TW201410927A - Iron plating apparatus - Google Patents

Abstract

An iron plating apparatus (100) according to the present invention includes: a plating treatment section (10) for forming an iron plating layer on the surface of an item to be plated which is made of an aluminum alloy; a main bath (20) for supplying a plating solution to the plating treatment section (10); a pH adjustment section (30) for adjusting the pH of the plating solution discharged from the plating treatment section (10); and an iron dissolution bath (40) in which iron is allowed to be dissolved by the plating solution whose pH has been adjusted by the pH adjustment section (30). The plating solution into which iron has been dissolved in the iron dissolution bath (40) is supplied to the main bath (20).

Description

Iron plating device

The present invention relates to a plating apparatus, and more particularly to a plating apparatus for performing iron plating treatment on a plated object formed of an aluminum alloy.

In recent years, in order to meet the demand for high performance and light weight of internal combustion engines, aluminum alloying of components for internal combustion engines has been developed. As one of the wear resistance treatments of aluminum alloy parts, it is known that iron plating treatment for forming a plating film on the surface of the parts is known.

Patent Document 1 discloses a plating apparatus for performing iron plating treatment on aluminum alloy parts. The iron plating apparatus disclosed in Patent Document 1 includes a plating bath that immerses the object to be plated in the plating solution, and an adjustment bath that adjusts the concentration of the component of the plating solution discharged from the plating bath.

The adjustment bath includes a dissolution tank for replenishing the insufficient components in the plating solution. In the dissolution tank, iron is dissolved in order to replenish Fe ²⁺ ions which are reduced by the iron plating treatment in the plating bath. Specifically, iron powder is introduced into the plating solution in the dissolution tank, and is dissolved by stirring with a propeller. Thereby, the plating solution whose composition concentration is adjusted is again sent to the plating bath for the plating treatment.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2000-265295

However, in the iron plating apparatus disclosed in Patent Document 1, it is difficult to form the iron plating film at a high speed. This is because the pH of the plating solution is not controlled in the iron plating apparatus of Patent Document 1 as will be described in detail later.

The present invention has been made in view of the above problems, and an object thereof is to provide a plating apparatus capable of forming an iron-plated layer on a plated object formed of an aluminum alloy at a high speed.

The iron plating apparatus of the present invention includes: a plating treatment portion that forms a plating iron layer on a surface of the object to be plated formed of an aluminum alloy; a main groove that supplies a plating solution to the plating treatment portion; and a pH adjusting portion; The pH of the plating solution discharged from the plating treatment unit is adjusted; and the iron dissolution tank dissolves iron by using a plating solution whose pH has been adjusted by the pH adjustment unit; The plating solution in which iron is dissolved in the iron dissolution tank is supplied to the main tank.

In one embodiment, the pH adjusting unit reduces the pH of the plating solution.

In one embodiment, the iron plating apparatus of the present invention further includes a tube that connects the main groove, the plating treatment portion, and the iron dissolution tank to each other; the plating solution is applied to the main groove and the plating treatment The portion, the iron dissolution tank, and the inner tube are circulated.

In one embodiment, the steel wool is dissolved in the iron dissolution tank.

In one embodiment, the iron plating apparatus of the present invention further includes an intermediate tank, and the intermediate tank is disposed between the iron dissolution tank and the main tank.

In one embodiment, the intermediate tank includes: a first tank that supplies a plating solution from the iron dissolution tank; and a second tank that is provided so that a supernatant portion of the plating liquid supplied to the first tank flows in .

In one embodiment, the pH adjustment unit adjusts the pH of the plating solution discharged from the plating treatment unit based on the pH value of the plating solution in the second tank.

In one embodiment, the pH of the plating solution supplied to the plating treatment portion is 1.25. Up and below 1.40.

In one embodiment, the iron plating layer is an iron-phosphorus alloy film.

According to the present invention, it is possible to provide a plating apparatus capable of forming an iron-plated layer at a high speed on a plated object formed of an aluminum alloy.

