KR101291556B1 - Barrel plating method using trivalent chromium - Google Patents

Abstract

PURPOSE: A barrel plating method using trivalent chromium is provided to obtain an environment-friendly effect and an excellent yield by performing trivalent chromium plating, thereby reducing manufacturing costs. CONSTITUTION: A barrel plating method using trivalent chromium is as follows. A plating tub (2) is filled with trivalent chromium plating solution (4) including trivalent chromium, humectants, and a nickel material. An anode body (6) is installed in the plating tub so that a copper cathode bus bar (10), which is extended across a space between rotary shafts of both ends of a barrel (8), is fixed transversely by being spaced from the bottom surface of the barrel which is axially rotated. A conductive ball (12) and an object (14) to be plated are input inside the barrel, and an electric current is applied to the barrel. The object to be plated inside the plating solution in which electric current is applied is plated so that the continuous growth of plating is possible.

Description

Barrel plating method using trivalent chromium {BARREL PLATING METHOD USING TRIVALENT CHROMIUM}

The present invention relates to a plating method, and more particularly to a method capable of performing trivalent chromium plating while taking the barrel plating method.

In general, when setting the plating method and plating conditions, it is necessary to consult with the customer based on the plating standard to suit the application. Therefore, considering the characteristics of the material, size, shape, and appearance of the product to set the plating method suitable for the function and use.

Plating method can be largely divided into rack plating and barrel plating.

Rack plating is a method of plating a plated body by hanging it on a hook or a hook, and barrel plating is a method of placing a large number of plated materials in one barrel. Rack plating is advantageous in that it can be plated with less restrictions on the size and shape of the product, the uniformity of plating thickness is good, and the time required to obtain a constant plating thickness is shorter than that of barrel plating. There is a disadvantage in that workability is inferior and manpower consumption is high because it requires a procedure of hanging and detaching one by one.

Barrel plating can be plated at one time by putting a large amount of small plated body into the barrel at once, so it is highly productive and can be polished due to its characteristics, and it does not use a rack, so it does not need to hang or remove the object to be plated. On the other hand, there is a disadvantage that it is not applicable to a large plated body, and the uniformity of the plating thickness is not as good as that of the rack plating, and it takes longer time to obtain the same plating thickness as compared with the rack plating. In addition, higher voltages should be used rather than rack plating, and care must be taken when conducting electricity.

On the other hand, there are many platings in the plating material such as nickel tungsten alloy plating, tin copper alloy plating, etc., but the physical properties thereof do not reach chromium plating. For this reason, high-grade products that require beautiful decoration and chemical resistance are often made of chrome plating as a finishing film.

Chromium plating is mainly used for high quality products that require abrasion resistance, heat resistance, corrosion resistance, and lubrication properties.Chromium plated plating material has high hardness, smoothness and luster, and it does not discolor in the air, and it has high corrosion resistance and wear resistance. Aesthetics are given.

The chromium used for chromium plating is trivalent chromium and hexavalent chromium. Trivalent chromium is stable and harmless to human body, whereas hexavalent chromium is known to be harmful to human body. Since hexavalent chromium is scattered, it is dangerous for plating workers, it is not easy to treat waste water, and it is buried in the product. It is contaminated in Europe because it contaminates water and soil during disposal.

Trivalent chromium is not generalized compared to hexavalent chromium, which is because trivalent chromium is darker and less glossy than hexavalent chromium, and trivalent chromium is more expensive than hexavalent chromium. .

Nevertheless, since hexavalent chromium has been defined as a hazardous substance, plating methods using environmentally friendly trivalent chromium have been sought, and practical use is being made for decorative plating on electric and electronic products such as washing machines and mobile phone parts.

By the way, the plating method of trivalent chromium is mostly plating using a rack.

Barrel plating using trivalent chromium is defective due to deterioration and poor yield due to problems such as staining of plating surface, deterioration of adhesion of plating and uneven surface of plating products due to chrome electrical and barrel plating characteristics. It does not apply to.

Therefore, barrel plating using trivalent chromium can produce large quantities of products that are environmentally friendly, have excellent plating properties, and have small sizes, and will have great response from many people.

Domestic patent registration No. 10-0550860 "Rotary barrel plating device"

Accordingly, an object of the present invention is to provide a plating method capable of barrel plating using trivalent chromium that is environmentally friendly and has excellent plating properties.

