EP2058417A1 - Method for forming corrosion resistant plating layer and rotating machine - Google Patents
Method for forming corrosion resistant plating layer and rotating machine Download PDFInfo
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- EP2058417A1 EP2058417A1 EP07831881A EP07831881A EP2058417A1 EP 2058417 A1 EP2058417 A1 EP 2058417A1 EP 07831881 A EP07831881 A EP 07831881A EP 07831881 A EP07831881 A EP 07831881A EP 2058417 A1 EP2058417 A1 EP 2058417A1
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- Prior art keywords
- plating
- plating layer
- corrosion
- electroless
- penetrating
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/10—Etching compositions
- C23F1/14—Aqueous compositions
- C23F1/16—Acidic compositions
- C23F1/28—Acidic compositions for etching iron group metals
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/1601—Process or apparatus
- C23C18/1633—Process of electroless plating
- C23C18/1646—Characteristics of the product obtained
- C23C18/165—Multilayered product
- C23C18/1651—Two or more layers only obtained by electroless plating
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/18—Pretreatment of the material to be coated
- C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
- C23C18/1824—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by chemical pretreatment
- C23C18/1827—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by chemical pretreatment only one step pretreatment
- C23C18/1834—Use of organic or inorganic compounds other than metals, e.g. activation, sensitisation with polymers
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
- C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/02—Selection of particular materials
- F04D29/023—Selection of particular materials especially adapted for elastic fluid pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2260/00—Function
- F05D2260/95—Preventing corrosion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2300/00—Materials; Properties thereof
- F05D2300/10—Metals, alloys or intermetallic compounds
- F05D2300/16—Other metals not provided for in groups F05D2300/11 - F05D2300/15
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2300/00—Materials; Properties thereof
- F05D2300/60—Properties or characteristics given to material by treatment or manufacturing
- F05D2300/611—Coating
Definitions
- the present invention relates to a method for forming a corrosion-resistant plating layer by electroless nickel-based plating and a rotary machine processed by the method for forming a corrosion-resistant plating layer.
- Compressors used in power-generating plants and chemical plants compress gases containing corrosive gases such as CO 2 , H 2 S, and H 2 O.
- gases containing corrosive gases such as CO 2 , H 2 S, and H 2 O.
- carbon steel cast iron, cast steel, or forged steel
- electroless nickel-based plating such as Ni-P plating
- Fig. 11 defects, such as cavities, are liable to be formed, particularly, in carbon steel during casting, and pores 100a having openings are formed in a surface of a base material 100.
- penetrating pinholes 101a are formed in an electroless plating layer 101 to penetrate the surface thereof.
- a corrosive liquid infiltrates the base material 100.
- corrosion products 100b are formed on the base material 100.
- the electroless plating layer 101 is eventually peeled away.
- the penetrating pinholes as described above may originate at a complex-shaped portion, such as a diaphragm or an impeller.
- Patent Document 1 In order to seal the penetrating pinholes as described above, as disclosed in Patent Document 1, a technique in which a plating layer is further formed on an electroless plating layer has been known.
- the present invention has been conceived in consideration of the above situation, and an object of the present invention is to provide a method for forming a superior corrosion-resistant plating layer by sealing penetrating pinholes formed in an electroless plating layer and to provide a rotary machine.
- a method for forming a corrosion-resistant plating layer and a rotary machine according to the present invention use the following solutions. That is, a method for forming a corrosion-resistant plating layer according to the present invention is a method for forming a corrosion-resistant plating layer in which the corrosion-resistant plating layer is formed by performing electroless nickel-based plating on a base material, and the above method comprises: a first plating step of performing electroless nickel-based plating on the base material; an etching step of etching a surface of a first plating layer formed by the first plating step; and a second plating step of performing electroless nickel-based plating on the first plating layer processed by the etching step.
- the first plating layer is formed by performing electroless nickel-based plating on the base material.
- penetrating pinholes having openings at a surface side are formed due to the shapes of pores or the like formed in the surface of the base material.
- corners forming opening portions of the penetrating pinholes are removed to form tapered shapes. As a result, the opening portions of the penetrating pinholes each have a mortar shape.
- a second plating layer is formed on the first plating layer.
- the second plating layer is formed so as to be laminated on the tapered surfaces each having a mortar shape, that is, is formed so as to be grown in an oblique direction with respect to an extending direction of the penetrating pinholes. Since the second plating layer is grown obliquely at the opening portions of the penetrating pinholes, the opening portions of the penetrating pinholes are sealed.
- the present invention is particularly effective when carbon steel (cast iron, cast steel, or forged steel) is used as the base material.
- Ni-P plating or Ni-B plating is preferably performed.
- the present invention is not limited to the first plating step, the etching step, and the second plating step; for example, after the second plating step, another surface treatment may also be performed.
- the etching step is preferably performed using sulfuric acid.
- the etching step is preferably performed by an acid treatment using sulfuric acid, hydrochloric acid, nitric acid, or the like, and in particular, an acid treatment using sulfuric acid is preferable.
- an acid treatment using sulfuric acid is preferable.
- concentration of sulfuric acid approximately 5 percent by weight is preferable.
- the thickness of the first plating layer is preferably set to 5 ⁇ m or more.
- the base material may be corroded in the etching step through pinholes formed in the first plating layer.
- a thickness of 5 ⁇ m or more is necessary.
- the thickness of the second plating layer is preferably set to 10 ⁇ m or more.
- the thickness of the second plating layer is less than 10 ⁇ m, penetrating pinholes formed in the first plating layer cannot be sufficiently sealed. Hence, as the second plating layer, a thickness of 10 ⁇ m or more is necessary.
