High-pressure wear behavior of laser clad MoNiTaTiV high-entropy alloy coating sliding against QBe2.0 beryllium bronze under dry and oil-lubricated conditions

Abstract

Sealing engineering equipment, especially in a harsh environment (e.g. high-pressure), is frequently subjected to tribological impacts during service, leading to an accelerated failure of the seal parts. In this study, an effective strategy was proposed to reduce the wear of the seal part, utilizing high entropy alloy (HEA) coating. A novel wear-resistant MoNiTaTiV HEA coating was designed and prepared on the substrate of GCr15 steel via laser cladding. The microstructure, chemical composition and microhardness of the HEA coating were examed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and nanoindentation. The wear property of the HEA coating sliding against its QBe2.0 counterpart under dry and oil-lubricated conditions at high-pressure was investigated deeply. As a result, the HEA coating exhibits BCC and TiN ceramic phases and its hardness reaches approximately 1099.7 HV, which is 3.7 times higher than that of the substrate. Additionally, the HEA coating shows superior wear properties to substrate under dry and oil-lubricated conditions, which is closely related to the high hardness of HEA coating reinforced by TiN particles. The adhesion layer and oxide layer were formed on the HEA coating, transferring the two-body to three-body wear. The QBe2.0 counterpart and MoNiTaTiV coating could be a promising anti-wear tribo-pair for seal parts under dry and oil-lubricated conditions.