The coating has low porosity (≤ 0.1%), the surface is easy to passivate, and the resistance to salt spray test is up to 500-1000 hours, which is especially suitable for acidic, saline, and other harsh environments.
Author: Anna
I. Corrosion resistance
Chemical nickel plating
The coating has low porosity (≤ 0.1%), the surface is easy to passivate, and the resistance to salt spray test is up to 500-1000 hours, which is especially suitable for acidic, saline, and other harsh environments.
Ni-P coating (phosphorus content of 8-10%) to form an amorphous structure, inhibit grain boundary corrosion, in the mineral acid, chemical media life than nickel plating 2-3 times higher.
Electroplated nickel
Plating layer has high porosity (0.5-2%), is prone to pitting corrosion in humid or Cl-containing environments, and the salt spray test is generally only 200-500 hours.
II. Wear resistance and hardness
Electroless nickel plating
The hardness of the plated layer after heat treatment (280-400℃) can reach 800-1000HV, which improves the wear resistance by 3-5 times, and is suitable for high friction parts such as hydraulic cylinders and gears.
Low-phosphorus plating (phosphorus content 3-6%) has strong bonding strength and can withstand repeated impact loads without flaking.
Electroplated Nickel
Native hardness of the plated layer is 200-500HV, which can meet the general wear-resistant demand without heat treatment, but the hardness will be significantly reduced at high temperature.
Plating density of 99.5%, suitable for printing molds, shaft parts and other precision wear-resistant scene.
III. The stability of the plating layer
Electroless nickel plating
Coefficient of thermal expansion and steel substrate match high (13 × 10-⁶ / ℃), temperature fluctuations in the plating layer is not easy to crack.
No risk of hydrogen embrittlement, no need for dehydrogenation after plating, suitable for springs, thin-walled parts and other sensitive parts.
Electroplated Nickel
Large difference in thermal expansion between the plated layer and the substrate (e.g. aluminum-based alloys), prone to stress cracking in high temperature environments.
Hydrogen embrittlement is easily introduced during the plating process, and 200-250°C heat treatment is required to eliminate the hidden danger.
Electroless nickel plating is superior to electroless nickel plating in terms of corrosion resistance, high-temperature stability and adaptability to complex working conditions, and its comprehensive durability is improved by 50-200%. Electroless nickel plating, however, still has an advantage in room-temperature, high hardness requirements (e.g., decorative surfaces) or rapid deposition scenarios (e.g., PCB conductive layers).