Glass spacer, hard disk drive apparatus, and method for manufacturing glass spacer
A glass material of a glass spacer has a surface resistivity of 10 3 to 10 9 (Ω/sq) at 22 (° C.). The surface resistivity of a surface of the glass material of the glass spacer at 22 (° C.) is lower than the surface resistivity of an inner portion of the glass material at 22 (° C.). The glass spacer contains at least one oxide selected from the group consisting of TiO 2 , Nb 2 O 5 , WO 3 , and Bi 2 O 3 , as a glass component.
1. A ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus,
wherein a glass material of the glass spacer has a surface resistivity of 10 3 to 10 9 (Ω/sq) at 22 (° C.), and
a surface resistivity of a surface of the glass material of the glass spacer at 22 (° C.) is lower than a surface resistivity of an inner portion of the glass material at 22 (° C.).
2. The glass spacer according to claim 1 ,
wherein grooves that extend along an outer circumference of the glass spacer are formed in an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk.
3. The glass spacer according to claim 1 ,
wherein a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.
4. The glass spacer according to claim 2 ,
wherein a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.
5. A ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus,
wherein a glass material of the glass spacer has a surface resistivity of 10 3 to 10 9 (Ω/sq) at 22 (° C.), and
a surface roughness Rz of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is at least 1.5 μm.
6. The glass spacer according to claim 5 ,
wherein the glass spacer contains at least one oxide selected from the group consisting of TiO 2 , Nb 2 O 5 , WO 3 , and Bi 2 O 3 , as a glass component.
7. The glass spacer according to claim 6 ,
wherein a surface roughness Ra of a main surface of the glass spacer that comes into contact with the magnetic disk is not larger than 1.0 μm.
8. The glass spacer according to claim 5 ,
wherein the surface roughness Rz of the outer circumferential edge surface is not larger than 20 μm.
9. A hard disk drive apparatus comprising
the glass spacer according to claim 5 and the magnetic disk.
10. The hard disk drive apparatus according to claim 9 ,
wherein the magnetic disk includes a glass substrate and a magnetic film that is formed on the glass substrate.
11. The glass spacer according to claim 5 ,
wherein a surface resistivity of a surface of the glass material of the glass spacer at 22 (° C.) is lower than a surface resistivity of an inner portion of the glass material at 22 (° C.).
12. The glass spacer according to claim 5 ,
wherein grooves that extend along an outer circumference of the glass spacer are formed in an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk.
13. The glass spacer according to claim 11 ,
wherein grooves that extend along an outer circumference of the glass spacer are formed in an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk.
14. The glass spacer according to claim 5 ,
wherein a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.
15. The glass spacer according to claim 11 ,
wherein a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.
16. The glass spacer according to claim 12 ,
wherein a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.
17. The glass spacer according to claim 13 ,
wherein a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.
18. A ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus,
wherein a glass material of the glass spacer has a surface resistivity of 10 3 to 10 9 (Ω/sq) at 22 (° C.), and
grooves that extend along an outer circumference of the glass spacer are formed in an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk.
19. The glass spacer according to claim 18 ,
wherein a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.
20. A ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus,
wherein a glass material of the glass spacer has a surface resistivity of 10 3 to 10 9 (Ω/sq) at 22 (° C.), and
a skewness of an outer circumferential edge surface of the glass spacer that does not come into contact with the magnetic disk is not larger than 1.2.