- the first plating step and the second plating step are preferably performed by electroless Ni-P plating, and a P concentration of an electroless Ni-P plating layer is preferably set in the range of 7 to 10 percent by weight.
- a rotary machine according to the present invention has a surface provided with a corrosion-resistant plating layer formed by one of the methods for forming a corrosion-resistant plating layer described above.
- the rotary machine has a surface provided with a corrosion-resistant plating layer formed by one of the methods for forming a corrosion-resistant plating layer described above, even when this surface is exposed to a corrosive gas, such as CO 2 , H 2 S, and H 2 O, a rotary machine having sufficient durability can be provided.
- a corrosive gas such as CO 2 , H 2 S, and H 2 O
- a rotary machine having sufficient durability can be provided.
- a compressor may be mentioned.
- an anti-corrosion treatment is performed on surfaces of an impeller (rotor blade) and a diaphragm, which is a stationary member.
- the second plating layer is formed on the first plating layer by the second plating step, and hence the opening portions of the penetrating pinholes can be sealed. Accordingly, a plating layer having superior corrosion resistance can be formed, and as a result, a rotary machine having superior corrosion resistance can be provided.
- a corrosion prevention treatment is performed on a diaphragm and an impeller of a compressor which is exposed to a corrosive gas, such as CO 2 , H 2 S and H 2 O, by electroless Ni-P plating.
- Carbon steel (cast iron, cast steel, or forged steel) is used as a base material to be processed by the anti-corrosion treatment.
- Fig. 1 shows steps of performing the anti-corrosion treatment on the base material by electroless Ni-P plating. As shown in the above figure, after cleaning, degreasing, and water washing are performed for the base material, pickling is performed, followed by water washing.
- a first plating step is completed.
- a first plating layer 3 is formed on a base material 1.
- a penetrating pinhole 3a formed in the first plating layer 3 is shown.
- the surface of the first plating layer 3 is etched by an acid treatment using diluted sulfuric acid or the like.
- a corner 3c forming an opening portion 3b of the penetrating pinhole (or penetrating defect) 3a is removed to form a tapered shape.
- a mortar shape 3d is formed at the opening portion 3b of the penetrating pinhole 3a.
- second plating step a second plating layer 5 is formed on the first plating layer 3.
- the second plating layer 5 is formed so as to be laminated on a tapered surface forming this mortar shape portion 3b, that is, is formed so as to grow in an oblique direction with respect to an extending direction of the penetrating pinhole 3a.
- the opening portion 3b of the penetrating pinhole 3a is sealed. Subsequently, after water washing is performed, drying is performed, followed by baking, so that the anti-corrosion treatment is completed.
- the etching step is preferably performed by an acid treatment using sulfuric acid, hydrochloric acid, nitric acid, or the like.
- an acid treatment using diluted sulfuric acid is preferable.
- concentration of sulfuric acid approximately 5 percent by weight is preferable.
- the thickness of the first plating layer is preferably 5 ⁇ m or more. The reason for this is that, in some cases, when the thickness of the first plating layer 3 is less than 5 ⁇ m, an acid treatment using diluted sulfuric acid or the like may corrode the base material 1 in the etching step through the penetrating pinhole 3a formed in the first plating layer 3.
- the thickness of the second plating layer 5 is preferably 10 ⁇ m or more. The reason for this is that when the thickness of the second plating layer 5 is less than 10 ⁇ m, the penetrating pinhole 3a formed in the first plating layer cannot be sufficiently sealed.
- the corrosion rate was evaluated by measuring polarization properties performed while the P concentration was varied.
- JIS SPCC cold-rolled carbon steel
- electroless Ni-P plating layer was formed on a surface of the base material by varying the P concentration from 2.5 to 12.5 percent by weight under the conditions shown in Table 1.
- Table 1 Electroless Ni-P plating test Types of prepared solutions [Table 1] No. P concentration [wt%]/(average) Plating solution [Trade name] Plating thickness [mm]
- Producer 1 2 ⁇ 3 (2.5) Nimuden LPX 20 C. Uyemura & Co., Ltd. 2 7 ⁇ 8 (7.5) Nimuden 5X 20 C. Uyemura & Co., Ltd. 3 9 ⁇ 10 (9.5) Nimuden SX 20 C. Uyemura & Co., Ltd. 4 12 ⁇ 13 (12.5) Nimuden HDX 20 C. Uyemura & Co., Ltd.
- FIG. 4 an electrolytic corrosion test apparatus used in this test is shown.
- a sample 12 is immersed in a test solution 10 and is disposed to face a counter electrode 14 made of Pt.
- the test solution 10 is temperature-controlled by a heater 18 disposed around the periphery.
- the temperature of the test solution 10 is measured by a thermometer 16.
- CO 2 and H 2 S gases are introduced as simulated corrosive gases.
- the test solution 10 is agitated by a stirrer 20.
- the sample 12 and the counter electrode 14 are each connected to a potentio-galvanostat 21.
- a salt bridge 22 is connected to the sample 12. The other end of the salt bridge 22 is immersed in a bath 24 together with a reference electrode (Ag/AgCl electrode) 23 connected to the potentio-galvanostat 21.
- the measurement conditions of this test are shown in Table 2.
- Table 2 Measurement conditions for polarization properties [Table 2] Items Conditions Solution Bubbling aqueous solution containing CO 2 + 10 vol% of H 2 S (gas composition including maximum H 2 S concentration estimated in compressor) Solution temperature 80°C Sweeping rate 20 mV/min
- the test procedure is as shown below.
- Fig. 5 shows an anti-corrosion evaluation result obtained by the above electrolytic corrosion test.
