Patent attributes
A magnetic disk glass substrate manufacturing method includes a step of polishing a surface of a glass substrate to a mirror surface, a gas heating process step of causing a heated atmosphere and the glass substrate to contact each other so as to heat the glass substrate at a temperature T0, a step of causing a chemically strengthening salt melted exceeding a freezing temperature TF and the glass substrate to contact each other so as to chemically strengthen the glass substrate at a temperature T1, a gas cooling process step of causing a gas coolant and the glass substrate to contact each other so as to cool the glass substrate to a temperature T2, and a liquid cooling process step of causing a liquid coolant and the glass substrate to contact each other so as to cool the glass substrate to a temperature T3, the above-mentioned steps being included in this order, wherein the temperature T2 is set to a temperature less than the freezing temperature TF of the chemical strengthening salt in a gas cooling process.
