Novel amorphous coating to replace Hexavalent Chrome for Small Caliber Barrels

Small caliber barrels (SCBs) operate under extreme conditions, experiencing high temperatures, wear, and erosion during firing. Traditional hexavalent chromium plating is used to protect bores from wear, erosion, and some oxidation. However, this coating exhibits non-uniformity on rifling edges and inherent tensile stress cracking, which can lead to corrosion, oxidation, and eventual delamination. Furthermore, hexavalent chromium is a toxic carcinogen, subject to strict regulations and bans globally.To address these issues, a new coating must offer density, uniformity, high-temperature oxidation resistance, and environmentally friendly processing. IBC proposes an environmentally friendly amorphous chromium carbide (a-CrC) coating as a direct replacement for hexavalent chromium in SCBs. This low-temperature (<480°C), non-line-of-sight Chemical Vapor Deposition (CVD) technology provides uniform coverage of high-aspect-ratio bores. The dense, amorphous structure is free of cracks and grain boundaries, offering superior corrosion and oxidation resistance. Additionally, its high hardness (1500-2000 HV) provides 3-5 times better wear resistance than hexavalent chromium. Prior, Current, or Pending Support of Similar Proposals or Awards.FA8649  USAF RESEARCH LAB AFRL SBRK  (AWARDED)CP 937 904 97002275 D STREETWRIGHT PATTERSON AFB, OH 45433UNITED STATESCHRISTA PHILLIPS, Contracting Officer, Email: christa.phillips.1@us.af.mil Telephone: 777-7807 ARIANNA REID, Contract Specialist, Email: arianna.reid@us.af.mil Telephone: 0000000Effective: 10 Feb 2023Title: High Temperature, Corrosion, Erosion, and Wear Resistant Coating for Gun BarrelsPI: Dr. Solomon BermanBAA Title and Date: DEPARTMENT OF THE AIR FORCE (DAF) SMALL BUSINESS INNOVATION RESEARCH PROGRAM COMMERCIAL SOLUTIONS OPENING (CSO) DIRECT-TO-PHASE-II X23.4 AMENDMENT 2 // 10 NOVEMBER 2022Contract #: FA864923P0518SBIR Ph IIKey Differences:Certain process refinements have been made based on past experience, hence coupon level coating and characterization will be performed on alloys typically used in small caliber firearms.For this Proposal a numerical simulation will be developed to predict the thermal-mechanical erosion of the coating.Validation of numerical simulation model with coupon level coating characterization will be performed to help refine the simulation. Refined numerical simulation model will be used for future application of coating in armaments.