| As an important hydraulic machinery,circulating pump is widely used in hydropower,thermal power,mineral processing,petrochemical,papermaking and sewage treatment industries.For a long time,impeller,volute and other flow passage parts are subject to wear,cavitation or corrosion of fluid containing solid particles,resulting in a large number of fish scale pits or honeycomb cracks on their surface,causing vibration and unstable operation of the pump,reducing pump efficiency,increasing energy consumption and even scrapping.In order to prolong the service life of the pump,the non-metallic anticorrosive and erosion resistant composite coating can be used to remanufacture and repair the pump,which can effectively reduce the abrasion damage of the pump.At present,the commercial epoxy based composite coating materials have been used to repair the worn over-current parts,but there are few similar researches in China.Therefore,the preparation and properties of epoxy/ceramic anti erosion composite coating were studied in this paper.The influence of modified isoflurone diamine(IPDA)and 1618 curing agent on the bonding strength of epoxy(EP)coating was studied.The effect of CTBN and Si O2 on the adhesive strength and erosion resistance of EP coating was investigated.On the basis of this,the effects of surface treatment,content,particle size and fiber composite on the erosion resistance of EP coating were further investigated.The main research contents and results are as follows.(1)The modified IPDA was prepared by ppgdge,and then the epoxy composite coating was prepared by using the appropriate amount of modified IPDA and 1618 curing agent.FTIR analysis showed that the epoxy group on ppgdge had completely reacted with IPDA.The amine value of modified IPDA showed that the amine value tended to be stable when the reaction time was 2.5-3.5 h.The mechanical properties test shows that the modified IPDA cured epoxy composite coating has higher shear strength,positive tensile bond strength and impact strength than that of the unmodified IPDA.The positive tensile bonding strength of the composite coating was improved after the proper addition of modified IPDA in the 1618 curing agent.Considering the water absorption of the coating,the modified ipda:1618 curing agent=1:3 was used as the proportion of curing agent.(2)The effects of CTBN and nano Si O2 on the positive tensile strength and erosion resistance of epoxy composite coating were investigated by using the curing agent in(1).By FTIR analysis,the carboxyl group in CTBN has completely reacted with epoxy group.The results of the test of adhesive and erosion resistance show that the bond strength of epoxy composite coating increases 33.2%and the erosion rate decreases 22.6%when the content of CTBN is 13 phr compared with pure EP.The mechanical properties test shows that when Si O2,KH-550 and KH-560(Si O2-g-KH560)are added to the epoxy composite coating,the adhesive strength of the epoxy composite coating is the highest,which is 6.26 MPa,compared with the epoxy composite coating prepared by adding the unmodified nano Si O2,The bonding strength of the adhesive was increased by 15.3%;On this basis,the influence of Si O2-g-KH560 content on the bonding strength of epoxy coating was further investigated.With the increase of content,the bonding strength showed a trend of rising first and then decreasing.When the content of nano Si O2-g-KH560 was 2 phr,the maximum bonding strength was 8.24 MPa.Finally,the epoxy coating modified by 13 phr CTBN and 2 phr nano Si O2-g-KH560 was investigated.Compared with the addition of CTBN and nano Si O2-g-KH560,the epoxy composite coating has higher bonding strength,reaching 9.33 MPa and erosion wear reduced to 0.51 g.(3)Based on(1)and(2),the surface modification of Si C particles was carried out by using silane coupling agent KH560.The surface treatment,content,particle size of Si C and the influence of the composite with K2Ti8O17 on the erosion resistance and wear resistance of epoxy composite coating were investigated.FTIR analysis showed that the oil-friendly siloxane structure and epoxy group were introduced after the surface modification of Si C.The results of erosion resistance test show that with the increase of the amount of Si C modified,the erosion weight loss of Si O2-g-KH560/CTBN/EP composite coating decreases first and then increases.When the content of Si C is 170 phr,the erosion weight loss reaches the minimum,which is 0.41g.On this basis,the influence of adding different Si C particle size and K2Ti8O17 fiber on the composite coating was further discussed.When only fiber was added,the erosion resistance and wear resistance of epoxy composite coating increased,while the composite epoxy resin modified by Si C and K2Ti8O17 fiber was added at the same time,the erosion resistance and wear resistance was the best,and the erosion loss was 0.11 g.Therefore,the best ratio of the epoxy/ceramic anti erosion composite coating is:100 phr60 mesh Si C+5 phr K2Ti8O17+2 phr nano Si O2+170 phr grading Modified Si C+13 phr CTBN+100 phr EP. |
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