Erosion Wear Performance Of Epoxy Powder Coatings

Epoxy powder is a kind of thermosetting powder that has good corrosion-erosion resistance,and widely used as coating material in the sphere of resistance to erosion and corrosion,on the protection fence of highways coating and anticorrosive pipeline with external polyethylene and internal epoxy coating,it's a common coating material.In the process of using the protection fence of highways,the coating is often eroded by sand blown by the wind,but anticorrosive pipeline with external polyethylene and internal epoxy coating is often eroded by fluid flow and sand it carries.In this paper,it adopts electrostatic spraying and high pressure airless spray to prepare the two different coating,uses electron microscope,nano indentation apparatus and so on to study on the microstructure,mechanical properties of the two samples;And utilizes gas erosion test and slurry/water jet erosion test to research the erosion wear characteristic of two samples,and the wear mechanism of erosion wear on the coating surface was analyzed.The protection fence of highways epoxy powder coating was prepared by electrostatic spraying.Anticorrosive pipeline with external polyethylene and internal epoxy coating was prepared by high pressure airless spray.The phase structure,microstructure and physical-mechanical properties of two samples were studied.Results show that the coating of anticorrosive pipeline with external polyethylene and internal epoxy coating with the minimum thickness of 664.64 microns,coating internal bonds a lot of solid particles ranges from 5 microns to 40 microns,besides the coating within many blowhole defects in diameter between 10 microns and 30 microns.The main components of the solid particles in the coating are CaSiO3 and contain a small amount of Al2O3,the content of organic material(epoxy resin)in the coating of the anticorrosive pipeline is 53%,and the content of inorganic substance(solid particles)is 47%.The epoxy powder coating of the protection fence of highways with minimum thickness of 105.33 microns,the inherent solid particles in the coating are mostly square or circular particles,grain size less than or equal to 5 microns,the main components of the particle is Al2O3.The content of organics(epoxy resin)in the epoxy powder coating of the protection fence of highways is 57%,and the content of inorganic substance(solid particles)is 43%.Point at the condition that the protection fence of highways eroded by wind carrying sand all the year round.Using gas erosion test,study the erosion wear characteristics of the epoxy powder coating on the high pressure airless spray,and the mechanism of erosion wear is revealed.The results show that during the erosion process,the wear extent of epoxy powder on the protection fence of highways is maximum when the erosion Angle is 45 °,that was 11.8 g/mm2 at the erosion time was 20 min.In 30° and 90° Angle of erosion in smaller,respectively at the erosion of time 20 min was 7.9 g/mm2 and 8.9 g/mm2.The erosion process can be divided into two stages according to the erosion time.Erosion in the early time,the erosion with 30 0 makes the cutting effects higher than other two,the erosion extent of coating increased with the extension of time and presented plasticity.With the growth of erosion time,Erosion characteristics transits from plastic to semi-plastic material,then erosion of 45 °gradually became the maximum angle for erosion wear.The reason is that during the erosion process,the exposure of solid particles Al2O3 in the coating reduces the plasticity of the erosion contact area,and at the same time reduces the micro-cutting action of the erosion particles to the material.The erosion abrasion behavior of the coating surface is the result of the joint action of normal and tangential components.The normal component mainly causes the extrusion of epoxy resin and the crushing behavior of the solid filling particles,and the cutting behavior of epoxy resin is produced by tangential component.In view of the situation that the anticorrosive pipeline with external polyethylene and internal epoxy coating always eroded by liquid flow or liquid flow with sand,using slurry/water jet erosion test,to study the erosion wear properties of the coating on anticorrosive pipe,and reveal erosion wear mechanism.The results show that under the erosion by slurry with 1%of river sand the coating present semi plastic,the maximum angle of erosion was 60 °.It is 6.4 g/mm2 at 5 minutes.At this angle the epoxy resin was removed by cutting in the coating is the most serious.In erosion Angle of 30° and 90 °,erosion during 5 min is 5.9 g/mm2 and 6.1 g/mm2 respectively.The erosion abrasion characteristic of the slurry is similar to gas erosion of the protection fence of highways epoxy powder coating.The reason for the erosion Angle is relatively high is that,the content of inorganic substances in anticorrosion pipe internal coating is 47%,more than 43%of epoxy powder coating on the protection fence of highways,and the size of solid grain of internal coating is larger,material is more brittleness.In the case of only water jet erosion,the internal coating of anticorrosive pipe presented as plastic material,with the maximum erosion wear Angle of 30 °.The energy of pure droplet can cause the elastic deformation of epoxy resin on the coating surface,but the energy is not enough to destroy the solid filling phase particles.The micro-cutting of epoxy resin material is mainly occurred atthe low Angle erosion,and the crushing and peeling of solid filling phase is mainly happened to high Angle erosion.