CN101935815A - A kind of alloy coating of transmission line fastener and its preparation process - Google Patents

Abstract

The invention relates to a transmission line fastening piece alloy coating and a preparation process thereof. The alloy coating is characterized by comprising the following components in percentage by weight: 0.045 to 3 percent of aluminum, 0.03 to 3 percent of magnesium, 0.03 to 3 percent of rare earth, 0.01 to 2 percent of copper and the balance of zinc. The preparation process comprises the following steps of: 1) washing a coating piece with an acid and water, namely performing acid washing on the coating piece for 5 to 30 minutes before a hot dip process by adopting 10 to 20 percent hydrochloric acid; and washing the coating piece with the water after the acid washing; 2) fluxing treatment, namely performing fluxing on the coating piece obtained from the step 1) in a fluxing agent for 20 to 120 seconds at the temperature of between 50 and 120 DGE C; and 3) performing the hot dip process. The alloy coating can effectively prolong the anti-corrosion lifetime of a hot dip coating of a fastening piece in a transmission tower in power industry, make the fastening piece of a stressed part of the transmission tower have prolonged anti-corrosion lifetime under complex corrosive environment conditions, ensure that the thickness of a coating is not increased, and simultaneously improve the anti-corrosion lifetime for over 3 times compared with hot-dip plated pure zinc in industry.

Description

A kind of alloy coating of transmission line fastener and its preparation process

[technical field]

The invention relates to a hot-dip plating technology for metal materials of fasteners of transmission lines in the electric power industry, in particular to a hot-dip anti-corrosion coating applied to fasteners between connecting structural parts on transmission line poles and towers in the electric power industry.

[Background technique]

The loss caused by the corrosion damage of steel is huge. In the United States, it costs more than 30 billion U.S. dollars for corrosion damage and repair of steel every year. According to data, China’s annual loss of steel corrosion is about 500 billion yuan, accounting for 10% of the total national product. It can be seen that the corrosion of steel has caused a great waste of materials and energy, and hot-dip galvanizing can effectively improve the corrosion resistance of steel, thereby reducing the loss of steel due to corrosion by 20~ 30%.

The fasteners connecting the stressed parts of the transmission tower are mainly bolts. The anti-corrosion technology is mainly hot-dip galvanized according to the national standard and industrial production. The service life of the fasteners of the stressed parts will directly affect the service life of the entire transmission tower. The fasteners often fail due to corrosion. Therefore, the improvement of the long-term anti-corrosion technology level of the fasteners connecting the stressed parts of the transmission tower can effectively prolong the service life of the transmission tower, reduce the loss of steel, and increase the input and production of the transmission line. out than.

With the development of hot-dip galvanizing anti-corrosion technology, the traditional hot-dip galvanizing method can no longer meet the requirements of industrial production due to its shortcomings such as large zinc consumption and residual zinc dross. Alloy components are often added to the zinc solution to improve the hot-dip process. During the hot-dip plating process, a layer of alloy coating is deposited on the surface of the fastener, which improves the corrosion resistance of the alloy coating and reduces the thickness of the coating, which can improve the anti-corrosion life of hot-dip galvanized components, save the consumption of plating solution, and save resources and energy. Reducing emissions has very good economic and social benefits. At present, due to its wide range of application fields, hot-dip galvanized products are developing rapidly worldwide in the development and research of alloy coating components. Alloy coatings that have appeared include aluminum-zinc alloy coatings, zinc-nickel alloy coatings, zinc-titanium alloy coatings, etc. Although they have achieved certain results in improving the life of coatings, they have not been widely promoted due to high costs and immature technologies. and apply.

At present, with the rapid development of industry worldwide, the discharge of a large amount of industrial waste gas has greatly increased the content of strong corrosive gases such as sulfide and nitrogen oxides in the atmosphere, and the fasteners of transmission towers corrode rapidly in an acidic gas environment. The acid rain formed accelerates the corrosion rate even more, especially in the coastal areas where the marine environment is severely corroded. The transmission line needs to be treated with anticorrosion every two years. Therefore, it is very important to develop and develop an alloy coating suitable for long-term anti-corrosion of transmission line iron tower fasteners, with good technical and economical efficiency, to improve the anti-corrosion life of transmission iron tower fasteners, and to reduce the anti-corrosion and operating costs of transmission lines. significance.

