glass composition

Abstract

The present invention provides a glass composition having a Young's modulus of 80 GPa or more and a density of 3.10 g / cm<3> or less. The glass composition contains SiO2, B2O3, Al2O3, CaO, and MgO, andthe glass has a Young's modulus of 80 GPa or more and a density of 3.10 g / cm<3> or less. Common chemical raw materials are adopted and the content of each component is reasonably designed so that obtained glass has a high Young's modulus, low density, good heat resistance, good chemical stability and relatively low high-temperature viscosity, and is suitable for hard disk manufacturing and for other fields requiring materials having high Young's moduli.

Description

technical field [0001] The invention relates to a glass composition, in particular to a glass composition with high Young's modulus and low density which can be used as a hard disk base material. Background technique [0002] In recent years, with the rapid development of industries such as big data cloud storage, higher requirements have been placed on the reading speed of hard disks. The most effective way to increase the reading speed of hard disks is to increase the rotational speed of hard disks. At present, the speed of the hard disk on the market is usually 5200rpm-7200rpm. To further increase the transmission speed of the hard disk, the speed of the hard disk needs to reach more than 10000rpm and keep it unchanged for a long time. The deformation of the disc under high-speed rotation is a fatal flaw for the hard disk, which requires the material for making the disc to have a very high specific spring rate. The specific elastic rate refers to the ratio between the Yo...

AI Technical Summary

Problems solved by technology

However, this type of glass has a very high viscosity at high temperature, and it is very difficult to remove air bubbles

In addition, this type of glass requires a melting temperature of about 1600 ° C, which is easy to generate inclusions inside the glass and lead to scrapping, and it is also necessary to add As 2 o 3 As a clarifying agent, glass with relatively good air bubbles can be obtained

This brings two problems. On the one hand, the furnace body working at 1600°C requires a special design, and the overhaul interval is more than 50% shorter than that at 1500°C, which brings more energy consumption and waste emissions. ; on the other hand As 2 o 3 According to the existing environmental protection regulations, it is forbidden to add to the glass, which does not meet the environmental protection requirements.

[0006] CN102432171A describes a SiO 2 -Al 2 o 3 -RO-R 2 0 system glass, where RO refers to alkaline earth metal oxides, R 2 O refers to alkali metal oxides, which contain more than 10 mol% of alkali metals, especially more than 5 mol% of Li 2 O, although a large amount of alkali metal oxides will reduce the high temperature viscosity and make the air bubbles better removed, but the heat resistance of the glass will drop rapidly, especially when using more Li 2 When O, the Tg temperature of the glass will drop rapidly, which will reduce the heat resistance of the glass substrate and cannot withstand higher temperatures in the disk manufacturing process.

At the same time, with the increase of the alkali metal content, the water and acid resistance of the glass will be greatly deteriorated, and its surface quality will be easily reduced during the cleaning process of the processing process.

More importantly, when the glass containing alkali metal is subjected to high temperature treatment in the disk manufacturing process, the alkali metal component is easy to precipitate, which brings fatal defects

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