred air bath (2)

Salts Ihinikkeru _{(NiC_ ^ 2 - 6¾0) 1} 5 09 / £醉酸Anmoniumu 50 // chloride Anmoniumu 1 20 "Sakkari emissions 1.0 /

2-Tin-1,4-diol · 0.1 "PH 4.0

twenty five. C Stirred air bath (3)

Nickel sulfate (N i S0 ₄ 6¾0) 240 nickel chloride _{_{(Ni C 2 6H 2 0)}} 4 0 // boric acid 40, / Application Benefits Chiruami Nporan 1.0 / PH 3.5

5 A / d ^

Stir air bath (4)

Nickel chloride _{(Ni C · 6H 2 0)} 3509- / i boric acid 20 1! EDA-2 N a 20 / ί

Saccharin 2 "

2-Chin-1,4-Di 0.2 l

pH 2

Stir air

Bath (5) PNS-100 bath (Hersho • Chemi-Carne clay, USA)

Nickel chloride (Ni C ^ ₂ · 6¾O) 25 0

PN-l 50 〃

PH (prepared with glacial acetic acid) 4.0

30. G

Stirred air Industrial applicability

The corrosion-resistant plating method according to the present invention provides a coating with high corrosion resistance, and is particularly suitable for plating of parts requiring high corrosion resistance, such as automobile parts, aircraft parts, and electric parts.

Re;

C "iFI

,

Claims

The scope of the claims

1. If necessary, apply a first nickel plating after applying an undercoating to the object to be coated, then apply a high-stress nickel plating, and then apply a final gloss nickel. This is a corrosion-resistant plating method that provides a high corrosion-resistant electrical plating film by applying a plating and finally performing a final plating.

2. If the bath used for high-stress nickel plating is to be used for direct plating after plating in this bath, apply a micro-opening to the plating film. The claim 1 which is selected from a bath for producing and a bath which gives nickel electrodeposition having a stress substantially equal to or higher than that of nickel bath obtained from this bath. Method.

3. The first nickel plating is a semi-gloss nickel plating, a glossy nickel plating, and a two-layer nickel plating with a glossy nickel plating followed by a glossy nickel plating 3. The method according to claim 1 or 2, wherein the final plating is a chrome plating.

4. The total thickness of the plating before high stress nickel plating is about 2 or more, and the thickness of the high stress nickel plating is about 0.5 to 3] 5. 3. The method according to claim 1, wherein the thickness of the plating is not less than about 0.5.

5. The total thickness of the plating before high stress nickel plating is about 5 to 30 *], and the thickness of the final bright nickel plating is about 0.5 to 1 Oί. The method according to range 4.

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