At present, alloy plating solutions and alloy coatings containing various alloy elements are used for hot-dip plating of transmission tower fasteners. Fasteners connected to power transmission tower stress components are hot-dipped with this alloy plating solution in complex corrosion environments. There is no report in the literature at home and abroad to obtain the alloy coating.

[Content of the invention]

The purpose of the present invention is to aim at the above-mentioned defects existing in the prior art, and provide a kind of alloy coating of transmission line fasteners, which can effectively improve the anti-corrosion life of the hot-dip coating of fasteners in power transmission iron towers, and can The fasteners of the transmission tower's stressed parts have a long anti-corrosion life under complex corrosion environment conditions, which can ensure that the anti-corrosion life is more than three times higher than that of industrial hot-dip pure zinc without increasing the thickness of the coating.

Another object of the present invention is to provide a process for preparing an alloy coating for a power transmission line fastener.

An alloy coating for a transmission line fastener provided by the present invention is improved. The alloy coating is prepared from the following components by weight percentage:

0.045-3% of aluminum, 0.03-3% of magnesium, 0.03-3% of rare earth, 0.01-2% of copper, and the balance is zinc.

The first preferred alloy coating for transmission line fasteners provided by the present invention is prepared from the following components by weight percentage:

Aluminum 0.1-2.5%, magnesium 0.12-2%, rare earth 0.1-2%, copper 0.1-1.5%, and the balance is zinc.

In the second preferred alloy coating for transmission line fasteners provided by the present invention, the alloy coating is prepared from the following components by weight percentage:

Aluminum 1-2%, magnesium 0.5-1.5%, rare earth 0.8-1.5%, copper 0.15-1%, and the balance is zinc.

In the third preferred alloy coating for a transmission line fastener provided by the present invention, the rare earth is a mixed rare earth of lanthanum and cerium.

A preparation process for an alloy coating of a transmission line fastener provided by the invention comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 10-20% to carry out pickling before the heating process of the plated parts, and the pickling time is 5-30 minutes, and then wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in a fluxing solution, and perform fluxing at a temperature of 50-120° C., and the fluxing time is 20-120s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt at 460-550°C to obtain an alloy plating solution. Dry the plated piece obtained in step 2) at 120-180°C for 20-60s, and wait for the sample Immediately put the plated parts into the alloy plating solution after the surface turns white, and control the temperature of the alloy plating solution at 460-550°C. After immersion plating for 10-30s, immediately take the sample out of the alloy plating solution for natural cooling.

The preparation process of the first preferred transmission line fastener alloy coating provided by the present invention, said step 2) the preparation of the fluxing solution in the fluxing treatment: 200-400 grams of ZnCl ₂ , 10-30 grams of NaCl, 10- Add 30 grams of NaF to 1 liter of water solvent, stir and mix well.

In the second preferred preparation process of the alloy coating of the transmission line fastener provided by the present invention, the temperature of the fluxing solution in the step 2) in the fluxing treatment is 80°C, and the fluxing time is 60s.

Zinc: the main alloy component of the alloy coating, which acts as a corrosion anode during the corrosion process, and protects the fastener base metal by sacrificing itself; aluminum: a microalloying element, aluminum can form an intermetallic compound with zinc in this content range, forming Adhering to the medium of the coating, the adhesion of the coating is strengthened. And during the crystal growth process of the alloy coating, an aluminum oxide film can be formed on the surface of the coating to protect the alloy coating and improve the corrosion resistance life of the overall coating; Magnesium: a microalloying element, the content of magnesium in this range can improve the corrosion resistance of the coating.

