Study On Preparation And Properties Of Micro/Nano Particles Iron-based Composite Coating

Low temperature iron plating technology is characterized by simple process, wide application scale, low cost and so on, therefore they are widely used in the process of repair damaged parts and have achieved good social and economic benefits. For many years, Dong’s Iron Plating Co., Ltd of Dalian Maritime University have repaired thousands of important parts such as crankshafts and cylinders by using low-temperature iron plating technology without pre-etching which has obtained the world leading position.This paper is based on the Dong’s alloy iron plating technology, by adding micro/nano particles of silicon (SiC) and molybdenum disulfide (MoS2) to make the Fe-SiC, Fe-MoS2 composite coatings. The micro-hardness tester, metallurgical microscope, scanning electron microscope (SEM) and X-ray diffraction spectrometer (XRD) were used to analyze the hardness, morphology, microstructure and elementary composition of composite coatings. And the composite coatings’ friction and wear properties were tested by method of friction wear testing. The composite coatings’ bonding strength was tested by thermal shock and file method. At last, the action mechanism of the particles’ deposition process, the hardness, the crack and the particles in tribological behavior were discussed and analyzed.The results of the tests show that the hardness of composite coatings’ is higher than the ordinary iron plating and increases with the particles concentration. Meanwhile when the voltage increases, the hardness of composite coatings increases first then gradually falls. There are many mesh micro cracks on the surface of composite coating and ordinary iron plating. At the cross section micro cracks are shaped with short strips and vertical to the matrix. However, the particles can make micro cracks shorter and thinner. The composite coatings have good wear resistance comparing to the ordinary iron plating layers. The composite coatings have a lower friction coefficient and wear. The SEM experiment shows that the composite coatings have a fine grain size, closely packed and have a good contact with the substrate. There weren’t cracking, peeling, shedding and other bad performance on the composite coatings by using the thermal shock test and the file test.