phosphatize
/ˈfɒsfətʌɪz/(also phosphatise)
verb
1 [with object] Chiefly Geology. To convert into a phosphate or phosphates.
2 [with object] To treat with a phosphate; especially to coat (metal) with a phosphate to protect it against corrosion.
Origin
Late 19th century; earliest use found in Quarterly Journal of the Geological Society of London. From phosphate + -ize.