The erosion behavior of Ni-base self-fluxing alloy, thermally sprayed
coating on a metal substrate is affected by several factors, including
the microstructure of the coatings, the porosity, the angle of imping
ement of solid particles and the hardness of the coatings. In this stu
dy, the erosion properties of thermally sprayed coatings with differen
t tungsten carbide contents were investigated. Reinforced by tungsten
carbide in the Ni(gamma) matrix, the erosion resistance of the coating
has been modified. With increasing tungsten carbide content, an erosi
on mechanism that involved a large amount of plastic deformation in th
e Ni(gamma) matrix was found to represent the brittle fracture of carb
ides. Test results showed that an Ni-WC coating with an optimum compos
ition ratio of Ni-base alloy to WC of 65:35 has the highest microhardn
ess and improved erosion resistance compared with coatings of other co
mpositions. (C) 1997 Elsevier Science S.A.