B2PCOE Corrosion Mitigation Activity Report on the Flashguard Process
From B2P Portal
The Benchmarking and Best Practices Center of Excellence (B2PCOE) Corrosion Mitigation Activity was focused on evaluating the corrosion mitigation performance of Coastal Carolina Fusion Technology’s Flashguard process. The United States Marine Corps (USMC) selected a variety of parts from the facilities at Camp Lejeune and sent those parts to Coastal Carolina Fusion Technology (CCFT) to be coated with the Flashguard process and subsequently brought to the Naval Surface Warfare Center (NSWC), Carderock Division for corrosion testing. The Flashguard process did not perform well in the corrosion testing, since it was not able to inhibit corrosion on the samples provided.
The corrosion testing that was performed at NSWC – Carderock followed two standards: ASTM D1654-08 – Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments and GM9540P – Accelerated Corrosion Test. ASTM D1654-08 describes how to evaluate and compare basic corrosion performance of a sample after exposure to corrosive environments. GM9540P describes how to perform an accelerated laboratory corrosion test method, which combines cyclic conditions of salt solution, various temperatures, humidity, and ambient environment to accelerate metallic corrosion.
The Flashguard process is a hard-chrome plating technique, and was coated a variety of USMC weapon and vehicle system components, including: two armor plates from a HMMWV armor kit, two tie-down shackles, one exhaust header, one M2 .50 caliber machine gun mount, one 9 mm magazine clip, and one 5.56 mm magazine clip.
After being received at NSWC-Carderock, one of the two armor plates, both magazine clips, and the .50 caliber gun mount were treated with Deft 53030 epoxy primer, and top-coated with green Hentzen 64159 type II Chemical Agent Resistant Coating (CARC). The remaining parts were left in the as-received condition for testing. In addition, both armor plates were scribed in three locations on the front face, 1 inch apart from each other, as specified in ASTM D1654-08.
The specimens where placed in an accelerated corrosion chamber, and received 32 cycles of GM9540P exposure. According to GM testing data, 8 cycles in GM9540P is approximately one year in the automotive world for locations similar to northeast United States and Newfoundland. The timeframe is 50 to 70% lower according to Marine Corps data, so 8 cycles can approximate around six to eight months of exposure to environments where Marine Corps materiel is stationed. The 32 cycles in GM9540P takes 32 days and is used to qualify organic coatings and process improvements. So, 32 cycles is equivalent to four years in the automotive world is roughly equivalent to a range of two to three years for typical environments that Marine Corps materiel are deployed. When testing organic coatings for corrosion mitigation effectiveness, the samples undergo 120 cycles of GM9540P with a quality rating of 7 required for passing. The quality rating of 7 means that corrosion distance from scribe mark on panel is on average 1/32 to 1/16 inch.
Photographs were taken after the samples following 8, 16, 24 and 32 GM9540P exposure cycles. Figures 1, 2, 3, and 6 show the samples after 8 cycles. Figures 7 and 8 show the samples after 16 cycles. Figures 4, 9, and 10 show the samples after 24 cycles. Figures 5, 11, and 12 show the samples after 32 cycles. After 8 cycles of GM9540P exposure, parts without a CARC topcoat exhibited surface rust over larger portions of the surface. Significant surface rust had formed on both the Flashguard and CARC top-coated armor plate specimens at the termination of testing (32 cycles of GM9540P exposure).
One armor plate was cross-sectioned and subjected to metallographic analysis to determine the coating thickness and continuity of Flashguard. Images of the cross-sections are found in Figures 13 and 14. The metallographic analysis shows discontinuous coating coverage and areas where corrosion product accumulated below the chrome plating. As shown in the cross-section images, the Flashguard coating appears to be approximately 5-10 microns thick. At the points where there is a break in the coating, there is some amount of undercutting of the plate.
GM9540P accelerated corrosion exposure showed that without CARC topcoat components treated with Flashguard began to rust within 8 cycles of testing. At the completion of testing, 32 cycles in GM9540P, the samples treated with Flashguard were rusted completely.
As a path forward, other products should be evaluated under the same conditions, preferably with the same testing chambers. There is a need for data on corrosion mitigation products that are compared on the same base substrates and using the same test conditions. Alternative corrosion mitigation systems should be evaluated with standards of each component, uncoated versus coated, and larger sample sets. The performance of each of the following coating systems, even those with environmental and health concerns, should be included: cadmium containing coatings (environmental and health concerns); chromium containing coatings (environmental and health concerns); MIL-PRF-23377 Class C, chromated primers; MIL-PRF-23377 Class N qualified non-chromate primers; magnesium containing coatings; zinc containing coatings; plasma electrolytic oxidation (PEO); pulsed thermal spray (PTS) coatings; carburized coatings; CARCs (toluene diisocyanate (TDI) released with health concerns); CARC primers (MIL-P-53022II at ~1 mil DFT); and CARC topcoats (MIL-DTL-53039B and MIL-DTL-64159II at ~2 mils DFT).
Included in the path forward, the central repository of corrosion testing information from a previous ONR effort should be evaluated for its continued usage and/or a similar effort should be used to create a Department of Defense wide database through which corrosion testing information can be searched and retrieved with ease.
Figure 1: Exhaust header after 8 cycles of GM9540P exposure
Figure 2: Tie down shackle after 8 cycles of GM9540P exposure
Figure 3: Tie down shackle after 8 cycles of GM9540P exposure
Figure 4: .50 caliber machine gun mount (with black CARC top coat) after 24 Cycles of GM9540P exposure
Figure 5: .50 caliber machine gun mount (with black CARC top coat) after 32 Cycles of GM9540P exposure
Figure 6: Armor plate (not scribed) after 8 cycles of GM9540P exposure
Figure 7: Scribed armor plate after 16 Cycles of GM9540P exposure
Figure 8: Scribed armor plate (with CARC top coat) after 16 cycles of GM9540P exposure
Figure 9: Scribed armor plate after 24 cycles of GM9540P exposure
Figure 10: Scribed armor plate (with CARC top coat) after 24 cycles of GM9540P exposure
Figure 11: Armor plate after 32 cycles of GM9540P exposure
Figure 12: Armor plate (with CARC topcoat) after 32 cycles of GM9540P exposure
Figure 13: Cross-section of armor plate with Flashguard treatment, after 8 cycles GM9540P exposure (20x magnification)
Figure 14: Cross-section of armor plate with Flashguard treatment, after 8 cycles GM9540P exposure (50x magnification)
