Powder for powder magnetic core, and powder magnetic core

A powder magnetic core, obtained by a process comprising

• compressively forming a powder, which comprises iron-based soft magnetic powder particles having a phosphoric acid-based chemical conversion coating on a surface thereof,
• wherein
• the phosphoric acid-based chemical conversion coating has a non-uniform thickness and recessed portions are formed on a surface of the phosphoric acid-based chemical conversion coating,
• when a broken-out section of the powder magnetic core is observed, in a portion surrounded by three or more of the iron-based soft magnetic powder particles:
• the phosphoric acid-based chemical conversion coating has a maximum thickness of 20-200 nm;
• the recessed portions form openings on the surface of the phosphoric acid-based chemical conversion coating;
• and
• a total length of surface of the three or more iron-based soft magnetic powder particles where the phosphoric acid-based chemical conversion coating is adhered is 50% or more relative to a total length of the surface of the three or more iron-based soft magnetic powder particles;
• and
• in the portion surrounded by three or more of the iron-based soft magnetic powder particles:
• one or more on average recessed portions comprising 50-1,000 nm-wide openings are present per 5 μm length of the surface of the iron-based soft magnetic powder particles in the phosphoric acid-based chemical conversion coating;
• a first oxide layer, the phosphoric acid-based chemical conversion coating, and a second oxide layer are laminated in this order on the surface of the iron-based soft magnetic powder particles where the phosphoric acid-based chemical conversion coating is adhered;
• and
• a thickness of the first oxide layer is 200 nm or less.