Aluminum oxide tiles coated in ZL-19 fluorescent penetrant and viewed under a UV light. The white spots on the left-hand tile indicate cracks and flaws.
Our customer is an armor solutions provider based in the UK and they were looking to use a fluorescent penetrant to inspect for cracks in aluminum oxide tiles used for armor protection.
The issue with aluminum oxide tiles is that they are semi-porous. It had been suggested that they use ZL-67B but our customer was concerned that, as a level 3 sensitivity penetrant, it would fill up all the surface pores and be difficult to remove.
After speaking with the customer, we established that the use of a lower sensitivity penetrant would be better for them as it would be easier to remove. We recommended ZL-19, a level 1 sensitivity, water-washable fluorescent penetrant.