A method of depositing a coating basede conversion to hydrated aluminum oxide on a substrate aluminiomagnesio, tin or zinc.

摘要

Conversion coatings of the hydrated metal oxide type are deposited on a substrate of Al, Mg, Sn or Zn or their alloys, from an aqueous solution of AlIII having a pH of 1.5 to 5.5 and containing NO3-. The coating produced is of hydrated aluminium oxide. Conversion coatings having further enhanced corrosion resistance are produced from solutions which include borate and have pH's in the range of 4 to 5.5