CN100516293C - Direct composite method for coating magnesium-alloy surface with nano-titanium dioxide - Google Patents

Abstract

The present invention discloses a direct nano-titanium dioxide chemical composite plating process on the surface of magnesium alloy including the following steps. (1)The plating bath is prepared and has the pH adjusted to 5.0-7.5 with ammonia and hydrofluoric acid and the temperature adjusted to 75-95DEG C, TiO2 nano-powder of 3-30g/l is dispersed with ultrasonic for 30-60 minutes, then stirred in the plating bath to be suspended evenly facilitating the formation of homogeneous coat. (2)The alloy is polished with 100-1000 sand paper, degreased, dried at room temperature, washed with alkaline followed by water, washed by acid at room temperature for 1-3 minutes and rinsed with distilled water, then it is activated in activator solution for 8-15 minutes and washed by water. (3)The alloy after the above treatment is dipped into the plating bath for 50-60 minutes, cleaned with water and dried at room temperature. The plating coat in this invention has nice corrosion and wearing resistance, homogeneous thickness, strong chemical stability and smooth surfaces.

Description

The method of the compound plating of the direct nano-titanium dioxide of a kind of Mg alloy surface

Technical field

The present invention relates to the method for the compound plating of the direct nano-titanium dioxide of a kind of Mg alloy surface.

Background technology

Magnesium alloy has higher specific tenacity and specific rigidity, damping performance and high-temp plastic, good polishing performance, good advantages such as heat conduction, electroconductibility and magnetic shielding preferably.In recent years, reduction along with the magnesium alloy materials production cost, particularly people are to economizing on resources and reducing the growing interest of pollution problem, the characteristics of " Sustainable development is strong " that magnesium alloy had make it in automobile making, aerospace, Communication Equipment, household electrical appliance, the application in fields such as opticinstrument and computer manufacturing is increasingly extensive, annual growth rate reaches 20%, especially the lightweight of magnesium alloy, good heat-conducting, good capability of electromagnetic shielding and low cost, make its a large amount of shell that is applied to the telecommunications series products, as notebook computer, mobile telephone, apparatus for making a video recording, products such as digital audiovisual.But the outstanding characteristics of this series products are: the chance that contacts with the people is many, carries easily, grows and infect various bacteriums, virus, thereby had influence on user's health.Magnesium alloy still is a kind of very promising bio-medical material, from both at home and abroad the report of magnesium and magnesium alloy each side being not difficult to find in recent ten years, magnesium is compared with the various metal implant materials that now dropped into clinical use as hard tissue implanting material, has very outstanding advantage.But because the standard potential very low (2.36V SCE) of magnesium, solidity to corrosion is relatively poor to have become the important factor of restriction magnesium alloy development, is especially containing Cl ^-All the more so in the ionic corrosive environment, this has just more seriously had influence on its development in the bio-medical field.And because the magnesium alloy activity is higher, at present also not to the corrosion essence of magnesium alloy and the effective ways that its surface carried out modification.

Summary of the invention

The object of the present invention is to provide the method for the compound plating of the direct nano-titanium dioxide of a kind of Mg alloy surface,, make the surface of magnesium alloy have anti-oxidant and corrosion-resistant, abrasion resistance properties directly to plate the nano titanium oxide composite deposite at Mg alloy surface.

To achieve these goals, technical program of the present invention lies in adopting the method for the compound plating of the direct nano-titanium dioxide of a kind of Mg alloy surface, may further comprise the steps:

(1) obtain solution

Each composition of plating bath is as follows, and the content of each composition is in every liter of solution: NiCO ₃2Ni (OH) ₂4H ₂O5～30g, concentration is HF 5～20ml of 40%, citric acid or Trisodium Citrate 0.5～15g, NH ₄HF ₂5～20g, complexing agent lactic acid 10～25g, stablizer thiocarbamide 0.5～2mg, NaH ₂PO ₂4H ₂O 10～50g, TiO ₂3～30g, the pH value of adjusting plating bath with ammoniacal liquor and hydrofluoric acid is 5.0-7.5, temperature is 75--95 ℃; Nano-TiO with 3～30g/l ₂The powder ultra-sonic dispersion added in the plating bath after 30-60 minute, and stirred, and made nano-TiO ₂Powder evenly is suspended in the plating bath, to obtain uniform Ni-P-TiO ₂Composite deposite;

(2) with magnesium alloy sample through 100～1000 coated abrasive workings, in the ultrasonic cleaning 10--20min oil removing of the solution of alcohol and acetone volume ratio 1: 0.8--1 the inside, at room temperature dry then; Alkali cleaning 6-12min in 50-70 ℃ alkaline wash, washing then then; At room temperature put into pickle solution and carried out pickling 1-3 minute, use distilled water flushing; And at room temperature put into activation solution activation treatment 8-15 minute that concentration is HF 250～400ml/l of 40%, wash then;

(3) sample of handling well is immersed in the plating bath, take out after 50-60 minute and clean, at room temperature dry getting final product.

