Study On Preparetion Of Magnetic Abrasives On Acidity Electroless Composite Plating

With the development of modern industry,More and more high accuracy parts ha ve been applied to Aerospace,Defense and military,Precision instruments and other fi elds.Magnetic abrasive finishing(MAF)has many outstanding features,such as superio r processing flexibility,processing quality and efficiency,which is one of the importan t method to machining complex surface and cavity.Magnetic abrasive is the core fact or in magnetic abrasive finishing,Currently,the magnetic abrasive which prepared by bonding,sintering,mechanical pressure process has the disadvantages of low abrasive concentration,misdistribution,short working life,those disadvantages restrict dramatical ly magnetic abrasive finishing commercial application.Electroless composite plating is a technology to plate partcles on workpiece surfac e by adding water-insoluble partcles,which is important method to obtain high abrasiv e pantal density,well distributed,long working life magnetic abrasive.this paper aims to the problem of preparetion of magnetic abrasives on acidity electroless composite plating,establishing and optimizing the Ni-P chemical plating system,the concrete res earch context and results on preparation technology of Electroless composite plating as follow:(1)According to the theory of electroless plating,Analyzing the effect of plating solution each component,confirm nickel sulfate as main salt,sodium hypophosphite a s reducing agent,citric acid,malic acid,succinic acid,glycine,lactic acid as complexin g agent,thiourea as stabilizer,sodium acetate as buffer.and formulating corresponding technological process.(2)Target to deposition rate and solution pH stability,optimize the chemical plati ng nickle formula by using orthogonal experiment,single factor experiment and contra st experiment,obtaining optimal formulation:32g/L nickel sulfate,32g/L sodium hypop hosphite,6g/L citric acid,19/L succinic acid,9g/L glycine,26g/L lactic acid,1mg/L thioure a,15g/L sodium acetate,and at the condition of pH=5.4,temperature of 85±2?.(3)Building test bench,target to SiC content in composite coating,using contrast experiment to study key process factors on the influence of particle phase distribution uniformity.Obtaining optimal formulation: 12g/L SiC concentration,1mg/L thiourea,1000 mesh number SiC,14 min consolidation time,300r/min magnetic stirring speed.