10‧‧‧Plating treatment department

20‧‧‧ main slot

30‧‧‧pH adjustment unit

31‧‧‧ pump

32‧‧‧pH adjustment liquid storage tank

40‧‧‧ iron dissolution tank

41‧‧‧ Inside slot

42‧‧‧ outer trough

50‧‧‧Intermediate trough

51‧‧‧1st slot

52‧‧‧2nd slot

61‧‧‧ pump

62‧‧‧pH sensor

63‧‧‧ check valve

64‧‧‧ filter cartridge

65, 66‧‧‧ valve

70‧‧‧The object to be plated

71‧‧‧Iron plating (iron-phosphorus alloy film)

72‧‧‧Stainless steel wool

100, 100A, 100B‧‧‧ iron plating device

Fig. 1 is a view schematically showing a plating apparatus 100 according to an embodiment of the present invention.

Fig. 2 is a view schematically showing a plating apparatus 100A according to an embodiment of the present invention.

Fig. 3 is a view schematically showing a plating apparatus 100B according to an embodiment of the present invention.

Figure 4 is a cross-sectional photograph of the iron-plated layer 71 to which the small piece 72 of steel wool is attached.

Fig. 5 is a view showing the transition of the pH value of the pH sensor 62 in the iron plating apparatus 100 shown in Fig. 1 (the pH value of the plating solution in the main tank 20) and the flow out from the iron dissolution tank 40. A graph showing the transition of the pH of the plating solution to the front of the main tank 20.

Fig. 6 is a view showing the detection of the pH value of the pH sensor 62 in the iron plating apparatus 100B shown in Fig. 3 (the pH value of the plating solution in the second tank 52) and the plating liquid in the main tank 20. A graph of the pH transition.

Fig. 7 is a cross-sectional photograph of an iron-phosphorus alloy film 71 having a fine crack that does not reach the plated object 70.

Fig. 8 is a graph showing the relationship between the amount (g) of dissolution of steel wool and iron powder and the dissolution time (minutes) in Examples 2 and 3.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, an iron-plating device in which an iron-phosphorus (Fe-P) alloy film is formed on the surface of the object to be plated as an iron-plated layer is exemplified below, but the present invention is not limited thereto.

Fig. 1 shows a iron plating apparatus 100 of this embodiment. As shown in FIG. 1, the iron plating apparatus 100 includes a plating treatment unit 10, a main tank 20, a pH adjusting unit 30, and an iron dissolution tank 40. Figure 1 Although not shown, the main groove 20, the plating treatment portion 10, and the iron dissolution tank 40 are connected to each other by a tube, and the plating solution is circulated in the main tank 20, the plating treatment portion 10, the iron dissolution tank 40, and the tube. .

The plating treatment unit 10 forms an iron plating layer on the surface of the object to be plated. Specifically, the plating solution is supplied so as to be in contact with the surface of the object to be plated placed inside the plating treatment unit 10, and in this state, the object to be plated is plated as a cathode to form an iron plating layer. . Here, the iron-phosphorus alloy film is formed as the iron plating layer, but the iron plating layer is not limited to the iron-phosphorus alloy film. For example, as the iron plating layer, an Fe-N alloy film, an Fe-TiO ₂ -P composite film, or an Fe-SiC-P composite film may be formed. The iron-phosphorus alloy film is easy to retain the lubricating oil, and thus is excellent in terms of preventing the wear of the sliding surface or the effect of leaving a mark. The object to be plated is formed of an aluminum alloy. As the aluminum alloy, an aluminum alloy of various known compositions can be used. For example, an Al-Si-based hypereutectic alloy can be preferably used. The object to be plated is, for example, a cylinder block or a piston for the internal combustion engine. In the case where the object to be plated is a cylinder block, the iron plating layer is formed on the inner circumferential surface of the cylinder inner diameter.

The main groove 20 supplies a plating solution to the plating treatment unit 10. A pump 61 is provided on the tube connecting the main tank 20 and the plating treatment unit 10. Further, in the configuration illustrated in Fig. 1, a pH sensor 62 for detecting the pH of the plating solution in the main tank 20 is provided. Further, a part of the plating liquid discharged from the plating treatment unit 10 after the plating treatment is returned to the main tank 20, and the remainder flows into the iron dissolution tank 40.

