Aluminum alloy phosphoric acid anodizing

Nickel-cadmium diffusion coating

Alkaline cyanide‑free copper plating is an environmentally friendly pre‑plating process that contains no highly toxic cyanides, instead using organic complexing agents to coordinate copper ions. The resulting coating exhibits fine crystallinity and excellent adhesion, making it suitable for pre‑plating on substrates such as steel and zinc alloys. It can replace conventional cyanide‑based pre‑copper plating, thereby reducing environmental regulatory pressures. With a broad process window and excellent stability, it is often employed as an intermediate layer to enhance the adhesion of subsequent platings and is widely used in precision components and as a preparatory step in surface‑treatment workflows.

Alkaline cyanide-free cadmium plating

SanYong—A proprietary process formulation developed in-house by Harbin Institute of Technology, offering surface‑plating services on a contract basis only. Key features: high current efficiency ≥70%, fast plating rate, low hydrogen evolution, and reduced hydrogen embrittlement. The plating bath exhibits excellent stability, with outstanding throwing power and deep‑plating capability.

Electroplated Low-Stress Zinc-Nickel Alloy

SanYong— the result of a research collaboration between Harbin Institute of Technology and SanYong—has developed the SY‑585 low‑stress alkaline zinc–nickel alloy electroplating process, which is capable of producing and supplying plating additives. The coating performance meets or exceeds that of Dipsol IZ‑17, the standard adopted by U.S. defense contractors and Boeing, making it a viable alternative to cadmium plating. As a Harbin Institute of Technology–SanYong solution for replacing cadmium plating in military‑grade applications, SY‑585 has been successfully submitted under “Operation HY” and is now being implemented at multiple defense‑industry enterprises.

Electroplated tin–bismuth alloy

Electroless nickel-phosphorus alloy

SY-335 Oxide Film Dyeing and Sealing Agent

SY-335 aluminum oxide film dyeing and sealing agent is a solid powder that effectively inhibits the leaching of organic dyes during the sealing process, thereby accelerating the pore‑closing rate of the anodized film. Its unique formulation enhances sealing quality, improves surface smoothness, and extends service life.

SY-333 room-temperature nickel-free sealant

SY-333, a room‑temperature, nickel‑free sealing agent, is a concentrated liquid formulation that delivers excellent pore sealing for aluminum anodized films at 35–43°C. This product is free of heavy metals, which not only simplifies wastewater treatment by eliminating the need to manage heavy metal contaminants but also prevents the greenish discoloration often caused by nickel‑salt adsorption onto the oxide layer during conventional nickel‑based sealing—since SY‑333 itself is colorless. Moreover, it is suitable for sealing both transparent anodized films and electrolytically colored anodized coatings. With proper maintenance and process control, the SY‑333 working solution can remain in service for extended periods without requiring replacement.