| Environmental and energy problems have been plaguing the healthy development of China ’s industrial economy.The development of environmentally friendly metal surface treatment technology can not only solve the energy waste caused by corrosion of steel,but also meet the emission requirements of the environmental protection department for the rust removal industry.Through the development and research of environmentally friendly rust remover,the problems of over-corrosion,easy return to rust,easy to produce acid mist and environmental pollution caused by the common rust removal process based on inorganic strong acid can be solved.Therefore,this project aims to develop an environmentally friendly rust removal with both rust removal and film formation functions.In this paper,the optimum process components of environmentally friendly rust remover were optimized by orthogonal test and single factor test.The optimum component content was : organic phosphonic acid(HEDP)80g / L,sodium gluconate 30 g / L,sodium citrate 10 g / L,polyethylene glycol 7g / L,anionic surfactant 0.03 mol / L,ester dispersant 0.04 mol / L,organic chelating agent0.03 mol / L,using Na OH to adjust the p H value of the system,the p H value is 6.5 ～ 7.It can be used for rust removal treatment of Q235 in conventional corrosion rust state,which can quickly remove rust and has certain corrosion resistance.The microstructure characterization and electrochemical test of the samples treated with environmentally friendly rust remover were carried out.It was found by SEM that a film layer with fine cracks was formed on the surface of the sample.EDS analysis showed that the film layer contained phosphorus.Combined with XPS and FT-IR analysis,P element formed a chelating film on the surface of the substrate through Fe-O-P and Fe-O-C as the main binding forms.The main components of the chelating film were [ HEDP-Na ] and [ HEDP-Na-Fe ].The corrosion current density of the sample after electrochemical test is much smaller than that of the conventional rust remover,and the ability to inhibit charge transfer is also stronger than that of the conventional rust remover.It has better corrosion resistance and practical effect than the ordinary inorganic acid rust removal process.The performance of the chelating film was tested.The copper sulfate drip time of the sample treated with neutral organic acid rust remover was 50 s,the outdoor placement time was 14 d,and the local corrosion began to occur after 24 h of neutral corrosion resistance test.The results show that the chelating film has good corrosion resistance.After the painting test of the sample,it is found that the adhesion of the film reaches grade 0,and the pencil hardness test is also carried out,and the hardness reaches 4H;it shows that the film adhesion of the sample under this process is very good,and the film is not easy to fall off,and the film is smooth without bulge.By exploring various factors to determine the indicators of the working fluid,the neutral rust remover prepared by this process is a colorless and transparent solution,no precipitation,good suspension,the working fluid can be diluted by 1 ～ 4 times,the effective date is about 90 d,it can be stable at 5 °C ～ 50 °C,the amount of rust removal is about 10 g / L,the rust removal object is all kinds of parts based on Q235 steel,which is suitable for conventional corrosion rust Q235 steel and its parts. |
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