Abstract:Ni-Mo-P and Ni-Mo-P/(h)BN composite coatings were prepared on the surface of GH4169 nickel-based high-temperature alloy by chemical composite plating technology. The tribological behaviour of the coatings at different temperatures and the microstructures of the coatings after friction wear at different temperatures were investigated. The tribological properties of the coatings at room temperature, 300℃, 500℃ and 700℃ were investigated by utilising a ball-disc friction and wear test. The chemical composition and organisational structure of the plated layer following the friction test at different temperatures were analysed by scanning electron microscope, energy spectrometer and X-ray diffractometer. The mechanical properties of the coatings were characterised by microhardness tester and Rockwell indentation tester following tribological tests at different temperatures.The results demonstrate that the deposited Ni-Mo-P and Ni-Mo-P/(h)BN composite coatings are predominantly amorphous structure containing small amounts of nancrystalline. The coatings transformed from amorphous to nanocrystalline structure with the increase of the friction test temperature. As the friction test temperature is increased, the plating layer undergoes a transformation from an amorphous to a nanocrystalline structure, accompanied by an increase in crystallinity. At temperatures exceeding 500℃, the The precipitation of the Ni3P hard phase in the plating layer occurs concurrently with the oxidative volatilisation of the Mo and P elements, resulting in the formation of pores within the plating layer and a reduction in its densification. As the temperature increased, the hardness of the plated layer exhibited a fluctuating trend, initially rising and then declining. Concurrently, the bonding strength of the film base exhibited a gradual decline, progressing from an HF1 grade to an HF6 grade. As the test temperature increased, the abrasive wear and oxidation of the plating layer became more pronounced. The highest wear rate was observed at 500℃. However, further increases in temperature resulted in a reduction in friction at the interface, with the average coefficient of friction of the Ni-Mo-P plating layer decreasing from 1 to 0.60. The coefficient of friction of the Ni-Mo-P/(h)BN composite layer was reduced from 0.88 to 0.53, which improved the friction reduction and wear-resistant performance of the plating layer at high temperatures. The incorporation of (h)BN particles into the plating layer enhances the P content, thereby increasing the toughness of the Ni-Mo-P/(h)BN composite plating layer, improving the hardness of the composite plating layer, and strengthening the film-base bonding. Furthermore, the composite plating layer exhibits superior wear resistance within the temperature range of room temperature to 700℃.