TECHNICAL FIELD

The present invention relates to a glass composition, in particular to a glass composition with high Young's modulus and specific modulus, suitable for hard disk substrate manufacturing and semiconductor sealing fields.

BACKGROUND

The reading speed of a hard disk is related to the rotation speed of the hard disk. The faster the rotation speed of hard disk is, the higher the reading speed will be. At present, a commercial hard disk generally rotates at a speed of 5200 RPM-10000 RPM. If the rotation speed needs to be further increased, the specific modulus of a hard disk substrate material must be increased, because if the specific modulus of the material used as the substrate is greater, the deformation of a hard disk substrate generated during high speed rotation will be less, and thus, the hard disk can achieve higher rotation speed. Since the specific modulus is the ratio of Young's modulus to density of a material (specific modulus=Young's modulus/density), higher Young's modulus and lower density are required for the material if the specific modulus needs to be increased. Currently, the specific modulus of the material used for the hard disk with rotation speed of 5200 RPM-10000 RPM is basically between 28 and 32. If the rotation speed of the hard disk needs to exceed 12000 RPM, or even 15000 RPM, the specific modulus of the glass material used needs to exceed 34 in order to meet the requirements.

The increase of the rotation speed of hard disk also causes the sharp increase in wear of a motor spindle, which requires thinner substrate for the high-speed hard disk to reduce weight, so as to reduce the wear of the motor spindle to prolong the service life of the hard disk. At present, the Young's modulus of a mainstream hard disk substrate is about 80 GPa, and the design thickness is about 0.65 mm. If the thickness of the hard disk substrate needs to be reduced to 0.4 mm or even less, the substrate material should have a Young's modulus of more than 100 GPa.

The storage density of the hard disk is now higher and higher, which requires sputtering magnetic materials onto the substrate material at higher temperature. Therefore, the substrate material of the hard disk is required to have higher heat resistance performance. It is generally believed that in order to meet the requirements of a new generation of hard disk technology in the future, the transition temperature (Tg temperature) of the glass material needs to be higher than 750° C. In addition, during the high temperature process of hard disk manufacturing, especially under the future process conditions with higher temperature, if the glass material contains alkali metal ions such as Na+, K+and Li+, these alkali metal ions are easy to precipitate contaminated magnetic materials during high temperature processing.

In the prior art, SiO2—Al2O3—RO (RO refers to alkaline-earth metal oxide) alkali-free glass system is generally applied. Although the glass system disclosed by CN1207086A can achieve a density of less than 3.00 and a specific modulus of about 36, the high-temperature viscosity of this system glass is very high, and the viscosity at a temperature of 1400° C. is generally 400 P-600 P. During the production process, temperature of up to 1550° C. to 1600° C. and long clarification process are required to eliminate bubbles, which means lower yield, shorter furnace life and higher power consumption. More importantly, in order to obtain a good degree of bubble, this kind of glass needs to use As2O3as clarifier, which is not allowed by the current environmental protection requirements. For the reading process with rotation speed up to 5200 RPM-15000 RPM, bubbles in the hard disk substrate will cause deviation from the center of gravity, resulting in fatal problems, so the hard disk substrate poses high requirements on the degree of bubble. In general, the degree of bubble in the glass blank needs to reach Grade A0 or above to meet the requirements. It is very difficult for the glass described in the above literature to reach Grade A0, in terms of the degree of bubble, in actual production.

SUMMARY

The technical problem to be solved by the present invention is to provide a glass composition with high Young's modulus and specific modulus.

To solve the technical problem, the technical solution of the present invention provides: a glass composition, comprising the following components by weight percentage: 30-46% of SiO2, 0-6% of B2O3, 10-30% of Al2O3, 4-20% of CaO, 2-15% of MgO, and 13-32% of Y2O3.

Further, also comprising the following components by weight percentage: 0-7% of TiO2, 0-5% of ZrO2, 0-5% of SrO, 0-5% of BaO, 0-5% of ZnO, 0-15% of La2O3, 0-2% of Sb2O3, 0-2% of CeO2, and 0-2% of SnO2.

