1984 Volume 70 Issue 14 Pages 1765-1772
Electrolysis method for extracting phosphides in Fe-P-M (M: Ti, Nb, or Mo) ternary alloys has been investigated. The experimental results obtained were as follows;
(1) Solute P in steel is anodically oxidized by electrolysis, and reacts with ferrous ion and ion of alloying element to form Fe-P-M-O type compound insoluble in non-aquous electrolyte. This compound is produced in large quantities in 10% acetylacetone-1% tetramethylammoniumchloride-methanol, 4% methylsalicylate-0.5% salicylic acid-1% tetramethylammoniumchloride-methanol and 5% HCl-methanol, and gives positive error to the analytical results of P as phosphide.
(2) By use of 20% calciumsalicylate-0.5% salicylic acid-1% LiCl-methanol solution (termed 20% CaSA electrolyte), developed in this study, formation of Fe-P-M-O type compound can advantageously be prevented.
(3) FeMoP, FeNbP and FeTiP are found in Fe-Mo-P, Fe-Nb-P and Fe-Ti-P ternary alloys, respectively. These phosphides are found to be chemically stable in 20% CaSA electrolyte and to be quantitatively extracted, by controlled-current electrolysis.
(4) It is proved that cold-work embrittlement in extra-low carbon titanium-added steel can be improved by decreasing the amount of solute P in the steel.
