KR830001328B1 - Hot-Plated Lead Alloys - Google Patents

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Description

Hot-Plated Lead Alloys

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead alloy for hot dip plating, and in particular, can promote the formation of an alloy phase between the base of the plated material and the plating layer, and also has excellent corrosion resistance, solderability, and sacrificial bipolar property. The present invention relates to a lead alloy for hot-dip plating capable of forming a plating layer having high properties and high hardness.

Conventionally, in order to impart corrosion resistance to steel plates, wire rods, pipes, various containers, and various mechanical parts made of steel, copper and copper alloys, Ni and Ni alloys, and the like, Although hot dip plating is performed, satisfactory results have not been obtained in terms of plating adhesion. For example, in the case of hot lead plating on steel members, iron and lead do not form intermetallic compounds or solid solutions, and thus have not been satisfactory.

Therefore, in order to improve the wettability or plating adhesion to the base material of the plated material, it is proposed to add 0.3-30.0% by weight of tin to lead, which is currently widely used.

However, even with this Pb-Sn alloy for hot dip plating, satisfactory corrosion resistance was not obtained due to insufficient formation of an alloy phase between the base of the plated material and the plating layer, and the solderability was also extremely poor.

The main object of the present invention is to promote the formation of an alloy phase between the possession of the plated material and the plated layer to obtain a solid plating adhesion, further improve the corrosion resistance of the plated layer, and further provides a solder alloy for hot-dip plating with solderability. It is.

Another object of the present invention is to provide a lead alloy for hot-dip plating capable of forming a plating layer imparting sacrificial anode properties.

Still another object of the present invention is to provide a hot alloy lead alloy having a high hardness.

According to the invention, tin: (1) 0.3-30.0% by weight, preferably 0.3-8.0% by weight, (2) at least one selected from phosphorus, tin phosphide, zinc phosphide, antimony phosphide, bismuth phosphide and lead phosphide A lead alloy for hot-dip plating of 0.001-0.3% by weight, preferably 0.05-0.3% by weight, and (3) balance of lead and unavoidable impurities in terms of phosphorus content is provided.

In this alloy, phosphorus in the alloy contributes to improvement of the wettability of the plated material, promotion of alloy phase formation between the base and the plated layer, and formation of a plated layer having improved corrosion resistance and solderability. The alloy may again contain zinc: 0.1-7.0% by weight, preferably 1-6% by weight, or antimony: 0.5-35.0% by weight, preferably 3-10% by weight, if necessary. The sacrificial anode is imparted to the silver plating layer, and the antimony contributes to the improvement of the hardness of the plating layer.

The inventors of the present invention promote the formation of alloy phases formed between the material to be plated and the plating layer when performing the hot dip plating process, thereby obtaining a strong adhesion and further improving the corrosion resistance of the plating layer and also having a solderability. When the lead alloy for gold was obtained and studied, the following results were obtained.

(a) phosphorus (hereinafter referred to as P) and tin phosphide (hereinafter referred to as P-Sn) in a lead alloy containing 0.5-3.0% by weight of conventional tin, preferably 0.3-8.0% by weight of tin; At least among zinc phosphide (hereinafter referred to as P-Zn), antimony phosphide (hereinafter referred to as P-Sb), bismuth phosphide (hereinafter referred to as P-Bi), and phosphide (hereinafter referred to as P-Pb) When one or more kinds are contained, wettability to the base material is improved during hot dip plating, alloy formation is promoted between the plating layer and the base material, so that a plating layer with extremely high adhesion can be formed, and the P component By containing, the corrosion resistance further improves and the plating layer which improved the solderability is obtained.

(b) Furthermore, when zinc is added to a lead alloy containing phosphorus or a phosphorus compound as described in the above (a), the electrode potential is lower than that of the zinc-plated metal (for example, steel), thereby providing sacrificial bipolarity. To obtain coated plating layers

(c) In addition, when antimony is added to the lead alloys described in the above (a) and (b), a plating layer having improved hardness can be obtained.

The present invention has been made on the basis of the above results, and the following elements or compounds are added to a lead alloy containing Sn: 0.3-30.0% by weight, preferably 0.3-8.0% by weight, to prepare a hot alloy lead alloy. .

(1) at least one or more of P, P-Sn, P-Zn, P-Sb, P-Bi, and P-Pb: 0.001-0.3% by weight, preferably 0.05-0.3% by weight, also required according to

(2) Zn: 0.1-7.0 wt% preferably 1-6 wt% or

(3) Sb: 0.5-35.0 weight%, Preferably it is 3-10 weight%.

As a result, P in the alloy improves the wettability to the base, promotes the formation of the alloy phase between the base and the plated layer, improves the solderability and the corrosion resistance of the plated layer, and imparts sacrificial polarity to the plated layer by the Zn. In addition, the hardness of the plating layer is improved by the Sb.

The reason for limiting the numerical value of the component content of the lead alloy of the present invention is as follows.