Rare earth (La and Ce mixed rare earth): Microalloying elements, due to the outstanding chemical activity and strong affinity of rare earth, the viscosity of the zinc-aluminum molten plating solution is greatly reduced, the fluidity of the zinc solution is improved, and the wetting angle of the zinc solution is reduced and surface tension to make the coating uniform. And impurities in the plating solution are purified, thereby improving the wettability of the steel base. Make the alloy coating form a bright and complete coating, and the surface corrosion resistance and formability are greatly improved and improved.

Copper: a microalloying element that can reduce the thickness of the alloy layer in the middle of the coating and improve the atmospheric corrosion resistance of the coating.

The corrosion resistance of the alloy is stronger than that of pure metal, and the hot-dip galvanizing process is simple. The existing hot-dip galvanizing equipment can fully meet the needs of industrial production. The appearance time of yellow rust is used as the failure criterion of the alloy coating. Under the same coating conditions, this The corrosion resistance of the alloy-coated bolts of the invention is 8 times higher than that of industrial hot-dip pure galvanized bolts; as the corrosion resistance assessment standard of the alloy coatings, the corrosion resistance of the alloy-coated bolts of the present invention can be reduced under the condition of the same thickness of the coatings. The corrosion resistance is 5-8 times higher than that of industrial hot-dip galvanized bolts. While ensuring the same corrosion life as the industrial bolt coating, the thickness of the alloy coating of the present invention can be reduced to about 30 μm.

Compared with the prior art, the alloy coating of a transmission line fastener provided by the present invention and its preparation process have the following advantages:

1. The alloy coating can effectively improve the anti-corrosion life of the hot-dip coating of fasteners in power transmission towers in the power industry;

2. And it can make the fasteners of the power transmission tower's stressed parts have a long anti-corrosion life under complex corrosion environment conditions;

3. It can ensure that the anti-corrosion life is more than three times longer than that of industrial hot-dip pure zinc without increasing the thickness of the coating;

4. The preparation process is simple and the cost is low;

5. Under the same coating conditions, the corrosion resistance of the prepared alloy-coated bolts is 8 times higher than that of industrial hot-dip pure zinc bolts;

6. The corrosion resistance of the prepared alloy-coated bolts is 5-8 times higher than that of industrial hot-dip pure galvanized bolts.

[Detailed ways]

The alloy coating for a transmission line fastener provided by the present invention and its preparation process will be described in more detail below through specific implementation methods.

[Example 1]

The alloy coating of the transmission line fastener of the present embodiment, wherein the alloy coating is prepared from the following components by weight percentage:

Aluminum 0.045%, magnesium 0.03%, lanthanum and cerium mixed rare earth 0.03%, copper 0.01%, and the balance is zinc.

The preparation process of the alloy coating of the transmission line fastener of the present embodiment comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 10% to carry out the pickling before the heating process of the plated parts, and the pickling time is 5 minutes, and then wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in a fluxing solution, and perform fluxing at a temperature of 50° C., and the fluxing time is 20 s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt them at 460°C to obtain an alloy plating solution. Dry the plated parts obtained in step 2) at 120°C for 20s, and immediately put them on after the surface of the sample turns white. Put the plated parts into the alloy plating solution, and control the temperature of the alloy plating solution to 469 ° C. After dipping for 10 seconds, immediately take the sample out of the alloy plating solution for natural cooling.

Wherein, step 2) preparation of the plating flux in the flux treatment: 200 grams of ZnCl ₂ , 10 grams of NaCl, and 10 grams of NaF are added to 1 liter of water solvent, stirred and mixed evenly; in step 3), the alloy plating solution is made of smelted The alloy ingot is heated to 460°C and melted; the formula of the alloy ingot is the same as that of the coating.

The alloy composition (wt%) of table 1 plating solution

Zn Al Mg rare earth elements copper Surplus 0.045 0.03 0.03 0.01

The alloy bath whose alloy composition is shown in Table 1 is used. The temperature of the alloy bath is 460°C. The plated parts are industrially produced bolts that have not been hot-dipped.

