Treatment liquid for chromium-free tension coating, method for forming chromium-free tension coating, and method for producing grain-oriented electrical steel sheet with chromium-free tension coating

摘要

Provided is a treatment solution for chromium-free tension coating that can simultaneously achieve excellent moisture absorption resistance and a high iron loss reduction effect obtained by imparting sufficient tension, by using an inexpensive Ti source instead of expensive Ti chelate. The treatment solution for chromium-free tension coating contains: one or more of phosphates of Mg, Ca, Ba, Sr, Zn, Al, and Mn; colloidal silica in an amount of 50 parts by mass to 120 parts by mass per 100 parts by mass of the phosphate in terms of solid content of SiO 2 ; Ti source in an amount of 30 parts by mass to 50 parts by mass per 100 parts by mass of the phosphate in terms of solid content of TiO 2 ; and H 3 PO 4 , and the number of moles of metallic elements in the phosphate and of phosphorus in the treatment solution satisfy: 0.20 ‰¤ Mg + Ca + Ba + Sr + Zn + Mn + 1.5 Al / P ‰¤ 0.45