Research On Structure And Properties Of High Strength And High Modulus Glass Fiber Doped With Rare Earth

High strength and high modulus glass fiber can be widely used in many fields such as aerospace,construction,transportation and medical equipment.At present,On the one hand the high strength and high modulus fiber cannot meet the higher demand of the strength and modulus in terms of performance,on the other hand there are some problems such as high melting and forming temperature,high surface tension.Therefore,to improve properties and optimize the process of high strength and high modulus glass fiber is one of the important directions of the development of glass fiber industry.Rare earth oxides can not only decrease the melting temperature and viscosity of high temperature,but also improve the mechanical properties of glass and so on.So we were based on the composition of SiO₂-Al₂O₃-CaO-MgO high strength and high modulus glass fiber to study the effects of the doping methods and content of La₂O₃and Y₂O₃ on the structure and some properties such as elastic modulus,chemical stability,dielectric performance,thermal expansion and liquidus temperature.And,the tensile strength and possibility of drawing-wire of the glass with higher elastic modulus were analyzed.The main results were as follows:?1?Doping La₂O₃ into the SiO₂-Al₂O₃-CaO-MgO glass caused to decreasing glass network connectivity.With the increasing of La2O3 from 0 to 1.00mol%,the thermal expansion coefficient of the glass decreased first and then increased?exception of that the La₂O₃ content was 0.20mol%?,the density,dielectric constant and dielectric loss increased,while,the chemical stability decreased.The liquidus temperature decreased to 1209.3?when the La₂O₃ content varied from 0 to0.60mol%,then increased.The elastic modulus increased to 93.63GPa,then decreased.When the La₂O₃ content was 0.60mol%,the glass had the lowest liquidus temperature and the highest modulus of elasticity,and the modulus of elasticity was3.07GPa higher than that of the basic glass.?2?Doping Y₂O₃ into the SiO₂-Al₂O₃-CaO-MgO glass caused to breaking glass network and decreasing glass network connectivity,the content of structure species Qn changed.With the increasing of Y2O3 from 0 to 1.00mol%,the liquidus temperature decreased to 1212.6?when the Y₂O₃ content varied from 0 to0.40mol%,then increased.And the Y2O3 content was 0.40mol%when the temperature was lowest.The elastic modulus increased to 94.99 GPa,then decreased.The Y₂O₃ content of the maximum elastic modulus was 0.80 mol%,and it was4.43GPa higher than that of the basic glass.The thermal expansion coefficient of the glass decreased first and then increased?exception of that the Y₂O₃ content was0.20mol%?,the density,dielectric constant and dielectric loss increased,but the chemical stability decreased.?3?Co-doping La₂O₃ and Y₂O₃ into the SiO₂-Al₂O₃-CaO-MgO glass caused to breaking glass network,however,the effect of co-doping with La₂O₃ and Y₂O₃ on the structure of SiO2-Al2O3-CaO-MgO glass was less than that of doping with La2O3 or Y₂O₃ solely.With the increasing of Y₂O₃ content from 0 to 1.00mol%,the density of glass decreased,the dielectric constant and dielectric loss increased.The chemical stability increased,then decreased.While,the liquidus temperature decreased,then increased.And the elastic modulus gradually increased.?4?The tensile strength and possibility of drawing-wire of the glass with higher elastic modulus was analyzed.And the results showed the glass had better drawing-wire properties.In addition,the glass fiber whose La₂O₃ content was0.60mol%had best drawing-wire properties,and the Y₂O₃ content of the glass fiber whose tensile strength was 0.37N/tex was 0.60mol%,that was the maximum value of tensile strength of these glass fibers,and it was 0.12N/tex higher than that of the basic glass.?5?Among the high strength and high modulus glass fibers doped with La₂O₃and Y₂O₃,the mechanical properties of the glass fiber doped with 0.60mol%Y₂O₃were the best,the tensile strength was 0.37N/tex,and the elastic modulus of glass was94.72GPa.