[Example 2]

The alloy coating of the transmission line fastener of the present embodiment, wherein the alloy coating is prepared from the following components by weight percentage:

Aluminum 0.1%, magnesium 0.12%, lanthanum and cerium mixed rare earth 0.1%, copper 0.1%, and the balance is zinc.

The preparation process of the alloy coating of the transmission line fastener of the present embodiment comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 10-20% to carry out pickling before the heating process of the plated parts, and the pickling time is 5-30 minutes, and then wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in a fluxing solution, and perform fluxing at a temperature of 50° C., and the fluxing time is 20 s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt them at 490°C to obtain an alloy plating solution. Dry the plated parts obtained in step 2) at 180°C for 60 seconds, and immediately put them on after the surface of the sample turns white Put the plated parts into the alloy plating solution, control the temperature of the alloy plating solution at 490°C, and after dipping for 30s, immediately take the sample out of the alloy plating solution for natural cooling.

Wherein, step 2) the preparation of plating flux solution in flux treatment: add 250 grams of ZnCl ₂ , 15 grams of NaCl, 10 grams of NaF in 1 liter of water solvent, stir and mix evenly; in step 3), the alloy plating solution is made of smelted The alloy ingot is heated to 460-550°C and melted; the formula of the alloy ingot is the same as that of the coating.

The alloy composition (wt%) of table 2 plating solution

Zn Al Mg rare earth elements copper Surplus 0.1 0.12 0.1 0.1

The alloy bath whose alloy composition is shown in Table 2 is used. The temperature of the alloy bath is 490°C. The plated parts are industrially produced bolts that have not been hot-dipped.

[Example 3]

The alloy coating of the transmission line fastener of the present embodiment, wherein the alloy coating is prepared from the following components by weight percentage:

Aluminum 2%, magnesium 1.5%, lanthanum and cerium mixed rare earth 1.5%, copper 1%, and the balance is zinc.

The preparation process of the alloy coating of the transmission line fastener of the present embodiment comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 20% to pickle the plated parts before the heating process, pickle for 30 minutes, and wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in the fluxing solution, and perform fluxing at a temperature of 120° C., and the fluxing time is 120s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt them at 520°C to obtain an alloy plating solution. Dry the plated parts obtained in step 2) at 160°C for 40 seconds, and immediately put them on after the surface of the sample turns white Put the plated parts into the alloy plating solution, and control the temperature of the alloy plating solution at 520°C. After dipping for 20s, immediately take the sample out of the alloy plating solution for natural cooling.

Wherein, step 2) preparation of the plating flux in the fluxing treatment: 400 grams of ZnCl ₂ , 30 grams of NaCl, and 30 grams of NaF are added in 1 liter of water solvent, stirred and mixed uniformly: in the step 3), the alloy plating solution is made of smelted The alloy ingot is heated to 550°C and melted; the formula of the alloy ingot is the same as that of the coating.

The alloy composition (wt%) of table 3 plating solution

Zn Al Mg rare earth elements copper Surplus 2 1.5 1.5 1

The alloy bath whose alloy composition is shown in Table 3 is used. The temperature of the alloy bath is 520°C. The plated parts are industrially produced bolts that have not been hot-dipped.

[Example 4]

The alloy coating of the transmission line fastener of the present embodiment, wherein the alloy coating is prepared from the following components by weight percentage:

Aluminum 3%, magnesium 3%, lanthanum and cerium mixed rare earth 3%, copper 2%, the balance is zinc.

The preparation process of the alloy coating of the transmission line fastener of the present embodiment comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 20% to pickle the plated parts before the heating process, pickle for 30 minutes, and wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in the fluxing solution, and perform fluxing at a temperature of 120° C., and the fluxing time is 20-120s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt them at 550°C to obtain an alloy plating solution. Dry the plated parts obtained in step 2) at 190°C for 50 seconds, and immediately put them on after the surface of the sample turns white. Put the plated parts into the alloy plating solution, and control the temperature of the alloy plating solution to 550°C. After dipping for 20s, immediately take the sample out of the alloy plating solution for natural cooling.

