Alkaline non-cyanide zinc plating nickel alloy plating solution and electroplating process thereof

Abstract

The invention discloses an alkaline non-cyanide zinc plating nickel alloy plating solution and an electroplating process thereof. The plating solution is prepared with hydantoin or a hydantoin derivative as a main coordination agent by adding an auxiliary coordination agent, zinc sulfate, nickel sulfate, potassium carbonate and water. The plating solution comprises 20 g-400 g / L of the main coordination agent, 5 g-300 g / L of the auxiliary coordination agent, 5 g-200 g / L of the zinc sulfate, 1 g-150 g / L of the nickel sulfate and 5 g-435 g / L of the potassium carbonate. The electroplating process of the plating solution comprises the steps of substrate pretreatment and zinc-nickel alloy electroplating. A constant current electroplating mode is adopted for zinc-nickel alloy electroplating. The electric current density is 0.5 A-5 A / dm2. The temperature of the plating solution is 30 DEG C-60 DEG C. The distance between a cathode and an anode is 0.5 cm-25 cm. The stirring speed of the plating solution is 0 rpm-3000 rpm. The electroplating time is 1 min-120 min. According to the plating solution and the electroplating process thereof, the hydantoin or the hydantoin derivative serves as the main coordination agent for the first time, and zinc-nickel alloy with the nickel content of 10 wt.%-13 wt.% is obtained through electro-deposition by using the main coordination agent and the auxiliary coordination agent in a combination mode. An obtained coating is good in corrosion resistance. The stability of the plating solution is improved immensely compared with using of a single coordination agent.

Description

technical field

[0001] The invention relates to an alkaline cyanide-free zinc-nickel alloy plating solution and an electroplating process thereof. Background technique

[0002] According to the statistics of developed countries, the annual direct loss due to corrosion accounts for 1.5-4.2% of the national economic output value, and the annual loss of steel due to corrosion in my country is as high as 6 million tons. At this stage, electro-galvanizing is commonly used as an anodic coating for steel substrates, which can provide electrochemical protection for the substrates. However, the corrosion resistance of the galvanized layer is poor in corrosive media, and the requirements for the thickness of the coating are relatively high, generally greater than 25 μm, resulting in poor formability and weldability of the coating. The corrosion resistance of the alloy coating composed of adding iron group metals (Fe, Co, Ni) to the zinc layer will be greatly improved compared with th...

Examples

Embodiment approach 1

[0029] Embodiment 1: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dibromo-5,5-dimethylhydantoin 125g / L, triethanolamine 20g / L, potassium carbonate 130g / L, Zinc Sulfate 55g / L, Nickel Sulfate 20g / L, the copper sheet is used as the cathode after alkaline degreasing, 1:1 HCI aqueous solution pickling and water washing, and the inert metal is used as the anode, and the distance between the cathode and the anode is 5cm, bath temperature is 60℃, pH is 10, current density is 1.5A / dm 2 , the stirring speed is 600rpm, the electroplating time is 40min, the current efficiency of the obtained plating solution is more than 85%, the appearance of the coating is bright, uniform and smooth, the nickel content of the coating is 13.58wt.%. figure 1 Shown), the XRD detection coating is composed of a single γ phase.

Embodiment approach 2

[0030] Embodiment 2: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dimethylol-5,5-dimethylhydantoin 135g / L, triethylenetetramine 10g / L , Potassium carbonate 100g / L, zinc sulfate 65g / L, nickel sulfate 30g / L, the copper sheet is used as the cathode after alkaline degreasing, 1:1 HCI aqueous solution pickling and water washing, and the inert metal is used as the anode. The distance between them is 4cm, the temperature of the bath is 50°C, the pH is 10, and the current density is 4A / dm 2 , the stirring speed is 800rpm, the electroplating time is 10min, the current efficiency of the obtained plating solution is more than 85%, the appearance of the coating is bright, uniform and smooth, and the nickel content is 13.71wt.%. Composed of a single γ phase.