The present invention according to the above object, while filling the plating bath (2) with a trivalent chromium plating solution (4) containing 20 ° ~ 30 ° in the bume ratio and contains a trivalent chromium, a humectant and a chloride bath material, the chloride bath material Silver includes any one or more of barium chloride and ammonium chloride, and the plating bath 2 filled with the trivalent chromium plating solution 4 is provided with a positive electrode body 6 and is rotated between both ends of the barrel barrel body 8 which rotates. The negative electrode busbar 10 of the same material extending transversely is formed to be horizontally fixed to the bottom surface in the barrel barrel 8 which is axially rotated, and the conductive ball 12 and The plated body 14 is put together at a volume ratio of 6: 4 to conduct electricity using the positive electrode 6 and the negative electrode busbar 10, but the negative busbar 10 has a high current of 17 to 20 V and 400 to 500 A. Is applied so that the unit current density is 2 to 3 A / mm 2, and each of the plated bodies 14 in the plating solution 4 that is uniformly energized through the conductive balls 12. Using trivalent chromium characterized in that a plating film having a thickness of 0.1 to 2 μm is formed on the to-be-plated body 14 by plating 40 to 80 minutes at a plating bath temperature of 25 to 35 ° C. to enable continuous plating on the substrate. Barrel plating method.

Since the present invention performs trivalent chromium plating, it is not only environmentally friendly, but also has excellent advantages such as plating products having excellent abrasion resistance, heat resistance, corrosion resistance, lubricity, decorative aesthetics, and plating by barrel plating. In addition, despite the mass production of trivalent chromium plated products, the defective rate is in the range of 2 to 3%, so the yield is quite good, which has the advantage of lowering the manufacturing cost of the product.

1 is a schematic configuration diagram of a trivalent chrome barrel plating apparatus according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, while performing the barrel plating using trivalent chromium, the defective rate is less than 10%, preferably to be almost 2 to 3%.

1 is a schematic configuration diagram of a trivalent chromium barrel plating apparatus according to an embodiment of the present invention, the plating bath (2) for storing the plating solution (4), and transportable into the plating bath (2) in a horizontal lying state It is provided with the barrel barrel 8 installed rotatably.

Barrel cylinder (8) is shaft-mounted on the left and right lifting platform (16), and has an opening for inserting the plated body (14) or to remove the plated plated body 14 and the door attached to the opening, the plating bath (2) The large number of remaining holes 9 for allowing the plating liquid 4 in the inside to flow into the cylinder is formed evenly on the entire surface of the cylinder.

A driven gear 18 is formed on one of the left and right sides of the barrel barrel 8, and the driven gear 18 is connected to the drive gear 20 provided on the left and right lift tables 16 and driven by the rotation of the external motor 22. As the gear 20 transmits rotation, the barrel cylinder 8 is rotated.

According to the present invention, a negative electrode is formed in the barrel barrel 8, and the same negative electrode bus bar 10 that intersects between the rotary shafts of the barrel barrel 8 is spaced apart from the bottom surface of the barrel barrel 8. Extend horizontally and position it securely. That is, the barrel barrel 8 is axially rotated by being installed on the left and right lifting tables 16, but the same negative electrode busbar 10 is fixed to be spaced apart from the bottom without being rotated. The same negative electrode booth bar 10 is electrically connected to the negative power source through an external negative electrode cable.

In addition, the plating bath 2 in which the barrel barrel 8 is submerged is configured such that the anode 6 is installed.

Trivalent chromium used in the present invention has about three times the hardness of nickel, but the electrical conductivity is only about half that of nickel due to the chromium properties.

In addition, barrel plating requires that all the plated material 14 to be introduced should be under uniform and constant current influence because a large amount of the plated body 14 is put into the barrel barrel 8. When the plating body 14 exists, the film growth by the electrolytic plating solution of trivalent chromium 4 stops. After that, even if the plated body 14 enters the current-affecting zone, the formed trivalent chromium makes the film growth of the electrolytic plating solution 4 difficult due to the low electrical conductivity, and even if the layer grows, it is eventually defective due to the multilayer. It becomes a plated body to be plated.

Therefore, in the present invention, conduction management and plating solution management are performed to allow barrel plating using trivalent chromium.

First, as related to the current management of the present invention, the positive electrode 6 is configured in the form of a plate or mesh and uses an iridium coated positive electrode. The iridium anode body 6 employed in the present invention contributes to increasing the current efficiency.

In the negative electrode structure, as shown in FIG. 1, a similar negative electrode bus bar 10 transversely between the rotational axes of the left and right ends of the barrel barrel 8 is positioned near the bottom in the barrel barrel 8. Extending and fixedly positioned. The same negative electrode busbar 10 was formed to extend from side to side to allow the current influence zone to be evenly formed at almost all positions in the barrel barrel 8.

In addition, the inventors of the present invention have a homogeneous cathode booth which is fixed and integrally laid horizontally as shown in FIG. 1 so that the trivalent chromium plating solution 4 with weak electrical conductivity can be electrolyzed and adhered to and grown on the conductive material 14. In the case of the bar 10, it has been confirmed through many experiments that the unit current density of the same material negative electrode busbar 10 is most preferably 2 to 3 A / mm 2, and the current required for the rack plating to improve the current efficiency. 2 to 3 times of the high current was implemented to flow in the cathode busbar (10). That is, in the present invention, the conduction current flowing in the negative electrode busbar 10 was 400-500A, and preferably high current of 450A, and the diameter of the integrated homogeneous negative electrode busbar 10 was set to accommodate up to 700A. . At this time, the use voltage in the present invention is 17 ~ 20V.