(A) P, P-Sn, P-Zn, P-Sb, P-Bi and P-Pb:

If the P content is less than 0.001% by weight, there are too few compounds formed on the base of the plated material by the reaction between P and the metal of the plated material, so that sufficient alloy phase can not be formed between the base and the plating layer, while the P content If the content is more than 0.3% by weight, the alloy phase becomes too thick to cause peeling of the plating layer, so that the P content is set at 0.001-0.3% by weight.

The best result can be obtained at 0.05-0.3% by weight of P content.

(B) Zn:

Zn is generally known to have a lower electrode potential than a plated material, for example, steel. Therefore, by applying Zn, sacrificial bipolarity is imparted to the lead alloy plating layer, and if the content is less than 0.1% by weight, the content is too small to be plated. It was not possible to lower the dislocation of the plating layer with respect to the ash, and on the other hand, when it exceeds 7.0% by weight, white rust was generated on the surface of the plating layer, so the content was set at 0.1-7.0% by weight.

In particular, at 1-6% by weight, the most satisfactory results can be obtained.

(C) Sb:

If the content of Sb is less than 0.5% by weight, it is too small to obtain sufficient hardness improvement effect. On the other hand, if the content of Sb exceeds 35.0% by weight, the melting point of the Pb alloy exceeds 400 °, making it difficult to obtain a plated layer having a uniform thickness. Therefore, the content was set at 0.5-35.0 weight%. In addition, particularly good results can be obtained at 3 to 10% by weight.

The invention will be more clearly understood in the following examples.

EXAMPLE

First, a plated material of each of extension, stainless steel, copper, and brass having a square of 100 mm on one side and a thickness of 0.5 mm was prepared.

At the same time, the following composition of ingredients,

Flux was prepared.

In addition, alloys of Pb alloys of the present invention having the same composition as shown in Tables 1 to 3 (wherein P compounds in the table are represented by P content) and the conventional Pb alloys 1-13. Ally baths were prepared respectively.

TABLE 1

TABLE 2

TABLE 3

For each of the above-described plated materials, ① degreased by dipping 10-30 minutes in 80-90 ° C. trichloroethylene or an alkaline solution, ② washed with water, and ③ in 5--15% hydrochloric acid solution at room temperature. It was immersed for 10 minutes, washed with acid, and 4) pretreated with water.

Next, the following flux treatment was performed on the plated material subjected to the pretreatment:

In the aqueous flux treatment of mild steel and stainless steel in each of the plating materials, a mixed aqueous solution obtained by adding 350 g of the above-mentioned composition to 1 l of aqueous hydrochloric acid at a concentration of 2-3% is used. A mixed aqueous solution obtained by containing 270 g of the flux in 1 L of 3% aqueous hydrochloric acid was used.

In the bonding of the respective plated materials with the alloy as shown in the first to third tables, after immersion in the mixed flux aqueous solution prepared as described above for 10-30 seconds, the coating is performed with the above-described melt flux. A specimen was prepared by immersing it in a Pb alloy bath having a composition as shown in the first to third tables having a bath temperature of 320 to 360 ° C. for 10 to 20 seconds.

As a result, on the surface of each specimen obtained by immersing the plated material in the bath of Pb alloy 1-46 of the present invention, a plated layer of a Pb alloy having a uniform thickness of 8-10 mu was obtained in an extremely good plating state. In addition, conventional Pb alloy On the surfaces of the specimens immersed in the baths of 1-4, 8-11, and 13, the plating layer of Pb alloy having a thickness of 8-10 mu is in the normal plating state, and on the surface of the specimens immersed in the bath of conventional Pb alloy 12 Plating layers of Pb alloys having a thickness of 8-10 µ were each obtained in a poor plating state, and plating was impossible with respect to specimens immersed in a bath of conventional Pb alloy 5-7.

Next, for the present invention Pb alloy 1-25 and conventional Pb alloys 1-4 and 8-11, a wettability test was conducted under the following conditions for the purpose of testing the wettability to the base material:

A plate of 30 mm square, 0.2 mm thick, mild steel, stainless steel, copper, and brass was prepared, and the plate was subjected to the same treatment as described above to clean the surface, and then the molar ratio was 1 :. Pb of the present invention shown in the first table of the present invention, shown in Table 1, for 9-10 seconds immersion in a flux aqueous solution containing 1 ZnCl ₂ and NH ₄ Cl at a rate of 200 g per 1 mol. Alloy 1-11 and conventional Pb alloy 1-4, inventive Pb alloy 12-17 and conventional Pb alloy 5,6, inventive Pb alloy 18-21 and conventional Pb alloy 8,9, also inventive Pb alloy 22-25 and the conventional Pb alloys 10 and 11 were placed on a plate of mild steel, stainless steel, copper and brass, respectively, with one Pb alloy applied to each sheet, and then placed in an inert gas atmosphere having a temperature of 350 ° C. Heated in an electric furnace for 30 seconds and pulled out of here. And the area (wet area) of each Pb alloy spread on the surface of each board was measured.

The results are shown together in the first table. In this table, it is evident that in the same Sn content, the Pb alloy of the present invention has a very large wet area compared to the conventional Pb alloy, that is, the wettability is extremely excellent.

