Microstructure and mechanical characteristics of iron-based coating prepared by plasma transferred arc cladding process

This paper investigated the effect of electromagnetic stirring (EMS) on the microstructure and abrasive wear behavior of iron-based coatings. A series of coatings were prepared by using plasma transferred arc cladding (PTAC) process. The phase and structure of the coatings were characterized by means of SEM, EDXA and X-ray diffraction. The microstructure of the coatings was mainly gamma-Fe matrix and (Cr, Fe)(7)C-3 carbide reinforced phases. Without EMS, the average size of (Cr, Fe)(7)C-3 carbide was about 73 mu m, while that of the carbide reached a minimum value of about 20 mu m with stirring current of 3 A. The mechanical properties, especially wear resistance, were analyzed in detail. The results showed that the microstructure of the coating plays an important role on abrasive mechanism and the main mechanism is micro-cutting. When the stirring current is 3 A, the coating exhibits excellent wear resistance, which contributes to the good microstructures that hexagonal (Cr, Fe)(7)C-3 carbide with the highest volume fraction are uniformly distributed in the matrix. The microhardness of the coatings increase at first, and then decrease as a function of stirring current. The maximum microhardness value of the coating is about 1050 HV. (c) 2008 Elsevier B.V. All rights reserved.