The Research On Performance And Preparation Of Metallic Matrix EP/PU FGM Wear-Resistant Coating

This paper gave a brief overview on the present development, the design theories and the preparation method of Functionally Graded Materials(FGM).The classifications,the preparation methods, the characterization techniques and the applications of polymer FGM were introduced. In order to find a foundamental formula meeting the requirements of epoxy/polyurethane (EP/PU) FGM system, EP, PU and some ordinarily used solidified agents of the tow resins were selected to mix to cure by using orthogonal method. Triethanolamine and MOCA were tested to be the suitable solidified agents respectively for EP and PU by the experiments. The curing mechanisms, the curing kinetics and the thermal cracking process of this mixed coating were investigated in depth. The optimum formula was achieved: PU: MOCA=100:14 and EP: Triethanolamine =100:15. According to the non-linear theory of composition of the graded function materials distribution, the volume content function of polyurethane in the mixed resin was achieved. After the coating was divided into 11 layers, the volume content of polyurethane in each layer can be calculated out by integraled the volume content function. By tested the density, the surface hardness, and the abradability of the coatings and searched SEM and stereoscope, with the increasing of the volume content of polyurethane, the performances and the microstructures of all coatings appeared continuously graded changes in general. Keeping laminated hot melt liquid method together film direct confectioning method, EP/PU function graded coatings had been prepared. The first mixed resin layer was brushed on a piece of A3 steel plate and pre-solidified on 80℃. After reaching its skin drying time ,the second layer was brushed over the first layer and pre-solidified on 80℃. After reaching its skin drying time, the third layer was brushed over the second layer, analogically until all layers were brushed. The whole mixed resin was completely solidified on 120℃ for 1h at last. The ideal EP/PU graded function coating was prepared. By showing the microstructures of different thickness positions' SEM of EP/PU coating, the continuous graded of coating had been signified. At different thickness positions of the coating, flaky texture on the sub layer, graininess on the interface layer and sinewy on the superficial layer can be clearly observed .Furthermore there was no out-phase-of interface in the coating. The paper studied the abrasion resistant and the erosive wear of the EP/PU function graded coatings at the same time. The result points out: after the metal substrate was treated by KH-550 type silane coupling agent, the coating had excellent corrosion resistant property; EP/PU function graded coatings not only had the strong adhesive power like EP, but also had the excellent corrosion resistant property like PU: the adhesive power achieved the first level ,and resistance to impact 65kg·cm,and coefficient of attrition rate 0.042.