Study On The Preparation Of Enamel Coatings With Different ZrO₂ Additions And Corrosion And Tribological Properties Resistance Of Its

As an inorganic nonmetallic material,enamel coating has excellent properties such as high temperature resistance,impact resistance,corrosion resistance,oxidation resistance,friction resistance and damage resistance.In addition,the enamel coating has the advantages of simple preparation process,low energy consumption and low cost,so it has high application value in the field of industrial pipeline anticorrosion.Although enamel coating has good acid corrosion resistance,its poor alkaline resistance limits its large-scale application in the field of industrial pipeline corrosion resistance.In order to solve the enamel coating serious alkali corrosion problems,the enamel paste was prepared by wet ball milling,and the enamel coating with different ZrO₂added amount was prepared by one-dip enameling technique.The mechanism of action of ZrO₂on the bonding property,acid and alkali corrosion resistance and friction and wear property of enamel coatings was studied.This work is of great significance for the preparation of enamel coatings with alkali resistance and the expansion of the application of enamel coatings.Specific research contents are as follows:The phase composition,microstructure and bonding properties of the enamel coatings with 0%,2%,4%,6%and 8 wt.%ZrO₂additions were studied.The results show that the coating without adding ZrO₂is mainly amorphous phase and residual quartz phase.However,the coating with ZrO₂contains partially unmelted ZrO₂phase.The evenly dispersed ZrO₂particles in the coating increased the nucleation site of pores,and promoted more gas to gather around ZrO₂particles and exhaust,which weakened the growth of pores,as a result,the pore size and porosity in the coating decreased with the increase of ZrO₂addition.The bonding properties of coatings are mainly related to the interface roughness and the oxide layer on the substrate surface.At the initial stage of sintering,the oxide layer on the surface of substrate was melted,resulting in increased fluidity.At the late stage of sintering metal oxides react with Ni O and Co O,the Fe-Ni/Co alloy precipitation in coating the lateral growth,expansion,dendrite formation,to ensure the coating and substrate mechanical combination,and add the ZrO₂coating can reduce the size and porosity,reduce its brittleness fracture toughness increase,thus coating combined with performance under mechanical shock followed ZrO₂content increases.Corrosion behavior of enamel coatings with different ZrO₂additions in acid and alkali solution was studied.The results show that Si O₂and Na₂Si O₃phases agglomerate on the surface of the coating without adding ZrO₂after immersion in 10wt.%Na OH solution,and there are obvious signs of crack propagation.However,Na₂Zr Si O₅films are formed after long-term corrosion of the ZrO₂coating,which hinders the further diffusion of the corrosive medium.However,when immersed in 30vol.%H₂SO₄solution for corrosion,the surface silicon oxygen network hydrolyzes to form Si O₂gel layer,and the gel layer loses water to form cracks and corrosion pits.During long-term corrosion,cracks propagate longitudinally and laterally,and the depth of crack propagation is consistent with the thickness of gel layer.Corrosion electrochemical data show that ZrO₂addition amount of 6%coating corrosion in acid and alkali solution after 120 d impedance values are still higher than 10¹¹?·cm²,compared with other ZrO2 coating,the coating has better acid and alkali corrosion resistance.Shows that when adding ZrO₂,coating density can be improved,and the coating effect enhancement of acid and alkali corrosive medium.However,the formation of cracks and pore corrosion channels on the surface of coatings leads to the diffusion of corrosive media,which reduces the impedance and dielectric properties of coatings.The effects of ZrO₂addition on the porosity,microhardness and friction and wear properties of the coatings were investigated.Results show that adding ZrO₂can improve the pore nucleation sites,promote more gas discharge by ZrO₂particles melt,melt,and ZrO₂can combine with Si-O-broken bond to form Si-O-Zr bond.In addition,the porosity of the coating decreases with gas nucleation and migration to the melt surface,the hardness of the coating increases with the increase of the density.When the addition amount of ZrO₂was 8%,the porosity and stomatal density decreased by 44.97%and 7.72%,respectively.The coating serious brittle fracture of ZrO₂addition amount of 0%and 2%during the process of friction,this is due to poor coating toughness and large size pores of crack nucleation extension resistance caused by a small,with ZrO₂content continues to increase,the coating hardness and toughness was further improved and leads to friction coating surface produce solid transfer membrane softening occurs,and stable friction coefficient,the brittle fracture gradually transforms to the adhesive wear.