PROCESS FOR PRODUCING GLASS SUBSTRATE FOR HDD, GLASS SUBSTRATE FOR HDD, AND MAGNETIC RECORDING MEDIUM FOR HDD

摘要

Provided is a process for producing a glass substrate for HDDs which inhibits head crushing even when used in a magnetic recording medium for HDDs that is to be mounted in an HDD equipped with a DFH head mechanism. Also provided are a glass substrate for HDDs and a magnetic recording medium for HDDs. The process for producing a glass substrate for HDDs includes a chemical strengthening step in which a glass substrate is chemically strengthened by immersing the glass substrate in a liquid for chemical strengthening. In the chemical strengthening step, the increase in the circumferential-direction TIR of the glass substrate through the chemical strengthening step is regulated to 0.5 µm or less by changing the attitude of the glass substrate within the chemical strengthening liquid in which the glass substrate is being immersed, and/or by flatting the temperature distribution of the chemical strengthening liquid, and/or by stirring the chemical strengthening liquid.