Defect Detection in Narrow Bore Components with Quantum Dot Liquid Penetrants

Physical Sciences Inc. (PSI) will develop a liquid penetrant system based on colloidal quantum dots (QDs) and a high resolution dual-channel fiberscope to enable nondestructive examination of micron sized cracks in the bore evacuator holes of gun tubes. The ligand-free QDs will eliminate hydrocarbon contaminants found in conventional penetrants and mitigate hydrogen embrittlement of steel components. The Phase I program established concept feasibility by demonstrating the synthesis of water soluble QDs with emission quantum yields of 30%, while in parallel, validating a system model with a breadboard system that mimics the specifications of a high resolution dual channel fiberscope. Risk mitigation experiments performed on corroded and cracked steel coupons successfully demonstrated the full CONOP, while reducing program risks. PSI will perform QD material scale-up to 500 mg/hr and develop an advanced penetrant prototype system that includes: 1) techniques for application and removal of excess QD penetrant from bore holes, and 2) a rugged fiberscope for imaging QD emission. An initial prototype will be demonstrated in Year 1 through laboratory inspection of government furnished bore evacuators. A TRL 5 capability will be achieved in Year 2 through in-field inspection of evacuator tubes at an Army sustainment facility.