Electrochemical Detection On Surface Of Remanufacturing Parts And Electroless NiP Composite Plating Repairing

As the important component of circular economy, remanufacturing technology isenvironmental and economical, has attracted a lot of attention in recent years.Engineering machinery remanufacturing technology includs three major parts,cleaning, testing and repairing. Testing and repairing technology in china are in theirinitial stage, further researchs are badly needed. Firstly through the electrochemicalexperiments, influence of the surface defect on electrochemical test results can befound. A new kind of defect detection method is invented, and through practicalapplication, it is proved to be reliable. Then through the chemical plating, theinfluences of different nanoparticles concentration on the performance ofNi-P-nanoparticle composite coating are founded, which will be theoretical basis forNi-P-nanoparticle composite plating used on manufacturing parts. The main researchresults are as follows:Through EIS tests, EN tests and electron microscopic observations, connectedwith the EIS and EN test principle, the influences of surface defect on test results arefounded and the reasons are analyzed. The results show that compared to intactsample, impedance radius of sample with defect is smaller, impedance die value islower, there were waves with big amplitude and obvious peaks in the time domainspectrum diagram of EN, PSD slope k in frequency domain spectrum of EN is closerto-20db.dec-1, which is the characteristics of local corrosion. The three kinds of testresults are anastomotic, prove that electrochemical characterization on surface crack isfeasible.Electrochemical method is used to detect the defects on surface ofremanufacturing parts of mechanical engineering, together with the three dimensionalmicroscope observation and ultrasonic phased array experiment to evaluate the effectof the electrochemical method. The results show that the electrochemical method ondetecting surface defects is accurate and can be used for practical application.Ni-P-chemical composite plating is used to find the influence regularity ofdifferent nanoparticle concentration such as CNTs (0g/L,0.5g/L,1.0g/L,1.5g/L)and nanometer TiO2(0g/L,1g/L, and2g/L,3g/L) respectively on the properties ofthe composite coating， including corrosion resistance, wear resistance, surfacehardness. The results showe that compared with Ni-P coating, corrosion resistance ofcomposite coating is better, but it become worse with the increase of the CNTs concentration, it achieve the best value when the CNTs concentration is0.5g/L. Itbecome better with the increasing of nanometer TiO2concentration; Compared toNi-P coating, wear resistance and surface hardness value of Ni-P-CNTs coating arebetter, and they become much better with the increasing of the CNTs concentration;Wear resistance and surface hardness value of Ni-P-nanometer TiO2plating are worse,and they become much better with the increasing of the nanometer TiO2concentration.