- a composition region in which the P concentration in an electroless Ni-P plating layer is from 7 to 10 percent by weight is considered to have the most superior corrosion resistance.
- the reasons why a P concentration in an electroless Ni-P plating layer in the range of 7 to 10 percent by weight is considered to have superior corrosion resistance are as follows.
- a concentration in the range of 7 to 10 percent by weight is preferable as the P concentration of the electroless Ni-P plating layer.
- Nimuden SX manufactured by C. Uyemura & Co., Ltd. is used, which can form a plating film having a P concentration in the range of 9 to 10 percent by weight.
- Nimuden SX Nimuden SX, P concentration: 9 to 10 percent by weight
- a plating base material used as the base material JIS SC480 cast steel was used, which was obtained by casting simultaneously performed during manufacture of a diaphragm of an actual compressor.
- a base material having a size of 30 ⁇ 30 ⁇ L 200 was cut into a size of W 30 ⁇ L 100 ⁇ t 3 mm by wire cutting as shown in Fig. 6 , to form the plating base material.
- a plating process for laminating layers (in this case, two-layer plating is considered) is performed as shown in Fig. 7 . That is, by a lower layer electroless Ni-P plating process corresponding to the first plating step, an underlying Ni-P plating layer is formed to have a thickness of 20 ⁇ m, followed by etching, and by an upper layer electroless Ni-P plating process corresponding to the second plating step, upper layer Ni-P plating is perfomed. Table 3 shown factors affecting penetrating defects (penetrating pinholes) in the plating layer and the reasons for the determining standards.
- Control factors of the test for reducing penetrating defects in electroless Ni-P plating layer [Table 3] Control factors
- Standards Reasons for determining standards Type of etching solution Hydrochloric acid, sulfuric acid, nitric acid Commonly used solutions are selected. Concentration of etching solution 1, 5, and 10 percent by weight Commonly used concentration range is selected. Etching treatment time 1, 3, and 5 minutes Times are determined in consideration of etching rate of Ni-P plating and thickness of lower plating layer of 20 ⁇ m. Thickness of upper plating layer 10, 20, and 30 ⁇ m Thicknesses are determined in order to obtain total thickness of 50 ⁇ m or less, which is current plating thickness.
- FIG. 8 A factor effect graph (smaller-the-better characteristic) of the penetrating defect density is shown in Fig. 8 .
- a summary of the results is as follows.
- the base material dimensions were set to W 30 ⁇ L 100 ⁇ t 3 mm.
- FIG. 9 An upper layer plating (etching and second plating layer) process and conditions thereof are shown in Fig. 9 .
- the thickness of the upper plating layer was used as a parameter, and the target thickness was varied from 10 to 30 ⁇ m.
- the number density of penetrating defects was measured by a ferroxyl test.
- Fig. 10 the relationship between the thickness of the upper Ni-P plating layer and the number density of penetrating defects, which is obtained by the confirmation test, is shown. A summary of the results is as described below. By increasing the thickness of the upper plating layer, the number density of penetrating defects is decreased.
- the two-layer plating material of this test and a current single-layer plating material are compared, the results are as shown in Table 5. It is understood that the effect of a two-layer lamination including the etching step and the second plating step is significant.
- the corner 3c forming the opening portion 3b of the penetrating pinhole 3a is removed by the etching step to form a tapered shape, so that the mortar shaped portion 3d is formed.
- the second plating layer 5 is formed on the first plating layer 3 by the second plating step, the opening portion of the penetrating pinhole 3a can be sealed. Accordingly, a plating layer having superior corrosion resistance can be formed. As a result, a compressor having superior corrosion resistance can be provided.
- the present invention is not limited to the first plating step, the etching step, and the second plating step: for example, after the second plating step, another surface treatment may also be performed.
- another surface treatment may also be performed.
- electroless Ni-P plating electroless Ni-B plating may be used.
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Abstract
An object is to provide a method for forming a superior corrosion-resistant plating layer by sealing penetrating pinholes formed in an electroless plating layer. There are provided a first plating step of performing electroless Ni-P plating on a base material (1); an etching step of etching a surface of a first plating layer (3) formed by the first plating step; and a second plating step of performing electroless Ni-P plating to form a second plating layer (5) on the first plating layer (3) processed by the etching step.
Description
- The present invention relates to a method for forming a corrosion-resistant plating layer by electroless nickel-based plating and a rotary machine processed by the method for forming a corrosion-resistant plating layer.
- Compressors (rotary machines) used in power-generating plants and chemical plants compress gases containing corrosive gases such as CO2, H2S, and H2O. When carbon steel (cast iron, cast steel, or forged steel) is used as the base material for a compressor, since the anti-corrosion properties of the carbon steel are not sufficient, electroless nickel-based plating, such as Ni-P plating, is generally performed on a diaphragm and an impeller, which are exposed to corrosive gases.
However, as shown inFig. 11 , defects, such as cavities, are liable to be formed, particularly, in carbon steel during casting, andpores 100a having openings are formed in a surface of abase material 100. When thepores 100a as described above are present, even if electroless plating is performed on thebase material 100, penetratingpinholes 101a are formed in anelectroless plating layer 101 to penetrate the surface thereof.
When the penetratingpinholes 101a as described above are present, as shown inFig. 12 , a corrosive liquid infiltrates thebase material 100. As a result,corrosion products 100b are formed on thebase material 100. In addition, as thecorrosion products 100b gradually grow, theelectroless plating layer 101 is eventually peeled away.