A glass composition, comprising the following components by weight percentage: 30-46% of SiO2, 0-6% of B2O3, 10-30% of Al2O3, 4-20% of CaO, 2-15% of MgO, 13-32% of Y2O3, 0-7% of TiO2, 0-5% of ZrO2, 0-5% of SrO, 0-5% of BaO, 0-5% of ZnO, 0-15% of La2O3, 0-2% of Sb2O3, 0-2% of CeO2, and 0-2% of SnO2.

Further, the content of each component satisfies one or more of the following 8 conditions by weight percentage:

(1) (SiO2+Al2O3)/B2O3is 10-80;

(2) Al2O3/B2O3is 4-36;

(3) Al2O3/TiO2is 3-41;

(4) CaO+MgO is not more than 21%;

(5) CaO/MgO is 0.8-8.0;

(6) (CaO+MgO)/Y2O3is 0.2-1.0;

(7) (CaO+MgO+Y2O3)/SiO2is 0.5-1.5;

(8) La2O3/Y2O3is not greater than 0.8.

Further, comprising 32-42% of SiO2, and/or 0.5-6% of B2O3, and/or 15-28% of Al2O3, and/or 5-15% of CaO, and/or 3-10% of MgO, and/or 15-30% of Y2O3, and/or 0.5-7% of TiO2, and/or 0-3% of ZrO2, and/or 0-3% of SrO, and/or 0-3% of BaO, and/or 0-3% of ZnO, and/or 0-9% of La2O3, and/or 0-1% of Sb2O3, and/or 0-1% of CeO2, and/or 0-1% of SnO2.

Further, the content of each component satisfies one or more of the following 8 conditions by weight percentage:

(1) (SiO2+Al2O3)/B2O3is 15-70;

(2) Al2O3/B2O3is 6-30;

(3) Al2O3/TiO2is 6-30;

(4) CaO+MgO is not more than 19%;

(5) CaO/MgO is 0.9-5.0;

(6) (CaO+MgO)/Y2O3is 0.3-0.9;

(7) (CaO+MgO+Y2O3)/SiO2is 0.7-1.4;

(8) La2O3/Y2O3is not greater than 0.4.

Further, comprising 34-40% of SiO2, and/or 1-5% of B2O3, and/or 19-25% of Al2O3, and/or 6-10% of CaO, and/or 4-8% of MgO, and/or 18-26% of Y2O3, and/or 1-6% of TiO2, and/or 0-2% of ZrO2, and/or 0-2% of ZnO, and/or 0-5% of La2O3, and/or 0-0.5% of Sb2O3, and/or 0-0.5% of CeO2, and/or 0-0.5% of SnO2.

Further, the content of each component satisfies one or more of the following 8 conditions by weight percentage:

(1) (SiO2+Al2O3)/B2O3is 20-60;

(2) Al2O3/B2O3is 8-20;

(3) Al2O3/TiO2is 8-20;

(4) CaO+MgO is not more than 18%;

(5) CaO/MgO is 1-2.5;

(6) (CaO+MgO)/Y2O3is 0.4-0.8;

(7) (CaO+MgO+Y2O3)/SiO2is 0.8-1.3;

(8) La2O3/Y2O3is not greater than 0.15.

Further, the specific modulus of the glass is above 34, preferably above 35, further preferably above 36; the Young's modulus is 100-130 Gpa, preferably 105-125 GPa, further preferably 110-120 GPa.

Further, Tg temperature of the glass is above 740° C., preferably above 750° C., more preferably above 760° C.; the devitrification resistance performance is Class B or above, preferably Class A or above.

Further, the viscosity of the glass is not more than 150 P at 1400° C., preferably not more than 130 P, further preferably not more than 110 P; the degree of glass bubble is Grade A0 or above, preferably Grade A00 or above.

A hard disk substrate, formed by the above glass composition.

Application of the above glass composition for the semiconductor sealing.

The beneficial effects of the present invention are as follows: the present invention uses common chemical raw materials; by reasonably arranging the contents of each component, the glass provided by the present invention is good in heat resistance, chemical stability and press-molding devitrification resistance performance, low in high-temperature viscosity, convenient in bubble elimination, with specific modulus above 34 and Young's modulus above 100 GPa, and is suitable for hard disk substrate manufacturing, semiconductor sealing and other fields.