Each composition of described alkaline wash is as follows, and the content of each composition is in every liter of solution: NaOH or Na ₂CO ₃30～60g, Na ₃PO ₄12H ₂O 10～30g.

Each composition of described pickle solution is as follows, and the content of each composition is in every liter of solution: concentration is 70% HNO ₃80～120ml, CrO ₃100～150g, Fe (NO ₃) ₃20～50g, KF 2～6g.

Described nano titanium oxide is preferably anatase-type nanometer titanium dioxide.

Because virus and bacterium and organic pollutent, be mostly by-O-H ,-groups such as C-H constitute, so they can be by nano-TiO ₂Generation CO is decomposed in catalysis ₂And H ₂O, and the nano-TiO of Mg alloy surface among the present invention ₂Have following characteristics: the photo-catalyst performance that (1) is good, therefore be applied to can autocatalysis under the condition of light arranged on the magnesium-alloy materials such as 3C class, medical sanitary apparatus, engineering component, kill various bacteriums, virus; (2) have automatic cleaning action, be applied to magnesium alloy utensil and component surface, can under the photochemical catalysis condition, remove organic dirt, resolving harmful gas; (3) have good bio-compatibility, be applied to like this on medical sanitary apparatus and the body implanting material class magnesium-alloy material, can improve the compatibility of itself and human body.The present invention adopts the method for Ni-P with Electroless Ni-P Plating and nano-TiO ₂Combine, promptly on magnesium alloy, adopt the direct chemical composite plating method, its surface is coated go up Ni-P-TiO ₂Composite deposite like this, just can make magnesium alloy can either play anti-oxidant and corrosion-resistant, anti abrasive effect, can play the effect of sterilization and disinfection again, has improved the Application of Magnesium scope greatly.The present invention improves the corrosion resistance nature of magnesium alloy at the overlay coating of magnesium alloy, makes magnesium alloy have the performance of photochemical catalysis, automatically cleaning and antibacterial and deodouring.The coating of Mg alloy surface of the present invention not only has good corrosion-resistant, wear resistance, also has advantages such as thickness is even, chemical stability good, and any surface finish is smooth simultaneously.

The photochemical catalysis effect detection result of magnesium alloy of the present invention is as follows:

Methylene blue is in certain wavelength region, easily at TiO ₂Be catalyzed oxidation in the environment of catalyzer, generate water and carbonic acid gas, and the color of methylene blue solution also can by mazarine become more and more shallow.

The methylene blue solution of preparation 0.001mol/L, each test tube 7.5ml stoste of packing into is put into solution with ready-made magnesium alloy sample of the present invention, 36w ultra violet lamp 10 hours, methylene blue is oxidized fades in observation.

As can be seen, methylene blue is broken down into water and carbonic acid gas in the test, and carbonic acid gas is emitted with the form of bubble, and solution surface has carbon dioxide foaming and exists; Several groups of nano-TiOs ₂The photocatalysis Decomposition effect of compound plating can represent that changing value is big more with the absorbancy changing value, and then catalytic effect is obvious more.Absorbancy changing value experimental result as shown in Figure 5.

Description of drawings

Fig. 1 is the electropotential graphic representation of matrix in 3.5% NaCl of the magnesium alloy before the plating;

Fig. 2 is of the present invention through nano-TiO ₂The electropotential graphic representation of the matrix of the magnesium alloy after the compound plating in 3.5% NaCl;

Fig. 3 is the XRD diffracting spectrum of chemically coating nickel by magnesium-alloy sample;

Fig. 4 is of the present invention through nano-TiO ₂The XRD diffracting spectrum of the magnesium alloy after the compound plating;

Fig. 5 is the beam split rate experimental result chart of the photochemical catalysis effect of magnesium alloy of the present invention.

Embodiment

The method of the compound plating of the direct nano-titanium dioxide of Mg alloy surface of the present invention may further comprise the steps: (1) obtain solution, and each composition of plating bath is as follows, and the content of each composition is in every liter of solution: NiCO ₃2Ni (OH) ₂4H ₂O 15g, concentration is 40% HF 12ml, citric acid or Trisodium Citrate 12g, NH ₄HF ₂10g, complexing agent lactic acid 12g, stablizer thiocarbamide 0.5mg, NaH ₂PO ₂4H ₂O 25g, the pH value of adjusting plating bath with ammoniacal liquor and hydrofluoric acid is 6.0, temperature is 90 ℃; The anatase-type nanometer titanium dioxide powder ultra-sonic dispersion of 8g/l was added in the plating bath after 30 minutes, and stir, make nano-TiO ₂Powder evenly is suspended in the plating bath, to obtain uniform Ni-P-TiO ₂Composite deposite;

(2) with magnesium alloy sample through 100～1000 coated abrasive workings, in the ultrasonic cleaning 10min oil removing of the solution of alcohol and acetone volume ratio 1: 0.8--1 the inside, at room temperature dry then; Alkali cleaning 8min in 65 ℃ alkaline wash, washing then then; At room temperature put into pickle solution and carried out pickling 1 minute, use distilled water flushing; And at room temperature put into the activation solution activation treatment 10 minutes that concentration is 40% HF 400ml/l, wash then.

