Part II of this paper is focused on studying the droplet spreading and the subsequent evaporation/film-formation characteristics of the graphene oxide colloidal solutions that were benchmarked in Part I. A high-speed imaging investigation was conducted to study the impingement dynamics of the colloidal solutions on a heated substrate. The spreading and evaporation characteristics of the fluids were then correlated with the corresponding temperature profiles and the subsequent formation of the residual graphene oxide film on the substrate. The findings reveal that the most important criterion dictating the machining performance of these colloidal solutions is the ability to form uniform, submicron thick films of graphene oxide upon evaporation of the carrier fluid. Colloidal suspensions of ultrasonically exfoliated graphene oxide at concentrations < 0.5 wt.% are best suited for micromachining applications since they are seen to produce such films. The use of thermally reduced (TR) graphene oxide suspensions at concentrations < 0.5 wt.% results in nonuniform films with thickness variations in the 0–5 μm range, which are responsible for the fluctuations seen in the cutting force and temperatures. At concentrations ≥ 0.5 wt.%, both the TR and ultrasonically exfoliated graphene oxide solutions result in thicker and nonuniform films that are detrimental for machining results. The findings of this study reveal that the characterization of the residual graphene oxide film left behind on a heated substrate may be an efficient technique to evaluate different graphene oxide colloidal solutions for cutting fluids applications in micromachining.

References

References
1.
Chu
,
B.
,
Singh
,
E.
,
Samuel
,
J.
, and
Koratkar
,
N.
,
2015
, “
Graphene Oxide Colloidal Suspensions as Cutting Fluids for Micromachining—Part I: Fabrication and Performance Evaluation
,”
ASME
Manufacturing Science and Engineering Congress
, Charlotte, NC.
2.
Dreyer
,
D. R.
,
Park
,
S.
,
Bielawski
,
C. W.
, and
Ruoff
,
R. S.
,
2010
, “
The Chemistry of Graphene Oxide
,”
Chem. Soc. Rev.
,
39
(
1
), pp.
228
240
.
3.
Hummers
,
W. S.
, Jr.
, and
Offeman
,
R. E.
,
1958
, “
Preparation of Graphitic Oxide
,”
J. Am. Chem. Soc.
,
80
(
6
), p.
1339
.
4.
Ehmann
,
K. F.
,
Bourell
,
D.
,
Culpepper
,
M. L.
,
Hodgson
,
T. J.
,
Kurfess
,
T. R.
,
Madou
,
M.
,
Rajurkar
,
K.
, and
DeVor
,
R. E.
,
2005
, “
Micromanufacturing: International Research and Development
,” World Technology Evaluation Center (WTEC) Panel Report, Baltimore, MD, http://www.wtec.org/micromfg/report/Micro-report.pdf
5.
Ghai
,
I.
,
Wentz
,
J.
,
DeVor
,
R. E.
,
Kapoor
,
S. G.
, and
Samuel
,
J.
,
2010
, “
Droplet Behavior on a Rotating Surface for Atomization-Based Cutting Fluid Application in Micromachining
,”
ASME J. Manuf. Sci. Eng.
,
132
(
1
), p.
011017
.
6.
Kwon
,
P.
,
Schiemann
,
T.
, and
Kountanya
,
R.
,
2001
, “
An Inverse Estimation Scheme to Measure Steady-State Tool-Chip Interface Temperatures Using an Infrared Camera
,”
Int. J. Mach. Tools Manuf.
,
41
(
7
), pp.
1015
1030
.
7.
Girard
,
F.
,
Antoni
,
M.
,
Faure
,
S.
, and
Steinchen
,
A.
,
2006
, “
Evaporation and Marangoni Driven Convection in Small Heated Water Droplets
,”
Langmuir
,
22
(
25
), pp.
11085
11091
.
8.
Samuel
,
J.
,
Rafiee
,
J.
,
Dhiman
,
P.
,
Yu
,
Z.-Z.
, and
Koratkar
,
N.
,
2011
, “
Graphene Colloidal Suspensions as High Performance Semi-Synthetic Metal-Working Fluids
,”
J. Phys. Chem. C
,
115
(
8
), pp.
3410
3415
.
You do not currently have access to this content.