100 5 One- and Two-Dimensional Nanoparticles
Figure 5.23 Influence of MoS 2 addition to the friction coefficient of a grease. It is important
to realize that the addition of MoS 2 reduces friction. This phenomenon is more pronounced
in the case of the fullerene-like particles (Tenne, R., Weizmann Institute, Israel, private
communication 2012.).
0
500 1000 1500 2000 2500 3000 3500
load [N]
0
0.005
0.01
0.015
0.02
0.025
friction
coefficient
MoS2 addition
Base grease
Platelets
Fullerenes
are squeezed out. During application, the dangling bonds of the platelets react
with the metal surfaces and, therefore, these particles lose their properties as
lubricants.
The fullerene-like structures of MoS 2 and WS 2 have a high potential as solid-state
lubricants; however, they act differently: As they have no open bonds at the circumference, the particles cannot react with the surface of the metal. This extends
the lifetime of these lubricants. Also, the mechanism of reducing friction is different: The fullerene-like particles act like balls in a ball bearing [17]. Figure 5.23
compares the tribological behavior of the base grease with that of this grease using
additions of MoS 2 platelets and fullerene-like particles. It is clearly visible that the
addition of MoS 2 reduces friction. Furthermore, it is obvious that the addition of
fullerene-like particles prevents the increase of the friction coefficient up to significantly higher loads as compared to the platelet addition. These experimental
results vindicate the statement that fullerene-like MoS 2 and WS 2 particles improve
the friction behavior significantly as compared to the platelet shaped material.
Figure 5.24 displays in a large scale industrially produced MoS 2 fullerene-like
particles.
Comparable improvements as in the case of sliding contact bearings are observed
using WS 2 particles as an additive to metal-working fluids applied for highprecision machining, such as drilling or lathing. The advantage in such an application is twofold: Due to reduced friction, the applied forces and the temperature
increase are reduced. In the case of high-precision parts with narrow tolerances,
controlled temperature is essential to obtain the intended dimensions. Due to the
reduced temperature, the amount of metal-working fluid needed is reduced and
the lifetime of the cutting tools is extended.
Figure 5.23 Influence of MoS 2 addition to the friction coefficient of a grease. It is important
to realize that the addition of MoS 2 reduces friction. This phenomenon is more pronounced
in the case of the fullerene-like particles (Tenne, R., Weizmann Institute, Israel, private
communication 2012.).
0
500 1000 1500 2000 2500 3000 3500
load [N]
0
0.005
0.01
0.015
0.02
0.025
friction
coefficient
MoS2 addition
Base grease
Platelets
Fullerenes
are squeezed out. During application, the dangling bonds of the platelets react
with the metal surfaces and, therefore, these particles lose their properties as
lubricants.
The fullerene-like structures of MoS 2 and WS 2 have a high potential as solid-state
lubricants; however, they act differently: As they have no open bonds at the circumference, the particles cannot react with the surface of the metal. This extends
the lifetime of these lubricants. Also, the mechanism of reducing friction is different: The fullerene-like particles act like balls in a ball bearing [17]. Figure 5.23
compares the tribological behavior of the base grease with that of this grease using
additions of MoS 2 platelets and fullerene-like particles. It is clearly visible that the
addition of MoS 2 reduces friction. Furthermore, it is obvious that the addition of
fullerene-like particles prevents the increase of the friction coefficient up to significantly higher loads as compared to the platelet addition. These experimental
results vindicate the statement that fullerene-like MoS 2 and WS 2 particles improve
the friction behavior significantly as compared to the platelet shaped material.
Figure 5.24 displays in a large scale industrially produced MoS 2 fullerene-like
particles.
Comparable improvements as in the case of sliding contact bearings are observed
using WS 2 particles as an additive to metal-working fluids applied for highprecision machining, such as drilling or lathing. The advantage in such an application is twofold: Due to reduced friction, the applied forces and the temperature
increase are reduced. In the case of high-precision parts with narrow tolerances,
controlled temperature is essential to obtain the intended dimensions. Due to the
reduced temperature, the amount of metal-working fluid needed is reduced and
the lifetime of the cutting tools is extended.