CN104294328B - Nickel-molybdenum-aluminum-rare earth coating and preparation method thereof - Google Patents

Abstract

The invention discloses a nickel-molybdenum-aluminum rare-earth coating and a preparation method thereof. The nickel-molybdenum-aluminum rare-earth coating is composed of four elements: nickel, molybdenum, aluminum and rare earth. Calculated by mass percentage, the ratio of nickel:molybdenum:aluminum:rare earth is 72.95-21.57 %, 21.33~43.70%, 3.50~16.70%, 2.22~18.02%. The preparation method is to add nickel salt, molybdenum compound, aluminum salt, rare earth salt, complexing agent and chloride to water, and adjust the pH value to 7.5-9.5 to obtain nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent- Chloride electroplating solution; then the plated piece to be plated is used as the cathode, and the anode is nickel and put into it for pulse electroplating. Nickel molybdenum aluminum rare earth coating. The oxidation and corrosion resistance of the nickel-molybdenum-aluminum rare earth coating is stronger than that of the nickel-molybdenum coating and the nickel-molybdenum-aluminum coating.

Description

A kind of nickel-molybdenum-aluminum rare earth coating and preparation method thereof

technical field

The invention relates to a nickel-molybdenum-aluminum rare earth coating and a preparation method thereof.

Background technique

With the development of aero-engines toward high thrust-to-weight ratios, the design inlet temperature of aero-engines continues to increase, and the use of high-temperature structural materials alone cannot meet the urgent requirements of the rapid development of advanced aero-engines. At present, the practical way to greatly increase the operating temperature of aero-engines is to use thermal barrier coating technology. Most of the thermal barrier coatings that have been applied in practice have a double-layer structure, and the ceramic layer is used as the surface layer of the thermal barrier coating because of its heat insulation, corrosion resistance, erosion and erosion properties. Due to the thermal expansion coefficient mismatch between ceramics and high-temperature structural materials, a metal bonding layer is required to resist high-temperature oxidation corrosion and improve the physical compatibility between the substrate and the ceramic coating, and the metal bonding layer is the bottom layer.

At present, the thermal barrier coating uses nickel coating, nickel molybdenum coating, nickel molybdenum rare earth coating, nickel molybdenum-molybdenum disilicide composite coating, nickel molybdenum rare earth-molybdenum disilicide composite coating as bonding layer, but the above bonding layer materials all exist Oxidation and corrosion resistance is not very strong and other technical problems.

Contents of the invention

One of the objects of the present invention is to provide a nickel-molybdenum-aluminum rare-earth coating in order to solve the technical problems of the above-mentioned coatings such as nickel and molybdenum having weak oxidation and corrosion resistance. That is, adding aluminum and rare earth to the nickel-molybdenum coating can make the coating form an Al ₂ O ₃ protective oxide film during the oxidation process and improve the oxidation and corrosion resistance of the coating, which can solve the problem that the oxidation and corrosion resistance of the nickel-molybdenum coating is not very strong. technical problem.

The second object of the present invention is to provide the above-mentioned preparation method of nickel-molybdenum-aluminum rare earth coating.

Technical scheme of the present invention

A nickel-molybdenum-aluminum rare-earth coating, composed of four elements: nickel, molybdenum, aluminum, and rare earth. Calculated by mass percentage, nickel: molybdenum: aluminum: rare earth is 72.95-21.57%, 21.33-43.70%, 3.50-16.70%, 2.22 ~18.02%.

The above-mentioned preparation method of a nickel-molybdenum-aluminum rare earth coating specifically comprises the following steps:

(1) Dissolving rare earth oxides in acid to obtain rare earth salts;

The rare earth oxides are one or more of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, scandium rare earth oxides mixture;

Described acid is nitric acid or hydrochloric acid;

(2) Add nickel salt, molybdenum compound, aluminum salt, rare earth salt, complexing agent, and chloride obtained in step (1) to water, adjust the pH value of the solution to 7.5 to 9.5 with sodium carbonate solution, and make nickel salt- Molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride plating solution;

Wherein the nickel salt is one or a mixture of two or more of nickel chloride, nickel nitrate and nickel sulfate;

The molybdenum compound is one or a mixture of two or more of molybdenum pentachloride, ammonium molybdate, ammonium phosphomolybdate, and sodium molybdate;

The aluminum salt is aluminum trichloride, aluminum sulfate or a mixture of aluminum trichloride and aluminum sulfate;

The complexing agent is one or a mixture of two or more of glycolic acid, glycine, oxalic acid, citric acid, tartaric acid, lactic acid, succinic acid, and malic acid;

