I= PREPARATION AND CHARACTERIZATION OF NON FERROUS AMORPHOUS METALLICALLOYS
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Title of Thesis
PREPARATION AND CHARACTERIZATION OF NON FERROUS AMORPHOUS METALLICALLOYS

Author(s)
Muhammad Saeed Khan
Institute/University/Department Details
University Of The Punjab
Session
1995
Subject
Physics
Number of Pages
165
Keywords (Extracted from title, table of contents and abstract of thesis)
non ferrous amorphous metallic alloys, glassy alloys, auger spectroscopy

Abstract
Non ferrous amorphous metallic alloys (Co100-x Bx (40‰ x ‰17) system of glassy alloys) were prepared by rapid quenching of the melt. The dynamic temperature X-ray diffraction (DTXD), dynamic temperature resistivity measurement (DTRM), Auger electron spectroscopy (AES), scanning electron microscopy microcopy (SEM), magnetometry and Fourier transform infrared spectroscopy (FTIR) were used to investigate the electrical , structural, thermal, magnetic and optical properties of Co-B system of glassy alloys. The preliminary theoretical calculations were also performed by using the drude model and Kramers-kronig equations for the measurement of optical properties.

The crystallization behavior of co-B glassy alloy was observed of four types. In concentration range, 40‰ X ‰31 , a-co and tet- co2 B phases were detected as primary phases. At higher temperature. Tet-co2 B was observed as stable phase. In concentration range. 30‰ X ‰27. Hex-co was detected as primary phase contrary to the previously reported bet-co3 B phase. In case of X=25 at. % B. phase was detected as primary phase. with the increase of temperature . o-Co3 B and bet- Co2 B phases along with fee-co phase were found. In 26‰ X ‰ 20.5 concentration range bet co3 B phase was primary phase while at higher temperature complex phase like bet-Co3+B and pt Co3+ B were detected. In the concentration range 20‰ X ‰17. hep €“ co was found as primary phase and the origin of crystallization process at eutectic point was explained on the basis of mathematical equations. At higher temperatures. O-co2 B and fee- co phases were detected from the analysis of crystallization behavior, a crystallization behavior. a crystallization phase diagram is presented for the Co-B system glassy alloys. In DTRM curves. Sharp peaks at the crystallization temperatures and the subsequent phase transition temperatures were detected and were to supplement the DTXD results. From DTXD. DTRM results. It was observed that the crystallization temperatures of Co-B system of glassy alloys vary with the change of boron concentration in the 570 k to 660 k. in DTAresults. Temperature change due to Tg was found insignificantly small and tg was masked by the exothermic trend. The exothermic trend of co-B glassy alloy is significantly high to suppress any endothermic effect on heating. Activation energy was found 190 Kj/mole. The SEM results show some voids of crystalline nature present on the surface of co-B23 glassy alloy. Heating at 1073 k. the formation f boron rich crystal flakes about 15 um long at surface. As was to analysis the thermal, structural and SEM results. From the as results. It was observed that the crystallization of co-b glassy alloy commences at the interface between oxygen and the amorphous matrix. The carbon and oxygen impurities were detected on the surface. The impurities sharply

The carbon and oxygen impurities were detected on the surface. The impurities sharply decrease with the increase of sputtering time . Heating at 973 k results the excess of boron at the co content of the surface layer decreases with the increase of temperature and this makes the surface more unstable. The saturation magnetization and magnetic moments decrease with the increase of boron content. Curie temperature after x ‰ at. % B sharply drops with the increase of boron concentration. the saturation magnetization is maximum at the liquid nitrogen temperature. The results indicate that the saturation magnetization decreases with the increase of temperature. The drude models correctly explicate infrared optical experimental studies of co-B alloy at low frequencies but deviations at higher frequencies are observed. Higher absorption is observed at lower frequencies. Both the plasma frequency and the inverse scattering time decrease with increasing boron content. The results are found consistent with the rigid band model proclaiming gradual filling of co-d bands by electrons from boron. Thereby decreasing the plasma frequency and total density of state at the Fermi level. These and electron density of stated enter additively in to a single drude term. The results are described the superposition of interurban and an interband processes. At higher concentration of boron. The co-b glassy alloy has been found to have prosperities resembling to those of amorphous semiconductors.

Download Full Thesis
2931.23 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
98.91 KB
2 1 Introduction 1
45.34 KB
3 2 Prologue Of The Study 4
264.99 KB
  2.1 Basics Of Glassy Alloys 4
  2.2 Rules Of Crystallization 6
  2.3 Kinetic Features 8
  2.4 Literature Survey 9
  2.5 Scope And Significance Of The Present Study 11
  2.6 References 17
4 3 Preparation And Diagnostic Techniques
327.9 KB
  3.1 Preparation 19
  3.2 Dynamic Temperature Resistivity Measurements 20
  3.3 Dynamic Temperature X-Ray Diffraction 22
  3.4 Differential Thermal Analysis 22
  3.5 Basics Of Magnetization 25
  3.6 Fourier Transform Infrared Spectroscopy 29
  3.7 References 37
5 4 Crystallization Behavior-Study Of Co 100-X B x (40 ‰ X ‰ 17) Glassy Alloy By Dynamic Temperature X-Ray Diffraction And Dynamic Temperature Resistivity Measurement.
921.06 KB
  4.1 Introduction 38
  4.2 Experiment 41
  4.3 Results And Discussion 42
  4.4 References 74
6 5 Thermal Properties Of Co 100-X B X ( 31 ‰ X ‰ 17) Glassy Alloy By Differential Thermal Analysis
398.57 KB
  5.1 Introduction 76
  5.2 Methods Of Determination Of Activation Energy 77
  5.3 Experiment 79
  5.4 Results And Discussion 80
  5.5 References 95
7 6 Auger Spectroscopy Of Co 77 B 23 Glassy Alloy
156.05 KB
  6.1 Introduction 96
  6.2 Experiment 97
  6.3 Results And Discussion 98
  6.4 References 105
8 7 Magnetic Properties Of Co 100-X B x (40 ‰ X ‰17) Glassy Alloy
240.02 KB
  7.1 Introduction 106
  7.2 Experiment 108
  7.3 Results And Discussion 109
  7.4 References 120
9 8 Infrared Optical Properties Of Co 100-X B x (31 ‰ X ‰17) Glassy Alloy.
363.55 KB
  8.1 Introduction 121
  8.2 Previous Studies 122
  8.3 Theory 123
  8.4 Experiment 127
  8.5 Results And Discussion 127
  8.6 References 142
10 9 Conclusion 143
103.02 KB