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.
The customer found that they could dip the aluminum oxide tiles into ZL-19 for 15 – 20 minutes, rinse them off, dry them overnight and then clean them briefly in the morning, prior to inspecting them under a UV light.
ZL-19 allowed them to see specific defects that meant a tile had to be rejected, and to distinguish this from any general background indications caused by the structure of the tile surface. Specific rejectable defects include cracks, chips and areas of porosity.
“Through the support of Magnaflux team, we were able to find a simple method to put in quality control test in place for pass/fail of the aluminum oxide tiles which we had not been able to inspect previously. It was interesting to see the flexibility of penetrant inspection on what is essentially a semi-porous surface.”
Published November 27, 2018