Study On Corrosion And Wear Characteristics Of Coating For Involute Internal Gear Pump

The hydraulic system is widely used in construction machinery,energy industry,metallurgical industry and building materials industry due to its stable operation,fast response,compact structure and stepless speed regulation.Power components provide power for the hydraulic system and are an important part of it.Involute internal gear pumps are widely used due to their simple structure and allow higher speeds.In the seawater development industry,due to direct contact and long-term exposure to the seawater environment,the meshing gear teeth are subject to the interaction of corrosion and wear at the same time,which leads to the reduction of the service life of the involute internal meshing gear pump.Therefore,the gear pump protective coating The preparation of the layer is of great significance.Metal alloy coating is the most common form of coating.It can effectively protect the interior of the substrate from damage and has a good application prospect.Traditional alloys are mainly based on one element as the main element,which limits the alloy’s good performance in terms of mechanical properties.As a new type of alloy,high-entropy alloy is formed by mixing five or more elements in equal proportions.The high-entropy effect of high-entropy alloys makes them show good properties in terms of mechanical properties.In this paper,laser cladding technology was used to prepare Fe Co Ni Ti Alx(x=0,0.5,1.0)and Fe Co Ni Ti Al Mox(x=0,0.5,1.0)two high-entropy alloy coating systems,and their microstructure and mechanical properties were analyzed.At the same time,the Solidworks three-dimensional modeling software is used to model the key components of the involute internal gear pump,and the ANSYS WORKBENCH software is used to simulate the statics of its shell and the transient dynamics of the internal gear.First,an electronic balance was used to weigh the corresponding alloy powder,and use a ball mill for ball milling to make it evenly mixed.Then use laser cladding equipment for coating cladding.Finally,the micro-morphology and mechanical properties of the coating are analyzed,mainly including SEM,EDS,XRD,micro-hardness analysis,electrochemical polarization curve analysis,dry friction and wear,corrosion friction and wear,wear morphology analysis,and wear scar profile curve analysis.Studies have shown that in the Fe Co Ni Ti Alx system,the addition of Al promotes the transformation of FCC phase to BCC phase,the dendritic structure in the microstructure of the coating is obvious,the structure is refined,and the hardness of the coating is increased up to 623 HV.Under dry friction conditions,the friction coefficient of the coating decreases with the increase of Al content.The sliding friction coefficient of Al1 coating is the smallest.The wear volume also decreases with the increase of Al content,which is consistent with the trend of friction coefficient.In the corrosion and wear experiment,the corrosion current density of the coating increased due to the addition of Al,so that the wear volume of the coating increased first and then decreased with the increase of Al content.In order to improve the corrosion resistance of the coating under the premise of ensuring the wear resistance of the coating,Mo element was selected to improve the performance of the coating.In the Fe Co Ni Ti Al Mox system,the coating is mainly composed of BCC and FCC phases.As the Mo element increases from 0 to 1,the lattice distortion of the coating increases,and the Mo-rich phase(σ phase)gradually precipitates.The addition of Mo element refines the grains and increases the microhardness of the coating.With the addition of Mo element,the corrosion current density gradually decreases,the corrosion wear volume decreases,and the corrosion resistance of the Fe Co Ni Ti Al Mo coating reaches the best.The wear volume of Fe Co Ni Ti Al Mo coating under different applied potentials was analyzed.When the applied potential is lower than the self-corrosion potential of the coating itself,the coating is only affected by friction,and the corrosion current density is negative.With the increase of the applied potential,the corrosion current density increases to more than0,and the corrosion effect is obvious.At the same time,the corrosion of the coating surface further aggravates the friction,resulting in an increase in the volume of corrosion wear.The simulation analysis shows that at the moment of meshing,stress concentration occurs at the tooth tip and tooth surface of the internal gear close to the center of rotation,while the stress and deformation of the tooth part of the external gear are significantly reduced.Through simulation comparison,it can be found that the stress concentration and deformation of the Fe Co Ni Ti Al Mo coating are significantly reduced compared to the substrate,so the coating can effectively protect the gear substrate.