use of metal templates for microcavity formation in alumina

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Figure 4.29. EDS line analysis of the sample (CR30F-Ti). Titanium diffusion in alumina is illustrated in Figure 4.30. It is considered that titanium diffuses into alumina among the grain boundaries, more thoroughly. At the same time, the diffusion of Ti +4 happened and also by Kirkendall effect creeping occurred. By slipping among grains, new phases and also micro-pores occurred in the structure of alumina. Ti +4 Wt (%) 69 59 49 39 29 19 9 -1 Al2O3 Grain 0 50 100 150 200 Ti +4 Al +3 Al (wt%) Ti (wt%) Ti +4 Ti +4 Distance (µm) O2 + Ti TiO2 Al +3 Ti wire Al +3 Figure 4.30. Ti diffusion in alumina. Ti +4 Al +3 Al +3 Ti +4 Al2O3.TiO2 Micro-pores 50
4.3.5. Stainless Steel Diffusion into Alumina Figure 4.31 shows that the stainless steel wire has almost completely diffused into the surrounding alumina leaving behind a cylindrical void. The control of the void diameter shows that it is larger than the original wire diameter. It is the expected result of sintering densification (Goodshaw et al., 2009). (a) (b) A B Figure 4.31. SEM micrographs of alumina CR15-St that used stainless steel wire (a) 5 o C/min at magnification of 500X (b) 5 o C/min at magnification of 5000X. According to Figure 4.31, it is observed approximately 100µm expansion for stainless steel in alumina for 4 hours as soaking time. The phase diagram of Fe2O3 - Al2O3 system is shown in Figure 4.32. According to this diagram, it is clear that Al2Fe2O6 (heamatite structure) occured at 1350 o C. 51
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USE OF METAL TEMPLATES FOR MICROCAV
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ACKNOWLEDGEMENTS I would like to ex
Page 5 and 6:
ÖZET ALÜMİNA İÇİNDE MİKROBO
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4.3.1. Alumina ....................
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Figure 3.4. Pressed samples: (a) be
Page 11 and 12: Figure 4.35. Phase equilibrium diag
Page 13 and 14: CHAPTER 1 INTRODUCTION Porous oxide
Page 15 and 16: 2.1. Porous Materials CHAPTER 2 LIT
Page 17 and 18: Alumina ceramic is one of the most
Page 19 and 20: 2.3. Properties and Applications of
Page 21 and 22: Selection of stainless steels based
Page 23 and 24: Some physical properties of copper
Page 25 and 26: of some of the oxygen from the air
Page 27 and 28: not occupied by the flow of Cu from
Page 29 and 30: During the 4 hours soaking time at
Page 31 and 32: y the technique of dilatometry (Rah
Page 33 and 34: CHAPTER 3 EXPERIMENTAL In this chap
Page 35 and 36: Table 3.1. Properties of alumina po
Page 37 and 38: 3.2.1. Co-Pressing with Single-acti
Page 39 and 40: 3.3. Density Measurements The final
Page 41 and 42: Figures 4.3 and 4.4 show relative d
Page 43 and 44: Densification Rate (1/ o C) 0,005 0
Page 45 and 46: Densification Rate (1/ o C) 0,009 0
Page 47 and 48: (a) (b) (c) (d) (e) Figure 4.8. SEM
Page 49 and 50: Figure 4.10. EDS analysis of the Ti
Page 51 and 52: 4.3.3. Ti Diffusion into Alumina In
Page 53 and 54: Titanium advanced through alumina a
Page 55 and 56: Wt (%) Wt (%) 100 80 60 40 20 0 100
Page 57 and 58: Figure 4.22. EDS line analysis of t
Page 59 and 60: Densification Rate (1/ o C) 0,0069
Page 61: Figure 4.27, 28 and 29 belong to ED
Page 65 and 66: Wt (%) 50 45 40 35 30 25 20 15 10 5
Page 67 and 68: Wt (%) 70 60 50 40 30 20 10 0 Al (w
Page 69 and 70: 4.3.7. Results of Sintering of Alum
Page 71 and 72: Wt (%) 40 35 30 25 20 15 10 5 0 Al
Page 73 and 74: CHAPTER 5 CONCLUSIONS Densification
Page 75 and 76: REFERENCES Alcoa, Inc., 2010, Alumi
Page 77 and 78: Isobe, T., Tomital, T., Kameshima,
Page 79: Yalamaç, E., 2010, Sintering, Co-S
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