Chloride is one of sodium chloride, ammonium chloride, potassium chloride or a mixture of more than two chlorides;

In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentrations of rare earth elements, complexing agent and chloride in nickel salt, molybdenum compound, aluminum salt and rare earth salt are respectively 5 ~400g/L, 5~800g/L, 5~350g/L, 0.06~10g/L, 1~100g/L, 5~300g/L;

(3) The plated piece to be plated is used as the cathode, and the anode is nickel, and the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution obtained in step (1) is used for pulse electroplating. During the pulse electroplating process, the pulse frequency is 2000-5000Hz, the duty ratio is 0.5-0.9, the current density is 10-25A/dm ² , the temperature is 40-60°C, the rotation speed is 100-600rpm, and the time is 10-60min. Rinse the parts with water, air dry, and get a nickel-molybdenum-aluminum rare earth coating on the surface of the plated parts.

Beneficial effects of the present invention

Nickel molybdenum aluminum rare earth coating of the present invention, owing to adding aluminum and rare earth in nickel molybdenum coating, can make coating form _Al2O3 protective _oxide film and improve the oxidation corrosion resistance of coating in oxidation process, thereby make the obtained nickel The oxidation and corrosion resistance of the molybdenum-aluminum rare earth coating is stronger than that of the nickel-molybdenum coating and the nickel-molybdenum-aluminum coating.

Further, since generally electroplating in an aqueous solution cannot obtain an aluminum-containing coating, the present invention uses a pulse power supply and adds rare earth elements to the plating solution. The added rare earth elements not only provide a source of rare earth for the formation of the nickel-molybdenum-aluminum rare-earth coating, but also Elements are also used as electroplating accelerators. It is further verified by experiments that when the concentration of rare earth salt in the plating solution is low, that is, only 0.01 to 0.05g/L, the rare earth element is only used as an electroplating accelerator, that is, when adding a rare earth element in the plating solution as an electroplating accelerator, Using a pulse power supply, a nickel-molybdenum-aluminum coating can only be obtained by electroplating in an aqueous solution; only when the concentration of the rare earth salt in the plating solution reaches 0.06~10g/L, the rare earth element can not only provide a source of rare earth for the formation of the nickel-molybdenum-aluminum rare earth coating, And it is also used as an electroplating accelerator. At this time, the nickel-molybdenum-aluminum rare earth coating can be obtained by electroplating in an aqueous solution.

The content of aluminum and rare earth in nickel-molybdenum-aluminum rare earth coating was determined by Bruker AXS Microanalysis GmbH energy spectrometer to be 3.5-16.7% and 2.22-18.02%, respectively.

detailed description

The present invention is further illustrated below by specific examples, but the present invention is not limited.

The specifications of various raw materials used in each embodiment of the present invention and the information of the manufacturer are all commercially available.

Example 1

A nickel-molybdenum-aluminum rare-earth coating is composed of four elements: nickel, molybdenum, aluminum, and rare earth. Calculated by mass percentage, nickel: molybdenum: aluminum: rare earth is 72.95%: 21.33%: 3.50%: 2.22%.

The above-mentioned preparation method of a nickel-molybdenum-aluminum rare earth coating specifically comprises the following steps:

(1) Dissolve 0.5856g of rare earth oxide in 6mL of acid, heat to dissolve it, and after it cools down, transfer it to a 50mL volumetric flask, dilute to the mark with water, and obtain a rare earth salt with a cerium concentration of 10g/L solution;

The rare earth oxide is cerium oxide;

Described acid is concentrated nitric acid;

(2) Add 5g of nickel salt, 5g of molybdenum compound, 5g of aluminum salt, 6mL of rare earth salt solution with a cerium concentration of 10g/L obtained in step (1), 1g of complexing agent, 5g of chloride in 980mL of water, and use sodium carbonate The pH value of the solution is adjusted to 7.5, and the volume is adjusted to 1L by adding water to obtain nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride plating solution, namely nickel chloride-molybdenum pentachloride-aluminum trichloride- Cerium nitrate-oxalic acid-sodium chloride electroplating solution;

Wherein the nickel salt is nickel chloride;

The molybdenum compound is molybdenum pentachloride;

Aluminum salt is aluminum trichloride;

The complexing agent is oxalic acid;

Chloride is sodium chloride;

In described nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentration of rare earth element cerium, complexing agent, chloride in nickel salt, molybdenum compound, aluminum salt, rare earth salt is respectively 5g/L, 5g/L, 5g/L, 0.06g/L, 1g/L, 5g/L;

