posted on 2022-07-07, 11:34authored byHaosheng Pang, Liqi Li, Xuan Yin, Bing Zhang, Chenghui Gao, Dameng Liu
We
report a long-term lubrication for a PbS QD nanocoating sliding
against bearing steel balls in the air. Through tribo-physchemical
interactions, ultralow friction (μ ≈ 0.078 ± 0.0026)
is achieved for the system tested under 1 N for 60 min. During the
rubbing process, the tribo-film of the counterfacing ball is covered
by a degraded PbS QD layer and amorphous mixed phase. Meanwhile, the
disc track surface is composed of degraded PbS QD layers, clustered
rearranged PbS QD districts, induced decomposed Pb-enriched multilayers,
and an amorphous mixed phase via friction-induced structural transformation.
The PbS QDs are transferred onto the sliding contacts to form a robust
tribo-film, which is the key to realizing ultralow friction. Consequently,
a long-term lubrication mechanism is attributed to the synergetic
tribo-physchemical interaction along sliding interfaces upon shift,
redirection, and decomposition of nanoparticles. These discoveries
reveal QD-based nanolubricants in common working conditions for mechanical
engineering.