Quiz-2-soln - Stability requires that the ratio of cation...

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Name_____________________________ Team No._______ ENGR 213 Quiz 2 16 SE 02 CLOSED BOOK and NOTES, INDIVIDUAL WORK 1. List the common crystal types for metallic bonded materials. 3 pts BCC, FCC, HCP 2. Sketch on the graph the energy of attraction, repulsion, and their sum as two atoms approach each other. Show the point where two atoms would be in equilibrium. 3 pts 3. List two differences between ceramic and metallic crystals. 3 pts Ceramics have two or more elements, metallic have only one element Ceramics have ionic to covalent bonds, metallic have metallic bonds Ceramics have many more crystal structures than metallic 4. Explain the concept of stability and how it is affected by coordination number. 3 pts Stability means that the crystal structure does not easily change (e.g., with thermal agitation).
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Unformatted text preview: Stability requires that the ratio of cation to anion size ion be sufficiently large for the cation to touch all the anions surrounding it. The smaller an ion is, the fewer ions can surround it i.e., smaller coordination number, and be stable. 5. Define anisotropy and give an example of a material property which might show anisotropy. 3 pts Anisotropy is the ability of a material to respond differently to the same stimulus applied in different directions. Anisotropy may exist for the elastic modulus, electrical conductivity, index of refraction, and other properties. Interatomic separation Energy of attraction Energy of repulsion E A E R E N r...
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This homework help was uploaded on 03/26/2008 for the course ENGR 213 taught by Professor Dr.stubbs during the Fall '04 term at Texas A&M.

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