(3) The nickel alloy plate to be plated is 100mm×100mm×0.5mm as the cathode, and the anode is an electrolytic nickel plate of 150mm×150mm×2mm, and the nickel salt-molybdenum compound obtained in step (1) is put in -Pulse electroplating in aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, control pulse frequency 2000Hz, duty ratio 0.5, current density 10A/dm ² , temperature 40°C, speed 100rpm, time After 60 minutes of electroplating, the plated parts were rinsed with water and air-dried to obtain a layer of nickel-molybdenum-aluminum-rare-earth coating, that is, nickel-molybdenum-aluminum-cerium coating on the surface of the plated part.

Bruker AXS Microanalysis GmbH was used to measure the contents of nickel, molybdenum, aluminum and cerium in the nickel-molybdenum-aluminum-cerium coating obtained above, and they were 72.95%, 21.33%, 3.50%, and 2.22% by mass percentage, respectively.

The nickel-molybdenum-aluminum-cerium-plated parts were oxidized at a constant temperature in an air atmosphere of 1100 ° C for 48 hours, then cooled to room temperature in a natural furnace, and the mass of the plated parts before oxidation and the mass after oxidation were measured with a BS224S electronic balance to obtain The mass increase of the plated piece after oxidation is 0.025 mg/cm ² .

Example 2

A nickel-molybdenum-aluminum rare earth coating is composed of four elements: nickel, molybdenum, aluminum and rare earth. Calculated by mass percentage, nickel: molybdenum: aluminum: rare earth is 21.57%: 43.70%: 16.70%: 18.03%.

The above-mentioned preparation method of a nickel-molybdenum-aluminum rare earth coating specifically comprises the following steps:

(1) Put 6.3500g of yttrium oxide in a 100mL small beaker, add 30mL of hydrochloric acid with a mass concentration of 37% under stirring, heat to dissolve it, and after it cools down, transfer it to a 100mL volumetric flask and dilute with water to Scale, the concentration of yttrium in the solution is 50g/L rare earth hydrochloric acid aqueous solution 1;

Put 5.7175g of erbium oxide in a 100mL small beaker, add 25mL of hydrochloric acid with a mass concentration of 37% under stirring, heat to dissolve it, and after it cools down, transfer it to a 100mL volumetric flask and dilute it to the mark with water. Middle erbium concentration is the rare earth hydrochloric acid aqueous solution 2 of 50g/L;

(2) Add 400g nickel salt, 800g molybdenum compound, 350g aluminum salt, 100mL rare earth hydrochloric acid aqueous solution 1 with 50g/L yttrium concentration and 100mL rare earth hydrochloric acid aqueous solution 2 with 50g/L erbium concentration in 785mL water, 100g complexing agent, 300g chloride, use sodium carbonate solution to adjust the pH value of the solution to 9.5, add water to make the volume to 1L, and obtain nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, that is, nickel nitrate-nickel chloride- Ammonium molybdate-aluminum sulfate-yttrium chloride-erbium chloride-tartaric acid-ammonium chloride-potassium chloride electroplating solution;

Wherein the nickel salt is a mixture of nickel nitrate and nickel sulfate in a mass ratio of 1:1;

The molybdenum compound is ammonium molybdate;

Aluminum salt is aluminum sulfate;

Complexing agent is tartaric acid;

Chloride is a mixture of ammonium chloride and potassium chloride in a mass ratio of 1:1;

In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentration of rare earth element yttrium and erbium, complexing agent, chloride in nickel salt, molybdenum compound, aluminum salt, rare earth salt 400g/L, 800g/L, 350g/L, 10g/L, 100g/L, 300g/L respectively;

(3) The nickel plate to be plated is 100mm × 100mm × 0.5mm as the cathode, and the anode is an electrolytic nickel plate of 150mm × 150mm × 2mm, and the nickel nitrate-nickel chloride obtained in step (1) is placed -Ammonium molybdate-aluminum sulfate-yttrium chloride-erbium chloride-tartaric acid-ammonium chloride-potassium chloride electroplating solution is used for pulse electroplating. During the pulse electroplating process, the pulse frequency is controlled at 5000Hz, the duty ratio is 0.9, and the current Density 25A/dm ² , temperature 60°C, rotation speed 600rpm, time 40min. After electroplating, rinse the plated parts with water and air dry. A layer of nickel-molybdenum-aluminum-rare-earth coating, that is, nickel-molybdenum-aluminum-yttrium-erbium coating is obtained on the surface of the plated piece.

