title = "Corrosion Testing: Salt Spray and Humidity Tests"

content = """
Corrosion testing evaluates the protective performance of coatings and surface treatments under accelerated conditions that simulate corrosive service environments. At Ridgecrest Metalworks, corrosion testing is conducted on qualification samples, production process validation panels, and periodic audit specimens.

Salt spray (salt fog) testing per ASTM B117 / ISO 9227 is the most widely specified accelerated corrosion test. Test panels or parts are placed in an enclosed cabinet and exposed to a continuous fog of 5 % sodium chloride solution at 35 °C. The fog is acidic (pH 6.5–7.2) and highly oxidizing. Results are expressed as hours to first visible corrosion (red rust on steel, white corrosion on zinc or aluminum). Typical performance requirements:
- Bare steel: < 1 hour (used only as baseline reference)
- Iron phosphate + primer + topcoat: 240–500 hours
- Zinc phosphate + epoxy primer + polyurethane topcoat: 500–1000 hours
- Hot-dip galvanized (85 µm): > 1000 hours
- Zinc-nickel electroplate: 500–1000 hours per specification

Scribe testing is often combined with salt spray: a cross-hatch scribe cut through the coating to bare metal is made before exposure. After testing, the panel is assessed for creep (undercutting) from the scribe, in addition to blistering and face corrosion. Maximum acceptable creep from the scribe is defined per standard (e.g., < 2 mm per side per 500 hours).

Humidity testing (ASTM D2247 / ISO 6270) exposes panels to 100 % relative humidity at 38 °C or 40 °C without the salt solution. This test reveals blistering, loss of adhesion, and whitening caused by moisture ingress without the chemical aggression of salt spray. It is often used for interior or low-corrosivity environment coatings.

Cyclic corrosion testing (CCT) such as SAE J2334 or Volvo VCS 1027 alternates between salt spray, humidity, and dry conditions to better simulate real-world freeze-thaw and wet/dry cycles. Cyclic tests generally correlate better to field performance than continuous salt spray but are longer and more resource-intensive.

At Ridgecrest, corrosion test samples are exposed in the on-site salt spray cabinet (for internal process control) or sent to an external accredited laboratory for certification. All test records include panel identification, process batch, test start and end times, and photographic evidence of panel condition at intervals and at conclusion of test.
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version = "0.0.1"