The penetrating pinholes as described above may originate at a complex-shaped portion, such as a diaphragm or an impeller. - In order to seal the penetrating pinholes as described above, as disclosed in
Patent Document 1, a technique in which a plating layer is further formed on an electroless plating layer has been known. -
- Patent Document 1: Japanese Unexamined Patent Application Publication No.
2003-147548 - However, even when a plating layer is overlapped on the electroless plating layer as disclosed in the
Patent Document 1, the penetrating pinholes formed in the lower electroless plating layer are liable to continuously grow also in the upper plating layer in many cases. As a result, the penetrating pinholes are essentially not sealed. - The present invention has been conceived in consideration of the above situation, and an object of the present invention is to provide a method for forming a superior corrosion-resistant plating layer by sealing penetrating pinholes formed in an electroless plating layer and to provide a rotary machine.
- In order to solve the problem described above, a method for forming a corrosion-resistant plating layer and a rotary machine according to the present invention use the following solutions.
That is, a method for forming a corrosion-resistant plating layer according to the present invention is a method for forming a corrosion-resistant plating layer in which the corrosion-resistant plating layer is formed by performing electroless nickel-based plating on a base material, and the above method comprises: a first plating step of performing electroless nickel-based plating on the base material; an etching step of etching a surface of a first plating layer formed by the first plating step; and a second plating step of performing electroless nickel-based plating on the first plating layer processed by the etching step. - In the first plating step, the first plating layer is formed by performing electroless nickel-based plating on the base material. In the first plating layer, penetrating pinholes having openings at a surface side are formed due to the shapes of pores or the like formed in the surface of the base material.
In the etching step, corners forming opening portions of the penetrating pinholes are removed to form tapered shapes. As a result, the opening portions of the penetrating pinholes each have a mortar shape.
In the second plating step, a second plating layer is formed on the first plating layer. In this step, since the opening portions of the penetrating pinholes are each formed to have a mortar shape by the etching step, the second plating layer is formed so as to be laminated on the tapered surfaces each having a mortar shape, that is, is formed so as to be grown in an oblique direction with respect to an extending direction of the penetrating pinholes. Since the second plating layer is grown obliquely at the opening portions of the penetrating pinholes, the opening portions of the penetrating pinholes are sealed.
The present invention is particularly effective when carbon steel (cast iron, cast steel, or forged steel) is used as the base material. The reason for this is that since many pores having openings are formed in the surface of carbon steel, pin holes are liable to be formed in a plating layer.
As the electroless nickel-based plating, Ni-P plating or Ni-B plating is preferably performed.
The present invention is not limited to the first plating step, the etching step, and the second plating step; for example, after the second plating step, another surface treatment may also be performed. - Furthermore, in the method for forming a corrosion-resistant plating layer according to the present invention, the etching step is preferably performed using sulfuric acid.
- The etching step is preferably performed by an acid treatment using sulfuric acid, hydrochloric acid, nitric acid, or the like, and in particular, an acid treatment using sulfuric acid is preferable. For the concentration of sulfuric acid, approximately 5 percent by weight is preferable.
- Furthermore, in the method for forming a corrosion-resistant plating layer according to the present invention, the thickness of the first plating layer is preferably set to 5 µm or more.
- When the thickness of the first plating layer is less than 5 µm, the base material may be corroded in the etching step through pinholes formed in the first plating layer. Hence, as the first plating layer, a thickness of 5 µm or more is necessary.
- Furthermore, in the method for forming a corrosion-resistant plating layer according to the present invention, the thickness of the second plating layer is preferably set to 10 µm or more.
- When the thickness of the second plating layer is less than 10 µm, penetrating pinholes formed in the first plating layer cannot be sufficiently sealed. Hence, as the second plating layer, a thickness of 10 µm or more is necessary.
- Furthermore, in the method for forming a corrosion-resistant plating layer according to the present invention, the first plating step and the second plating step are preferably performed by electroless Ni-P plating, and a P concentration of an electroless Ni-P plating layer is preferably set in the range of 7 to 10 percent by weight.
- Through intensive research carried out by the inventors of the present invention, it was found that when the P concentration of the electroless Ni-P plating layer is set in the range of 7 to 10 percent by weight, superior corrosion resistance can be obtained.
- A rotary machine according to the present invention has a surface provided with a corrosion-resistant plating layer formed by one of the methods for forming a corrosion-resistant plating layer described above.
- Since the rotary machine has a surface provided with a corrosion-resistant plating layer formed by one of the methods for forming a corrosion-resistant plating layer described above, even when this surface is exposed to a corrosive gas, such as CO2, H2S, and H2O, a rotary machine having sufficient durability can be provided.
As the rotary machine, for example, a compressor may be mentioned. In the case of the compressor, an anti-corrosion treatment is performed on surfaces of an impeller (rotor blade) and a diaphragm, which is a stationary member. - After the corners of the opening portions of the penetrating pinholes are removed by the etching step to form tapered shapes, that is, mortar shaped portions, the second plating layer is formed on the first plating layer by the second plating step, and hence the opening portions of the penetrating pinholes can be sealed. Accordingly, a plating layer having superior corrosion resistance can be formed, and as a result, a rotary machine having superior corrosion resistance can be provided.