Next, for the purpose of testing the solderability of the plating layer of the Pb alloy of the present invention, according to the combination of the Pb alloy and the specimen as shown in the first table (test size, plating conditions) and Under the same conditions, a solderability test plate plated on the surface was prepared, and a predetermined amount of ordinary lump-shaped solder was placed on the surface of the test plate, and subjected to heat treatment in the same manner as the wettability test. The area of the solder spread on all of the Pb alloys of the present invention was much larger than that of the conventional Pb alloy having the same Sn content, and on average, about 120% of the solder area of the conventional Pb alloy.

Moreover, about the plating layer of this invention Pb alloy 26-35 containing Sb, Zn, and Sb, and the conventional Pb alloy 12, the hardness was measured and this is shown together in the 2nd table, In this table, this invention Pb alloy It is apparent that 26-35 has an extremely high hardness as compared to the conventional Pb alloy 12.

In addition, when 5% saline at a temperature of 35 ° C. was sprayed on the surface of each specimen plated with Pb alloy 36-46 and conventional Pb alloy 13, spraying time 360 was applied to the surface of the plated layer of Pb alloy 36-46. No abnormality was observed even after -400 hours, and red rust occurred at a time elapsed time as shown in the third table, respectively. Two points of red blue occurred. As a result, it is clear that the Pb alloy plating of the present invention exhibits extremely excellent corrosion resistance as compared with the conventional Pb alloy plating, and in particular, the Pb alloy plating of the present invention containing Zn shows even better corrosion resistance. It is obvious.

As described above, the Pb alloy of the present invention has extremely excellent wettability due to the action of P, and is required for corrosion resistance and solderability, which is remarkably superior to conventional Pb alloy plating on various metal material surfaces. As a result, Pb alloy plating with sacrificial bipolarity and high hardness can be performed.

Aspects of the Preferred Embodiments

(1) A lead alloy for hot-dip plating as described in the claims, characterized in that it contains 0.3-8% by weight of tin.

(2) A lead alloy for hot-dip plating according to the claims, which contains 0.05-0.3% by weight of phosphorus, at least one of phosphorus, phosphate, zinc phosphide, antimony phosphide, bismuth phosphide, and lead phosphate.

(3) 0.3-30.0% by weight of tin, at least one or more of phosphorus, phosphate, zinc phosphide, antimony phosphide, bismuth phosphide, and lead phosphate at 0.001-0.3% by weight, 0.1-7.0% by weight of zinc, A lead alloy for hot-dip plating composed of lead and unavoidable impurities as the remainder.

(4) The lead alloy for hot-dip plating according to the above item 3, containing 0.3-8% by weight of tin.

(5) The lead alloy for hot-dip plating according to the above item 3, which contains 0.05-0.3% by weight of at least one of phosphorus, phosphate, zinc phosphide, antimony phosphide, bismuth phosphide, and lead phosphate in a phosphorus content.

(6) The lead alloy for hot-dip plating according to the above item 3, containing 1-6% by weight of zinc.

(7) 0.3-30.0 wt% tin, 0.001-0.3 wt% antimony 0.5-35.0 wt%, with phosphorus content of at least one or more of phosphorus, phosphate, zinc phosphide, antimony phosphide, bismuth phosphide and lead phosphide; Lead alloy for hot-dip plating containing lead and unavoidable impurities as the remainder.

(8) The lead alloy for hot-dip plating according to the above item 7, which contains 0.3-8% by weight of tin.

(9) The lead plating for hot-dip plating according to the above item 7, which contains 0.05-0.3% by weight of at least one of phosphorus, phosphate, zinc phosphide, antimony phosphide, bismuth phosphide, and lead phosphate in a phosphorus content.

(10) The lead alloy for hot-dip plating according to the above item 7, which contains 3-10% by weight of antimony.

(11) 0.3-30.0% by weight of tin, 0.001-1.3% by weight of phosphorus, phosphate, zinc phosphide, antimony phosphide, bismuth phosphide and lead phosphate in a phosphorus content of 0.001-1.3% by weight, zinc 0.1-7.0% by weight antimony Lead alloy for hot-dip plating consisting of 0.5-35.0% by weight and the balance lead and unavoidable impurities.

(12) The lead alloy for hot-dip plating according to item 11, containing 0.3-8% by weight of tin.

(13) The lead alloy for hot-dip plating according to the above-mentioned 11, containing 0.05-0.3% by weight of at least one of phosphorus, phosphate, zinc phosphide, antimony phosphide, bismuth phosphide, and lead phosphate.

(14) The lead alloy for hot-dip plating according to item 11, containing 1-6% by weight of zinc.

(15) The lead alloy for hot-dip plating according to item 11, containing 3-10% by weight of antimony.

Claims (1)

In the lead alloy for hot-dip plating containing 0.3-30.0% by weight of tin, at least one or more of phosphorus, tin phosphide, zinc phosphide, antimony phosphide, bismuth phosphide, and lead phosphide in the lead alloy is 0.001-0.3% by weight A lead alloy for hot-dip plating, comprising: improving the wettability of the material to be plated, promoting the formation of an alloy phase between the material and the plating layer, and improving solderability and corrosion resistance of the plating layer.