Effect And Mechanism Of RO(R=Ca,Mg,Sr,Ba)on The Physical And Chemical Properties Of Electronic Substrate Glass

Electronic substrate glass is one of the most popular materials for LCD industry because of its good performance.Electronic substrate glass is mainly divided into alkali-containing glass and alkali-free glass.The alkali metal ions in the alkali-containing glass will seriously affect the display performance and life of the display and cause pollution to the production line.In contrast,alkali-free glass has become the mainstream formulation of current electronic substrate glass.In this paper,alkaline earth metal oxide(RO)was prepared by using high temperature melting method to study the physical and chemical properties of electronic substrate glass and the mixed alkaline earth effect.The physical and chemical properties and microstructure of glass were characterized by FTIR,NMR,and XPS methods.This paper studied the influence of RO on the physical and chemical properties of glass and analyzes its influence mechanism,and simulated the internal structure of glass.The conclusions of this paper were as follows:(1)The density of MgO and CaO glass samples increased,because the small radius of Mg2+and Ca2+filled the gap in the network structure made the structure more compact.The reason for the increase in the density of SrO glass samples in the early stage was that the relative atomic mass of Sr2+was higher than the average relative atomic mass.Then the network structure was broken and the density decreased.The density of BaO glass sample was first reduced and then increased.The reason was that the radius of Ba2+led to the decrease of the density due to the expansion of the network structure.After that,BaO provided free oxygen and[BO3]was gradually converted to[BO4],which made the network structure denser.(2)The hardness of glass tended to decrease due to the role of RO in breaking the net.The hardness of glass samples with the same amount of RO added decreases continuously in the order of MgO,CaO,SrO and BaO due to the radius.(3)Except for the fluctuation of the dielectric constant of the glass sample with MgO,the others all showed a trend of rising first and then falling.The reason was that the positive charge of the cationic nucleus will attract the electron cloud of O2-,making the outermost electron cloud of O2-deformed.Too much negative charge on O2-repelled the cationic electron cloud and deformed it.These two aspects made the dielectric constant of glass change.However,electrons with a smaller radius of Mg2+were closely linked to the nucleus.The electron cloud was not easily deformed and the polarization force of Mg2+w as small.It could not change the outermost electron cloud of O2-,resulting in a lower polarization rate.The constant change was not obvious.(4)HF acid and glass cannot form protective film to prevent the continuation of the reaction,which reduces the acid resistance.At the same time,the increase of R2+ promotes the reaction to accelerate erosion.The alkali resistance of the glass gradually increased with the increase of RO,and the increasing amount of RO in the component resulted in the production of more substances insoluble in alkali solution on the glass surface,resulting in R2+unable to move to the glass surface,preventing the glass from being further eroded.The water resistance of the glass showed a trend of increasing first and then decreasing,and the water resistance of the other three groups of samples with MgO added finally increased.The water resistance of the sample was improved due to the formation of silicic acid gel film by hydration reaction.After that,the bridge oxygen was continuously destroyed to form non-bridge oxygen and[BO3]was easily eroded by the electrophilic erosion of polar water molecules,resulting in the decrease of water resistance.Finally,the reason for the increased water resistance of the other three groups was that[BO3]was constantly converted to[BO4],which was gradually weakened by the electron-friendly erosion of polar water molecules.(5)the hardness,dielectric constant and thermal expansion coefficient of the glass sample replaced by CaO by MgO all changed nonlinear and obtained a minimum value near k=0.5.The mismatch of vacancy will change the properties of vacancy and lead to the decrease of hardness.The blocking effect in the glass network structure results in the decrease of its dielectric constant.Replacing CaO with MgO will reduce the asymmetry of the[AlO4]unit,and the weak interaction between magnesium ions and the network will reduce the thermal expansion.