(3) sample of handling well is immersed in the plating bath, take out after 50 minutes and clean, at room temperature dry getting final product.

Each composition of alkaline wash in the present embodiment is as follows, and the content of each composition is in every liter of solution: NaOH40g, Na ₃PO ₄12H ₂O 20g.

Each composition of pickle solution is as follows, and the content of each composition is in every liter of solution: concentration is 70% HNO ₃110ml, CrO ₃125g.

The anticorrosion effect of magnesium alloy of the present invention is as follows:

As shown in Figure 1, the solidity to corrosion of the magnesium alloy of plating is not very poor, not the electropotential of the magnesium alloy of plating in 3.5%NaCl approximately have only-1.55V about.

As shown in Figure 2, the electropotential of the magnesium alloy after plating of the present invention brings up to-0.4V about, and coating is amorphous structure, intercepted magnesium alloy and extraneous contacting, and therefore can improve the solidity to corrosion of matrix significantly.Neutral salt spray test through 48 hours, the corrosion of tangible homogeneity takes place in magnesium alloy substrate, and white powdery corrosion product appears in the surface, through electroless plating sample major part except surface color to some extent the deepening, other obvious corrosion vestiges do not occur, show that quality of coating is good.

Phase Structure Analysis of the present invention

Fig. 3 is the XRD diffraction analysis collection of illustrative plates of chemically coating nickel by magnesium-alloy sample, as can be seen: coating is the diffuse scattering peak of tangible broadening, ° locate to be maximum diffraction intensity in 2 θ=45, just in time with Ni (1,1,1) position of diffraction peak coincide, and disperses to both sides and to come, become the steamed bun shape, show typical non-crystalline state feature.

And through nano-TiO ₂The XRD diffraction analysis collection of illustrative plates of the sample after the compound plating then as shown in Figure 4, as can be seen: the collection of illustrative plates of this collection of illustrative plates and Fig. 3 is very alike, the diffuse scattering peak is still formed by nickel, how has located a sharp-pointed diffraction peak but equal 25.3 ° at 2 θ, and this peak is just in time corresponding to Detitanium-ore-type TiO ₂Diffraction peak.

It should be noted last that: above embodiment is the unrestricted technical scheme of the present invention in order to explanation only, although the present invention is had been described in detail with reference to the foregoing description, those of ordinary skill in the art is to be understood that: still can make amendment or be equal to replacement the present invention, and not breaking away from any modification or partial replacement of the spirit and scope of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (1)

1, the method for the compound plating of the direct nano-titanium dioxide of a kind of Mg alloy surface is characterized in that: may further comprise the steps:

(1) obtain solution

Each composition of plating bath is as follows, and the content of each composition is NiCO in every liter of solution ₃2Ni (OH) ₂4H ₂O5-30g, concentration is 40% HF5-20ml, citric acid or Trisodium Citrate 0.5-15g, NH ₄HF ₂5-20g, complexing agent lactic acid 10-25g, stablizer thiocarbamide 0.5-2mg, NaH ₂PO ₂4H ₂O 10-50g, TiO ₂3-30g, the pH value of adjusting plating bath with ammoniacal liquor and hydrofluoric acid is 5.0-7.5, temperature is 75-95 ℃; Nano-TiO with 3-30g/l ₂The powder ultra-sonic dispersion added in the plating bath after 30-60 minute, and stirred, and made nano-TiO ₂Powder evenly is suspended in the plating bath, to obtain uniform Ni-P-TiO ₂Composite plating bath; Wherein said nano-TiO ₂Be anatase type nano TiO ₂

(2), in the ultrasonic cleaning 10-20min oil removing of the solution the inside of alcohol and acetone volume ratio 1: 0.8-1, at room temperature dry then with magnesium alloy sample process 100-1000 coated abrasive working; Alkali cleaning 6-12min in 50-70 ℃ alkaline wash washes then; At room temperature put into pickle solution and carried out pickling 1-3 minute, use distilled water flushing; And at room temperature put into activation solution activation treatment 8-15 minute that concentration is 40% HF250-400ml/l, wash then; Wherein, each composition of alkaline wash is as follows, and the content of each composition is in every liter of solution: NaOH or Na ₂CO ₃30-60g, Na ₃PO ₄12H ₂O 10-30g; Each composition of described pickle solution is as follows, and the content of each composition is in every liter of solution: concentration is 70% HNO ₃80-120ml, CrO ₃100-150g, Fe (NO ₃) ₃20-50g, KF 2-6g;

(3) sample of handling well is immersed in the plating bath, take out after 50-60 minute and clean, at room temperature dry getting final product.

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