STUDY OF THE TRIBOLOGICAL BEHAVIOR OF AN NI ELECTRON BRUSH-PLATING LAYER ON A BASE OF AN ARC SPRAYED COATING

Toolmaking by Arc sprayed metal is a new field of Arc spraying applica tion, a low cost, high efficiency method for producing molds for plast ic products. Al- or Zn-based wires can only be used as spray materials at the present stage. In order to improve the anti-wear property of t he Arc sprayed mold, the Ni layer is electron brush plated on the Are sprayed coating to enhance the service life of the mold. Tribological properties of the Ni layer on a base of Al-Zn pseudo-alloy coating and the effects of loads and temperature on wear of specimens were evalua ted using a Falex tester; at the same time, an Al-Zn pseudo-alloy Arc sprayed coating and an Ni brush plating layer on #45 mild steel were u sed for a comparative test. Behaviors and mechanisms of wear of the Ni brush plating layer were studied in detail by X-ray diffraction (XRD) , scanning electron microscopy (SEM), energy dispersive spectroscopy ( EDS), and morphology analysis. Results show that the microstructure, m icrohardness, cohesion strength and antiwear of the Ni plating layer o n the Al-Zn pseudo-alloy Arc sprayed coatings are the same as those of the Ni plating layer on the #45 steel. The Ni electron brush plating layer shows delamination wear, the relative anti-wear property of the Ni plating layer is 2-4 times higher than that of the Al-Zn pseudo-all oy coating, and the Ni electron brush plating on the Arc sprayed coati ng is an effective way to improve the anti-wear property of the mold's coating surface. (C) 1997 Elsevier Science S.A.