Adopt Bruker AXS Microanalysis GmbH energy spectrometer to measure nickel, molybdenum, aluminum, yttrium, erbium content in the nickel-molybdenum-aluminum-yttrium-erbium coating of above-mentioned gained, calculate by mass percentage and be respectively 21.57%, 43.70%, 16.70%, 8.91%, 9.12% .

The nickel-molybdenum-aluminum-yttrium-erbium-coated parts were oxidized at a constant temperature of 1100°C for 48 hours in an air atmosphere, then cooled to room temperature in a natural furnace, and the quality of the plating parts before oxidation and the quality after oxidation were respectively measured with a BS224S electronic balance. The mass increase of the plated piece after oxidation was 0.03 mg/cm ² .

Example 3

A nickel-molybdenum-aluminum rare earth coating is composed of four elements: nickel, molybdenum, aluminum and rare earth. Calculated by mass percentage, nickel: molybdenum: aluminum: rare earth is 30.82%: 40.27%: 13.90%: 15.01%.

The above-mentioned preparation method of a nickel-molybdenum-aluminum rare earth coating specifically comprises the following steps:

(1) Put 2.8688g of dysprosium oxide in a 50mL small beaker, add 15mL of concentrated nitric acid under stirring, heat to dissolve it, after it cools down, transfer it to a 100mL volumetric flask, dilute with water to the mark, and obtain the dysprosium concentration 25g/L rare earth nitrate aqueous solution 1;

Put 2.8816g of gadolinium oxide in a 50mL small beaker, add 15mL of concentrated nitric acid under stirring, heat to dissolve it, after it cools down, transfer it to a 100mL volumetric flask, dilute with water to the mark, and obtain a gadolinium concentration of 25g/L Rare earth nitrate aqueous solution 2;

(2) Add 200g nickel salt, 400g molybdenum compound, 175g aluminum salt, 100mL rare earth nitrate aqueous solution 1 with a dysprosium concentration of 25g/L and 100mL rare earth nitrate aqueous solution 2 with a gadolinium concentration of 25g/L, 50g complex in 780mL water Mixture, 150g chloride, adjust the pH value of the solution with sodium carbonate solution to be 8.5, add water and settle to 1L to obtain nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, that is, nickel chloride-nitric acid Nickel-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-dysprosium nitrate-gadolinium nitrate-lactic acid-oxalic acid-ammonium chloride-sodium chloride plating solution;

Wherein the nickel salt is a mixture of nickel chloride and nickel nitrate in a mass ratio of 3:1;

The molybdenum compound is a mixture of molybdenum pentachloride and ammonium molybdate in a mass ratio of 1:1;

The aluminum salt is a mixture of aluminum trichloride and aluminum sulfate in a ratio of 4:3;

The complexing agent is a mixture of oxalic acid and lactic acid in a mass ratio of 5:3;

Chloride is that sodium chloride and ammonium chloride are formed from a mixture of 2:1 by mass ratio;

In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentration of rare earth elements dysprosium and gadolinium, complexing agent, chloride in nickel salt, molybdenum compound, aluminum salt, rare earth salt 200g/L, 400g/L, 175g/L, 5g/L, 50g/L, 150g/L respectively;

(3), the nickel single crystal plate to be plated is 100mm x 100mm x 0.5mm as the cathode, and the anode is an electrolytic nickel plate of 150mm x 150mm x 2mm, and the nickel chloride obtained in step (1)- Nickel nitrate-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-dysprosium nitrate-gadolinium nitrate-lactic acid-oxalic acid-ammonium chloride-sodium chloride plating solution for pulse plating, pulse plating process control The frequency is 3500Hz, the duty ratio is 0.7, the current density is 17.8A/dm ² , the temperature is 60°C, the rotation speed is 550rpm, and the time is 35min. After the electroplating is completed, the plated parts are rinsed with water and air-dried to obtain a layer of nickel-molybdenum on the surface of the plated parts. Aluminum rare earth coating is nickel molybdenum aluminum dysprosium gadolinium coating.

The content of nickel, molybdenum, aluminum, dysprosium, and gadolinium in the nickel-molybdenum-aluminum-gadolinium coating obtained above was measured by Bruker AXS Microanalysis GmbH energy spectrometer, and calculated by mass percentage, they were 30.82%, 40.27%, 13.90%, 5.23%, and 9.78% respectively .

