Sheet Copper And Zinc Alloy Powder Surface Coating Modification Research

In order to improve application performances of flaky pinchbeck alloy(bronze powder),such as dispersibility and corrosion resistance, silicon dioxide or polyacrylate/bronze composite particles with core-shell structure were prepared by Sol-Gel method or polymerization of acrylate on the surface of flaky bronze.Based on the determination of high concentration copper spectrophotometrically,percentage of grafting(PG), and grafting efficiency(GE) in the preparation were systematically studied.In addition,the properties of resulting composite particles were evaluated.1.The measuring method and application of high concentration copper in the bronze powder.High concentration copper was determined spectrophotometrically in a medium of HAc-NaAc where Cu(Ⅱ) can form a blue 1:1 coordination compound with EDTA,which can shelter the disturbance of Zinc,Aluminum.The maximum absorption wavelength was at 730nm,ε=88.9.The Beer's law was obeyed when the concentration of copper in the range of 12-24mg/50 mL.The linear regression equation was A =0.0354+0.02317C(mg/50mL),with a linear correlation coefficient of 0.9995.This method provided the definition of PG and GE which was of direction to the evaluation of the particles next.2.Preparation and characterization of SiO₂/Bronze composite particle by Sol-Gel method.Sols were prepared with Ti(OC₄H₉)₄ as precursor, NH₄OH as catalyst and C₃H₇OH as solvent.The reaction time, temperature,the addition of TEOS(as the m(SiO₂)/m(bronze powder) calculated),the proportion of distilled water to TEOS,the kinds and concentration of the catalyst were studied in order to get the better condition,and the bronze powder coated was characterized by FTIR,TG,XRD,SEM and Grading analysis.It was found that the lustrousness of the composite particles was 81.8 under the appropriate conditions,PG and GE were 11.37%,75.48%.79.01%of raw material was eroded in 3%HNO₃ for 1h but 61.75%of the bronze powder coated where Si-O-Si,Si-OH existed.The unformed film SiO₂ made the rate of weight increment from 0.00904mg/s to 0.00632mg/s at 470℃. 3.Preparation and characterization of PMMA/Bronze composite particle by in situ polymerization.In order to improve its anticorrosion property at the least decrease of luster,bronze powder pigment was encapsulated with the copolymer of MMA in situ copolymerization.In the case, m(MMA)/m(bronze powder),the reaction temperature,the reaction time, the dosage of initiator(m(AIBN)/m(bronze powder)),dispersing stabilizationagent(m(PVP)/m(bronzepowder)),and3-Methacryloxypropyl trimethotysilan(m(MPS)/m(bronze powder)) were studied.It was found that the best conditions were as follows:the temperature was 75℃～80℃the dosage of AIBN(m(AIBN)/m(bronze powder)) 1%,the dosage of PVP(m(PVP)/m(bronze powder)) was 5%,the dosage of MPS (m(MPS)/m(bronze powder)) was 9%,MMA and AIBN were dropped into reactor simultaneously,where the encapsulated samples had good luster and anticorrosion property.The lustrousness of the encapsulated samples was 80.1,PG and GE were 9.55%,47.75%.37.00%of raw material was eroded in 2%HNO₃ for 0.5h but 28.94%of the bronze powder coated.Furthermore,the encapsulated samples were analyzed and characterized by FTIR,XRD,SEM,which indicated that it was coated by a hydrocarbon polymer containing methyl,carbonyl,and contained amorphous multipolymer films.4.Preparation and characterization of TMPTMA-St-AA/Bronze composite particle by ternary copolymerization.In order to improve the surface chemical reaction characteristic,bronze powder coated with a polymer membrane was investigated through terpolymerization,which used acrylic acid,styrene and trimethylol propane trimethacrylate as monomers,2,2'-Azo-bis-isobutyronitrile as initiator and butanol as the dispersion medium with the protection of nitrogen.The effect of the condition of copolymerization reaction was also considered,such as the reaction time,the reaction temperature,the amount of the monomer, initiator and others.The corrosion inhibition efficiency,the lustrousness, the coating efficiency were carried out to evaluate the effect.The composite particles were analyzed and characterized by Fourier transform infrared(FTIR),SEM etc.The results showed that the feasible reaction condition were as follows:the weight ratio of the AA and St monomer were 0.4%and 0.9%respectively,the TMPTMA was 10.6%and the initiator was 1%,temperature was 80℃,reaction time was 4h and the material-feed way was constant pressure average rate dropping the St and TMPTMA into the reactor.In this way,the sample had the best corrosion inhibition efficiency,the lustrousness was 82.0,PG and GE were 10.49%, 88.15%.65.49%of raw material was eroded in 2%HNO₃ for 1h but 49.37%of the bronze powder coated where a hydrocarbon polymer containing benzene ring,carbonyl.The percentage of liveweight growth of the composite particles was from 19.17%to 14.74%。...