Wherein, step 2) preparation of the plating flux in the fluxing treatment: 280 grams of ZnCl ₂ , 15 grams of NaCl, and 20 grams of NaF are added in 1 liter of water solvent, stirred and mixed evenly; in step 3), the alloy plating solution is made of smelted The alloy ingot is heated to 550°C and melted; the formula of the alloy ingot is the same as that of the coating.

The alloy composition (wt%) of table 4 plating solution

Zn Al Mg rare earth elements copper Surplus 3 3 3 2

The alloy bath whose alloy composition is shown in Table 4 is used. The temperature of the alloy bath is 550°C. The plated parts are industrially produced bolts that have not been hot-dipped.

[Example 5]

The alloy coating of the transmission line fastener of the present embodiment, wherein the alloy coating is prepared from the following components by weight percentage:

Aluminum 2.5%, magnesium 2%, lanthanum and cerium mixed rare earth 2%, copper 1.5%, and the balance is zinc.

The preparation process of the alloy coating of the transmission line fastener of the present embodiment comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 20% to pickle the plated parts before the heating process, pickle for 30 minutes, and wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in the fluxing solution, and perform fluxing at a temperature of 120° C., and the fluxing time is 120s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt them at 490°C to obtain an alloy plating solution. Dry the plated parts obtained in step 2) at 170°C for 50 seconds, and immediately put them on after the surface of the sample turns white. Put the plated parts into the alloy plating solution, control the temperature of the alloy plating solution at 490°C, and after immersion plating for 15s, immediately take the sample out of the alloy plating solution for natural cooling.

Wherein, step 2) preparation of the plating flux in the flux treatment: 300 grams of ZnCl ₂ , 20 grams of NaCl, and 20 grams of NaF are added to 1 liter of water solvent, stirred and mixed evenly; in step 3), the alloy plating solution is made of smelted The alloy ingot is heated to 500°C and melted; the formula of the alloy ingot is the same as that of the coating.

The alloy composition (wt%) of table 5 plating solution

Zn Al Mg rare earth elements copper Surplus 2.5 2 2 1.5

The alloy bath whose alloy composition is shown in Table 5 is used. The temperature of the alloy bath is 490°C. The plated parts are industrially produced bolts that have not been hot-dipped.

[Example 6]

The alloy coating of the transmission line fastener of the present embodiment, wherein the alloy coating is prepared from the following components by weight percentage:

Aluminum 1%, magnesium 0.5%, lanthanum and cerium mixed rare earth 0.8%, copper 0.15%, and the balance is zinc.

The preparation process of the alloy coating of the transmission line fastener of the present embodiment comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 20% to pickle the plated parts before the heating process, pickle for 30 minutes, and wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in the fluxing solution, and perform fluxing at a temperature of 120° C., and the fluxing time is 120s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt them at 500°C to obtain an alloy plating solution. Dry the plated parts obtained in step 2) at 130°C for 45 seconds, and immediately put them on after the surface of the sample turns white. Put the plated parts into the alloy plating solution, and control the temperature of the alloy plating solution at 470°C. After dipping for 25s, immediately take the sample out of the alloy plating solution for natural cooling.

Wherein, step 2) preparation of the plating flux solution in the flux treatment: add 350 grams of ZnCl ₂ , 25 grams of NaCl, and 20 grams of NaF into 1 liter of water solvent, stir and mix evenly; in step 3), the alloy plating solution is made of smelted The alloy ingot is heated to 550°C and melted; the formula of the alloy ingot is the same as that of the coating.

The alloy composition (wt%) of table 6 plating solution

Zn Al Mg rare earth elements copper Surplus 1 0.5 0.8 0.15

The alloy bath with the alloy composition shown in Table 6 is used. The temperature of the alloy bath is 500°C. The plated parts are industrially produced bolts that have not been hot-dipped.

[Example 7]

The alloy coating of the transmission line fastener of the present embodiment, wherein the alloy coating is prepared from the following components by weight percentage:

Aluminum 2%, magnesium 0.15%, lanthanum and cerium mixed rare earth 2%, copper 1.5%, and the balance is zinc.