The nickel-molybdenum-aluminum-dysprosium-gadolinium-coated parts were oxidized at a constant temperature of 1100°C for 48 hours in an air atmosphere, then cooled to room temperature in a natural furnace, and the mass of the plated parts before oxidation and the mass after oxidation were respectively measured with a BS224S electronic balance. The mass increase of the plated piece after oxidation was 0.02 mg/cm ² .

Embodiment 4 (the comparative example of embodiment 3)

A nickel-molybdenum coating is composed of nickel and molybdenum. Calculated by mass percentage, nickel: molybdenum is 67.73%: 32.27%.

The preparation method of above-mentioned a kind of nickel-molybdenum coating specifically comprises the steps:

(1) Add 200g of nickel salt, 400g of molybdenum compound, 175g of aluminum salt, 50g of complexing agent, and 150g of chloride into 990mL of water, adjust the pH of the solution to 8.5 with sodium carbonate solution, add water to 1L to obtain nickel salt-molybdenum Compound-aluminum salt-complexing agent-chloride plating solution is nickel chloride-nickel nitrate-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-lactic acid-oxalic acid-ammonium chloride-sodium chloride electroplating liquid; wherein the nickel salt is a mixture of nickel chloride and nickel nitrate in a mass ratio of 3:1;

The molybdenum compound is a mixture of molybdenum pentachloride and ammonium molybdate in a mass ratio of 1:1;

The aluminum salt is a mixture of aluminum trichloride and aluminum sulfate in a ratio of 4:3;

The complexing agent is a mixture of oxalic acid and lactic acid in a mass ratio of 5:3;

Chloride is that sodium chloride and ammonium chloride are formed from a mixture of 2:1 by mass ratio;

In described nickel salt-molybdenum compound-aluminum salt-complexing agent-chloride electroplating solution, the concentration of nickel salt, molybdenum compound, aluminum salt, complexing agent, chloride is respectively 200g/L, 400g/L, 175g/L L, 50g/L, 150g/L;

(2), use the nickel single crystal plate to be plated with 100mm×100mm×0.5mm to be plated as the cathode, and the anode is an electrolytic nickel plate with 150mm×150mm×2mm, and put the nickel chloride obtained in step (1)- Electroplating is carried out in nickel nitrate-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-lactic acid-oxalic acid-ammonium chloride-sodium chloride electroplating solution. During the electroplating process, the current density is controlled at 17.8A/dm ² and the temperature 60°C, rotating speed 550rpm, time 35min, after electroplating, rinse the plated parts with water, air dry, and obtain a layer of coating on the surface of the plated parts.

Adopt Bruker AXS Microanalysis GmbH energy spectrometer to measure nickel, molybdenum, aluminum content in the coating of above-mentioned gain, do not detect aluminum in the coating, nickel, molybdenum content, calculate by mass percentage and be respectively 67.73%, 32.27%.

The above nickel-molybdenum coating was oxidized at a constant temperature in an air atmosphere of 1100°C for 48 hours, then cooled to room temperature in a natural furnace, and the quality of the coating before oxidation and the quality after oxidation were measured with a BS224S electronic balance to obtain the coating. The mass increase of the piece after oxidation was 0.415 mg/cm ² .

Embodiment 5 (the comparative example of embodiment 4)

A nickel-molybdenum-aluminum coating is composed of three elements: nickel, molybdenum and aluminum. Calculated by mass percentage, nickel: molybdenum: aluminum is 55.50%: 36.92%: 7.58%.

The preparation method of above-mentioned a kind of nickel-molybdenum-aluminum coating specifically comprises the steps:

(1) Put 2.8688g of dysprosium oxide in a 50mL small beaker, add 15mL of concentrated nitric acid under stirring, heat to dissolve it, after it cools down, transfer it to a 100mL volumetric flask, dilute with water to the mark, and obtain the dysprosium concentration 25g/L rare earth nitrate aqueous solution 1;

Put 2.8816g of gadolinium oxide in a 50mL small beaker, add 15mL of concentrated nitric acid under stirring, heat to dissolve it, after it cools down, transfer it to a 100mL volumetric flask, dilute with water to the mark, and obtain a gadolinium concentration of 25g/L Rare earth nitrate aqueous solution 2;

(2) Add 200g nickel salt, 400g molybdenum compound, 175g aluminum salt, 1mL rare earth nitrate aqueous solution 1 with a dysprosium concentration of 25g/L and 1mL rare earth nitrate aqueous solution 2 with a gadolinium concentration of 25g/L, 50g complex in 780mL water Mixture, 150g chloride, adjust the pH value of the solution with sodium carbonate solution to be 8.5, add water and settle to 1L to obtain nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, that is, nickel chloride-nitric acid Nickel-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-dysprosium nitrate-gadolinium nitrate-lactic acid-oxalic acid-ammonium chloride-sodium chloride plating solution;