In the present invention, the positive electrode body and the negative electrode body are constituted as described above, and the current influence zone of the same material negative electrode busbar 10 is extended to and uniformly applied to each of the plated bodies 14 in the barrel barrel 8. The conductive ball 12 is also put together with the plating body 14. The mixing ratio of the conductive balls 12 and the plated body 14, which is required to enlarge and uniformly form the current-affecting zone, is 6: 4, and the size of the conductive balls 12 is larger than that of the plated body 14. It can be small and up to 1/2 smaller.

The current by the same negative electrode busbar 10 is transferred directly to the plated body 14 near the negative electrode busbar 10, even though the plated body 14 is located at a position away from the negative electrode busbar 10. The conductive balls 12 near the negative electrode busbar 10 can be easily and continuously delivered.

Next, the plating liquid composition and the management thereof in the present invention will be described. The plating solution 4 used in the present invention is a trivalent chromium plating solution having a concentration of 20 ° to 30 ° with a Be 'ratio, and includes trivalent chromium, a humectant, a chlorinated bath substance, and the like.

If the concentration of the trivalent chromium plating solution 4 is less than 20 ° in the bleaching ratio, the plating speed may be slowed and the plating surface may be inferior. If the concentration exceeds 30 ° in the bleaching ratio, precipitation may occur with unnecessary chemical loss. There is a critical significance of the concentration range to occur.

The humectant contained in the trivalent chromium plating solution 4 acts to cause the plating to adhere well to the surface of the plated body 14. Examples of the chloride bath material for the composition of the chloride bath include barium chloride and ammonium chloride. Iron may also be added. The trivalent chromium plating solution 4 of the present invention forms a chloride bath by inputting a chloride bath material. The chloride bath has a good characteristic of high current efficiency and high plating speed.

And the plating bath temperature in the present invention is maintained at 25 ~ 35 ℃. If the temperature is less than 25 ℃ crystallization and precipitation of the dissolved chemicals occurs, if the temperature exceeds 35 ℃ there is a critical significance that the plating color can be darkened by the action of barium chloride, etc., resulting in poor appearance.

 In addition, the plating time in this invention is 40-80 minutes. The plating time correlates with the plating thickness and is for the film thickness forming range of 0.1 to 2 탆, and more preferably suitable for forming the 0.5 탆 coating thickness. If the film thickness is thick enough to exceed 2 μm, cracks or peeling may occur in the chromium film, and if the film thickness is less than 0.1, it cannot function as a chrome film.

And the pH of the plating liquid is maintained at 2.6 ~ 3.6pH, if the pH is not within the range affects the quality of the product.

In the present invention, by carrying out the electricity management together with the management of the trivalent chromium plating solution as described above, the barrel can be plated while using trivalent chromium, and the defective rate of less than 10%, more preferably, the low defective rate of almost 2 to 3%. There was a barrel plating with this.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the scope of claims and equivalents thereof.

The present invention can be used for barrel plating small parts and the like which require environmentally friendly trivalent chromium plating.

(2)-Plating bath (4)-Trivalent chromium plating solution
(6)-bipolar body (8)-barrel barrel
(10)-cathode busbar (12)-conductive ball
(14)-Plated Body (16)-Platform
(18)-Driven Gear (20)-Drive Gear

Claims (3)

Fill the plating bath (2) with a trivalent chromium plating solution (4) having 20 ° to 30 ° of bome ratio and containing trivalent chromium, a humectant, and a chloride bath material. The chloride bath material is any one of barium chloride and ammonium chloride. Including more than
The anode bath 6 is installed in the plating bath 2 filled with the trivalent chromium plating solution 4, and the same cathode busbar 10 extending across the rotation shafts of both ends of the barrel barrel 8 that rotates. Is formed to be fixed horizontally spaced apart from the bottom surface in the barrel barrel (8) for axial rotation,
In the barrel barrel 8, the conductive balls 12 and the plated body 14 are put together at a volume ratio of 6: 4 to conduct electricity using the positive electrode 6 and the negative electrode busbar 10, but the negative electrode busbar In (10), high current of 17 ~ 20V, 400 ~ 500A is applied so that the unit current density is 2 ~ 3A / mm2.
The plated material was plated by plating the film 14 to 40 to 80 minutes at 25 to 35 ° C. plating bath temperature to enable continuous plating on each of the plated materials 14 in the plating solution 4 evenly conducted through the conductive balls 12. Barrel plating method using trivalent chromium characterized in that the plated film of 0.1 ~ 2㎛ thickness is formed in 14).
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