Plating solution of magnesium alloy nickle sulfate main salt and technology of chemical plating thereof

Abstract

The invention discloses a plating solution of magnalium alloy Nickel sulfate and its chemical plating technique. The plating solution is made up of: (1) 5 to 40g.dm-3 of Nickel sulfate, (2) 10 to 50g.dm-3 of reducing agent of hypo-phosphite sodium; (3) one or several of the 2.5 to 30g.dm-3of the citric acid or tri-sodium citric acid, 2.5 to 30g.dm-3of the lactic acid, 2.5 to 30g.dm-3of the acetic acid, 2.5 to 30g.dm-3of the malic acid, 2.5 to 30g.dm-3 of the third acid and 2.5 to 30g.dm-3of the buta-acid; (4) one or several of the 5 to 30g.dm-3of Potassium fluoride, 5 to 30g.dm-3of sodium fluoride, 5 to 30g.dm-3of lithium fluoride and 5 to 30g.dm-3of NH4HF2; (5) 0.1 to 3g.dm-3of sulphur carbamide. The plating steps include: washing with ultrasonic->washing with alkali->washing with acid->activation->dipping it in the zinc solution->getting rid of the activation solution->secondary dipping it in the zinc solution->chemical plating->passivation and sealing the holes. The invention is featured by little pollution to the environment, low cost, uniform film and simpel technique.

Description

technical field

[0001] The invention relates to a plating solution formula for electroless nickel plating and a plating process thereof, in particular to a plating solution formula for electroless nickel plating of a magnesium alloy and a plating process thereof. Background technique

[0002] Magnesium alloys have low electrode potential and high chemical activity. In humid air, sulfur-containing atmosphere and marine atmosphere, they will suffer severe electrochemical corrosion, which hinders the application of magnesium alloy products to their advantages and limits their application range. The use of magnesium alloy as a structural material must be protected before it can be applied. Electroless nickel plating is one of the most effective protection methods for magnesium alloy protection.

[0003] At present, electroless nickel plating on magnesium alloys has two processes: Dow immersion Zn cyanide plating Cu primer and direct electroless plati...

Examples

Embodiment 1

[0044] The material is AZ91D magnesium alloy, and the specific operation steps are as follows:

[0045] (1) Pre-plating treatment

[0046] 1) Mechanical polishing

[0047] Use a grinder or sandpaper to remove burrs, oxide scales, adhered release agents, and various oil stains to reduce the surface roughness, and wash with water to remove slag;

[0048] 2) Ultrasonic degreasing

[0049] Acetone or trichlorethylene organic solvent ultrasonic degreasing, operating temperature: room temperature, operating time: 10min;

[0050] 3) Alkaline washing

[0051] Solution preparation and operating conditions are as follows: NaOH 50g dm -3 , Na 3 PO 4 12H 2 O 10g·dm -3 ;Temperature 60±5℃; Time 8-10min;

[0052] 4) pickling

[0053] Solution preparation and operating conditions are as follows: CrO 3 125g·dm -3 , HNO 3 (68%)110cm 3 · dm -3 Temperature 20℃, time 1min;

[0054] 5) activation

[0055] Solution preparation and operating conditions are as follows: HF (40%) 385cm...

Embodiment 2

[0070] Material AZ91D magnesium alloy. Mechanical polishing, degreasing and degreasing are identical with embodiment 1.

[0071] pickling

[0072] The solution and operation are as follows: CrO 3 180g·dm -3 , KF 1g·dm -3 ;Temperature 20℃; Time 10min;

[0073] Activation, secondary zinc dipping solution and operation are the same as in Example 1.

[0074] Electroless Nickel

[0075] Plating solution containing NiSO 4 ·6H 2 O 30g·dm -3 , potassium fluoride 25g·dm -3 , sodium hypophosphite 30g·dm -3 ; Lactic acid 30g·dm -3 , Thiourea 2mg·dm -3 , NH 3 ·H 2 O 35cm 3 · dm -3 , pH value 5.0, bath temperature 75°C, bath time 3.0h;

[0076] Post-plating treatment

[0077] Passivation solution and operation are the same as in Example 1.

[0078] After hot air drying, heat treatment at 230°C for 2 hours in a heat treatment furnace with no dust, hot air circulation and uniform temperature distribution;

[0079] Each step of the process is washed with water.

[0080] Th...

Embodiment 3

[0083] Material AZ31B magnesium alloy.

[0084] The difference from Example 1 is that

[0085] pickling

[0086] The solution and operation are as follows: CrO 3 180g·dm -3 , Fe(NO 3 ) 3 9H 2 O 400g·dm -3 , NaF3.5g·dm -3 ;Temperature 20℃; Time 10min;

[0087] activation

[0088] The solution and operation are as follows: H 3 PO 4 (85%) 150-200g·dm -3 , NH 4 HF 2 80-100g·dm -3 Temperature 20℃; Time 2min

[0089] Electroless Nickel

[0090] Plating solution containing NiSO 4 ·6H 2 O 15g·dm -3 , Sodium Fluoride 15g·dm -3 , lithium fluoride 10g·dm -3 , sodium hypophosphite 20g·dm -3 ;Acetic acid 20g·dm -3 , Thiourea 0.5mg·dm -3 , NH 3 ·H 2 O 40cm 3 · dm -3 , pH value 6.0; bath temperature 85 ° C; bath time 1.5h.