The pH adjusting unit 30 adjusts the pH value (hydrogen ion index) of the plating liquid (plating liquid that has flowed into the iron dissolution tank 40) discharged from the plating treatment unit 10. Typically, the pH adjusting unit 30 reduces the pH of the plating solution. The pH adjusting unit 30 of the present embodiment includes a pump 31 and a pH adjusting liquid storage tank 32 in which hydrochloric acid as a pH adjusting liquid is stored, and the pump 31 is used based on the pH value detected by the pH sensor 62. The pH of the plating solution is adjusted by adding hydrochloric acid in the pH adjusting liquid storage tank 32 to the plating liquid. In addition, in the configuration illustrated in FIG. 1 , a check valve 63 for preventing the plating solution from flowing into the pH adjusting unit 30 from the tube of the iron plating tank 40 and the iron dissolution tank 40 is provided.

In the iron dissolution tank 40, iron is dissolved by a plating liquid whose pH has been adjusted by the pH adjusting unit 30. Further, the plating solution in which iron is dissolved in the iron dissolution tank 40 is supplied to the main tank 20. In the configuration illustrated in Fig. 1, the plating solution is removed by the filter cartridge 64 disposed between the iron dissolution tank 40 and the main tank 20.

In addition, FIG. 1 shows a valve 65 provided in a tube connecting the plating treatment unit 10 and the iron dissolution tank 40, and a valve 66 provided in a tube connecting the iron dissolution tank 40 and the main tank 20, but the valve The number or configuration is not limited to the one illustrated in FIG.

As described above, the iron plating apparatus 100 of the present embodiment includes the pH adjusting unit 30 that adjusts the pH of the plating liquid discharged from the plating processing unit 10, and the iron dissolution tank 40 is adjusted by the pH value. In the portion 30, the plating solution adjusted in pH dissolves iron. Thereby, the iron plating layer can be formed at a high speed. Hereinafter, the reason will be described in more detail.

In the case where an iron-phosphorus alloy film is formed as a plated iron layer at a high speed and a high current density, an insoluble anode is used. The insoluble anode is, for example, a substrate formed of titanium (Ti) coated with platinum (Pt) or cerium oxide (IrO ₂ ). In the case of using an insoluble anode, in the anode, Fe ³⁺ ions are generated by anodization reaction of Fe ²⁺ ions represented by the following formula (1), and electrolysis of water represented by the following formula (2) is utilized. The reaction produces H ⁺ ions.

Fe ²⁺ → Fe ³⁺ +e ^- ...(1)

2H ₂ O → O ₂ +4H ⁺ +4e ^- ...(2)

The increase of Fe ³⁺ ions in the plating solution and the decrease in pH (caused by the formation of H ⁺ ions) may cause a decrease in the surface roughness of the plating film (granular precipitation), or a plating film and a plated object. The adhesion is reduced to reduce the quality of such a plating film (iron plating layer). In addition, the cathode current efficiency is also lowered, and the plating speed is also lowered.

Therefore, in order to form a high-quality plating film at a high speed, it is preferable to increase Fe ²⁺ ions in the plating solution supplied to the plating treatment unit 10 and to reduce Fe ³⁺ ions. In the iron plating apparatus 100 of the present embodiment, the plating solution after the plating treatment is poured into the iron dissolution tank 40 to dissolve the iron to supplement the Fe ²⁺ ions, and to reduce the Fe ³⁺ ions to Fe ^{2 . +} ion.

The dissolution reaction of iron in the iron dissolution tank 40 is represented by the following formulas (3) and (4).

Fe+2H ⁺ → Fe ²⁺ +H ₂ ...(3)

Fe+2Fe ³⁺ → 3Fe ²⁺ ...(4)

By the reaction represented by the formula (3), H ⁺ ions are reduced, and Fe ²⁺ ions are generated (the pH value increases accompanying the reaction). Further, Fe ³⁺ ions are reduced to Fe ²⁺ ions by the reaction represented by the formula (4).

