Response time scales of anodized-aluminum pressure-sensitive paints

The response time scales of anodized-aluminum pressure-sensitive paints (AA-PSPs) are characterized by measuring their luminescent lifetimes and response times to a step-like pressure change. The luminescent lifetime is measured by a picosecond fluorescence measurement system at atmospheric conditions. The results show that the twelve AA-PSPs tested fall into two groups according to their luminescent lifetimes; one group includes AA-PSPs with organic luminophores and the other one includes AA-PSPs with metal complex luminophores. The former possesses the lifetime on the order of one nanosecond and the latter possesses that on the order of hundred nanoseconds. The AA-PSPs are also characterized by the response time to a step change in pressure generated in a shock tube. It is observed that the 90% rise times to a step change in pressure are on the order of 10 μs and range from 30 μs to 50 μs, which lie within the tolerance caused by the thickness uncertainty in fabricating the anodized-aluminum layer. It is also found that the luminescent lifetimes are 2–4 orders of magnitude shorter than the step response times.