Influence Of Rare Earth Oxides On Dielectric And High Temperature Properties Of Aluminoborosilicate Glass

As the skeleton supporting material of copper clad plate,low dielectric glass fiber can be used in the fields of aerospace,supercomputers,communication equipment and other electronic components.Moreover,the appearance of 5G communication indicates that communication will develop towards the direction of high frequency and high speed,which also puts forward requirements for the performance of copper clad plate,which needs to have lower dielectric constant and dielectric loss.The most direct method is to optimize the dielectric properties of low dielectric glass fiber.Therefore,it is necessary to study new low dielectric glass fiber.In this example,the doping of single rare earth oxides and the co-doping of two rare earth oxides in aluminoborosilicate glass were studied.The structure of glass samples mixed with rare earth oxides was characterized by FTIR spectrum and density analysis and the properties of dielectric and thermal of glass samples were tested,so as to the relationship between glass properties and structural changes can be understand.And then,the influence of glass composition changes on its structure and properties can be studied.Thermal expansion test and high temperature viscosity test were carried out on the glass samples with better dielectric properties to determine the expansion coefficient as well as the relationship between viscosity and temperature of each glass sample,so as to determine the characteristic temperature for the reference of glass production process.（1）Firstly,the network structure and the properties of dielectric and thermal stability of aluminoborosilicate glass doped with Pr₂O₃,Gd₂O₃ and Yb₂O₃ were studied.Due to its own properties,rare earth oxides doping can introduce free oxygen to promote the formation of[AlO₄]and[BO₄],and rare earth oxide have high ion field strength to play a role in network polymerization,but at the same time it will deform[SiO₄]in the glass and weaken it and be easy to fracture.The details are as follows:comparing the effects of three rare earth oxides（Pr₂O₃,Gd₂O₃ and Yb₂O₃）on the dielectric properties of aluminum borosilicate glass,it can be seen that the dielectric properties of aluminoborosilicate glass doped with Yb₂O₃ glass are better than other samples doped with Pr₂O₃ and Gd₂O₃ at the test frequency is 1MHz.The optimal dielectric constant is 4.52（Yb₂O₃=1.5mol%）and the dielectric loss is 3.18×10^-3（Yb₂O₃=1.0mol%）.The measured density and calculated density of aluminoborosilicate glasses increased with the addition of three kinds of rare earth oxides.Moreover,when the content of rare earth oxides is within a certain range,the thermal stability of glass can be optimized.When the content of Pr₂O₃ and Yb₂O₃ is 1mol%and Gd₂O₃ is 1.5mol%,the thermal stability of glass samples is better.（2）In the second part of the paper,the effects of co-doped La₂O₃ with Gd₂O₃ and Yb₂O₃on the structure,thermal properties and dielectric properties of aluminum borosilicate glass were studied.In the experiment,the total content of rare earth oxides was maintained at1.5mol%,and La₂O₃ was replaced by Gd₂O₃ and Yb₂O₃ in equal amounts respectively.With the increase of substitutions,the permittivity of the two groups was optimized.However,the dielectric loss is increased,and the dielectric loss of the glass sample co-doped with rare earth oxides is bigger than that of the glass sample doped with single rare earth oxides.The better dielectric constant obtained when the ratio of La₂O₃ to Gd₂O₃ was 1:3,which was 4.55.The better dielectric loss obtained when contain 1.5 mol%Gd₂O₃ only.The better dielectric constant obtained when the ratio of La₂O₃ to Yb₂O₃ was 1:1,which was 4.5.The better dielectric loss obtained when contain 1.5 mol%Yb₂O₃ only.（3）The properties of viscosity and thermal expansion of aluminoborosilicate glass doped with rare earth oxides（La₂O₃、Pr₂O₃、Gd₂O₃ and Yb₂O₃）ware investigated by the rotating crucible viscometer and dilatometry.The VFT equation and arrhenius equation were used to analyze the data of viscosity and temperature.The results show that,introduction of rare earth oxides decreases the coefficient of thermal expansion and viscosity of aluminoborosilicate glass.The reduction of glass forming temperature and rapid hardening are beneficial to the drawing and forming of glass fiber.The glass molding temperature of aluminoborosilicate without rare earth oxide is 1357.40℃,the glass molding temperature of the sample added lanthanum oxide（La₂O₃）dropped to 1304.78℃,the temperature range of glass harden（△T₂）changed from469.31℃to 424.85℃.La₂O₃ has the most obvious effect on reducing the viscosity of glass.Drawing temperature range（△T₁）become shorter but△T₁>50℃,which can satisfy the wire drawing requirements.