In the iron plating apparatus 100 of the present embodiment, the pH value of the plating liquid discharged from the plating treatment unit 10 can be adjusted by the pH adjusting unit 30. Therefore, the pH of the plating solution flowing into the iron dissolution tank 40 can be controlled to a value suitable for dissolution of iron. Typically, by reducing the pH of the plating solution after the plating treatment, the pH becomes suitable for the dissolution of iron. Therefore, the amount of iron dissolved per unit time can be increased, and more Fe ³⁺ ions can be reduced to Fe ²⁺ ions. Therefore, according to the iron plating apparatus 100 of the present embodiment, the iron plating layer can be formed at a high speed on the object to be plated.

On the other hand, in the iron plating apparatus disclosed in Patent Document 1, although the concentration of the plating solution is adjusted, the pH of the plating solution is not controlled, so that it is difficult to form the iron plating layer at a high speed.

Further, the specific configuration of the pH adjusting unit 30 is not limited to the one illustrated in FIG. 1 . Further, the pH adjusting liquid is not limited to hydrochloric acid, and may be, for example, sulfuric acid or a mixture of hydrochloric acid and sulfuric acid. In order to form a good plating film (iron plating layer), when the plating solution is a chlorination bath, it is preferred that the pH adjusting liquid is hydrochloric acid. Similarly, when the plating solution is a sulfuric acid bath, it is preferred that the pH adjusting solution is sulfuric acid.

Further, FIG. 1 exemplifies an example in which the pH value of the plating solution in the main tank 20 is detected by the pH sensor 62, but it may be sensed by pH value as in the iron plating apparatus 100A shown in FIG. The device 62 detects the pH of the plating solution flowing out of the iron dissolution tank 40 and flowing into the main tank 20. In this case, the pH adjusting unit 30 adjusts the pH of the plating solution before flowing into the main tank 20 (detected The pH value is slightly larger than the pH of the plating solution in the main tank 20 (that is, the pH of the plating solution supplied to the plating treatment unit 10), and the pH is adjusted (specifically, the supply of hydrochloric acid) The amount is adjusted). The pH of the plating solution discharged from the plating treatment unit 10 and returned to the main tank 20 is smaller than the pH of the plating solution supplied from the autonomous tank 20 to the plating treatment unit 10, and thus the self-plating treatment unit 10 is directly The plating liquid returned to the main tank 20 and the plating liquid flowing in from the iron dissolution tank 40 are mixed in the main tank 20, and the pH of the plating liquid in the main tank 20 is adjusted to a fixed range.

From the viewpoint of miniaturization of the iron dissolution tank 40, it is preferred to dissolve the steel wool in the iron dissolution tank 40. In the case of using iron powder (that is, dissolving iron powder in the iron dissolution tank 40), in order to prevent the aggregation of the iron powder and improve the reduction efficiency, it is preferred to provide a stirrer in the iron dissolution tank 40. In this case, the iron dissolution tank 40 will be large. On the other hand, when steel wool is used, the contact area with the solution (plating solution) can be sufficiently large even without providing a stirrer, so that the iron dissolution tank 40 can be miniaturized.

Further, as shown in FIG. 2, the iron dissolution tank 40 preferably has a two-layer structure including an inner tank 41 and an outer tank 42 (for example, cylindrical shapes, respectively). The iron dissolving tank 40 having a two-layer structure has an inflow portion of a plating liquid at a lower portion of the outer tank 42 and an outflow portion of a plating liquid at a lower portion of the inner tank 41. Further, the iron dissolving tank 40 having a double-layer structure has a detachable cylinder in the inner tank 41, and the cylinder is filled with steel wool. The plating solution flows into the iron dissolution tank 40 from the inflow portion at the lower portion of the outer tank 42, and flows from the upper portion of the inner tank 41 to the upper end portion of the cylinder through the inner side of the outer tank 42 (and the outer side of the inner tank 41). While the plating liquid flows in from below the upper direction of the cylinder, the steel wool is dissolved while passing through the steel wool, and flows out from the outlet portion of the lower portion of the inner tank 41 to the outside of the iron dissolution tank 40. At this time, the inside of the inner tank 41 is immersed in the plating liquid as a whole, and is filled with the plating liquid. By adopting such a structure, the dissolution of the steel wool can be further promoted. Further, since the upper portion of the inner tank 41 is provided with an opening for attaching and detaching the cylinder, the cylinder in which the steel wool is placed can be easily replaced. Therefore, work efficiency is improved, and continuous plating treatment can be easily performed.

