Effect Of WC Particle Reinforcement On Microstructure And Properties Of Plasma Cladding Layer

Particle reinforced metal matrix composite materials plays an important role in improving the performance of materials and prolonging the service life of parts.Especially,it can improve the wear resistance of the composites by adding ceramic particles into metal matrix.It is a hotspot in the field of wear resistant materials research.At present,most of the studies on the performance of plasma cladding coatings use a certain type of WC particles to study the wear resistance and hardness of the coating.However,the size and shape of WC particles used in the plasma cladding process are not fixed and different The influence of WC particles on the metal-based cladding layer is also different,and the distribution of the WC particles in the cladding layer also varies when the shape and size of the WC are changed.Different metal groups also have the same effect on the properties of the cladding layer different effects.In this paper,we choose two kinds of particles,polygon WC and spherical WC,to prepare WC particle reinforced Fe based cladding and Ni based cladding on 45#steel surface respectively.The cladding layer has no macroscopical defects and the WC particles distribute evenly.The effects of different WC particles on particle reinforced Fe and Ni cladding layers were studied by analyzing the microstructure,thermal fatigue and corrosion resistance of different cladding layers.The microstructure and composition of cladding layer were analyzed by SEM,EDS and XRD.The thermal fatigue properties of cladding layer were tested by heat treatment furnace,and the corrosion resistance of cladding layer was detected by electrochemical test.The results show:The WC particles in the cladding layer are evenly distributed and the hardness of the cladding layer is significantly improved.The main phases in the Fe based cladding layer reinforced by WC particles are WC?W₂C??-Fe?Cr₂₃C₆?Fe₃W₃C?Fe₂₃B₆?Cr₇C₃,the hardness is about 850¹100 HV2.The main phases in the Ni based cladding layer reinforced by WC particles are Fe₆W₆C,Cr₇C₃,NiW?WC??-NiFe?W₂C.,the hardness is about 750¹000 HV2.The main phase in the Fe based cladding layer without WC particles is:?-Fe,?-Fe,Fe₂₃?C,B?₆,Fe₃C,and the hardness of 600⁷00 HV2.The phase of the Ni based cladding layer without WC particles is:?-Ni,Ni₃B,Ni₃Fe and some complex carbide phases,with a hardness of about 500⁶50 HV2.In the thermal fatigue test,the thermal fatigue crack initiates at the edge of the cladding layer and the stress concentration area.The polygonal WC particle reinforced cladding layer has faster crack growth rate in the initial stage.When circulating to about 50 times,a large number of cracks began to appear near the WC particles.In the later stage,the crack growth rate of spherical WC particle reinforced cladding layer was higher than that of polygonal WC particles.The results of electrochemical tests showed that the corrosion resistance of the spherical WC particles to the cladding layer was the best for the Fe-based cladding layer and the addition of the polygonal WC particles reduced the corrosion resistance of the cladding layer.For the Ni-based cladding layer,The corrosion resistance of polycrystalline WC particles is the best for the cladding layer.The effect of spherical WC particles on the corrosion resistance of the cladding layer is not obvious.