Biomedical Engineering Reference
In-Depth Information
46
45
44
43
42
41
40
39
0
1
2
3
4
Level of factor M
FIGURE 3.16
S/N response graph for factor M.
TABLE 3.6
Strong Effects and Elements
First tier
(G) Reducing/stirring time in the first reduction process
(J) Reducing agent concentration in the second reduction process
(L) Reducing/stirring time in the second reduction process
Second tier
(A) Surface roughening
(K) Reducing bath temperature in the second reduction process
platinum penetration is measured by SEM cross-sectioning, and four-point surface
resistivities (sheet resistivity) of the samples were measured by Guardian Manufac-
turing's model SRM-232. The surface resistivity of the samples appears to be linear
despite scatters.
Overall, it should be noted that samples with low surface resistivities tend to
produce larger blocking forces.
The tensile testing of the samples was performed by an Instron 1011 table-top
machine. The standard sample size was 9
55 mm. The strain rate was set at roughly
2.33 (s
-1
). In figures 3.19(a) and 3.19(b), tensile testing results are provided in terms
of normal stresses,
×
ε
N
, for a number of samples 1, 2, 3, 28,
and 29, and Nafion-117 (dry and wet states).
All Taguchi IPMNC samples (these are wet samples) show the Young's modulus
of approximately 50-100 MPa at a normal strain of 0.02 (at 2%) similar to that of
wet Nafion-117. The dry Nafion-117 (H
+
form) is stiffer than that of all Taguchi
samples, as expected. Approximate value of the modulus for dry Nafion-117 is
220-260 MPa at a normal strain of 0.02 (2%). The tensile strength of all Taguchi
samples is around 10-13 MPa. The IPMNC appears to exhibit a little more stiffness
and less yielding than Nafion-117 due primarily to the composited metal portion
σ
N
, and normal strain,