Wherein the nickel salt is a mixture of nickel chloride and nickel nitrate in a mass ratio of 3:1;

The molybdenum compound is a mixture of molybdenum pentachloride and ammonium molybdate in a mass ratio of 1:1;

The aluminum salt is a mixture of aluminum trichloride and aluminum sulfate in a ratio of 4:3;

The complexing agent is a mixture of oxalic acid and lactic acid in a mass ratio of 5:3;

Chloride is that sodium chloride and ammonium chloride are formed from a mixture of 2:1 by mass ratio;

In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentration of rare earth elements dysprosium and gadolinium, complexing agent, chloride in nickel salt, molybdenum compound, aluminum salt, rare earth salt 200g/L, 400g/L, 175g/L, 5g/L, 0.05g/L, 150g/L respectively;

(3), the nickel single crystal plate to be plated is 100mm x 100mm x 0.5mm as the cathode, and the anode is an electrolytic nickel plate of 150mm x 150mm x 2mm, and the nickel chloride obtained in step (1)- Nickel nitrate-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-dysprosium nitrate-gadolinium nitrate-lactic acid-oxalic acid-ammonium chloride-sodium chloride plating solution for pulse plating, pulse plating process control The frequency is 3500Hz, the duty ratio is 0.7, the current density is 17.8A/dm ² , the temperature is 60°C, the rotation speed is 550rpm, and the time is 35min. After the electroplating is completed, the plated parts are rinsed with water and air-dried to obtain a layer of nickel-molybdenum on the surface of the plated parts. Aluminum coating is nickel molybdenum aluminum coating.

The contents of nickel, molybdenum and aluminum in the nickel-molybdenum-aluminum coating obtained above were measured by Bruker AXS Microanalysis GmbH energy spectrometer, and calculated by mass percentage, they were 55.50%, 36.92%, and 7.58%, respectively.

The above nickel-molybdenum-aluminum coating was oxidized at a constant temperature in an air atmosphere of 1100°C for 48 hours, then cooled to room temperature in a natural furnace, and the mass of the plating piece before oxidation and the mass after oxidation were measured with a BS224S electronic balance to obtain the The mass increase of the plated parts after oxidation is 0.140mg/cm ² .

Embodiment 6 (the comparative example of embodiment 4)

A nickel-molybdenum-aluminum coating is composed of three elements: nickel, molybdenum and aluminum. Calculated by mass percentage, nickel: molybdenum: aluminum is 58.85%: 34.23%: 6.92%.

The preparation method of above-mentioned a kind of nickel-molybdenum-aluminum coating specifically comprises the steps:

(1) Put 2.8688g of dysprosium oxide in a 50mL small beaker, add 15mL of concentrated nitric acid under stirring, heat to dissolve it, after it cools down, transfer it to a 100mL volumetric flask, dilute with water to the mark, and obtain the dysprosium concentration 25g/L rare earth nitrate aqueous solution 1;

Put 2.8816g of gadolinium oxide in a 50mL small beaker, add 15mL of concentrated nitric acid under stirring, heat to dissolve it, after it cools down, transfer it to a 100mL volumetric flask, dilute with water to the mark, and obtain a gadolinium concentration of 25g/L Rare earth nitrate aqueous solution 2;

(2) Add 200g nickel salt, 400g molybdenum compound, 175g aluminum salt, 0.2mL rare earth nitrate aqueous solution 1 with a dysprosium concentration of 25g/L and 0.2mL rare earth nitrate aqueous solution 2 with a gadolinium concentration of 25g/L in 780mL water 50g complexing agent, 150g chloride, use sodium carbonate solution to adjust the pH value of the solution to 8.5, add water to make the volume to 1L to obtain nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, namely nickel chloride -nickel nitrate-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-dysprosium nitrate-gadolinium nitrate-lactic acid-oxalic acid-ammonium chloride-sodium chloride electroplating solution;

Wherein the nickel salt is a mixture of nickel chloride and nickel nitrate in a mass ratio of 3:1;

The molybdenum compound is a mixture of molybdenum pentachloride and ammonium molybdate in a mass ratio of 1:1;

The aluminum salt is a mixture of aluminum trichloride and aluminum sulfate in a ratio of 4:3;

The complexing agent is a mixture of oxalic acid and lactic acid in a mass ratio of 5:3;

