Mainstream PV bracket substrate is Zn-Al-Mg coated carbon steel, matched with SUS304/316 stainless steel fasteners. Large standard electrode potential difference between two metals triggers electrochemical corrosion under direct contact, white rust and perforation appear quickly on bracket surface and shorten the 25-year design life of power stations. Insulating isolation gaskets are mandatory to block potential conduction, two mainstream types are EPDM rubber and PTFE gaskets with distinct adaptability for different corrosion environments.
| Gasket Material | Long-term Operating Temp Range | Chloride Aging Service Life | Insulation Resistance Value | Elastic Buffering Capacity | Procurement Cost | Forbidden Application Scenarios |
| EPDM EPDM Rubber Gasket | -40℃~110℃ | 8 years stable for inland & riverside sites | ≥10^8 Ω | High elasticity, adapt to tiny profile deformation | Base low price | Tidal flat intertidal zone, permanent high-temperature tracker brackets |
| PTFE Teflon Insulating Gasket | -60℃~200℃ | 15 years no aging crack for coastal & offshore sites | ≥10^12 Ω, top-level insulation performance | Rigid zero elasticity, no deformation buffering | +140% cost increase | Thin-wall light-duty simple fixed brackets (easy gasket crushing) |
1. Inland mountain distributed PV: 0.8mm standard EPDM gasket for basic galvanic corrosion isolation with best cost performance; 2. Riverside & lakeside mild corrosion PV stations: 1.2mm thickened EPDM gasket to improve waterproof isolation and resist long-term rainy season humidity; 3. Coastal tidal flat PV within 5km coastline: 1.5mm thin PTFE gasket, resistant to long-term high salt mist aging and prevent gasket pulverization failure; 4. Offshore floating & intertidal PV tracker brackets: 2.0mm glass fiber composite thick PTFE gasket, no brittle crack under large day-night temperature difference.
1. Long-term gasket brittle crack & pulverization: Upgrade to thickened EPDM for inland sites, switch to PTFE for coastal projects; 2. Insulation failure caused by crushed gasket: Select gasket size matching flange width, forbid gasket smaller than bolt flange diameter; 3. Water seepage & bracket white rust: Fully cover metal contact surface with gasket during assembly without exposed direct metal contact area; 4. Reciprocating slip on tracker brackets: Pre-coat tiny amount of solid lubricant on PTFE gasket surface to reduce reciprocating friction wear.