[0091] passivation

[0092] Put in 5-40g·dm -3 The epoxy resin adhesive (a mixture of epoxy resin and ethylenediamine in a ratio of 10:1) was immersed in the solution for 10 minutes, and dried at 120°C.

[0093] The thickness of the obta...

technical field

[0001] The invention relates to a plating solution formula for electroless nickel plating and a plating process thereof, in particular to a plating solution formula for electroless nickel plating of a magnesium alloy and a plating process thereof. Background technique

[0002] Magnesium alloys have low electrode potential and high chemical activity. In humid air, sulfur-containing atmosphere and marine atmosphere, they will suffer severe electrochemical corrosion, which hinders the application of magnesium alloy products to their advantages and limits their application range. The use of magnesium alloy as a structural material must be protected before it can be applied. Electroless nickel plating is one of the most effective protection methods for magnesium alloy protection.

[0003] At present, electroless nickel plating on magnesium alloys has two processes: Dow immersion Zn cyanide plating Cu primer and direct electroless plati...

Examples

Embodiment 1

[0044] The material is AZ91D magnesium alloy, and the specific operation steps are as follows:

[0045] (1) Pre-plating treatment

[0046] 1) Mechanical polishing

[0047] Use a grinder or sandpaper to remove burrs, oxide scales, adhered release agents, and various oil stains to reduce the surface roughness, and wash with water to remove slag;

[0048] 2) Ultrasonic degreasing

[0049] Acetone or trichlorethylene organic solvent ultrasonic degreasing, operating temperature: room temperature, operating time: 10min;

[0050] 3) Alkaline washing

[0051] Solution preparation and operating conditions are as follows: NaOH 50g dm -3 , Na 3 PO 4 12H 2 O 10g·dm -3 ;Temperature 60±5℃; Time 8-10min;

[0052] 4) pickling

[0053] Solution preparation and operating conditions are as follows: CrO 3 125g·dm -3 , HNO 3 (68%)110cm 3 · dm -3 Temperature 20℃, time 1min;

[0054] 5) activation

[0055] Solution preparation and operating conditions are as follows: HF (40%) 385cm...

Embodiment 2

[0070] Material AZ91D magnesium alloy. Mechanical polishing, degreasing and degreasing are identical with embodiment 1.

[0071] pickling

[0072] The solution and operation are as follows: CrO 3 180g·dm -3 , KF 1g·dm -3 ;Temperature 20℃; Time 10min;

[0073] Activation, secondary zinc dipping solution and operation are the same as in Example 1.

[0074] Electroless Nickel

[0075] Plating solution containing NiSO 4 ·6H 2 O 30g·dm -3 , potassium fluoride 25g·dm -3 , sodium hypophosphite 30g·dm -3 ; Lactic acid 30g·dm -3 , Thiourea 2mg·dm -3 , NH 3 ·H 2 O 35cm 3 · dm -3 , pH value 5.0, bath temperature 75°C, bath time 3.0h;

[0076] Post-plating treatment

[0077] Passivation solution and operation are the same as in Example 1.

[0078] After hot air drying, heat treatment at 230°C for 2 hours in a heat treatment furnace with no dust, hot air circulation and uniform temperature distribution;

[0079] Each step of the process is washed with water.

[0080] Th...

Embodiment 3

[0083] Material AZ31B magnesium alloy.

[0084] The difference from Example 1 is that

[0085] pickling

[0086] The solution and operation are as follows: CrO 3 180g·dm -3 , Fe(NO 3 ) 3 9H 2 O 400g·dm -3 , NaF3.5g·dm -3 ;Temperature 20℃; Time 10min;

[0087] activation

[0088] The solution and operation are as follows: H 3 PO 4 (85%) 150-200g·dm -3 , NH 4 HF 2 80-100g·dm -3 Temperature 20℃; Time 2min

[0089] Electroless Nickel

[0090] Plating solution containing NiSO 4 ·6H 2 O 15g·dm -3 , Sodium Fluoride 15g·dm -3 , lithium fluoride 10g·dm -3 , sodium hypophosphite 20g·dm -3 ;Acetic acid 20g·dm -3 , Thiourea 0.5mg·dm -3 , NH 3 ·H 2 O 40cm 3 · dm -3 , pH value 6.0; bath temperature 85 ° C; bath time 1.5h.

[0091] passivation

[0092] Put in 5-40g·dm -3 The epoxy resin adhesive (a mixture of epoxy resin and ethylenediamine in a ratio of 10:1) was immersed in the solution for 10 minutes, and dried at 120°C.

[0093] The thickness of the obta...