A New Phase in Industrial Corrosion Protection: Zinc-Aluminum Coating in Application

Against the backdrop of the dual carbon goals and the sustained development of high-end manufacturing, the requirements for corrosion protection of industrial products are continuously rising. The shift from traditional "basic protection" to "long-term and reliable protection" has become a key trend in manufacturing development. Particularly in sectors such as automotive, wind power, and construction machinery, high-strength fasteners and key structural components not only demand excellent corrosion resistance but must also comply with environmental regulations, meet lightweighting goals, and support automated production.

Traditional anti-corrosion technologies face numerous challenges in this context. For instance, although hot-dip galvanizing offers good corrosion resistance, its coating thickness is typically 50–80 μm, making it unsuitable for precision fasteners and threaded parts. Electro-galvanizing carries a risk of hydrogen embrittlement when applied to high-strength fasteners and involves high wastewater treatment costs. Standalone electrophoretic coatings lack sacrificial anode protection, so the base metal is prone to localized corrosion once the coating is damaged.

Against this background, zinc-aluminum coating technology has gradually emerged as an important technical route in industrial anti-corrosion and is widely used in high-end manufacturing fields such as automotive components, construction machinery, and wind power equipment.

Zinc-aluminum coating is a non-electrochemical deposition coating technology. A functional coating composed of flaky zinc and aluminum powder combined with organic/inorganic composite binders is formed on the metal substrate via dip-coating or spraying. After high-temperature curing, a dense laminated structure is created, providing multi-mechanism protection for the metal substrate.

Its core protection mechanisms are as follows:

• Barrier Protection

  The flaky zinc-aluminum powder forms a fish-scale-like laminated structure within the coating, significantly slowing the penetration of moisture and oxygen toward the substrate and establishing a stable physical protective barrier.

• Sacrificial Anode Protection

  Zinc has a lower electrochemical potential than steel substrates and preferentially undergoes oxidation in corrosive environments, delivering sustained electrochemical protection to the base material.

• Stable Passivation Protection

  With increasingly stringent environmental regulations, modern zinc-aluminum coating systems have evolved into chromium-free, eco-friendly formulations. Special binders and functional additives stabilize and passivate the zinc-aluminum flakes, meeting international environmental standards such as RoHS and REACH while effectively slowing the corrosion process.

Under standard neutral salt spray (NSS) testing, high-performance zinc-aluminum coatings can achieve red rust resistance of more than 720–1000 hours, greatly extending the service life of components in harsh environments.

Compared with traditional anti-corrosion processes, zinc-aluminum coating technology offers distinct advantages in manufacturing compatibility.

First, the coating process requires no electrochemical deposition or strong acid systems, eliminating the risk of hydrogen embrittlement associated with electroplating from the source. This makes it especially suitable for high-strength carbon steel fasteners (above 1000 MPa).

Second, zinc-aluminum coatings can be applied via dip-spin coating or spraying, ensuring uniform coverage on threaded parts, blind-hole components, and complex structures, effectively solving the problem of missed plating common in traditional electroplating.

In addition, by combining with various topcoat systems, further performance customization can be achieved:

• Friction coefficient control
• Improved chemical resistance
• Customized appearance and color

These meet the technical requirements of diverse applications in automotive, wind power, construction machinery, and other industries.

As manufacturing demands for reliability grow, the application scope of zinc-aluminum coating technology continues to expand.

Currently, the technology is widely used in:

• Automotive chassis components
• High-strength fasteners
• Construction machinery structural parts
• Wind power equipment components
• Port machinery and rail transit equipment

In these applications, zinc-aluminum coatings not only significantly enhance component corrosion resistance but also reduce maintenance and replacement costs, providing reliable assurance for the long-term stable operation of equipment.

As one of the early enterprises entering the zinc-aluminum coating sector in China, Changzhou Junhe Technology Co., Ltd. has long focused on the R&D and application of zinc-aluminum coating materials and processes, providing mature anti-corrosion coating products and technical services for the automotive, construction machinery, photovoltaic, and other industries.

To address diverse application needs, Junhe has developed a comprehensive product portfolio of zinc-aluminum coatings:

• General-purpose zinc-aluminum coatings: For corrosion protection of fasteners and various structural components
• High-corrosion-resistance zinc-aluminum systems: For applications requiring superior salt spray protection
• Special coatings for brake discs: Professional coatings developed for automotive braking system components

Alongside material R&D, Junhe continuously improves zinc-aluminum coating processes. Through sample testing, process optimization, and on-site technical support, the company helps customers achieve stable, efficient, and large-scale production.

With the advancement of green manufacturing and high-end equipment manufacturing, industrial anti-corrosion technology is evolving toward long-lasting, eco-friendly, and intelligent solutions. With outstanding corrosion resistance, environmental performance, and excellent manufacturing compatibility, zinc-aluminum coating technology is becoming a major development direction in industrial anti-corrosion.

From fasteners to key equipment components, zinc-aluminum coating technology provides reliable protection for an expanding range of industries and underpins the high-quality development of the manufacturing sector.

In the future, with continuous advances in materials and coating processes, zinc-aluminum coating technology will deliver value across a broader spectrum of industrial fields, building more durable and reliable protection systems for modern industrial equipment.