-
- [
FIG. 1] Fig. 1 is a flowchart showing steps of a treatment for forming a corrosion-resistant plating layer according to one embodiment of the present invention. - [
FIG. 2] Fig. 2 is a cross-sectional view time-sequentially showing a first plating layer and a second plating layer which are formed by following the flowchart shown inFig. 1 . - [
FIG. 3] Fig. 3 is a graph used in order to obtain a corrosion current density which is an evaluation index of the P concentration of an electroless Ni-P plating layer. - [
FIG. 4] Fig. 4 is a schematic view showing an electrolytic corrosion test apparatus used for investigation of the P concentration of an electroless Ni-P plating layer. - [
FIG. 5] Fig. 5 is a graph showing a corrosion-resistance evaluation result obtained by an electrolytic corrosion test. - [
FIG. 6] Fig. 6 is a perspective view showing a plating base material which is a test specimen used for investigation of lamination of plating layers. - [
FIG. 7] Fig. 7 is a flowchart showing a process used to determine experimental conditions. - [
FIG. 8] Fig. 8 is a graph showing a factor effect figure (smaller-the-better characteristic) related to a penetrating defect density. - [
FIG. 9] Fig. 9 is a flowchart showing a process used for a confirmation test and the conditions thereof. - [
FIG. 10] Fig. 10 is a graph showing the relationship between the number density of penetrating defects and the thickness of an upper Ni-P plating layer. - [
FIG. 11] Fig. 11 is a perspective cross-sectional view showing penetrating pinholes formed in a plating layer. - [
FIG. 12] Fig. 12 is a view showing a process in which a plating layer is peeled away by penetrating pinholes formed in the plating layer. -
- 1:
- base material
- 3:
- first plating layer
- 3a:
- penetrating pinhole
- 3b:
- opening portion
- 5:
- second plating layer
- Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In this embodiment, a corrosion prevention treatment is performed on a diaphragm and an impeller of a compressor which is exposed to a corrosive gas, such as CO2, H2S and H2O, by electroless Ni-P plating. Carbon steel (cast iron, cast steel, or forged steel) is used as a base material to be processed by the anti-corrosion treatment.
Fig. 1 shows steps of performing the anti-corrosion treatment on the base material by electroless Ni-P plating.
As shown in the above figure, after cleaning, degreasing, and water washing are performed for the base material, pickling is performed, followed by water washing. Subsequently, after pickling is performed with diluted sulfuric acid, water washing is performed, and the electroless Ni-P plating is then performed. Accordingly, a first plating step is completed. With this process, as shown inFig. 2 , afirst plating layer 3 is formed on abase material 1. In this figure, a penetratingpinhole 3a formed in thefirst plating layer 3 is shown. - Next, the surface of the
first plating layer 3 is etched by an acid treatment using diluted sulfuric acid or the like. By this etching step, acorner 3c forming anopening portion 3b of the penetrating pinhole (or penetrating defect) 3a is removed to form a tapered shape. Hence, as shown inFig. 2 , at theopening portion 3b of the penetratingpinhole 3a, amortar shape 3d is formed. - Next, after water washing is performed, electroless Ni-P plating is performed (second plating step). By this second plating step, a
second plating layer 5 is formed on thefirst plating layer 3. In this step, since themortar shape portion 3d is formed at theopening portion 3b of the penetratingpinhole 3a by the etching step, thesecond plating layer 5 is formed so as to be laminated on a tapered surface forming thismortar shape portion 3b, that is, is formed so as to grow in an oblique direction with respect to an extending direction of the penetratingpinhole 3a. Since thesecond plating layer 5 is obliquely grown at theopening portion 3b of the penetratingpinhole 3a, theopening portion 3b of the penetratingpinhole 3a is sealed.
Subsequently, after water washing is performed, drying is performed, followed by baking, so that the anti-corrosion treatment is completed. - The etching step is preferably performed by an acid treatment using sulfuric acid, hydrochloric acid, nitric acid, or the like. In particular, as described later, an acid treatment using diluted sulfuric acid is preferable. For the concentration of sulfuric acid, approximately 5 percent by weight is preferable.
- The thickness of the first plating layer is preferably 5 µm or more. The reason for this is that, in some cases, when the thickness of the
first plating layer 3 is less than 5 µm, an acid treatment using diluted sulfuric acid or the like may corrode thebase material 1 in the etching step through the penetratingpinhole 3a formed in thefirst plating layer 3. - The thickness of the
second plating layer 5 is preferably 10 µm or more. The reason for this is that when the thickness of thesecond plating layer 5 is less than 10 µm, the penetratingpinhole 3a formed in the first plating layer cannot be sufficiently sealed. - Next, Examples will be described.
- First, in order to optimize the P concentration of an electroless Ni-P plating layer, the corrosion rate was evaluated by measuring polarization properties performed while the P concentration was varied.
- JIS SPCC (cold-rolled carbon steel) was used as a base material, and electroless Ni-P plating layer was formed on a surface of the base material by varying the P concentration from 2.5 to 12.5 percent by weight under the conditions shown in Table 1.
Table 1 Electroless Ni-P plating test
Types of prepared solutions[Table 1] No. P concentration [wt%]/(average) Plating solution [Trade name] Plating thickness [mm] Producer 1 2∼3 (2.5) Nimuden LPX 20 C. Uyemura & Co., Ltd. 2 7∼8 (7.5) Nimuden 5X 20 C. Uyemura & Co., Ltd. 3 9∼10 (9.5) Nimuden SX 20 C. Uyemura & Co., Ltd. 4 12∼13 (12.5) Nimuden HDX 20 C. Uyemura & Co., Ltd. - After anode/cathode polarization curves were measured by an electrolytic corrosion test, a corrosion current density (Icorr) was obtained by the Tafel method (see
Fig. 3 ) to evaluate the anti-corrosion properties.
InFig. 4 , an electrolytic corrosion test apparatus used in this test is shown. Asample 12 is immersed in atest solution 10 and is disposed to face acounter electrode 14 made of Pt.