Chloride is that sodium chloride and ammonium chloride are formed from a mixture of 2:1 by mass ratio;

In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentration of rare earth elements dysprosium and gadolinium, complexing agent, chloride in nickel salt, molybdenum compound, aluminum salt, rare earth salt 200g/L, 400g/L, 175g/L, 5g/L, 0.01g/L, 150g/L respectively;

(3), the nickel single crystal plate to be plated is 100mm x 100mm x 0.5mm as the cathode, and the anode is an electrolytic nickel plate of 150mm x 150mm x 2mm, and the nickel chloride obtained in step (1)- Nickel nitrate-molybdenum pentachloride-ammonium molybdate-aluminum trichloride-aluminum sulfate-dysprosium nitrate-gadolinium nitrate-lactic acid-oxalic acid-ammonium chloride-sodium chloride plating solution for pulse plating, pulse plating process control The frequency is 3500Hz, the duty ratio is 0.7, the current density is 17.8A/dm ² , the temperature is 60°C, the rotation speed is 550rpm, and the time is 35min. After the electroplating is completed, the plated parts are rinsed with water and air-dried to obtain a layer of nickel-molybdenum on the surface of the plated parts. Aluminum coating is nickel molybdenum aluminum coating.

The nickel, molybdenum, and aluminum contents in the nickel-molybdenum-aluminum-gadolinium coating obtained above were measured by Bruker AXS Microanalysis GmbH energy spectrometer, and calculated by mass percentage, they were 58.85%, 34.23%, and 6.92%, respectively.

The above nickel-molybdenum-aluminum coating was oxidized at a constant temperature in an air atmosphere of 1100°C for 48 hours, then cooled to room temperature in a natural furnace, and the mass of the plating piece before oxidation and the mass after oxidation were measured with a BS224S electronic balance to obtain the The mass increase of the plated parts after oxidation is 0.145mg/cm ² .

Further, through the constant temperature oxidation of the plating parts of embodiment 3, embodiment 4, embodiment 5 and embodiment 6 respectively in the air atmosphere of 1100 ℃ for 48h, the data result of the quality that increases from the final plating part per square centimeter shows that the present invention The oxidation and corrosion resistance of the obtained nickel-molybdenum-aluminum rare earth coating is stronger than that of the nickel-molybdenum coating and the nickel-molybdenum-aluminum coating.

Further, the present invention uses a pulse power supply to add rare earth elements to the plating solution. The added rare earth elements not only provide a source of rare earth for the formation of the nickel-molybdenum-aluminum rare-earth coating, but also serve as an electroplating accelerator. As can be seen from Examples 5 and 6, when the rare earth salt concentration in the plating solution is low, that is, only 0.01 to 0.05g/L, the rare earth element is only used as an electroplating accelerator, that is, when the rare earth salt is added to the plating solution When the element is used as an electroplating accelerator, a nickel-molybdenum-aluminum coating can only be obtained by electroplating in an aqueous solution by using a pulse power supply;

Further, from Example 1, Example 2 and Example 3, it can be seen that only when the rare earth salt concentration in the plating solution reaches 0.06 ~ 10g/L, the rare earth element can not only provide the source of rare earth for forming nickel molybdenum aluminum rare earth coating, but also It can also be used as an electroplating accelerator. At this time, nickel-molybdenum-aluminum rare earth coating can be obtained by electroplating in aqueous solution.

The foregoing is only an example of the embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and Modifications should also be regarded as the scope of protection of the present invention.

Claims (4)

