The work is mainly to study the thermal stability including the phase stability, microstructure and tribo-mechanical properties of the AlB_2-type WB_2 and W–B–N(5.6 at.% N) films annealed in vacuum at various temper...The work is mainly to study the thermal stability including the phase stability, microstructure and tribo-mechanical properties of the AlB_2-type WB_2 and W–B–N(5.6 at.% N) films annealed in vacuum at various temperatures, which are deposited on Si and GY8 substrates by magnetron sputtering. For the WB_2 and W–B–N films deposited on Si wafers, as the annealing temperature increases from 700 to 1000 °C, a-WB(700 °C) and Mo_2B_5-type WB_2(1000 °C) are successively observed in the AlB_2-type WB_2 films, which show many cracks at the temperature ≥ 800 °C resulting in the performance failure; by contrast, only slight α-WB is observed at 1000 °C in the W–B–N films due to the stabilization eff ect of a-BN phase, and the hardness increases to 34.1 GPa fi rst due to the improved crystallinity and then decreases to 31.5 GPa ascribed to the formation of α-WB. For the WB_2 and the W–B–N films deposited on WC–Co substrates, both the WB_2 and W–B–N films react with the YG8(WC–Co) substrates leading to the formation of CoWB, CoW_2B_2 and CoW_3B_3 with the annealing temperature increasing to 900 °C; a large number of linear cracks occur on the surface of these two films annealed at ≥ 800 °C leading to the fi lm failure; after vacuum annealing at 700 °C, the friction performance of the W–B–N films is higher than that of the deposited W–B–N films, while the wear resistance of the WB_2 films shows a slight decrease compared with that of the deposited WB_2 films.展开更多
In the present study,WB 2（N） films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure（P （N2）） on the film microstructur...In the present study,WB 2（N） films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure（P （N2）） on the film microstructure and characteristics is studied systematically,including the chemical composition,crystalline structure,residual stress,surface roughness as well as the surface and the cross-section morphology.Meanwhile,nano-indentation and ball-on-disk tribometer are performed to analyze the mechanical and tribological properties of the films.The results show that the addition of nitrogen apparently leads to the change of the structure from（1 0 1） to（0 0 1） orientation then to the amorphous structure with the formation of BN phase.And the addition of nitrogen can greatly refine the grain size and microstructure of the films.Furthermore,the residual stress of the film is also found to change from tensile to compressive stress as a function of P （N2）,and the compressive stress increases with P （N2）,The WB 2（N） films with small nitrogen content,which are deposited at P （N2） of 0.004 and 0.006 Pa,exhibit better mechanical,tribological and corrosion properties than those of other films.Further increase of nitrogen content accelerates the formation of BN phase and fast decreases the film hardness.In addition,the large N 2 partial pressure gives rise to the target poisoning accompanied by the increase of the target voltage and the decrease of the deposition rate.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 51701157 and 51505378)the Natural Science Foundation of Shaanxi Province of China (No. 2017JQ5031)
文摘The work is mainly to study the thermal stability including the phase stability, microstructure and tribo-mechanical properties of the AlB_2-type WB_2 and W–B–N(5.6 at.% N) films annealed in vacuum at various temperatures, which are deposited on Si and GY8 substrates by magnetron sputtering. For the WB_2 and W–B–N films deposited on Si wafers, as the annealing temperature increases from 700 to 1000 °C, a-WB(700 °C) and Mo_2B_5-type WB_2(1000 °C) are successively observed in the AlB_2-type WB_2 films, which show many cracks at the temperature ≥ 800 °C resulting in the performance failure; by contrast, only slight α-WB is observed at 1000 °C in the W–B–N films due to the stabilization eff ect of a-BN phase, and the hardness increases to 34.1 GPa fi rst due to the improved crystallinity and then decreases to 31.5 GPa ascribed to the formation of α-WB. For the WB_2 and the W–B–N films deposited on WC–Co substrates, both the WB_2 and W–B–N films react with the YG8(WC–Co) substrates leading to the formation of CoWB, CoW_2B_2 and CoW_3B_3 with the annealing temperature increasing to 900 °C; a large number of linear cracks occur on the surface of these two films annealed at ≥ 800 °C leading to the fi lm failure; after vacuum annealing at 700 °C, the friction performance of the W–B–N films is higher than that of the deposited W–B–N films, while the wear resistance of the WB_2 films shows a slight decrease compared with that of the deposited WB_2 films.
基金supported by the National Key Basic Research Program of China (973 Program,No.2012CB625100)the Natural Science Foundation of Liaoning Province of China (No.2013020093)
文摘In the present study,WB 2（N） films are fabricated on silicon and YG8 substrates at different N 2 pressures by reactive magnetron sputtering.The influence of N 2 partial pressure（P （N2）） on the film microstructure and characteristics is studied systematically,including the chemical composition,crystalline structure,residual stress,surface roughness as well as the surface and the cross-section morphology.Meanwhile,nano-indentation and ball-on-disk tribometer are performed to analyze the mechanical and tribological properties of the films.The results show that the addition of nitrogen apparently leads to the change of the structure from（1 0 1） to（0 0 1） orientation then to the amorphous structure with the formation of BN phase.And the addition of nitrogen can greatly refine the grain size and microstructure of the films.Furthermore,the residual stress of the film is also found to change from tensile to compressive stress as a function of P （N2）,and the compressive stress increases with P （N2）,The WB 2（N） films with small nitrogen content,which are deposited at P （N2） of 0.004 and 0.006 Pa,exhibit better mechanical,tribological and corrosion properties than those of other films.Further increase of nitrogen content accelerates the formation of BN phase and fast decreases the film hardness.In addition,the large N 2 partial pressure gives rise to the target poisoning accompanied by the increase of the target voltage and the decrease of the deposition rate.
