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Old 01-06-2025, 05:35 PM   #211 (permalink)
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We're 210 post in. I checked your Profile, twenty-one posts since you cared about Anthropogenic Climate Shenanigans. Are we all still doomed, anyway?

You never commented on the Photomolecular Effect

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Old Yesterday, 08:30 AM   #212 (permalink)
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These links are currently for my own edification and so I don't lose the links.
They have little to do with BA in engine oil at this point of study.
This is of interest (to me alone it would seem) as a means of understanding what happened upon adding BA (aq) to the engines I treated.
https://sci-hub.ru/https://pubmed.nc....gov/29505262/

Liquid Superlubricity of Polyethylene Glycol Aqueous Solution Achieved with Boric Acid Additive
The mixture of pure PEG200 and boric acid
was prepared by dissolving 4 mM of boric acid in 25 mM of PEG200 without pure water and
denoted as B-PEG200

Notably, the COF of H3BO3(aq) decreased from 0.5 to 0.03 after a running-in period of
approximately 800 s, indicating boric acid could greatly reduce the friction of pure water...

the superlubricity state was dominated by both the composite
tribochemical film formed via the tribochemical reaction on the contact surfaces and the
hydrodynamic lubricating film between the contact surface

a higher viscosity can result in a higher COF. Therefore, it is concluded
that the initial viscosity of the solution can influence both the running-in and superlubricity
periods...

superlow friction is closely related to the
concentration of residual water on the surface, and there is a critical concentration of residual
water for superlow friction...

the friction behavior of PEG200(aq) in the absence of boric acid
was also tested...After a running-in period of 1500 s, its COF
decreased to approximately 0.02... attributed to the presence of water, which leads to
the formation of an ultra-smooth surface after the running-in period...beneficial for
the hydrodynamic lubrication
... B-PEG200(aq)
could achieve superlubricity (μ<0.01). Its COF gradually decreased to less than 0.01, entered
the superlubricity state after a running-in of period 600 s, and thereafter decreased for a
further 300 s to reach the minimum value of 0.004...its specificity originates from the presence of BO3-

...It can be concluded from these results that there is an appropriate sliding speed range (0.05–0.25 m/s) to achieve superlubricity by B-PEG200(aq).

boric acid can react with polyols [in oil] such as glycerol and PEG
to form a boron chelate complex (BCC).36,37 Herein, during the running-in period, the rubbing
motion between asperities inputs energy into the lubricant and accelerates this chemical
reaction between PEG (marked as HOROH, R stands for alkyl chain) and boric acid
after short running-in period

results confirm that there is a tribofilm
deposited on the worn surface after the running-in period of superlubricity, which is believed
to contribute to the relatively low friction

residual water concentration
after the running-in period on the worn surface remains constant, which dominates the
solution viscosity; therefore, it is concluded that the hydrodynamic lubricating films are also
important for superlubricity

At the contact region of solid asperities, BCC is produced by the synergy
effect between boric acid and PEG200, and meanwhile provides sufficient H+ ions to realize
the running-in process, which contributes to the surface smoothening and contact pressure
reduction.

colloidal silica [in both Alu and steel alloys], which is a
good boundary lubricant, with electric double layer may be formed.33,34 And since the
superlubricity is achieved in neutral conditions (pH≈6), in which the colloidal silica system
can maintain stable, thus the sufficient electrostatic support can provide repulsive force to
increase the surface separation and avoid some direct contact

the existence of water makes it possible to form hydrated PEG
network, which might be cross-linked by hydrogen-bonding interactions mediated by boric
acid and ordered due to shear (like shear-thinning of branched polymer solutions). Thus, the
viscosity and shearing force of such solution are very low, leading to superlow friction

Decrease Friction with Hydrogen Ions
...reduction of friction by attachment of hydrogen ions to the rubbing surfaces. An ultra-low friction coefficient of \mu=0.004 was achieved between SiO_2 and Si_3N_4 in presence of ethylene glycol. Generation of ultra-low shear strength hydration layer \mu_r=0.0002 was claimed to be responsible for superlubricity regime.

During the running-in, the surfaces absorb hydrogen ions by means of tribochemical reaction induced by normal and shear pressures. The resultant hydrated layer is low-shear strength, but also delicate. It cannot carry much of the load and therefore, the researchers used a low-viscous lubricant to separate the surfaces by a thin film. This film protects the hydrogen layer from being worn, whereas hydrogen layer accommodates the difference in the wall velocity by its low shear strength and the resultant friction becomes low.

The researchers showed, that the proposed mechanism is applicable for any surfaces capable of absorbing hydrogen and aqueous lubricants with low viscosity

https://www.tribonet.org/news/decrea...hydrogen-ions/

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