Claims
- 1. A process for producing a glass substrate for a magnetic disk for a magnetoresistive head comprising:(a) providing a chemical reinforcement tank comprising a chemical reinforcement liquid contained therein, and a holding means for holding a glass substrate; and (b) chemically strengthening said glass substrate by immersing said glass substrate in said chemical reinforcement liquid, wherein ions are exchanged on the surface of said glass substrate with ions in said chemical reinforcement liquid having a diameter larger than that in said glass substrate; wherein at least one of a wall surface of said chemical reinforcement tank and said holding means is made from a stainless alloy which exhibits corrosion resistance in a high temperature region of said chemical reinforcement liquid to prevent adherence of metallic dust on the surface of the substrate and to prevent a generation of thermal asperity, said stainless alloy being made from a martensitic stainless alloy or an austenitic stainless alloy.
- 2. The process according to claim 1, wherein said process further comprises a step of forming at least a recording layer on said substrate.
- 3. The process according to claim 2, wherein said recording layer is a magnetic layer.
- 4. The process according to claim 1, wherein the wall surface of said chemical reinforcement tank is made from said stainless alloy.
- 5. The process according to claim 1, wherein the holding means is made from said stainless alloy.
- 6. The process according to claim 1, wherein both the wall surface of said chemical reinforcement tank and the holding means is made from said stainless alloy.
- 7. The process according to claim 1, wherein the stainless alloy is a martensitic stainless steel.
- 8. The process according to claim 1, wherein the stainless alloy is an austenitic stainless alloy.
- 9. The process according to claim 1, wherein the glass substrate is selected from the group consisting of aluminosilicate glass, soda-lime glass, soda aluminosilicate glass, aluminoborosilicate glass, borosilicate glass, quartz glass, chain silicate glass and glass ceramics.
- 10. The process according to claim 1, wherein the glass substrate is an aluminosilicate glass comprising 62 to 75 weight % SiO2, 5 to 15 weight % Al2O3, 4 to 10 weight % Li2O, 4 to 12 weight % Na2O and 5.5 to 15 weight % ZrO2, wherein the weight ratio of Na2O to ZrO2 is 0.5 to 2.0 and the weight ratio of Al2O3 to ZrO2 is 0.4 to 2.5.
- 11. The process according to claim 1, wherein the glass substrate has a composition of 57 to 74 mole % SiO2, 0 to 2.8 mole % ZrO2, 3 to 15 mole % Al2O3, 7 to 16 mole % Li2O and 4 to 14 mole % Na2O.
- 12. The process according to claim 1, wherein the chemical reinforcement liquid comprises potassium nitrate and sodium nitrate.
- 13. The process according to claim 1, wherein the chemically strengthening is carried out at a temperature of 350 to 450° C.
Priority Claims (4)
Number |
Date |
Country |
Kind |
8-357543 |
Dec 1996 |
JP |
|
8-357544 |
Dec 1996 |
JP |
|
8-357545 |
Dec 1996 |
JP |
|
9-41513 |
Feb 1997 |
JP |
|
REFERENCE TO RELATED APPLICATION
This is a Division of application Ser. No. 08/999,479 filed Dec. 29, 1997 now U.S. Pat. No. 6,119,483.
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