MANUFACTURING METHOD OF A GLASS SUBSTRATE FOR A MAGNETIC DISK

摘要

The present invention has an object to remove effectively metallic contaminants adhering to the glass substrate surfaces without increasing roughness of the glass substrate surfaces in the glass substrate for a magnetic disk. In a manufacturing method of a glass substrate for a magnetic disk having a cleaning step of the glass substrate, cleaning step having a treatment of contacting the glass substrate with a cleaning liquid containing oxalate and divalent iron ions and having a pH of not less than 2 and not more than 4. The divalent iron ions are added by adding ammonium iron (II) sulfate, iron (II) sulfate and iron oxalate (II) to oxalic acid.