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GATE MT 2016 Q.54 A liquid phase sintered SiC-Ni composite has a solid-solid grain boundary energy (γSiC-SiC) of 0.80 J.m-2 and a solid-liquid (γSiC-Ni) interfacial energy of 0.45 J.m-2. For a SiC grain size of 20 µm, the average interparticle (SiC-SiC) neck size (in µm) is:
Correct answer is option C. Given that, (γSiC-SiC)= 0.805 J.m-2 (γSiC-Ni) = 0.45 J.m-2 Using surface energy balanced theorem, 2γSiC-Ni = γSiC-SiC 2×0.45cos(Φ/2)=0.8 cos(Φ/2)=8/9 From the figure, sin(Φ/2)=(x/2)/(D/2) = x/D √1-cos2(θ/2)= x/D x=20√(81-64)/81 = 9.16
Correct answer is option C.
Given that, (γSiC-SiC)= 0.805 J.m-2
(γSiC-Ni) = 0.45 J.m-2
Using surface energy balanced theorem,
2γSiC-Ni = γSiC-SiC
2×0.45cos(Φ/2)=0.8
cos(Φ/2)=8/9
From the figure, sin(Φ/2)=(x/2)/(D/2) = x/D
√1-cos2(θ/2)= x/D
x=20√(81-64)/81 = 9.16
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