Further, as in the case of the iron plating apparatus 100B shown in FIG. 3, it is preferable to also use the following reasons. An intermediate groove 50 is provided between the iron dissolution tank 40 and the main tank 20.

The plating solution which flows into the main tank 20 from the iron dissolution tank 40 may contain steel wool (a small piece of steel wool) which is not completely dissolved and is fine. This is because the small pieces of steel wool which are not dissolved in the iron dissolution tank 40 cannot be removed by the filter cartridge 64 and flow into the main tank 20. When the plating bath autonomous tank 20 including the small piece of such steel wool is supplied to the plating treatment portion 10, there is a possibility that it adheres to the iron plating layer and becomes a defect. A cross-sectional photograph of the iron-plated layer to which the steel wool sheet is attached is shown in Fig. 4. In the example shown in FIG. 4, a small piece 72 of steel wool having a size of about 300 μm is adhered to the iron plating layer 71 formed on the surface of the object 70 to be plated.

If the intermediate groove 50 is provided between the iron dissolution tank 40 and the main tank 20, the small piece of steel wool is dissolved or precipitated in the intermediate tank 50, and thus does not flow into the main tank 20. Therefore, the occurrence of defects as described above is prevented.

In the configuration shown in FIG. 3, the intermediate tank 50 includes a first tank 51 to which a plating liquid is supplied from the iron dissolution tank 40, and a plating liquid supplied to the first tank 51 is provided to flow in a portion thereof. The second slot 52. The plating solution is supplied from the second tank 52 to the main tank 20. Since the intermediate groove 50 has such a double groove structure, the inflow of the small pieces of the steel wool into the main groove 20 can be more reliably prevented. Further, when the intermediate tank 50 is opened to the atmosphere (that is, if the intermediate tank 50 is provided with the atmosphere open), the hydrogen generated during the dissolution of the iron can be removed from the plating solution.

Further, in the configuration shown in FIG. 3, the pH sensor 62 detects the pH of the plating solution in the second tank 52. When the pH adjustment unit 30 adjusts the pH value of the plating solution discharged from the plating treatment unit 10 based on the pH value of the plating solution in the second tank 52, the pH of the plating solution in the main tank 20 is The variation is reduced, so the quality of the iron plating layer (here, the iron-phosphorus alloy film) is more stable.

Fig. 5 is a view showing the transition of the pH value of the pH sensor 62 in the iron plating apparatus 100 shown in Fig. 1 (i.e., the pH value of the plating solution in the main tank 20) and the inflow from the iron dissolution tank 40. The pH of the plating solution to the front of the main tank 20 is shifted. In addition, FIG. 6 shows the iron plating device shown in FIG. The pH value of the pH sensor 62 in 100B (i.e., the pH value of the plating solution in the second tank 52) and the pH value of the plating solution in the main tank 20 are set. In any of the cases shown in FIG. 5 and FIG. 6, when the pH value is detected to be 1.4, the supply of hydrochloric acid by the pump 31 is started. If the pH value is 1.36, the pump 31 is stopped. Supply of hydrochloric acid.

As in the iron plating apparatus 100 shown in FIG. 1, the pH value of the plating liquid in the main tank 20 is detected by the pH sensor 62, and the pH adjusting unit 30 performs pH adjustment based on the detected pH value. As shown in Fig. 5, the pH of the plating solution in the main tank 20 varies from 1.27 to 1.43.

On the other hand, if the pH value of the plating solution in the second tank 52 of the intermediate tank 50 is detected by the pH sensor 62 as in the iron plating apparatus 100B shown in FIG. 3, the pH adjusting unit 30 is based on this. When the pH value was measured and the pH was adjusted, as shown in Fig. 6, the pH of the plating solution in the main tank 20 gradually changed after the start of plating, and was almost not less than 1.36.

When the pH adjustment unit 30 adjusts the pH of the plating solution discharged from the plating treatment unit 10 based on the pH value of the plating solution in the second tank 52, the plating solution in the main tank 20 can be reduced. Change in pH.

