Study On Preparation And Properties Of Ni-P-Submicron Sn Composite Coating For Anti-Corrosion And Anti-Fouling Resistance

Ni-P coating with anti-fouling and corrosion-resistance is used in a wide range of applications,like thermal energy,petroleum,chemical and other fields.In this paper,the synergistic effect of low surface energy and high electron release capacity is proposed for the first time.Ni-P-submicron Sn composite coating is prepared based on using low surface energy of Ni-P coating and strong electron release ability possessed by metal Sn particles.The specific research work and the results obtained are as follows:The best technological parameters is NiSO₄·6H₂O 26g/L;NaH₂PO₂·H₂O 24g/L;OP-10100mg/L;Submicron Sn content 2g/L;C₆H₈O₇·H₂O 15 g /L;C₃H₆O₃ 3g/L;CH₃COONa 6g/L;PH 5.4;mechanical stirring speed 200r/min;temperature 90 ?.The content of Ni,P and Sn is 60.61%,8.04% and 9.88% respectively.The binding force of composite coating is about 30 N,which is smaller than that of Ni-P coating.The submicron Sn partiles are added to Ni-P coating and the hardness of the submicron composite coating is higher than that of the Ni-P coating after the same heat treatment.Through XRD analysis,it shows that the Ni-P-submicron Sn composite coating is amorphous structure,and after 500?heat treatment,the structure of the coating gradually changed to the crystalline structure.contained Sn,Ni₅P₄,Ni₂ P,Ni₃P,Ni₅P₂ and Ni₂ P.The friction and wear test of coating showes the friction coefficient of Ni-P-submicron Sn coating is 0.382,which is 16.04% lower than that of Ni-P coating,and the friction coefficient is better than that of Ni-P coating.When the Sn content is 6g/L,the wear resistance of the composite coating is best.That means not the more Sn content,the better the wear resistance of the coating.With the increase of heat treatment temperature,the composite coating is continuously crystallized,the hardness is improved,the ability to resist plastic deformation and friction is improved,and the wear resistance is increased.The corrosion resistance test of coating showes Ni-P-submicron Sn composite coating is respectively improved by 26.32% and 51.1%,compared with that of Q235.The electrochemicalcorrosion test shows that the corrosion resistance of the composite coating is more correct and the corrosion current is lower,compared with Ni-P coating.The AC impedance of the composite coating is larger,the capacitance is smaller,the porosity is lower,and the corrosion resistance is much better.When the content of submicron Sn is 2g/L,the corrosion resistance is the best.With the increase of particle content,the porosity of the coating also increases,but the corrosion resistance of composite coating is getting worse.when the best corrosion resistance is when heat treatment at 200 ?,the worst condition is at 400 ?.Heat treatment could change the coating structure,thus changing the corrosion resistance of the coating.The dirt addition of submicron Sn composite coating is significantly lower than that of Ni-P coating and Q235 matrix.Compared with Q235 matrix,the anti-fouling performance of submicron composite coating is improved by 55%,and the anti-fouling performance is improved 46%compared with that of Ni-P coating.The contact angle of the submicron composite coating is 120.2°,by the surface free energy calculated.It also shows the submicron composite coating has the minimum surface free energy of 15mJ/m²,and the calculation of the contact angle and the surface free energy is fully explained Sn particles that is added into Ni-P coating are beneficial to improve the anti-fouling properties of the coating.The effect of flow rate on the scale resistance of the coating is a combination of diffusion,deposition and denudation.When the flow rate is low,the diffusion plays a dominant role;when the flow rate is large,the denudation plays a dominant role.When the speed increases from 350r/min to 550r/min,the dirt significantly increases.But when the speed increases from550r/min to 750r/min,and the increase of dirt is slowed down.The higher the temperature,the lower the solubility of the sparingly soluble salt and the amount of fouling are increased well.With the increase of Sn content,the surface free energy of coating also increases.The dirt deposition gradually covers the whole surface with a cotton-like distribution,the amount of fouling is gradually increased,and the anti-fouling property decreases.when Sn content is 2g/L,the composite coating has the best anti-fouling performance.