How can we prevent premature corrosion of fasteners in solar mounting systems? The answer is actually quite clear: the key lies in implementing targeted protective strategies at every stage—from material selection, design, and installation to maintenance, monitoring, and system management. Although small, the fasteners in PV mounting systems act as the “joints” of the entire PV power plant. Once corrosion occurs, it can, at best, compromise structural stability, and at worst, lead to panel failure or even safety incidents. To systematically address this issue, we need to focus on the following core aspects.
First, what should be done? We must ensure the quality of materials right from the source. Selecting fastener materials with excellent corrosion resistance is fundamental. In common corrosive environments—such as coastal areas with high salt fog, industrial pollution zones, or high-humidity regions—stainless steel should be the preferred choice, particularly grades 304 or 316. These grades offer outstanding corrosion resistance due to their content of elements like nickel, chromium, and molybdenum. For extreme corrosive environments, higher-grade duplex stainless steel or special alloys may even be considered. In addition, hot-dip galvanized carbon steel is an economical and effective option, as its zinc coating provides reliable sacrificial anode protection. In recent years, certain composite materials or fasteners with specially reinforced surfaces have also shown promising application prospects. Remember, under no circumstances should ordinary carbon steel or products with inferior coatings be selected for short-term cost savings; doing so is tantamount to creating hidden hazards for the power plant.
Second, what should be done? It is essential to prioritize surface treatment and coating protection for fasteners. This serves as the first physical barrier against corrosive media. In addition to the aforementioned galvanizing, advanced processes such as Darco (zinc-chromate coating), powder coating, and epoxy coating can be employed. These coatings adhere tightly to the metal surface, effectively blocking the intrusion of moisture, oxygen, and corrosive ions. When selecting coatings, the coating system and thickness must be matched to the specific environment (such as corrosion classes C1 to C5M). For example, in highly corrosive environments, a composite system consisting of a “primer + intermediate coat + topcoat” may be required. At the same time, it is essential to ensure the coatings remain intact and free of defects, avoiding scratches during transportation and installation. Any minor damage caused during installation should be repaired promptly.
Third, what should be done? The principle of corrosion prevention must be implemented throughout the design and installation phases. A rational structural design can minimize conditions conducive to corrosion. For example, during design, avoid recesses or crevices where moisture and debris can accumulate, and ensure proper drainage. During installation, pay special attention to the contact between different metallic materials. If metals with different potentials (such as aluminum brackets and steel fasteners) must be connected, electrical isolation must be achieved using insulating washers, sleeves, or coatings to prevent galvanic corrosion, which often progresses very rapidly. Installation torque must also be strictly adhered to according to specifications; over-tightening may cause coating cracking or stress corrosion, while under-tightening can lead to loose connections, exacerbating wear and corrosion through micro-movement.
Fourth, what should be done? A regular inspection and maintenance system must be established. Even the best materials and designs cannot function without proper upkeep. A detailed inspection plan should be developed to periodically check the visual condition of fasteners for signs of rust, coating peeling, looseness, or damage. For fasteners in critical areas, professional methods such as ultrasonic testing and torque testing can be used to assess their condition. Once early signs of corrosion are detected, immediate action should be taken, such as cleaning rust, reapplying anti-rust grease, or replacing damaged components. Maintenance records should be kept complete to track corrosion trends and evaluate the effectiveness of protective measures.
Fifth, what should be done? Advanced auxiliary protection technologies can be utilized. For example, in specific situations, cathodic protection technology can be employed. By applying an external current or using sacrificial anodes, the fasteners are made cathodes and thus protected. Additionally, applying specialized long-lasting anti-rust sealants or compounds before and after fastener installation provides both lubrication and sealing, preventing corrosive media from penetrating thread gaps. These technologies serve as powerful supplements to the primary measures mentioned above.
Finally, what should be done? It is essential to adopt a lifecycle management mindset. Preventing premature corrosion of fasteners is not an isolated technical issue, but a management challenge that spans the entire project lifecycle—from planning and procurement to construction, operation, and maintenance. This means establishing clear anti-corrosion technical standards early in the project, strictly enforcing them during procurement, conducting quality supervision during construction, and implementing a responsibility system during operation and maintenance. At the same time, we must actively monitor developments in new technologies and materials within the industry to continuously optimize our solutions.
In summary, there is no single “magic bullet” for preventing premature corrosion of PV mounting system fasteners; it is a systematic engineering endeavor that requires a comprehensive consideration of materials science, engineering technology, on-site management, and ongoing maintenance. The key lies in “proactive prevention” rather than “reactive remediation.” Through a comprehensive approach combining scientific material selection, meticulous surface treatment, standardized installation, diligent maintenance, and systematic management, we can significantly extend the service life of fasteners, ensuring the safe and stable operation of PV mounting structures for up to 25 years or longer, thereby safeguarding the long-term investment returns of the power plant. This is not merely a technical requirement but also a reflection of a responsible attitude toward power plant assets.
