Cronak process

{{Short description|Chromate conversion coating process}}

The Cronak process is a conventional chromate conversion coating process developed in 1933 by The New Jersey Zinc Company.{{cite book|author=Gregory Zhang, Xiaoge|title=Corrosion and Electrochemistry of Zinc|url=https://books.google.com/books?id=Qmf4VsriAtMC|accessdate=12 December 2014|year=1996|publisher=Springer Verlag Gmbh|isbn=978-1-4757-9877-7|pages=16, 17}} It involves immersing a zinc or zinc-plated article for 5 to 15 seconds in a chromate solution, typically prepared from sodium dichromate and sulfuric acid.{{Cite magazine |date=May 28, 1936 |title=New Protective Zinc Coating Introduced |url=https://archive.org/details/sim_chiltons-iron-age_1936-05-28_137_22 |magazine=The Iron Age |volume=137 |issue=22 |page=94 |access-date=8 Mar 2023 |via=Internet Archive}} The process was patented in the United States on March 24, 1936 with USPTO number 2,035,380.{{ cite patent | country = US | number = 2035380 | status = patent | title = Method of coating zinc or cadmium base metals | pubdate = 1936-03-24 | gdate = 1936-03-24 | fdate = 1933-05-13 | pridate = 1933-05-13 | inventor = Ernest John Wilhelm | invent1 = Ernest, John Wilhelm | assign1 = The New Jersey Zinc Company| class = }}