The effects of the coupled heat-moisture transport are finally validated by ageing cycles and bond strength tests.
At irradiation intervals (between ~ 100 J/cm2 at the beginning of the aging cycle up to ~ 1200 J/cm2 at the end of the aging cycle), gloss at an angle of 60° was measured using a Sheen Instruments Ltd Tri-GLOSSmaster.
In order to eliminate this effect, a duplex aging cycle was designed for Beta-C.
Blocking, which would allow for a larger design size, was considered a too time-consuming option considering the time per aging cycle.
The remaining 16 samples do reach a degree of chalking, but five of them are not completely chalked at the end of the extreme aging cycle.
During an aging cycle, fuel is injected into the exhaust to achieve reproducible exotherms under lean and rich conditions with the average temperature approximating the target temperature.
One of the commonly used rapid catalyst aging tests is an exothermal aging cycle, which involves a combination of fuel-rich engine operation and supplemental air injection to generate high-temperature lean conditions within the catalyst bed.
This time can be compared with the period of the lean A/F operation during the aging cycle to determine the location and duration of high-temperature lean exposure.