Thetest solution 10 is temperature-controlled by aheater 18 disposed around the periphery. The temperature of thetest solution 10 is measured by athermometer 16. In thetest solution 10, CO2 and H2S gases are introduced as simulated corrosive gases. Thetest solution 10 is agitated by astirrer 20.
Thesample 12 and thecounter electrode 14 are each connected to a potentio-galvanostat 21. Asalt bridge 22 is connected to thesample 12. The other end of thesalt bridge 22 is immersed in abath 24 together with a reference electrode (Ag/AgCl electrode) 23 connected to the potentio-galvanostat 21.
The measurement conditions of this test are shown in Table 2.
Table 2 Measurement conditions for polarization properties[Table 2] Items Conditions Solution Bubbling aqueous solution containing CO2 + 10 vol% of H2S (gas composition including maximum H2S concentration estimated in compressor) Solution temperature 80°C Sweeping rate 20 mV/min - The test procedure is as shown below.
- (a) A test solution in a volume of 350 ml is received in an electrolytic bath made of glass (jacket type having a volume of 400 ml).
- (b) An Ag/AgCl electrode is set as a reference electrode, Pt is as a counter electrode, and the sample 12 (measurement test specimen) is set as a test electrode.
- (c) While agitation is performed at 0.3 m/s by bubbling CO2 and H2S gases, the temperature of the test solution is increased to 80°C.
- (d) A spontaneous potential (Ecorr) of the measurement test specimen (sample 12) is measured for 30 minutes.
- (e) Polarization is performed to 400 mV on the cathode side of the spontaneous potential at a sweeping rate of 20 mV/min.
- (f) Polarization is performed from the spontaneous potential to 1,000 mV on the anode side at a sweeping rate of 20 mV/min.
- (g) Polarization curves shown in
Fig. 3 are obtained from the above (e) and (f). -
Fig. 5 shows an anti-corrosion evaluation result obtained by the above electrolytic corrosion test.
Under this corrosion environment, a composition region in which the P concentration in an electroless Ni-P plating layer is from 7 to 10 percent by weight is considered to have the most superior corrosion resistance.
The reasons why a P concentration in an electroless Ni-P plating layer in the range of 7 to 10 percent by weight is considered to have superior corrosion resistance are as follows. - (i) Comparison with a plating material having a P concentration of 2 to 3 percent by weight.
In the case of a Ni-P plating layer having a P concentration of 2 to 3 percent by weight (approximately 5 percent by weight or less), the plating film is crystalline. When the P concentration is more than 7 percent by weight, the plating film is amorphous. It is believed that due to the presence of sources of corrosion at grain boundaries in a crystalline film, the corrosion resistance thereof was inferior to that of an amorphous film. - Initially, it was estimated that a higher P concentration gave superior corrosion resistance; however, according to this test, at a P concentration of 10 percent by weight or more, the corrosion resistance was unexpectedly degraded. As the reason for this, it is believed that many pits caused by corrosion are generated in a high P material. Thereby the corrosion resistance is degraded. Although a passivation film, such as phosphorus oxide, can be formed on a plating surface, it is believed that as the P concentration is increased, microcrystalline are formed. Since a microcrystalline passivation film containing a high P concentration has many points that are liable to be broken, many pits caused by corrosion are generated. As a result, the corrosion current was increased in a Tafel method.
- According to the results described above, a concentration in the range of 7 to 10 percent by weight is preferable as the P concentration of the electroless Ni-P plating layer.
Hence, in the investigation of the lamination of plating layers explained below, Nimuden SX manufactured by C. Uyemura & Co., Ltd. is used, which can form a plating film having a P concentration in the range of 9 to 10 percent by weight. - By using electroless Ni-P plating solution (Nimuden SX, P concentration: 9 to 10 percent by weight) from C. Uyemura & Co., Ltd. selected as described above, it was attempted to reduce defects (penetrating pinholes) by laminating plating layers.
- As a plating base material used as the base material, JIS SC480 cast steel was used, which was obtained by casting simultaneously performed during manufacture of a diaphragm of an actual compressor. A base material having a size of 30×30×L200 was cut into a size of W30× L100×t3 mm by wire cutting as shown in
Fig. 6 , to form the plating base material. - A plating process for laminating layers (in this case, two-layer plating is considered) is performed as shown in
Fig. 7 . That is, by a lower layer electroless Ni-P plating process corresponding to the first plating step, an underlying Ni-P plating layer is formed to have a thickness of 20 µm, followed by etching, and by an upper layer electroless Ni-P plating process corresponding to the second plating step, upper layer Ni-P plating is perfomed.
Table 3 shown factors affecting penetrating defects (penetrating pinholes) in the plating layer and the reasons for the determining standards.
Table 3 control factors of the test for reducing penetrating defects in electroless Ni-P plating layer[Table 3] Control factors Standards Reasons for determining standards Type of etching solution Hydrochloric acid, sulfuric acid, nitric acid Commonly used solutions are selected. Concentration of etching solution 1, 5, and 10 percent by weight Commonly used concentration range is selected. Etching treatment time 1, 3, and 5 minutes Times are determined in consideration of etching rate of Ni-P plating and thickness of lower plating layer of 20 µm. Thickness of upper plating layer 10, 20, and 30 µm Thicknesses are determined in order to obtain total thickness of 50 µm or less, which is current plating thickness. - (1) Experimental method
By the plating process shown inFig. 7 and the conditions shown in the L9 orthogonal array of the following Table 4, electroless Ni-P plating was performed on the base material using SC480 to form two layers, and subsequently, the number of penetrating defectives was investigated.
