Change Of Structure Of Micro-crystalline Muscovite In The Course Of High Temperatures & Its Impact On Dielectric Properties

Micro-crystal muscovite in west Sichuan is a new kind of muscovite resource , it also has some property such as uitrafine crystallization, pure mine, high-whiteness, low-cost, etc, beside a series of excellent property such as heat-durability, alkali-resistant , insulation, High-intensity, etc. So it is superior to the traditional muscovite resources. Its lattice is very stable, for muscovite mine has special type of layer crystal structure, it is one of most important species of the insulating material, which is widely used in electrical industry. Studying the change of structure of dielectric property of Micro-crystal muscovite calcined at different temperatures not only provides theoretical basis and advise to taking full advantage of excellent electrical insulation properties of micro-crystalline muscovite to Expand its application field and applications to expand of micro-crystalline muscovite in the field of insulating materials, but also it is important meaning to alleviating the status of the depletion of Muscovite resources and expanding applications of Muscovite electrical insulating material.This paper analyses the change of structure of micro-crystalline muscovite in the course of high temperatures by XRD,FTIR and DSC-TG, and dielectric properties of micro-crystalline muscovite and micro-crystalline muscovite calcined such as dielectric constant, dielectric loss, volume resistivity, ect, relationships between the dielectric properties and the frequencies. Determine the temperature of the micro-crystalline muscovite calcined whose dielectric properties optimal, in a particular frequency, which micro-crystalline muscovite calcined is the most suitable electrical insulating materials; Analyze the reasons and mechanism of change of dielectric property of micro-crystal muscovite. The Paper obtains the following main results:(1)Position of atomic in the structure of micro-crystal muscovite calcined at 400～700℃is not great change for removaling of a small amount of hydroxyl; Change of position of atomic in the structure of micro-crystal muscovite calcined at 800～900℃is greater for removaling of a large number of hydroxyl;more than 1000℃,the structure of micro-crystal muscovite destroys.(2)Dielectric constant and dielectric loss of micro-crystal muscovite drop with Increase of frequency, When the frequency is 1kHz, dielectric constant is 9.60,dielectric loss is 0.2042;When the frequency is 80kHz, dielectric constant is7.00 ,dielectric loss is 0.0810;When the frequency is 1000kHz, dielectric constant is 6.37 ,dielectric loss is 0.0579.(3)Dielectric constant of micro-crystal muscovite calcined is higher than micro-crystal muscovite's and it increases with increase of temperature. dielectric constant of micro-crystal muscovite calcined at 400～700℃increases slightly, it is 11.57～12.43,the Range of increase is greatest, dielectric constant is 18.86～18.88. Dielectric constant of micro-crystal muscovite calcined at 800℃is greatest ,it is 18.88, dielectric constant of micro-crystal muscovite is lowest ,it is 9.60; dielectric constant of micro-crystal muscovite calcined drop with Increase of frequency,The rate of drop is faster than micro-crystal muscovite.(4)Dielectric loss of micro-crystal muscovite calcined is higher than micro-crystal muscovite's and it increases with increase of temperature .dielectric loss of micro-crystal muscovite calcined at 400～700℃increases slightly, it is 0.3100～0.4159,the Range of increase is greatest, dielectric loss is 1.0302～1.0761. Dielectric loss of micro-crystal muscovite calcined at 900℃is greatest ,it is 1.0761, dielectric loss of micro-crystal muscovite is lowest ,it is 0.2042; dielectric loss of micro-crystal muscovite calcined drop with Increase of frequency ,The rate of drop is faster than micro-crystal muscovite.(5)Volume resistivity of micro-crystal muscovite calcined is lower than micro-crystal muscovite's, and it increases with increase of temperature, it is 0.223×1012～0.868×1012?·cm.Choice of dielectric materials depend on dielectric properties, studying dielectric properties provides scientific basis to development and application of new kind micro-crystal muscovite insulating material.