1. A preparation method of nickel-molybdenum-aluminum rare-earth coating, described nickel-molybdenum-aluminum rare-earth coating is made up of nickel, molybdenum, aluminum, rare earth four kinds of elements, calculates by mass percentage, nickel: molybdenum: aluminum: rare earth is 72.95～21.57 %, 21.33～43.70%, 3.50～16.70%, 2.22～18.03%; it is characterized in that the method specifically includes the following steps: (1) Dissolving rare earth oxides in acid to obtain rare earth salts; The rare earth oxides are one or more of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium, scandium rare earth oxides mixture; Described acid is nitric acid or hydrochloric acid; (2) Add nickel salt, molybdenum compound, aluminum salt, rare earth salt, complexing agent, and chloride obtained in step (1) to water, adjust the pH value of the solution to 7.5-9.5 with sodium carbonate solution, and make nickel salt-molybdenum Compound-aluminum salt-rare earth salt-complexing agent-chloride plating solution; Wherein the nickel salt is one or a mixture of two or more of nickel chloride, nickel nitrate and nickel sulfate; The molybdenum compound is one or a mixture of two or more of molybdenum pentachloride, ammonium molybdate, ammonium phosphomolybdate, and sodium molybdate; The aluminum salt is aluminum trichloride, aluminum sulfate or a mixture of aluminum trichloride and aluminum sulfate; The complexing agent is one or a mixture of two or more of glycolic acid, glycine, oxalic acid, citric acid, tartaric acid, lactic acid, succinic acid, and malic acid; Chloride is one of sodium chloride, ammonium chloride, potassium chloride or a mixture of more than two chlorides; In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentrations of rare earth elements, complexing agent and chloride in nickel salt, molybdenum compound, aluminum salt and rare earth salt are respectively 5 ~400g/L, 5~800g/L, 5~350g/L, 0.06~10g/L, 1~100g/L, 5~300g/L; (3) Use the plated piece to be plated as the cathode, and the anode is nickel, and put it into the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride plating solution obtained in step (2) for pulse plating. During the electroplating process, the pulse frequency is controlled at 2000-5000Hz, the duty ratio is 0.5-0.9, the current density is 10-25A/dm ² , the temperature is 40-60°C, the rotation speed is 100-600rpm, and the time is 10-60min. Rinse with water, dry in air, and get a nickel-molybdenum-aluminum rare-earth coating on the surface of the plated piece. 2. The preparation method of nickel-molybdenum-aluminum rare earth coating as claimed in claim 1, it is characterized in that the nickel salt described in the step (2) is nickel chloride, the molybdenum compound is molybdenum pentachloride, and the aluminum salt is trichloride Aluminum, the rare earth salt is cerium nitrate, the complexing agent is oxalic acid, and the chloride is sodium chloride; In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentrations of rare earth elements, complexing agent and chloride in nickel salt, molybdenum compound, aluminum salt and rare earth salt are respectively 5g /L, 5g/L, 5g/L, 0.06g/L, 1g/L, 5g/L; In the pulse electroplating process described in step (3), the pulse frequency is 2000 Hz, the duty ratio is 0.5, the current density is 10 A/dm ² , the temperature is 40° C., the rotation speed is 100 rpm, and the time is 60 min. 3. The preparation method of nickel-molybdenum-aluminum rare earth coating as claimed in claim 1, characterized in that the nickel salt described in step (2) is a mixture of nickel nitrate and nickel sulfate in a mass ratio of 1:1, and the molybdenum compound It is ammonium molybdate, the aluminum salt is aluminum sulfate, the rare earth salt is a mixture of yttrium chloride and erbium chloride, the complexing agent is tartaric acid, and the chloride is ammonium chloride and potassium chloride in a mass ratio of 1:1. mixture; In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentrations of rare earth elements, complexing agent and chloride in nickel salt, molybdenum compound, aluminum salt and rare earth salt are respectively 400g /L, 800g/L, 350g/L, 10g/L, 100g/L, 300g/L; In the pulse electroplating process described in step (3), the pulse frequency is 5000 Hz, the duty ratio is 0.9, the current density is 25 A/dm ² , the temperature is 60° C., the rotation speed is 600 rpm, and the time is 40 min. 4. The preparation method of nickel-molybdenum-aluminum rare earth coating as claimed in claim 1, characterized in that the nickel salt described in step (2) is a mixture of nickel chloride and nickel nitrate in a mass ratio of 3:1, molybdenum The compound is a mixture of molybdenum pentachloride and ammonium molybdate at a mass ratio of 1:1, the aluminum salt is a mixture of aluminum trichloride and aluminum sulfate at a ratio of 4:3, and the rare earth salt is a mixture of dysprosium nitrate and gadolinium nitrate , the complexing agent is a mixture of oxalic acid and lactic acid in a mass ratio of 5:3, and the chloride is a mixture of sodium chloride and ammonium chloride in a mass ratio of 2:1; In the nickel salt-molybdenum compound-aluminum salt-rare earth salt-complexing agent-chloride electroplating solution, the concentrations of rare earth elements, complexing agent and chloride in nickel salt, molybdenum compound, aluminum salt and rare earth salt are respectively 200g /L, 400g/L, 175g/L, 5g/L, 50g/L, 150g/L; In the pulse electroplating process described in step (3), the pulse frequency is 3500 Hz, the duty ratio is 0.7, the current density is 17.8 A/dm ² , the temperature is 60° C., the rotation speed is 550 rpm, and the time is 35 min.