Table 4 Two-layer plating test conditions L9 orthogonal array[Table 4] No. Control factors Error factors Type of etching solution Concentration of etching solution [wt%] Etching time [min] Thickness of upper Ni-P plating layer [µm] Temperature of etching solution [°C] 50 60 1 Hydrochloric acid 1 1 10 Condition 1Condition 102 Hydrochloric acid 5 3 20 Condition 2 Condition 11 3 Hydrochloric acid 10 5 30 Condition 3Condition 124 Sulfuric acid 1 3 30 Condition 4 Condition 13 5 Sulfuric acid 5 5 10 Condition 5Condition 146 Sulfuric acid 10 1 20 Condition 6 Condition 157 Nitric acid 1 5 20 Condition 7 Condition 168 Nitric acid 5 1 30 Condition 8 Condition 17 9 Nitric acid 10 3 10 Condition 9 Condition 18 -
- (a) In 500 ml of pure water, 2 g of reagent-grade hexacyano iron (II) potassium trihydrate, 2g of reagent-grade hexacyano iron (III) potassium, and 12 g of reagent-grade sodium chloride were dissolved, affording a test solution.
- (b) After a test piece was washed with ethyl alcohol, water washing was performed, and moisture was then wiped off.
- (c) Two types of dense quantitative filter paper (manufactured by Toyo Advantec Co., Ltd.) used as test paper were cut into a size of 50 mm square, were immersed in the test solution, and were then placed on test surfaces while the filters were wet.
- (d) After 5 minutes elapsed, the test paper was peeled away and was dried, and the number of blue spots that appeared on the test paper was examined.
- A factor effect graph (smaller-the-better characteristic) of the penetrating defect density is shown in
Fig. 8 . A summary of the results is as follows. - (i) The factor having the most significant effect on plating defects is the thickness of the upper plating layer; as the thickness is increased, the number of defects is decreased, and the robustness is also improved.
- (ii) The type of etching solution has a relatively small effect; however, in the case of nitric acid, it is believed that since the plating dissolving ability is high, and smut (impurities of oxides, carbides, and the like) is generated on the plating surface by long-term etching, the variation is increased when an actual machine with a large and complicated shape is processed.
- (iii) An etching solution concentration in the range of 1 to 5 percent by weight showed a good result without any differences therebetween.
- (iv) Although an etching time of 3 minutes did not show a good result, it is believed that this result is caused by the generation of smut due to 10 wt%-nitric acid (high concentration) etching and that the effect of an etching time of 1 to 5 minutes is essentially small.
- (v) According to the results described above, the following conditions are selected: sulfuric acid is used as the type of etching solution, the etching solution concentration is 5 percent by weight, and the etching time is 5 minutes, and a confirmation test is performed by using the thickness of the upper plating layer, which has the most significant effect, as a parameter.
- A cast iron material (SC 480) similar to that described above was used.
The base material dimensions were set to W30×L100×t3 mm. - The process shown in
Fig. 7 was carried out. - An upper layer plating (etching and second plating layer) process and conditions thereof are shown in
Fig. 9 . The thickness of the upper plating layer was used as a parameter, and the target thickness was varied from 10 to 30 µm. - The number density of penetrating defects was measured by a ferroxyl test.
InFig. 10 , the relationship between the thickness of the upper Ni-P plating layer and the number density of penetrating defects, which is obtained by the confirmation test, is shown. A summary of the results is as described below.
By increasing the thickness of the upper plating layer, the number density of penetrating defects is decreased. In particular, when the upper plating layer had a thickness of more than 15 µm, the defect reduction effect was significant, and when the thickness of the upper plating layer was 23 µm (20 (thickness of the lower plating layer) + 23 (thickness of the upper plating layer) = 43 µm (total thickness)), the number density of penetrating defects was decreased to 1.7 per 50 mm square.
When the two-layer plating material of this test and a current single-layer plating material are compared, the results are as shown in Table 5. It is understood that the effect of a two-layer lamination including the etching step and the second plating step is significant.
Table 5 Comparison of number of penetrating defects[Table 5] Name of test object Number density of penetrating defects Two-layer Ni-P plating of the invention 1.7/50 mm square Current Ni-P plating material (single layer: 50 µm) 15 to 20/50 mm square - As described above, according to this embodiment, the
corner 3c forming theopening portion 3b of the penetratingpinhole 3a is removed by the etching step to form a tapered shape, so that the mortar shapedportion 3d is formed. Subsequently, since thesecond plating layer 5 is formed on thefirst plating layer 3 by the second plating step, the opening portion of the penetratingpinhole 3a can be sealed. Accordingly, a plating layer having superior corrosion resistance can be formed. As a result, a compressor having superior corrosion resistance can be provided. - The present invention is not limited to the first plating step, the etching step, and the second plating step: for example, after the second plating step, another surface treatment may also be performed.
Instead of the electroless Ni-P plating, electroless Ni-B plating may be used.
Claims (6)
- A method for forming a corrosion-resistant plating layer in which a corrosion-resistant plating layer is formed on a base material by performing electroless nickel-based plating, comprising:a first plating step of performing electroless nickel-based plating on the base material;an etching step of etching a surface of a first plating layer formed by the first plating step; anda second plating step of performing electroless nickel-based plating on the first plating layer processed by the etching step.
- The method for forming a corrosion-resistant plating layer according to Claim 1, wherein the etching step is performed using sulfuric acid.
- The method for forming a corrosion-resistant plating layer according to Claim 1 or 2, wherein the thickness of the first plating layer is set to 5 µm or more.
- The method for forming a corrosion-resistant plating layer according to one of Claims 1 to 3, wherein the thickness of the second plating layer is set to 10 µm or more.