The preparation process of the alloy coating of the transmission line fastener of the present embodiment comprises the following steps:

1) Pickling and water washing plating

Use hydrochloric acid with a concentration of 20% to pickle the plated parts before the heating process, pickle for 30 minutes, and wash with water after pickling;

2) Assisted plating treatment

Place the plated piece obtained in step 1) in the fluxing solution, and perform fluxing at a temperature of 80° C., and the fluxing time is 60 s;

3) Hot-dip plating

Mix the above-mentioned components by weight percentage and melt them at 500°C to obtain an alloy plating solution. Dry the plated parts obtained in step 2) at 120°C for 200s. Put the plated parts into the alloy plating solution, and control the temperature of the alloy plating solution to 500°C. After dipping for 30s, immediately take the sample out of the alloy plating solution for natural cooling.

Wherein, step 2) preparation of the plating flux in the flux treatment: 300 grams of ZnCl ₂ , 20 grams of NaGl, and 20 grams of NaF are added in 1 liter of water solvent, stirred and mixed evenly; in step 3), the alloy plating solution is made of smelted The alloy ingot is heated to 500°C and melted; the formula of the alloy ingot is the same as that of the coating.

The alloy composition (wt%) of table 7 plating solution

Zn Al Mg rare earth elements copper

Surplus 2 0.15 2 1.5

The alloy bath whose alloy composition is shown in Table 7 is used. The temperature of the alloy bath is 500°C. The plated parts are industrially produced bolts that have not been hot-dipped.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: a skilled person reads this After the description of the application, the specific embodiments of the present invention can still be modified or equivalently replaced, but none of these modifications or changes departs from the protection scope of the pending claims of the present application.

Claims (7)

1. transmitting line fastening piece alloy layer is characterized in that described alloy layer is prepared from by by weight percentage following component:

Aluminium 0.045-3%, magnesium 0.03-3%, rare earth 0.03-3%, copper 0.01-2%, surplus is a zinc.

2. alloy layer according to claim 1 is characterized in that described alloy layer is prepared from by by weight percentage following component:

Aluminium 0.1-2.5%, magnesium 0.12-2%, rare earth 0.1-2%, copper 0.1-1.5%, surplus is a zinc.

3. alloy layer according to claim 1 is characterized in that described alloy layer is prepared from by by weight percentage following component:

Aluminium 1-2%, magnesium 0.5-1.5%, rare earth 0.8-1.5%, copper 0.15-1%, surplus is a zinc.

4. according to claim 1 or 2 or 3 described alloy layers, it is characterized in that described rare earth is lanthanum and cerium mishmetal.

5. the preparation technology of an alloy layer according to claim 1 may further comprise the steps:

1) pickling washing plating piece

Employing concentration is pickling, the pickling time 5-30 minute before the hydrochloric acid of 10-20% carries out the hot progress of plating piece, washes after the pickling;

2) help plating to handle

The plating piece that step 1) is obtained places quickening liquid, helps plating under 50-120 ℃ of temperature, and helping the plating time is 20-120s;

3) hot dip process

The component of the above-mentioned meter of percentage is by weight mixed, fusion under 460-550 ℃ of condition, obtain alloy electroplating bath, with step 2) plating piece that obtains dries 20-60s under 120-180 ℃ of temperature, treat immediately plating piece to be put to alloy electroplating bath after the specimen surface whiting, control alloy electroplating bath temperature is under the 460-550 ℃ of condition, behind the immersion plating 10-30s, immediately sample is proposed alloy electroplating bath and carries out naturally cooling.

6. preparation technology according to claim 5 is characterized in that described step 2) help the preparation of plating quickening liquid in the processing: 200-400 is restrained ZnCl ₂, 10-30 restrains NaCl, and 10-30 restrains NaF, adds in the 1 premium on currency solvent, mixes.

7. preparation technology according to claim 5 is characterized in that described step 2) help plating handle in the temperature of quickening liquid be 80 ℃, helping the plating time is 60s.