Research On The Preparation Of Anti-rust Agent By Supplementary Method:molecular Simulations Technology And Application In Rust Protection

The powder metallurgy materials is a kind of composite with metal matrix and pores,and the presence of inherent pores makes corrosion easier compared with the corresponding dense castings.The corrosion of the powder metallurgy materials takes place not only on the surface of the materials but also in the interior of the metal matrix.Among many anti-corrosion methods,the method of using anti-rust corrosion inhibitor is very economic and effective,and composite corrosion inhibitor has become the important study direction of corrosion inhibitor.In this paper,we focus on the development of high efficiency rust inhibitor for powder metallurgy metal.The corrosion inhibitor is selected by scientific method,and orthogonal experiment is carried out to obtain the appropriate anti-rust agent formula.In addition,We also explore the polymer polyamide amine(PAMAM)and lignin sulfonate as the corrosion inhibitor promoter,and their effect on the oil/water interface.The interfacial density,interfacial thickness,order parameter,interfacial tension and radial distribution function(RDF)were calculated to study the morphological evolution and properties of corrosion inhibitor with polymer at oil/water interface by the coarse-grained simulations.The specific contents of this paper are as follows:(1)In this paper,the anti-rust grease are conducted in the experimental way.First,we discuss the effect of one-component anti-rust corrosion inhibitor on powder metallurgy materials.The results show the one-component barium sulfonate inhibitor present the best salt rust resistance among the picked corrsion inhibitors(barium sulfonate,barium soap of petroleum ester oxide,N-oleylsarcosine and isooctanoic acid/zinc/zirconium).Secondly,the anti-rust effect of the two-component corrosion inhibitor is discussed.The results show that trace amount of isooctanoic acid and barium sulfonate can improve the corrosion resistant remarkably.Finally,the optimum anti-rust agent formula is obtained by orthogonal experiment.The mass fraction was 10% barium sulfonate,3% barium soap of petroleum ester oxide,5% N-oleylsarcosine and 1% isooctanoic acid.The time of salt rust resistance is 72 h,which reach far beyond the standard of enterprise for powder metallurgy materials,and the protective mechanism and synergistic interaction is discussed by electrochemical method.(2)The influence of the addition of PAMAM on the interfacial properties of oil sulfonate is investigated by MARTIN coarse-grained dynamics simulations.It is found that petroleum sulfonate molecules and PAMAM form a kind of complex by electrostatic interaction,and they occupied at the oil/water interface together.With the increase of interfacial coverage of petroleum sulfonate,the interfacial thickness and ordering parameters of the system increase,the petroleum sulfonate molecular arrangement is more upright and the interfacial tension decreases.At the same time,we also found that the addition of PAMAM molecules can further increase the interface thickness and order parameters,and further reduce the system interface tension.The RDF peaks prove the presence of strong interaction btween PAMAM molecules and petroleum sulfonate molecules.(3)A CG method is adopted to build a CG model of the linear lignin polymer.Firstly the distributions of the structural parameters including the CG bond length and bond angle and dihedral angle were approximated,based on a sum of Gaussian functions and a Fourier progression function.Secondly,the optimization of the CG nonbonded numerical potentials are obtained using an iterative Boltzmann inversion,and the static and dynamic properties derived from the lignin CG model are compared with the lignin atomistic model.In addition,a comparison is conducted between the solubility parameters calculated from the lignin CG model with those reported in the literature.All the test results validate that the constructed CG force field of the linear lignin is effective.(4)The agglomeration behavior and interfacial properties of sodium lignosulfonate and sodium dodecylsulfonate at the oil/water interface are studied by coarse-grained simulations.Firstly,the coarse-grained model of sodium lignosulfonate and sodium dodecylsulfonate are established.The results of NPT kinetics simulations show that the sodium lignosulfonate drived by sodium dodecylsulfate shift from water phase to oil phase through hydrophobic interactions.In addition,the increase of concentration of sodium lignosulfonate and surfactant can cause the the interface thickness increasing,and the increased number of sodium lignosulfonate also affects the interface order.The number of polymers in the system increases,the molecules on the interface are more ordered,and the interfacial tension decreases.Sodium lignosulfonate and sodium dodecylsulfate have the synergistical effect on reducing surface tension.