ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 12, pp. 1810−1816. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © N.P. Shapkin, L.B. Leont’ev, V.N. Makarov, I.G. Khal’chenko, V.V. Korochentsev, A.L. Shkuratov, 2014, published in Zhurnal Prikladnoi
Khimii, 2014, Vol. 87, No. 12, pp. 1727−1734.
INORGANIC SYNTHESIS AND INDUSTRIAL
Vermiculite-Based Organosilicate Antifriction Composites
as Coatings on Friction Surfaces of Steel Articles
N. P. Shapkin, L. B. Leont’ev, V. N. Makarov, I. G. Khal’chenko,
V. V. Korochentsev, and A. L. Shkuratov
Far-Eastern Federal University, ul. Sukhanova 8, Vladivostok, 690922 Russia
Received October 11, 2014
Abstract—Inﬂ uence exerted by modiﬁ cation of vermiculite on the tribotechnical characteristics of oil additives
was studied. The wear rates were compared for additives containing polytetraﬂ uoroethylene and vermiculite
treated with 5–7% hydrochloric acid, followed by modiﬁ cation with polytetraﬂ uoroethylene, and vermiculites
modiﬁ ed with chitosan and polyphenylsiloxane. The wear rate was studied in three stages: ﬁ rst (application of an
additive), 3 min; second (formation of a coating), 60 min; and third (tribotests), 180 min. Polytetraﬂ uoroethylene
and vermiculite modiﬁ ed with polytetraﬂ uoroethylene were compared. It is shown that introduction of polyphe-
nylsiloxane on the vermiculite surface leads to a sharp decrease in the wear rate in the second and third stages.
The worn-out oil was analyzed and the formation of a metal-siloxane coating was conﬁ rmed. The mechanical
and morphological characteristics of the ﬁ lms formed on friction surfaces were studied. The best results were
obtained for coatings with an additive containing polyphenylsiloxane.
Friction surfaces are modified and thin-layer
antifriction coatings are formed with wide application of
formulations of geomaterials (natural silicates having a
layered structure with weak binding between the layers,
which facilitates the interlayer slip) based on serpentinite
and vermiculite [1–3], polymer-silicate nanocomposites
based on polytetraﬂ uoroethylene (PTFE) and serpentinite,
and modiﬁ ed vermiculites [4, 5] capable of forming
protective metal-ceramic ﬁ lms on friction surfaces. This
can substantially reduce the loss of energy for overcoming
the friction and make the wear resistance of conjugated
articles 2–4 times higher. The roughness of metallic
friction surfaces may also decrease severalfold to become
= 0.03–0.05 μm.
The goal of our study was to modify vermiculites
and study processes in which coatings are formed from
modiﬁ ed vermiculites.
Based on the results of previous studies [4, 5], we
chose as the base material the vermiculite mineral, silicate
of natural origin, with the following composition (%):
11.78, MgO 29.47, Fe
CaO 5.75, TiO
O 0.14, MnO 0.17, Cr
0.47, others 0.27.
The particle sizes of the silicate upon its treatment
in a cavitation disperser are within the range 1–20 μm.
To improve its antifriction properties, vermiculite
was treated with 5–7% hydrochloric acid. The acid was
chosen as a surface modiﬁ er because of the sharp increase
in the speciﬁ c surface area upon the treatment from 8 to
. The increase in the speciﬁ c surface
area and the extraction of aluminum and iron ions from
vermiculite must lead to a better sorbability of the oil
and, accordingly, to better tribotechnical properties of
the additives. The elemental composition of vermiculite
upon its modiﬁ cation with hydrochloric acid (%): SiO
5.18, MgO 1.06, Fe
0.34, CaO 1.01,
O 0.36, MnO 0.17, Cl 2.19, others 0.19.
The particle sizes of vermiculite upon its chemical
treatment are within the range 20–100 nm.
A natural polysaccharide, chitosan, has the following