Application of noble cerium-based anti-corrosion sealing coating approach applied on electrical insulators installed in industrial regions

Abstract

Pin corrosion is a critical issue that causes premature rupture of high-voltage insulators. The development of efficient, defect-free, thermal resistive, hard, economical and environment-friendly sealing coating system is required to replace the current polymer-based highly toxic coatings for insulators. This study investigates the suitability of noble cerium (Ce)-based sealing coating film for use as an anti-corrosion coating for insulator pins installed in low-pH and highly corrosive sites. The coating bath parameters are optimized for the formation of a high-performance Ce-based protective sealing coating. After immersion in a 60 000 ppm CeCl 3 .7H 2 O sealing coating bath for 60 min, a Ce-rich and dense protective coating (24 µm) is formed on the pin surface. The life expectancy of the coated pin is 2.5 times higher than that of the non-coated galvanized pins. Electrochemical experiments and microstructural analysis demonstrate that Ce-based protective layers are suitable for long-term protection of high-voltage insulator pins in low-pH and high-corrosion-rate sites. We believe that this work would pave the way of developing ecofriendly anti-corrosion coatings for electric insulators and power industries.

Fabrication of Hierarchical Patterned Surfaces Using a Functionalized CeO2-EPDM Composite for Crevice Corrosion Prevention on High-Voltage Insulators

“…For the preparation of cerium sol precursors, 10 g of ceric ammonium nitrate, Ce­(NH 4 ) 2 NO 3 , were dissolved in 10 mL of ethanol, 5 mL of acetic acid, 1 mL of stearic acid, and 5 mL of DI. The obtained sols were initially dark due to the reduction reaction of Ce 4+ to Ce 3+ due to the presence of ethanol . The prepared sols were agitated for 1 h under 60 °C.…”

“…The obtained sols were initially dark due to the reduction reaction of Ce 4+ to Ce 3+ due to the presence of ethanol. 24 The prepared sols were agitated for 1 h under 60 °C. An EPDM-based lubricating oil was prepared by mixing the dispersant (0.10 mL), transparent paraffin oil (100 mL), toluene (4 mL), and L-EPDM (8 mL) blends and agitating at 2000 rpm for 1 h. The Ce-based obtained composite was sprayed (3–5 times) on insulator samples (T1) and dried at room temperature for 3 h. Finally, the EPDM lubricating oil was coated/sprayed on insulator specimens (T2) by a brush/spray and dried for 1 h at 50 °C.…”

“…Electrochemical impedance spectroscopy was determined by altering the frequency range between 10 –2 and 10 5 Hz, and the open circuit potential was kept at equilibrium. 24 The corrosion media was prepared by adding 24.12 g NaCl, 4.01 g Na 2 SO 4 , 5.02 g MgCl 2 , 1.20 g CaCl 2 , 0.7 g KCl, 0.20 g NaHCO 3 , 0.10 g KBr, 0.03 g H 3 BO 3 , 0.3 g SrCl 2 , and 0.02 g NaF in 1 L of deionized water.…”

“…In addition, electrochemical workstation tests were conducted by measuring Tafel curves by sweeping the potential from −0.6 to 0.6 V versus the open circuit potential at a rate of 1 mV/s. Electrochemical impedance spectroscopy was determined by altering the frequency range between 10 –2 and 10 5 Hz, and the open circuit potential was kept at equilibrium . The corrosion media was prepared by adding 24.12 g NaCl, 4.01 g Na 2 SO 4 , 5.02 g MgCl 2 , 1.20 g CaCl 2 , 0.7 g KCl, 0.20 g NaHCO 3 , 0.10 g KBr, 0.03 g H 3 BO 3 , 0.3 g SrCl 2 , and 0.02 g NaF in 1 L of deionized water.…”

Sealing effect on corrosion resistance of boric sulfuric acid anodizing on AA2024

“…However, the corrosion resistance of the anodized layer can be further enhanced by applying a sealing treatment to the anodized surface [11]. The sealing effect on corrosion resistance refers to the process of closing the pores and voids in the anodized layer by using various sealing agents such as hot water, nickel acetate, sodium dichromate, and others [12]. This process enhances the barrier properties of the anodized layer and protects the underlying metal from corrosive environments.…”