Abstract: A method of adjusting the pH of a strengthening melt to provide an adjusted melt for use in microetching glass substrates, such as glass disk substrates for use in data storage devices. A base is added to the strengthening melt to raise its pH. A desired degree of microetch is provided on an aluminosilicate glass disk substrate, for example, by immersion for 2-4 hours at 360° C. in a melt adjusted to have a pH of 10. This single operation both strengthens and microetches the glass substrate. A slight etching of the surface of a glass substrate, i.e., microetching, improves the performance and durability of a data storage disk made from the substrate. To avoid an overly aggressive etch that can create undesirable damage to the substrate surface, an acid may be added to the melt if the pH is subsequently determined to have shifted to above an upper limit.

Abstract: A method of adjusting the pH of a strengthening melt to provide an adjusted melt for use in microetching glass substrates, such as glass disk substrates for use in data storage devices. A base is added to the strengthening melt to raise its pH. A desired degree of microetch is provided on an aluminosilicate glass disk substrate, for example, by immersion for 2-4 hours at 360° C. in a melt adjusted to have a pH of 10. This single operation both strengthens and microetches the glass substrate. A slight etching of the surface of a glass substrate, i.e., microetching, improves the performance and durability of a data storage disk made from the substrate. To avoid an overly aggressive etch that can create undesirable damage to the substrate surface, an acid may be added to the melt if the pH is subsequently determined to have shifted to above an upper limit.

Abstract: A method of adjusting the pH of a strengthening melt for use in strengthening glass substrates, e.g., glass disk substrates for use in data storage devices. A non-particle-forming acid is added to the strengthening melt to lower the pH of the strengthening melt to ≦8. The acid is added while the strengthening melt is in a molten state and selected to avoid particle formation. Nitric acid, for example, is non-particle-forming with respect to nitrate based strengthening melts such as potassium nitrate and/or sodium nitrate. A base, e.g., sodium hydroxide, may be added if the pH of the strengthening melt falls below 5. Strengthening melts are subject to pH shift that can cause glass substrates strengthened therein to etch, creating pits on the substrate surface. Glass disk substrates treated in the pH adjusted strengthening melt are essentially free from such pits, as well as contamination caused by particle formation.

Abstract: A method of adjusting the pH of a strengthening melt for use in strengthening glass substrates, e.g., glass disk substrates for use in data storage devices. A non-particle-forming acid is added to the strengthening melt to lower the pH of the strengthening melt to ≦8. The acid is added while the strengthening melt is in a molten state and selected to avoid particle formation. Nitric acid, for example, is non-particle-forming with respect to nitrate based strengthening melts such as potassium nitrate and/or sodium nitrate. A base, e.g., sodium hydroxide, may be added if the pH of the strengthening melt falls below 5. Strengthening melts are subject to pH shift that can cause glass substrates strengthened therein to etch, creating pits on the substrate surface. Glass disk substrates treated in the pH adjusted strengthening melt are essentially free from such pits, as well as contamination caused by particle formation.