Biomedical Engineering Reference
In-Depth Information
Wear rate
(mm
3
/Nm)
Coeff.of
friction
0.08
Pure PAO-4
oil
8.40E-07
0.07-0.08
0.07
2H-MoS
2
platelets
Undoped
IF-MoS
2
NP
Re (0.12 at%):
IF-MoS
2
NP
8.15E-08
0.04
0.06
7.80E-08
0.04-0.05
0.06
4.70E-08
0.015
0.05
0.04
0.03
0.02
0.01
0
25
50
75
100
125
150
175
200
225
250
Time (offset) (min)
2H-MoS
2
platelets
Undoped IF-MoS
2
NP
Re (0.12 at%):IF-MoS
2
NP
Pure PAO-4 oil
FIGURE 13.5
Friction coefficient of different lubricating fluids based on PAO-4: pure purple; formulated with 2H-MoS
2
(dark brown); IF-MoS
2
(undoped—light brown) and Re-doped IF-MoS
2
(green). Wear rate of the different
lubricants are shown in the inset table. (For interpretation of the references to color in this figure legend,
the reader is referred to the web version of this topic.)
Refs.
[31
34]
. Therefore, it was almost natural, once the IF NP were known to have superior solid
lubrication behavior, to try to incorporate them in metallic coatings. This would be expected to
endow such films the genuine behavior of a very hard coating which is nonetheless also self-
lubricating. A series of articles, where electroless or electroplating baths containing IF NP are used
to prepare self-lubricating surfaces, were thus reported quite recently
[35
38]
. Different kinds of
films and substrates were used. While their potential applications go beyond dentistry or medical
devices, the focus of much of the present authors was in this direction.
13.4
Orthodontic appliances coated with nanoparticles
13.4.1
Challenges in designing the experimental setup
The study of medical devices in a materials laboratory, like the present one requires special consid-
erations. Once a medical issue addressable with the present technology has been identified
and evaluated, the next most intricate issue is to design a working model to be used for the experi-
ments. This working model should reflect the salient features of the medical problem being studied.
