摘要 |
PCT No. PCT/FR95/01296 Sec. 371 Date Aug. 19, 1996 Sec. 102(e) Date Aug. 19, 1996 PCT Filed Oct. 5, 1995 PCT Pub. No. WO96/11888 PCT Pub. Date Apr. 25, 1996The invention relates to glass substrates intended for use as a support in data storage units, reinforced by surface ion exchanges and whose matrix comprises the constituents given hereinafter in the following weight proportions: - SiO2 45-65% - Al2O3 0-20% - B2O3 0-5% - Na2O 4-12% - K2O 3.5-12% - MgO 0-8% - CaO 0-13% - ZrO2 0-20% - the sum of the oxides SiO2, Al2O3 and ZrO2 remaining equal to or below 70%, said composition optionally incorporating the oxides BaO and/or SrO in proportions 11%</=MgO+CaO+BaO+SrO</=24% and the alkaline oxides are introduced in the following weight percentages 0.22%</=Na2O/Na2O+K2O</=0.60. |