Research On Manufacturing Process And Microstructure Characteristics Of Electric Porcelain

Porcelain insulators play an important role in supporting and insulating the power transmission system.With the continuous increase of voltage levels in the domestic power grid system,the demand for high-performance,high-voltage grade porcelain insulators is increasing.Microstructure is the decisive factor influencing the main properties of electric porcelain materials.The manufacturing process determines the microstructure characteristics of electric porcelain materials.In this paper,starting from the electric porcelain manufacturing process,we focused on the research of the use of waste electric porcelain for the manufacture of electric porcelain,the influence of the microstructural factors on the destruction of electric porcelain,and the development and bonding of inorganic bonding glazes on the microstructure of electric porcelain.The following conclusions were obtained:(1)With the addition of high-alumina porcelain powder directly to the aluminum porcelain formula,the content of the corundum phase in the aluminum porcelain can be increased by appropriate addition and the strength of the porcelain was improved to a certain extent.When the addition amount was 10% by weight,the strength of the prepared porcelain was increased by 6%,reaching 155.58 MPa.The high-aluminum porcelain powder was added to the aluminum porcelain formula to replace the bauxite and a small amount of feldspar and the the corundum phase wasreducedin the aluminum porcelain.The high-alumina porcelain powder can promote the growth and development of secondary mullite in porcelain to a certain extent and improve the mechanical strength of the porcelain.When 12% of high-alumina porcelain powder was used to replace 10% of bauxite and 2%,the strength of the prepared porcelain was increased by 10% to reach 162.36 MPa.(2)The microstructure analysis was applied to control the production process of porcelain insulators.Through the analysis of the microstructure of the damaged porcelain,the decline of mechanical properties and failure mechanism were clarified.The microstructure of the porcelain was optimized through process control.Secondary mullite was well developed and interlocked.At the same time,a small amount of cristobalite phase appeared in the sample.Thus,the performance of the porcelain insulator has improved.An inorganic bonding glaze was prepared by mixing a frit made of a base glaze with a synthetic spinel pigment and a zinc oxide and a zirconium oxide acting as a nucleating agent.The expansion coefficient of the inorganic bonding glaze was similar to the high strength porcelain used for bonding and the high temperature fluidity was good.Prolonging the holding time of high temperature was beneficial to the discharge of the pores in the bonding glaze,and the strength of the bonding porcelain sample was improved to a certain extent.The adhesive surface of the V-joint porcelainspecimen was corroded with hydrochloric acid and hydrofluoric acid solution.Its strength was higher than that of non corrosion samples.After the corrosion,the contact area between the porcelain and the glaze has increased,and the bonding effect was better.The strength of the adhesive sample reached 62.5% of the strength of the original porcelain specimen.The inorganic bonding glaze was used for the bonding of large-sized hollow porcelain insulators.The test items of porcelain bushing were all qualified and the bonding performance was good.