This presentation presents the results of studying the effective Parameters of nano-Cupric oxide-based CO Gas-sensors on the Heat Transferring efficiency.

1. M. H. Mahmood
Department of Manufacturing and Material Engineering,
International Islamic University Malaysia, PO Box 10, 50728 Kuala Lumpur, Malaysia
Corresponding author E-mail: mahmoodfattah@yahoo.com

3. Highlights
 Nano CuO particles were grown on copper
substrate using electrochemical method.
 CO gas sensitivity of Nano CuO coating was
enhanced by decreased oxalate concentration.
 Coating thickness increased by increasing of
the oxalate concentration.
 The highest surface area was achieved for
coating prepared in the highest oxalate
concentration and the lowest temperature.
 Increase solution speed improves the ionic and
charging transfer leading to form a non-porous
coating with smaller grain size.
 Increase surface area of coating enhance the
heat transfer efficiency.
Fig. 2. Microstructure of coating prepared in oxalic acid
solution

4. Table 2; Average thickness of coating with their corresponding S/N ratio

5. Figures

6. Fig. 4. The average thickness of the coating as a function of oxalate concentration and temperature
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7. Fig. 5. Average grain size of the coating as a function of oxalate concentration and temperature
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8. Fig. 6. Average porosity of coating as a function of oxalate concentration and temperature
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9. Fig. 7. The total surface area of coating as a function of coatings oxalate concentra-tion and
temperature
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10. Fig. 8. Grain size and porosity of coating as a function of temperature and solution speed
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
0
10
20
30
40
50
60
70
80
90
100
0 0.18 0.55
Grain
size
(nm)
Solution speed (m/s)
Grain size at 0 οC
Grain size at 8 οC
Porosity at 0 οC
Porosity at 8 οC

11. Fig. 9. The grain size of the coating as a function of oxalate concentration and solu-tion speed
Wait for the rotation

12. Fig. 10. Porosity of coating as a function of oxalate concentration and solution speed
Wait for the rotation

13. Fig. 11. The total surface area of coating as a function of oxalate concentration and solution speed
Wait for the rotation

14. Fig. 12. The total surface area of coating as a function of temperature and solution speed
Wait for the rotation

15. Fig. 13. The testing system for gas-sensing performance

16. Gas-sensing performance and resistance of coating as a function of coating
grain size
Grain size nm
Resistance in air
Ra
Resistance in
gas Rg
Gas sensitivity
S %
Gas-sensing
response
R= Rg/Ra
25 526 605.952 15.2 1.152
30 400 456 14 1.14
35 310 350.3 13 1.13
40 260 291.2 12 1.12
45 245 272.44 11.2 1.112
48 210.9 233.4663 10.7 1.107
52 195.5 216.223 10.6 1.106
54 180 198.9 10.5 1.105
56 181.35 200.02905 10.3 1.103
58 162 178.524 10.2 1.102
59 155 170.81 10.2 1.102

17. Fig. 14. Gas-sensing performance and resistance of coating as a function of grain size

18. Conclusions
From the current study, the following notes can be concluded;
 The thickness of coating increased with the increase in oxalate concentration at fixed
coating temperature. The increase in coating thickness was due to the increase in electrical
conductivity of the coating solution which led to increased coating rate.
 The highest surface area was achieved for the coating pre-pared in the highest oxalate
concentration and the lowest temperature.
 The speed of the coating solution is an effective noise factor in the coating process.
Increased solution speed has improved the ionic and charging transfer and formed a
nonporous coating with smaller grain size.
 The CO gas sensitivity of nano-CuO coating was increased by 50% due to the improvement
of the surface area with de-creased oxalate concentration and temperature at fixed solution
speed of 0.5 m/s.
 The increase of surface area by the nano-CuO coating enhanced the efficiency of heat
transfer by 96.5%.

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