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Marine corrosion kinetics and ASTM B117 benchmarks

NP1 mesh exhibited a mean corrosion rate of 0.012 mm yr⁻¹ over a 2,000‑hour ASTM B117 neutral salt‑spray exposure, a 48 % improvement over commodity 316L mesh controls under identical conditions.

GTX Research · Marine desk21 April 202612 minCC-BY-4.0ScholarlyArticle

1. Setup

Salt‑spray benchmarking performed in a Q‑FOG CCT‑1100 chamber per ASTM B117, 5 wt % NaCl, pH 6.5–7.2, 35 °C, 2,000 h continuous. Coupons: 400‑count NP1 mesh, 316L mesh control, duplex 2205 mesh control (n = 6 per arm). Mass loss measured at 500, 1,000, 1,500 and 2,000 h intervals; corrosion rate computed per ASTM G1 mass‑loss convention.

2. Kinetics

Fig. 1 — Mean corrosion rate, 2,000 h ASTM B117.

NP1 outperformed duplex 2205 by 33 % and 316L by 48 %. No pitting was observed on NP1 coupons at 40× optical inspection; micrograph series is bound in the validation dataset.

3. IMO 2020 BWMS duty‑cycle mapping

Mapped to IMO ballast‑water‑management duty cycles (3,000–5,000 full‑flow hours over 8–12 year vessel drydock cycles), the NP1 corrosion budget supports a full drydock‑interval service life with a > 2× safety factor. Addressable fleet: ~90,000 vessels subject to IMO 2020 retrofit, per Lloyd's Register 2024 BWMS market review.

Corrosion rate
0.012 mm/yr
2,000 h ASTM B117 mean, NP1.
vs 316L
–48 %
Comparative performance delta.
Pitting
None observed
40× optical inspection, 2,000 h.
Addressable fleet
~90,000
IMO 2020 retrofit scope.

Sources & references

  1. ASTM International. B117‑19 — Standard Practice for Operating Salt Spray. astm.org
  2. Lloyd's Register. Ballast Water Management Systems Market Review 2024.
  3. IMO. International Convention for Ballast Water Management.