Research On The Compositions And Network Structure Of Non-alkali Aluminoborosilicate Glasses

Non-alkali aluminoborosilicate glasses are an ideal substrate material for LCD and OLED because of their excellent physicochemical properties.Chinese glass substrate of display panel is subject to leading companies such as Corning and AGC,and there are no related products of independent intellectual property.We are lack of formula patents,process technologies,theory and practical experience.The industrialization of high-generation electronic glass is listed as a key research and development project in the national“Thirteen Five Plan”.In this work,composition and network structure of non-alkali aluminoborosilicate glass is the main task and content.Improve the basic theory of electronic glass substrates,and comply with the trend of domestic production of electronic glass substrates.In this paper,we study the SiO₂-Al₂O₃-B₂O₃-RO?R=Mg?Ca?Sr?system glasses.The influence of network structure,Vickers hardness,elastic modulus,chemical durability,density and molar volume by changing the composition.The volatilization of B2O3 during melting process is determined by chemical titration.The experimental results are as follow:?1?In the non-alkali aluminoborosilicate glasses,H₃BO₃ is used as raw material to introduce B₂O₃.Under the melting conditions formulated in this work,when the content of B₂O₃ is higher,the volatilization rate is also relatively higher.When the content of B₂O₃ is in the range of 0 to 12 mol%,the volatilization rate of B₂O₃ does not exceed 10%.By compensating 15%B₂O₃ to offset the volatile part of the melting process.When the actual amount of B₂O₃ introduced into the glass is 9 to 15 wt%,the volatilization rate is 7¹0%,and the actual amount introduced is around 5 wt%,and the volatilization rate is also about 5%.The actual content of B₂O₃ in glasses are very close to the nominal values.The deviation of B₂O₃ content does not exceed 0.5 wt%,and the percentage deviation does not exceed 10%.?2?Q⁴ and Q³ are the main structural units of[SiO₄].The other Qⁿ units is ignored because their resonance signals are not detected by MAS-NMR.The proportion of Q⁴ units decrease and Q³ units increase with increasing the concentration of alkaline-earth metal oxides or B₂O₃.When the total concentration of RO exceeds 18 mol%or B₂O₃ content exceeds 12mol%,the ratio of Q³/Q⁴ will exceed 1.Al³⁺ mainly participates in the network structure of glass with[AlO₄]unit,and[AlO₆] in Al₂O₃ crystalline is completely converted into other coordinated structure in the glass.The asymmetry of chemical environment of Al³⁺reduced with increasing free oxygen.[BO₃]occupy the major proportion of B³⁺in the non-alkali aluminoborosilicate glasses,so the main function of B₂O₃ is network modifiers.When increasing RO content or decreasing the content of SiO₂ and Al₂O₃,[BO₃] will convert to[BO₄]and participate in three-dimensional network structure.SiO₂ and Al₂O₃ are advantage to increase the tightness of glass network structure,while B₂O₃ and RO both reduce the tightness of the glass network structure.The increase of free oxygen make the conversion rate of units follow this order:[AlO₄]>Si-NBO>[BO₄].?3?When RO replaces Al₂O₃ between 13.5¹9.5 mol%,the hardness monotonously increases in the range of 647⁶61 kgf/mm²,and the elastic modulus monotonously increases between 78.62 and 81.43 GPa;When RO replaces SiO₂ within 10²0 mol%.The overall trend of hardness is similar,the values are also similar,but not monotonously increasing,the elastic modulus monotonically increases from 73.83 to 82.49 GPa;B₂O₃ replaces Al₂O₃,the hardness decreases monotonically from 705 kgf/mm² to 634 kgf/mm²,and the elastic modulus is from 91.2GPa decreases monotonically to 77.5 GPa.The increase of R²⁺increases the hardness and elastic modulus of the glass,and the depolymerization of the structure decreases the hardness and the elastic modulus.Overall,the contribution of R²⁺to hardness and elastic modulus plays a leading role in this compositional interval.?4?The depolymerization of network structure weakens the erosion resistance of glass in HF,and this is the main factor determining the erosion resistance of glass in HF.The SiO₂ content below 63 mol%will enhance the corrosion resistance of glass in HF to some extent.B₂O₃ improve the corrosion resistance of the glass in HF.But when the content of B₂O₃ is more than 8 mol%,the network structure is excessively depolymerized,and the corrosion resistance of the glass in HF is significantly decreased.?5?The corrosion resistance of glass in NaOH solution is mainly determined by the content of R²⁺(mainly Ca²⁺)and the tightness of the network structure,in which the alkaline earth metal cation dominates.The increase of R²⁺content leads to the enhancement of the anti-NaOH corrosion property of glass.When the R²⁺content is constant,the anti-NaOH corrosion property of the glass decreases gradually with the depolymerization of the network structure.?6?In the compositional region studied in this paper,the density changes monotonically within 2.41².63 g/cm³,and the molar volume shows a monotonous change with the opposite trend.The molar volume of glass is mainly determined by the concentration of O^2-with large ionic radius and network structure in glass.