Mechanical forces (most common cause)
Physical impacts, friction, and abrasion can directly scratch, chip or peel the patina: e.g., collision with hard objects, rubbing from construction tools/equipment, sand/stone erosion in windy areas, or improper mechanical cleaning (wire brushing, high-pressure sandblasting). Light scuffs only damage the surface of the patina layer, while heavy impacts/abrasion can strip the entire patina to expose the bare steel substrate.
Harsh chemical exposure
Contact with high-concentration acidic/alkaline substances, strong oxidants, or industrial chemicals will chemically corrode and dissolve the patina: e.g., spilled industrial acid/alkali, high-concentration cleaning agents, heavy industrial pollutant mist (sulfuric acid, nitric acid mist), and concentrated chloride solutions. The alloyed patina is stable to mild atmospheric chemicals but not resistant to strong chemical corrosion, which can break down the patina's oxide structure and erase it completely in severe cases.
Extreme environmental & operational conditions
Long-term immersion in water (seawater, industrial wastewater), high-velocity salt spray scouring in severe coastal areas, and repeated freeze-thaw cycles with moisture trapped under the patina can damage the layer: immersion cuts off oxygen supply and causes the patina to blister/peel, high-concentration salt spray penetrates and degrades the patina's density, and freeze-thaw expands moisture to create microcracks in the patina, weakening its adhesion and barrier performance.
Improper surface cleaning & maintenance
Using abrasive cleaning tools (steel wool, hard bristle brushes) or corrosive cleaning products (bleach, strong solvents) to clean the SPA-H surface can scratch or dissolve the patina; over-washing with high-pressure water (≥80 bar) can also strip the loosely bonded patina edges and cause micro-damages.
