Cylinder piston rod uses nickel-cobalt-iron alloy instead of chrome plating

The development of "clean nickel-cobalt-iron alloy plating" marks a significant breakthrough in the evolution of electroplating technology. This innovation not only supports the sustainable growth of modern industries but also plays a vital role in environmental protection, with great potential to fully replace traditional hard chrome plating in the future.

1. Plating thickness: 0.03–0.05mm (single side), with additional plating up to 0.1–0.2mm;

2. Hardness: Before heat treatment, HV650–750; after heat treatment, HV850–1200;

3. Surface appearance: Similar to stainless steel, with a soft and delicate finish compared to chrome;

Surface roughness: Can reach Ra0.2 after super-finishing, though the color is slightly different from hard chrome, it still offers a smooth and uniform look;

4. Corrosion resistance: After salt spray testing, it performs better than conventional chrome plating;

5. Friction coefficient: When used on piston rods, the coating's friction with seals is comparable to that of chrome plating during movement.

Analysis of the Nickel-Cobalt-Iron Alloy Plating Process:

1. Energy Efficiency: The process includes degreasing, rinsing, activation, electroplating, cleaning, and recycling—similar to hard chrome plating. However, the current density used (7 A/dm²) is significantly lower, about 1/10 to 1/20 of that used for hard chrome, making it more energy-efficient.

2. Environmental Benefits: The entire process avoids hexavalent chromium, using mainly nickel and cobalt salts. Any gas released during electroplating contains no irritating amines, resulting in minimal environmental impact and low treatment costs.

3. Post-Plating Processing:

A. Superfinishing (such as polishing or honing) is typically required. Heat treatment at 240°C ± 20°C for 30–60 minutes can increase microhardness without affecting the base metal’s hardness;

B. Machinability: For components like horizontal rods (Φ45–0.02–0.06), the nickel-cobalt-iron coating requires less material removal (3–10μm) compared to hard chrome;

C. Substrate Precision: As a transparent coating, any minor defects in the base material are visible, which may lead to misinterpretation during inspection.

Future Prospects of the Chrome Plating Replacement:

Advantages: Energy saving, eco-friendly, lower cost than hard chrome plating.

Disadvantages: Requires heat treatment at 240°C ± 20°C, which may introduce deformation or bumps if not carefully controlled.

Suggested Improvements: Without heat treatment, the hardness of the coating cannot match that of hard chrome, so optimizing the process to enhance hardness without extra steps is recommended.

Benefits of Nickel-Cobalt-Iron Coating:

1. High hardness, excellent corrosion and wear resistance, matching or exceeding chrome plating performance;

2. Minimal pollution, no hexavalent chromium emissions, and a clean production system with zero wastewater discharge;

3. Superior leveling ability, with a bright finish even at a thickness of 3mm;

4. Excellent coverage and throwing power, with a deposition rate of around 60μm/h;

5. Complete plating and stripping processes available for various materials;

6. High current efficiency (over 95%) and high utilization rate (over 95%), leading to lower overall production costs.

This environmentally friendly and efficient electroplating technology combines advanced automation and green practices, ensuring clean production without harming the environment. Therefore, the realization of "clean nickel-cobalt-iron alloy plating" represents a major milestone in the evolution of electroplating, offering a sustainable alternative that could eventually replace traditional hard chrome plating entirely.