Method for chemical plating nickel-boron alloy on magnesium alloy surface

A surface chemical and magnesium alloy technology, applied in liquid chemical plating, metal material coating process, coating, etc., can solve the problems of chemical plating cost increase, environmental pollution, and nickel cannot be replenished, and achieve good practical application prospects. Good deposition effect, avoiding the effect of base alkali corrosion

Inactive Publication Date: 2006-07-19
XIAMEN UNIV
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Problems solved by technology

[0004] (1) Compounds containing chromium and fluorine in the pretreatment and chemical plating solution are harmful to the environment (Surface and Coatings Technology, 2004, 179: 124-134)
[0005] (2) The binding force of direct electroless plating Ni-P with fluoride activation is not high (patent CN02144834.5), and pre-plating is required in order to improve the binding force, resulting in cumbersome process (Corrosion Science, 2004, 46: 1467-1477)
[0010] (2) The Mg alloy is active, and loose MgO will form rapidly on the surface of the alloy, which hinders the formation of metal bonds between the deposited metal and the substrate
[0011] (3) Traditional electroless nickel plating generally chooses nickel chloride or nickel sulfate as the main salt, and most plating solutions are corrosive to magnesium, especially those containing Cl - , SO 4 2- In the salt solution of Mg, the corrosion rate of Mg is larger; under no stress state, the corrosion rate of Mg-Al-Zn alloy in different anion media is Cl - > SO 4 2- >NO 3 - >Ac - >CO 3 2-
But the price of basic nickel carbonate is too high, and the cost of electroless plating doubles; In addition, basic nickel carbonate is insoluble in water, and must be dissolved with hydrofluoric acid before preparation, and the dissolution process is time-consuming, and also produces environmental pollution, reducing Production efficiency; another problem of using basic nickel carbonate as nickel salt is that the bath life is short, because when nickel is supplemented during long-term use of the bath, the concentration of fluoride ions in the bath will inevitably increase, and the solubility of nickel fluoride is very small , and eventually precipitates are formed during the electroless plating process, causing nickel to be unable to be replenished and the life of the plating solution to be shortened
[0012] (4) Sodium borohydride as a reducing agent in the electroless Ni-B alloy is easily hydrolyzed in acidic and neutral solutions. In order to avoid hydrolysis and obtain a higher deposition rate, the plating solution must be kept strongly alkaline. In the alkaline medium with pH>11, insoluble Mg(OH) will form on the surface of Mg 2 film, which affects the bonding of the coating to the substrate

Method used

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  • Method for chemical plating nickel-boron alloy on magnesium alloy surface
  • Method for chemical plating nickel-boron alloy on magnesium alloy surface
  • Method for chemical plating nickel-boron alloy on magnesium alloy surface

Examples

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Effect test

Embodiment 1

[0028] 1) Alkali washing, at room temperature, add sodium carbonate (15g), sodium phosphate (15g), OP-10 (5mL) to deionized water (1L) in turn, heat to 75°C after the dissolution is complete, and process it into 10mm× AZ91D magnesium alloy samples with a size of 10mm×2mm were placed in the alkaline cleaning solution and continuously stirred by ultrasonic waves, and were taken out after 15 minutes of treatment. At room temperature, wash in flowing deionized water for 2 min and then take it out. The surface morphology of the treated AZ91D magnesium alloy sample is shown in figure 1 , indicating that a clean mechanically polished surface of the AZ91D magnesium alloy was obtained after alkaline washing.

[0029] 2) Pickling, at room temperature, add 36% glacial acetic acid (18mL) and sodium nitrate (36g) in sequence to deionized water (1L), put the AZ91D magnesium alloy after alkali washing into the pickling solution and continue ultrasonic Stir, process for 75 seconds and remov...

Embodiment 2

[0044] 1) Alkali washing, at room temperature, add sodium carbonate (20g), sodium phosphate (20g), OP-10 (10mL) in sequence to deionized water (1L), and heat to 60°C after the dissolution is complete, AZ91D magnesium alloy sample Put it into the alkaline cleaning solution and continue ultrasonic stirring, take it out after 10 minutes of treatment. At room temperature, put the treated AZ91D magnesium alloy into flowing deionized water and wash it for 4 minutes before taking it out.

[0045] 2) pickling, with embodiment 1.

[0046] 3) Electroless Ni-B plating, at room temperature, add nickel acetate (38g) into deionized water (700mL) to dissolve completely, then add ethylenediamine (52mL) under stirring, and add composite additives under stirring after cooling to room temperature , followed by: sodium p-benzenesulfonate (6g), malonic acid (3g), sulfosalicylic acid (50mg), after the dissolution is complete, add sodium hydroxide (28g) under stirring, and after the dissolution is ...

Embodiment 3

[0058] 1) alkali washing, with embodiment 1.

[0059] 2) Pickling, at room temperature, add 36% glacial acetic acid (22mL) and sodium nitrate (45g) to deionized water (1L) successively, put the treated AZ91D magnesium alloy into this solution and continue ultrasonic stirring for 30 seconds Take it out and wash it with deionized water.

[0060] 3) Electroless Ni-B plating, at room temperature, add nickel acetate (40g) in deionized water (700mL), after the dissolution is complete, add ethylenediamine (55mL) while stirring, and add the composite additive while stirring after cooling to room temperature , followed by: sodium p-benzenesulfonate (8g), malonic acid (6g), sulfosalicylic acid (60mg), add sodium hydroxide (48g) under stirring after the dissolution is complete, add boron after the dissolution is complete Sodium hydride (0.6g), finally add deionized water to 1L, heat to a constant temperature of 80°C, put the treated AZ91D magnesium alloy into this constant temperature s...

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Abstract

The technique to chemical plate Ni-B alloy on AZ91D surface comprises: treating the AZ91D alloy in solution with Na2CO3, Na3PO4 and polyethylene glycol octylphenyl ether, then cleaning in water; acid washing the alloy in solution with glacial acetic acid and NaNO3, then cleaning in water; chemical plating the alloy in solution with NiA, NaH2B, ethanediamine, NaOH and composite additive, finally, washing in water, and drying to obtain the target.

Description

technical field [0001] The invention relates to an AZ91D magnesium alloy surface chemical nickel-boron alloy plating process. Background technique [0002] Magnesium alloy has the advantages of light weight, high shock absorption and heat dissipation, good casting and cutting performance, high electromagnetic immunity barrier, anti-fatigue, non-toxic, non-magnetic, low crack tendency and recyclable use, etc., and has been successfully used in Transportation, computer, communication, consumer electrical appliances, national defense and military industry and many other fields. However, the corrosion resistance of magnesium is poor, which is the bottleneck restricting the potential of magnesium alloys. On the other hand, due to the low hardness and poor wear resistance of magnesium alloys, the large-scale use of magnesium alloys is restricted. In order to improve the corrosion resistance and wear resistance of magnesium alloys, appropriate surface modification is necessary. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C18/32C23G1/22C23G1/12
Inventor 王周成唐毅
Owner XIAMEN UNIV
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