- The method for forming a corrosion-resistant plating layer according to one of Claims 1 to 4, wherein the first plating step and the second plating step are each performed by electroless Ni-P plating, and a P concentration of the electroless Ni-P plating is set in the range of 7 to 10 percent by weight.
- A rotary machine having a surface provided with a corrosion-resistant plating layer formed by the method for forming a corrosion-resistant plating layer according to one of Claims 1 to 5.
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JP2006311522A JP4709731B2 (en) | 2006-11-17 | 2006-11-17 | Corrosion-resistant plating layer forming method and rotating machine |
PCT/JP2007/072151 WO2008059907A1 (en) | 2006-11-17 | 2007-11-15 | Method for forming corrosion resistant plating layer and rotating machine |
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EP (1) | EP2058417A1 (en) |
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Cited By (3)
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ITCO20120015A1 (en) * | 2012-04-12 | 2013-10-13 | Nuovo Pignone Srl | METHOD FOR THE PREVENTION OF CORROSION AND COMPONENT OBTAINED THROUGH THIS METHOD |
EP3276143A4 (en) * | 2015-03-25 | 2018-04-25 | Mitsubishi Heavy Industries, Ltd. | Impeller for rotary machine, compressor, supercharger, and method for manufacturing impeller for rotary machine |
US10598186B2 (en) | 2014-05-15 | 2020-03-24 | Nuovo Pignone Srl | Method for preventing the corrosion of an impeller-shaft assembly of a turbomachine |
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US20110027576A1 (en) * | 2009-07-28 | 2011-02-03 | General Electric Company | Sealing of pinholes in electroless metal coatings |
EP2875168B1 (en) * | 2012-07-17 | 2017-12-20 | Coventya, Inc. | Electroless nickel coatings and compositions and methods for forming the coatings |
JP5986924B2 (en) * | 2012-12-28 | 2016-09-06 | 三菱重工業株式会社 | Manufacturing method of rotating machine |
JP5986925B2 (en) * | 2012-12-28 | 2016-09-06 | 三菱重工業株式会社 | Rotating machine manufacturing method, rotating machine plating method |
CN107208655B (en) | 2015-03-17 | 2019-09-10 | 三菱重工发动机和增压器株式会社 | The impeller of rotating machinery, compressor, booster and rotating machinery impeller manufacturing method |
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JPS5919991B2 (en) * | 1977-07-29 | 1984-05-10 | 株式会社日立製作所 | Two-stage pickling method for pure silicon steel materials |
US5024591A (en) * | 1989-06-21 | 1991-06-18 | Diesel Kiki Co., Ltd. | Vane compressor having reduced weight as well as excellent anti-seizure and wear resistance |
JP3031045B2 (en) * | 1991-03-29 | 2000-04-10 | 株式会社日立製作所 | Fine particle composite plating equipment |
US5769544A (en) * | 1993-05-12 | 1998-06-23 | Ricoh Company, Ltd. | Dynamic pressure pneumatic bearing device and manufacturing method thereof |
JP2746830B2 (en) * | 1993-05-12 | 1998-05-06 | 株式会社リコー | Dynamic pressure air bearing device and method of manufacturing groove for generating dynamic pressure |
JPH08170178A (en) * | 1994-12-15 | 1996-07-02 | Mitsubishi Heavy Ind Ltd | Production of anticorrosive film |
JP2936129B2 (en) * | 1995-04-12 | 1999-08-23 | セイコー精機株式会社 | Anti-corrosion structure |
JP3629150B2 (en) * | 1998-08-11 | 2005-03-16 | 株式会社東芝 | Plating film forming method and forming apparatus |
JP3901495B2 (en) | 2001-11-13 | 2007-04-04 | 株式会社神戸製鋼所 | Aluminum or aluminum alloy reel |
JP2004323913A (en) * | 2003-04-24 | 2004-11-18 | Nippon Parkerizing Co Ltd | Lubrication surface treatment method for metal and lubricative metallic member having lubrication surface obtained by the same |
US7118933B2 (en) * | 2003-06-11 | 2006-10-10 | Hitachi Maxell, Ltd. | Method for manufacturing optical bench, optical bench, optical module, silicon wafer substrate in which wiring and groove are formed, and wafer |
JP2005206866A (en) * | 2004-01-21 | 2005-08-04 | Fuji Electric Device Technology Co Ltd | Pretreatment method for electroless plating, method for manufacturing substrate for magnetic recording media including the pretreatment method, and substrate for magnetic recording media manufactured by the manufacturing method |
JP4519548B2 (en) * | 2004-07-12 | 2010-08-04 | ポリプラスチックス株式会社 | Plating pretreatment method for liquid crystalline polymer molded products |
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ITCO20120015A1 (en) * | 2012-04-12 | 2013-10-13 | Nuovo Pignone Srl | METHOD FOR THE PREVENTION OF CORROSION AND COMPONENT OBTAINED THROUGH THIS METHOD |
WO2013153020A3 (en) * | 2012-04-12 | 2014-07-24 | Nuovo Pignone Srl | Method for preventing corrosion and component obtained by means of such |
US10161413B2 (en) | 2012-04-12 | 2018-12-25 | Nuovo Pignone Srl | Method for preventing corrosion and component obtained by means of such |
US10598186B2 (en) | 2014-05-15 | 2020-03-24 | Nuovo Pignone Srl | Method for preventing the corrosion of an impeller-shaft assembly of a turbomachine |
EP3276143A4 (en) * | 2015-03-25 | 2018-04-25 | Mitsubishi Heavy Industries, Ltd. | Impeller for rotary machine, compressor, supercharger, and method for manufacturing impeller for rotary machine |
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WO2008059907A1 (en) | 2008-05-22 |
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