DETERMINATION OF THIN FILM'S MECHANICAL PROPERTIES

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3 from surface, Fe 2 B phase forms in deeper region because of decreasing boron concentration form surface to inside of substrate. Upper part of multilayer consists of FeB phase which is more brittle than lower layer (Fe 2 B). Mechanical properties (Young’s modulus, Hardness, Yield strength) of FeB layer are difficult to characterize through uniaxial or other standard tests. So, micro indentation method became useful for determination of mechanical properties of layers.
4 CHAPTER TWO BORONIZING 2.1 Introduction Boriding, or boronizing, is a thermo chemical surface hardening process that can be applied to a wide variety of ferrous, nonferrous, and cermet materials. The process involves heating well-cleaned material in the range of 700 to 1000 o C, preferably for 1 to 12 h, in contact with boronaceous solid powder (boronizing compound), paste, liquid or gaseous medium. Other developments in the thermo chemical boriding include gas boriding techniques such as plasma boriding and fluidized bed boriding. There is a current trend toward the use of multicomponent boriding (Asm Handbook, vol.4, 2000). This article presents mainly various media used for thermo chemical boriding, their advantages, limitations and applications. Physical and chemical vapor depositions, plasma spraying and ion implantation are alternative nonthermochemical surface coating process for the deposition of boron or codepozition of boron and metallic elements onto suitable metallic or nonmetallic substrate material (Asm Handbook, vol.4, 2000). 2.2 Characteristic Features of Boride Layers During boriding, the diffusion and subsequent absorption of boron atoms into metallic lattice of component surface form interstitial boron compounds (A.G. von Matuschka, 1980). The resulting layer may consist of either a single phase boride or polyphase boride layer. The morphology, growth and phase composition of boride layer can be influenced by alloying element in the base material as represented in Fig 2.1 (R. Chatterjee and Fischer, 1981). The micro-hardness of the boride layer also depends strongly on the composition and structure of the boride layer and composition of the based material as shown in Table 2.1 (Galibois et al, 1980). 4
Page 1 and 2: 1 DOKUZ EYLUL UNIVERSITY GRADUATE S
Page 3 and 4: 3 M. Sc. THESIS EXAMINATION RESULT
Page 5 and 6: 5 DETERMINATION OF THIN FILM’S ME
Page 7 and 8: 7 CONTENTS Page THESIS EXAMINATION
Page 9 and 10: 9 4.3 Characterization Studies…
Page 11: 2 Sharp indentation tests also serv
Page 15 and 16: 6 2.3 Advantages of Boriding Boride
Page 17 and 18: 8 Other advantages of boriding incl
Page 19 and 20: 10 2.4 Boriding of Ferrous Material
Page 21 and 22: 12 Fe 2 B peritectoid reaction at a
Page 23 and 24: 14 elements should not be used for
Page 25 and 26: 16 layer, comprising the exterior (
Page 27 and 28: 18 time. The container should not e
Page 29 and 30: 20 wear, whereas thick layers are r
Page 31 and 32: 22 • Bends and baffle plates for
Page 33 and 34: 24 the indenter load and the actual
Page 35 and 36: 26 Figure 3.3 Schematic diagrams Br
Page 37 and 38: 28 specimen by artificially reducin
Page 39 and 40: 30 Recently, it is shown that since
Page 41 and 42: 32 determine the hardness and modul
Page 43 and 44: 34 From theoretical consideration i
Page 45 and 46: 36 4.2 Materials SAE 1020 and SAE 1
Page 47 and 48: 38 CHAPTER FIVE RESULTS AND DISCUSS
Page 49 and 50: 40 a) b)
Page 51 and 52: 42 a) b)
Page 53 and 54: 44 Average thickness measurement of
Page 55 and 56: 46 5.2 Surface Roughness Measuremen
Page 57 and 58: 48 30000 25000 1020-2-160 1020-4-16
Page 59 and 60: 50 45000 40000 35000 1040-2-320 104
Page 61 and 62: 52 Force (mN) 700 650 600 550 500 4
Page 63 and 64:
54 final or residual depth after un
Page 65 and 66:
56 90 80 70 60 Force (mN) 50 40 30
Page 67 and 68:
58 600 500 1020-2 1020-4 1020-6 400
Page 69 and 70:
60 a) b)
Page 71 and 72:
62 a) b)
Page 73 and 74:
64 a) c)
Page 75 and 76:
66 a) b) Figure 5.14 SEM images of
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
72 5.5 FEM Model In order to improv
Page 83 and 84:
74 The indenter was meshed by appro
Page 85 and 86:
76 a) b) Figure 5.21 Magnified view
Page 87 and 88:
78 720 640 560 Yield Strength=7000
Page 89 and 90:
80 CHAPTER SIX CONCLUSION 6.1 Gener
Page 91 and 92:
82 FeB layer increase from 0.4014 0
Page 93 and 94:
84 H.C. Child, 1981. Metallurgy and
Page 95:
86 Ugur Sen, Saduman Sen, Sakip Kok
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DETERMINATION OF THIN FILM'S MECHANICAL PROPERTIES

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