| Summary: | 碩士 === 國立中興大學 === 材料工程學研究所 === 86 === In this research, we investgated the changes of the
microstructure in the reactions between Cu and TiO2 at high
temperature. The effects of the oxygen partial pressure on the
reaction are discussed. The following gases used air, N2/O2=9,
N2 and N2/H2=9. We analyzed the resulting changes in the
topography and the composition by using optical microscop, SEM,
EDS, etc. The microstructural changes were characterized by XRD.
Copper was first embeded and in the TiO2 powder and then cold
pressed, The samples were heated at 1000℃ for 30 minutes.
Results show that samples melted and TiO2 turned from white to
black. The microstructures were found to be CuO and TiO2. When
copper was placedon the top of TiO2 and then heated up at 1000℃
for 30 minutes in air. Results also show that samples melted.
Since the eutectic point of CuO and TiO2 might be lower than
1000℃, copper would first oxidezed into CuO then diffuse in
liquid state into TiO2.At 1000℃ copper samples were placed on
the top of TiO2 for 5 minutes to 25 minutes. The whisker-like
material appeared on the top of copper surface and grew with
time. The whisker-like material might be mainly CuO after
analysis. In the atmosphere of N2/O2=9, we keep the
temperature at 1000℃ for 3 hr .The samples of the copper
embeded and pressed by TiO2 powder became black. The structures
were CuO and TiO2 and the copper melted but not as dramatic as
in air. The samples of copper embeded and then cold pressed
by TiO2 powder were heated at 1000℃ for 3 hrs in N2 atmosphere.
The copper surface oxidized into Cu2O and the color of TiO2
became red. And the structure was TiO2 only. Copper were
preheated at 1000℃for 9 hrs and then embeded and pressed by
TiO2 and heated at 1055℃ and 1075℃. The color of TiO2 became
red and the structure was only TiO2 still. The copper melted at
1075℃. It is because that 1075℃ is higher than the eutectic
point of Cu2O and Cu. It''s 1065℃. Copper embeded and cold
pressed by TiO2 are heated at 1000℃ for 3 hrs and 12hrs in N2/
H2=9 atmosphere. The structures were Cu and TiO2. There was no
obvious reaction occurred.
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