| Popis: |
Ni-based alloy is a typical high-temperature alloy material possessing high hardness, good thermal stability, and wear resistance. It is widely used as the surface strengthening and repair materials for aviation, vehicle engines, and industrial parts. In this study, Ni60 alloy coating was prepared on the surface of ZL109 aluminum alloy by plasma spraying technology, and its tribological properties at different temperatures (T = 25 ℃, 100 ℃ and 350 ℃) were evaluated. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) were used to characterize the phase analysis, micromorphology of Ni60 alloy coating fabricated with different spraying distance(D = 100 mm, 110 mm and 120 mm). The result shows that with the increase of spraying distance, the defects such as pores and microcracks decrease gradually. The porosity decreased from 2.2–0.76% and the fractal dimension decreased from 1.83 to 1.57. The element composition (Ni, Fe, Cr, Si, C, B) and phase composition (Ni3Fe, Cr23C6 and Cr7C3) of powder and coating were basically the same. The microhardness of the coating after spraying was about 5 times higher than that of the substrate. When D = 120 mm, the microhardness and bonding strength of the coating were the highest, which were 804 HV0.1 and 26 ± 0.05 MPa, respectively. The friction coefficient of the coating in the stable stage decreased with the increase of temperature, and all change in the range of 0.1 ~ 0.2. With the increase of temperature, the width, depth and volume wear rate of the coating increase gradually. |
