Threaded Part Evaluation

Following 5,040 hours of ASTM B117 salt fog exposure, significant red rust was present on the exposed threads of control (untreated) assemblies. The Gentoo-treated assemblies were removed from testing at the same time point. Upon disassembly, significant corrosion and white salt product was present on the unexposed threads of the control bolt and nut. The Gentoo-treated sample's unexposed threads were pristine and shiny on the nut and across large sections of the bolt.

Following plastic media blasting per ASTM G1 to remove paint and corrosion product, the Gentoo-treated bolt and nut threads remained light grey — indicating the undisturbed presence of the LHE Zn-Ni plating. The control bolt threads were dark and showed areas of red rust following blasting, indicating that the Zn-Ni plating had been completely consumed during the test period. Similar features were present on the control nut threads.

GMW14872 Results — 272 Cycles (6,528 Hours)

GMW14872 uses a multi-stage cyclic exposure protocol combining salt spray, high humidity, and elevated dry temperature — more representative of complex outdoor industrial conditions than continuous salt fog alone. After 272 cycles of GMW14872 exposure, results were consistent with the ASTM B117 findings.

Both control and Gentoo-treated threads accumulated white product on exposed thread surfaces. Critically, the white product on control panels could not be removed by washing or wiping — it was a corrosion product of LHE Zn-Ni consumption. The white product on Gentoo-treated threads could be rinsed away with water or removed with a gentle wipe, confirming it was salt deposit rather than corrosion product — and confirming the LHE Zn-Ni plating beneath was unaffected.

During the cyclic salt spray stages, Gentoo's hydrophobic surface caused the spray to bead on the exposed thread tips. When the water evaporated, salt deposits were left on the surface — building up over successive cycles. Despite this salt accumulation on the surface, Gentoo continued to provide an effective corrosion barrier, and the LHE Zn-Ni and underlying 300M steel beneath remained unaffected throughout the full 272-cycle test.

Atmospheric Exposure — Kennedy Space Center (16 Months)

To complement the accelerated laboratory testing, identical 300M threaded assemblies were exposed to real-world atmospheric conditions at the Kennedy Space Center beachside corrosion exposure facility in Florida for 16 months — one of the most corrosion-aggressive coastal test sites available in North America, comparable in salt exposure and humidity to UAE coastal and offshore environments.

After 16 months of atmospheric exposure, the exposed threads of control assemblies showed white LHE Zn-Ni consumption product on the top and sides of the threads. Gentoo-treated thread assemblies showed minimal LHE Zn-Ni consumption. The inner threads of the Gentoo-treated bolts remained shiny and unchanged.