Effect Of Nb₂O₅,B₂O₃ And Y₂O₃ On Structure And Properties Of Lead-free High Dielectric Fiber Glass

Titanium barium silicate lead-free glass fiber,which has high dielectric constant,low dielectric loss and environment-friendly,can be used as foil plate reinforced material with a high dielectric constant.It is helpful to realize the miniaturization of printed circuit boards.But fiber glass of this system easily devitrify in the continuous control forming process,which affect the normal production.Against its existing problems,in this work,the structure of titanium barium silicate system,glass devitrification behavior and mechanical properties were undertaken.It has important theoretical significance and application value.The samples of glass were prepared by melt quenching method.The effect of Nb₂O₅,B₂O₃ and Y₂O₃ on structure,devitrification behavior and mechanical properties was analysed by the magic Angle of nuclear magnetic resonance??NMR?NMR?,X-ray photoelectron spectrometer?XPS?,Raman spectroscopy?Raman?,Fourier infrared spectrometer?FTIR?,crystallization gradient furnace,X-ray diffractometer?XRD?,nano indentation and so on.The results of the study are as follows:?1?After the Nb₂O₅ addition,the quantity of bridge oxygen connection [SiO₄] tetrahedra increase.Introducing a small amount of Nb₂O₅,[NbO₆] octahedra formed.A model is suggested based on the glass network formed by Si-O-Nb bonds between [SiO₄] tetrahedra and [NbO₆] octahedra,it makes the relative content of asymmetric Bridging Oxygen increased,glass network connection degree of polymerization is higher.Density and molecular molar volume also gradually increase with the increment of Nb₂O₅,The range of density is 3.58 3.67 g/cm^-3.Elastic modulus first increase and then decrease,the upper devitrification temperature showe a trend of rise after the first reduce.When x is 4%,the elastic modulus is maximum,120 Gpa.Upper devitrification temperature reduced from 1200? to 1120?,its devitrification is caused by phase separation.?2?When the B₂O₃ instead of alkali metal oxide RO?R: Ca,Sr,Ba?,the content of Q⁴ and [BO₄] tetrahedra are gradually falling in titanium boron silicate system.Type of bridge oxygen is mainly symmetrical Bridging Oxygen?Si-O-Si?and asymmetric bridge oxygen?Si-O-Ti,and B-O-Ti?.When alkali metal oxide is substituted by B₂O₃,[BO₄] prior form,and it connects [SiO₄] to go into the network.When x is 1.5%,the elastic modulus reach the maximum,130 Gpa.The density is found to decrease from 3.58 to 3.28g/cm^-3;And the molar volume increase gradually.It is not obvious for B₂O₃ on the improvement of the devitrification,the temperature of minimum devitrification is only 1170?.With the addition of B₂O₃,it promotes the devitrification and the temperature reach to 1300?.XRD suggest that the devitrification behavior is caused by crystallization,crystallization phase is SiO₂ and CaSiO₂.?3?When MO₂?M:Ti,Zr?is substituted by Y₂O₃,the type of [SiO₄] distribution is mainly Q⁴,Q²,Q³ groups.With the increment of replacement,the content of Q³ groups increases gradually,But reduce,Q⁴ groups.It concludes that the content of overall Bridging Oxygen shows that increase after the first reduce from O1 s photoelectron spectroscopy analysis.the network of depolymerization of isolated island network units have to be polymerized,because Y³⁺ ion has potential big and the characteristics of high field strength.With the continuously increase content of Y₂O₃,its depolymerization of network is more than its polymerization of network,so the content of overall bridge oxygen gradually reduce.After Y₂O₃ addition,It significantly improves elastic modulus,which increases from 90 to 130 Gpa.Devitrification temperature is significantly reduced,which is reduced from 1200? to 1120?;Density and molar volume are also gradually increasing,the range of density is 3.58 3.70 g/cm^-3.