Here, a preferred composition of the plating solution will be described from the viewpoint of the quality of the iron-phosphorus alloy film. As a plating solution for electroplating of an iron-phosphorus alloy (also referred to as a plating bath in a state of being placed in a plating bath), as a supply source of Fe ²⁺ ions, ferrous sulfate is mainly used. A plating solution (sulfuric acid bath), a plating solution containing ferrous sulfate and ferrous chloride as a main component, and a plating solution (chlorinated bath) mainly composed of ferrous chloride.

However, if the first two plating solutions, that is, the plating solution containing ferrous sulfate, are used to form a thick iron-phosphorus alloy film at a high current density, sometimes it may be generated on the iron-phosphorus alloy film. A micro-crack like a plated object.

On the other hand, when a plating solution containing ferrous chloride as a main component is used and the concentration of hypophosphorous acid (H ₃ PO ₂ ) is relatively low, even if it is formed at a high current density, it is thick (for example, 100 μm to 150 μm). ) Iron-phosphorus alloy film can also inhibit the generation of micro-cracks. A cross-sectional photograph of the iron-phosphorus alloy film in which the generation of microcracks is suppressed is shown in Fig. 7. As can be seen from Fig. 7, micro-cracks such as reaching the object to be plated 70 were not generated on the iron-phosphorus alloy film 71.

In addition, when the hypophosphorous acid content of the plating solution is 0.01 g/L or more and 1.0 g/L or less, an iron-phosphorus alloy film having a smooth surface and excellent adhesion can be formed. Therefore, when such an iron-phosphorus alloy film is formed on the inner circumferential surface of the cylinder inner diameter of the cylinder block of the aluminum alloy, the polishing step or the honing step can be omitted. Further, as shown in Fig. 7, the surface of the iron-phosphorus alloy film has fine cracks (not microcracks until it reaches the object to be plated), so that lubricating oil is retained in the crack and slidability with the other material such as the piston. improve. The hypophosphorous acid content of the plating solution is more preferably 0.1 g/L or more and 0.5 g/L or less from the viewpoint of obtaining such effects more reliably.

The content of ferrous chloride as a supply source of Fe ²⁺ ions in the plating solution is preferably 350 g/L or more and 450 g/L or less. In addition, the pH of the plating solution supplied to the plating treatment unit 10 (that is, the pH of the plating solution in the main tank 20) is preferably 1.0 or more and 1.5 or less from the viewpoint of the improvement of the plating speed and the like. More preferably, it is 1.25 or more and 1.40 or less. Further, when the plating solution is applied at a high current density using such a plating solution, the temperature of the plating solution is preferably 50 ° C or more and 70 ° C or less, more preferably 60 ° C or more and 70 ° C or less. Further, the cathode current density is preferably 100 A/dm ² or more and 200 A/dm ² or less, more preferably 100 A/dm ² or more and 150 A/dm ² or less.

As described above, in the iron plating apparatuses 100, 100A, and 100B of the present embodiment, the plating liquid before flowing into the iron dissolution tank 40 is adjusted in pH. Here, in the case where hydrochloric acid is added to the plating solution flowing before the iron dissolution tank 40 (Example 1), and hydrochloric acid is added to the plating liquid which flows out from the iron dissolution tank 40 and flows into the main tank 20, (Comparative Example 1), the result of comparing the dissolved amounts of steel wool will be described. The conditions of the dissolved amount (the composition of the plating solution, the temperature of the plating solution, the pH of the plating solution in the main tank 20, the capacity of the iron dissolution tank 40, and the inflow rate of the plating solution toward the iron dissolution tank 40 were measured. The total amount of the plating solution was as shown in Table 1 with respect to any of Example 1 and Comparative Example 1. Also, about The fluctuations in the pH value of the plating solution before the inflow into the main tank 20 and the period and the supply time of the hydrochloric acid in each of the first embodiment and the comparative example 1 are shown in Table 2.

After the amount of molten steel was measured under the conditions shown in Tables 1 and 2, the amount of dissolution of the steel wool in Comparative Example 1 was 132 g/Hr, and the dissolution amount of the steel wool in Example 1 was 198 g/ Hr. As a result, it is confirmed that the amount of iron dissolved per unit time can be greatly increased by adjusting the pH of the plating solution flowing before the iron dissolution tank 40.

