CONTENTS 



Page 



Preface iii 



I. Introduction ' 1 



Historical 1 



Macroexamination ; etching 2 



Microexamination 2 



II. General types of meteoric iron 4 



Hexahedrites 4 



Octahedrites 4 



Ataxites 6 



Transitional forms 7 



Proportions of types 7 



Interpreting structures 8 



Analyses 9 



III. Primary constituents of meteoric iron 10 



Kamacite 10 



Taenite 14 



Plessite 15 



IV. Accessory constituents of meteoric iron 17 



Troilite 17 



Daubr6elite 18 



Schreibersite 18 



Carbon 21 



Cohenite 21 



Oxides 24 



Silicates 25 



Minor constituents 25 



V. Artificial irons 25 



Iron and its alloys 26 



Phases of pure iron 26 



Thermal critical points 27 



Hysteresis 28 



VI. Alloys 28 



Solid solutions 28 



Solidification of alloys 29 



Eutectics; eutectoids 29 



Phase changes in alloys 30 



VII. The iron-carbon system 32 



The iron-carbon diagram 32 



Martensite 35 



Troostite; sorbite 35 



Pearlite in meteorites 36 



VIII. The iron-nickel system 36 



Differences in transformation 36 



Early iron-nickel diagrams 37 



The supposed eutectoid 38 



The composition of taenite 39 



V 



