] The Si-Fe binary phase diagram is shown below (a) How many eutectics can you f
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Question
] The Si-Fe binary phase diagram is shown below
(a) How many eutectics can you find and at what composition (approximately)? [4]
(b) How many low temperature (below 800oC) stable compounds can you identify and what are they? [2]
(c) Do Si and Fe form random alloys, if so identify the regions? [4]
(d) Which compound can be made by repeating cycles of melting the stoichiometric amount of Fe and Si then solidifying the liquid by cooling it slowly? [4]
(e) Draw the cooling curves, for compositions (I) and (II) as the system cools from 1400oC to 600oC; describe what happens at each stage of the cooling [6]
12TheSike binary phase diagfinds hat whatoomp ston(approximately (a) How many eutectics can you find and at what composition (approximately)? [4] (b) How many low temperature (below 800°C) stable compounds can you identify and what are they? [2] (c) Do Si and Fe form random alloys, if so identify the regions? 4] (d) Which compound can be made by repeating cycles of melting the stoichiometric amount of Fe and Si then solidifying the liquid by cooling it slowly? [4] (c) Draw the cooling curves, for compositions (I) and (II as the system cools from 1400°C to 600°C; describe what happens at each stage of the cooling [6]Explanation / Answer
1) Two Eutectic points are clearly visible at 1200oC and compositions of 0.25 and 0.65 (% Si) .
2) Below 800 o only one alloy seems to exist - FeSi2.
3)Random alloys are formed at temperature ranges from 950 to 1200 and composition ranges of 0.26 to 0.67.
4)At equimolar condition, we have to follow the vertical line at 0.5% Si downwards. On cooling , at first , alloys like FeSi and Fe3Si are formed anf further cooling yields Fe5S3
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