Further, as described above, it is preferable to dissolve the steel wool in the iron dissolution tank 40. Here, the result of comparing the dissolved amount in the case where the steel wool is dissolved in the iron dissolution tank 40 (Example 2) and the case where the iron powder is dissolved (Example 3) will be described. The conditions of the dissolved amount (the composition of the plating solution, the temperature of the plating solution, the pH of the plating solution in the main tank 20, the capacity of the iron dissolution tank 40, the total amount of the plating solution, and the iron dissolution tank 40 were measured. The inflow rate and dissolution time of the plating solution are shown in Table 3 in any of Examples 2 and 3. Also, in the second embodiment The fiber center diameter of the steel wool used in the steel wool and the particle size distribution of the iron powder used in Example 3 are shown in Table 4.

The amount of steel wool in Example 2 and the amount of iron powder dissolved in Example 3 after measuring the amount of steel wool and iron powder dissolved under the conditions shown in Tables 3 and 4 are shown in Table 5 and Figure 8 shows.

As can be seen from Table 5 and Fig. 8, in Example 2 in which steel wool was used, the amount of dissolution was remarkably increased as compared with Example 3 in which iron powder was used. This is considered to be because, in the case where iron iron iron is dissolved in the dissolution tank 40, the iron powder is fixed and condensed at the bottom of the iron dissolution tank 40 to float. The iron powder of the tour is reduced, whereby the iron dissolution rate is lowered. The iron powder can be prevented from agglomerating by providing a stirrer in the iron dissolution tank 40. However, in this case, the iron dissolution tank 40 is increased in size.

Industrial availability

According to the present invention, it is possible to provide a plating apparatus capable of forming an iron-plated layer at a high speed on a plated object formed of an aluminum alloy. The iron plating apparatus of the present invention can be preferably used in a plating process for various aluminum alloy members such as a cylinder block for an internal combustion engine.

10‧‧‧Plating treatment department

20‧‧‧ main slot

30‧‧‧pH adjustment unit

31‧‧‧ pump

32‧‧‧pH adjustment liquid storage tank

40‧‧‧ iron dissolution tank

61‧‧‧ pump

62‧‧‧pH sensor

63‧‧‧ check valve

64‧‧‧ filter cartridge

65, 66‧‧‧ valve

100‧‧‧iron plating device

Claims (9)

An iron plating apparatus comprising: a plating treatment portion that forms an iron plating layer on a surface of an object to be plated formed of an aluminum alloy; a main groove that supplies a plating solution to the plating treatment portion; and a pH adjustment unit The pH of the plating solution discharged from the plating treatment unit is adjusted; and the iron dissolution tank dissolves iron by using a plating solution whose pH has been adjusted by the pH adjustment unit; The plating solution in which iron is dissolved in the iron dissolution tank is supplied to the main tank. The iron plating apparatus of claim 1, wherein the pH adjusting unit reduces the pH of the plating solution. The iron plating apparatus according to claim 1 or 2, further comprising a tube that connects the main groove, the plating treatment portion, and the iron dissolution tank to each other; the plating solution is in the main groove and the plating The treatment unit, the iron dissolution tank, and the inside of the tube are circulated. The iron plating apparatus according to any one of claims 1 to 3, wherein the steel wool is dissolved in the iron dissolution tank. The iron plating apparatus according to any one of claims 1 to 4, further comprising an intermediate tank, wherein the intermediate tank is disposed between the iron dissolution tank and the main tank. The iron plating apparatus according to claim 5, wherein the intermediate tank comprises: a first tank for supplying a plating liquid from the iron dissolving tank; and a first portion of the plating liquid supplied to the first tank 2 slots. The iron plating apparatus according to claim 6, wherein the pH adjustment unit is based on a pH value of the plating solution in the second tank to a pH value of the plating solution discharged from the plating treatment unit. Line adjustment. The iron plating apparatus according to any one of claims 1 to 7, wherein the plating solution supplied to the plating treatment unit has a pH of 1.25 or more and 1.40 or less. The iron plating apparatus according to any one of claims 1 to 8, wherein the iron plating layer is an iron-phosphorus alloy film.