Embodiment approach 3

[0031] Embodiment 3: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dimethylol-5,5-dimethylhydantoin 45g / L, sodium citrate 5g / L, Potassium carbonate 50g / L, zinc sulfate 25g / L, nickel sulfate 10g / L, copper sheet after alkaline degreasing, 1:1 HCI aqueous solution pickling and water washing as cathode, inert metal as anode, between cathode and anode The distance is 10cm, the temperature of the bath is 45°C, the pH is 8, and the current density is 0.5A / dm 2 , the stirring speed is 200rpm, the electroplating time is 60min, the current efficiency of the obtained plating solution is more than 85%, the appearance of the coating is bright, uniform and smooth, and the content of the coating is 12.63wt.%. SEM observes that the coating crystal is fine, dense, and has no pores. XRD detects the coating Composed of a single γ phase.

[0032] Embodiment 4: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dibromo-5,5-dimethylhyd...

technical field

[0001] The invention relates to an alkaline cyanide-free zinc-nickel alloy plating solution and an electroplating process thereof. Background technique

[0002] According to the statistics of developed countries, the annual direct loss due to corrosion accounts for 1.5-4.2% of the national economic output value, and the annual loss of steel due to corrosion in my country is as high as 6 million tons. At this stage, electro-galvanizing is commonly used as an anodic coating for steel substrates, which can provide electrochemical protection for the substrates. However, the corrosion resistance of the galvanized layer is poor in corrosive media, and the requirements for the thickness of the coating are relatively high, generally greater than 25 μm, resulting in poor formability and weldability of the coating. The corrosion resistance of the alloy coating composed of adding iron group metals (Fe, Co, Ni) to the zinc layer will be greatly improved compared with th...

Examples

Embodiment approach 1

[0029] Embodiment 1: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dibromo-5,5-dimethylhydantoin 125g / L, triethanolamine 20g / L, potassium carbonate 130g / L, Zinc Sulfate 55g / L, Nickel Sulfate 20g / L, the copper sheet is used as the cathode after alkaline degreasing, 1:1 HCI aqueous solution pickling and water washing, and the inert metal is used as the anode, and the distance between the cathode and the anode is 5cm, bath temperature is 60℃, pH is 10, current density is 1.5A / dm 2 , the stirring speed is 600rpm, the electroplating time is 40min, the current efficiency of the obtained plating solution is more than 85%, the appearance of the coating is bright, uniform and smooth, the nickel content of the coating is 13.58wt.%. figure 1 Shown), the XRD detection coating is composed of a single γ phase.

Embodiment approach 2

[0030] Embodiment 2: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dimethylol-5,5-dimethylhydantoin 135g / L, triethylenetetramine 10g / L , Potassium carbonate 100g / L, zinc sulfate 65g / L, nickel sulfate 30g / L, the copper sheet is used as the cathode after alkaline degreasing, 1:1 HCI aqueous solution pickling and water washing, and the inert metal is used as the anode. The distance between them is 4cm, the temperature of the bath is 50°C, the pH is 10, and the current density is 4A / dm 2 , the stirring speed is 800rpm, the electroplating time is 10min, the current efficiency of the obtained plating solution is more than 85%, the appearance of the coating is bright, uniform and smooth, and the nickel content is 13.71wt.%. Composed of a single γ phase.

Embodiment approach 3

[0031] Embodiment 3: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dimethylol-5,5-dimethylhydantoin 45g / L, sodium citrate 5g / L, Potassium carbonate 50g / L, zinc sulfate 25g / L, nickel sulfate 10g / L, copper sheet after alkaline degreasing, 1:1 HCI aqueous solution pickling and water washing as cathode, inert metal as anode, between cathode and anode The distance is 10cm, the temperature of the bath is 45°C, the pH is 8, and the current density is 0.5A / dm 2 , the stirring speed is 200rpm, the electroplating time is 60min, the current efficiency of the obtained plating solution is more than 85%, the appearance of the coating is bright, uniform and smooth, and the content of the coating is 12.63wt.%. SEM observes that the coating crystal is fine, dense, and has no pores. XRD detects the coating Composed of a single γ phase.

[0032] Embodiment 4: The alkaline cyanide-free zinc-nickel alloy plating solution is composed of: 1,3-dibromo-5,5-dimethylhyd...

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