Study On Effect Of Basalt Fiber Component On Elastic Modulus

Basalt fiber is widely used in civil engineering,transportation and other fields because of its composite material has the advantages of light weight,high mechanical strength and corrosion resistance.In recent years,with the increasing cost-effectiveness requirements of high-modulus fibers in industries such as wind power,pipelines,and bridge construction,basalt fiber,as a high-tech fiber,is expected to promote the development of these fields.At present,there are few researches on basalt fiber with high modulus at home and abroad.In this paper,the relationship between composition and elastic modulus,structure and basalt glass network energy,as well as the relationship between composition and spinnability in complex basalt are introduced.Research had been carried out on the structure,elastic modulus and spinnability of the glass/fiber after melting the three natural basalt rocks of neutral,basic and ultra-basic.The results show that the oxides Al₂O₃,Ti O₂,Mg O,Fe₂O₃ have coordination order in the short and medium range structure of basalt glass,which are four oxides that can improve the elastic modulus of basalt fibers.This is proved in the calculations of the Makshima-Mackenzie model.Subsequently,the neutral basalt was singly doped by a series of four types of oxides.Through the study of elastic properties,crystallization,viscosity,spinnability and fiber strength,the following conclusions are drawn:（1）The density and elastic modulus of the basalt fiber can be improved by adding Al₂O₃,Ti O₂,Mg O and Fe₂O₃ into the neutral basalt.When the mass fraction of Al₂O₃ is 25.13%,the elastic modulus of basalt fiber is 8.4%higher than that of unmodified fiber.The reason for the rapid increase of elastic modulus is the formation of more and stronger Al-O bonds and the dissociation of the glass network per unit volume reaches 76.85k J/cm³.When the mass fraction of Mg O is about 16%,the elastic modulus increases by 8.1%.The significant increase of elastic modulus is due to the fact that more atoms can be filled in the glass structure per unit volume to form more Ionic bond（M-O）,and the atomic packing density reaches 57.19%.The modified Makshima-Mackenzie model in this paper can better predict the measured elastic modulus of basalt fiber,and the decision coefficient R² is 0.87.The results show that the elastic modulus of the basalt fiber comes from the energy of the glass network,which depends on the radius of the metal cation,the atomic mass,the field strength and the ability of bonding with oxygen.（2）When the mass fraction of neutral basalt is 16.83%Fe₂O₃ or 13.67%Mg O,the viscosity curve appears an inflection point.The viscosity change indicates that the primary crystal（Mg,Fe）₂O₃ in the high temperature melt increase the viscosity sharply at low temperature.When the Mg O mass fraction is 15.96%,the suitable temperature range for fiber drawing rapidly shrinks to 32.6.When the mass fraction of Fe₂O₃ is 20.48%,spinnable temperature window decreases from 142℃to 12.5℃,and the fiber cannot be prepared successfully.The addition of Al₂O₃ makes the viscosity of glass melt increase slightly,and the spinnable temperature window decreases slightly.When the mass fraction of Al₂O₃ is 25.01%,the tensile strength of the fiber reaches 3159 MPa,and the elastic modulus rapidly increases to86.8 GPa.However,the temperature of the drawing is 20℃higher than that of the neutral basalt.