HW11-new

# HW11-new - and a unit cell of cubic symmetry with a cell...

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ME311 MATERIALS ENGINEERING SPRING 2011 HOMEWORK #11 DUE DATE: April 29, before class PROBLEM 1: The ceramic compound MnS is composed by manganese (atomic radius=0.8 Å) and sulfur (atomic radius = 1.84 Å). Determine a) the expected coordination number, b) the expected ceramic crystal structure and c) the expected density of the compound. PROBLEM 2: Compute the theoretical density of CaF 2 . PROBLEM 3: Predict and draw the ceramic crystal structures for the materials a) NiO, b) NiS and c) TiCaO 3 . Justify your choice. PROBLEM 4: The figure below shows the unit cell of a compound consisting of Thorium (Th 4 + ) and Oxygen (O 2 - ), where the small ions are Thorium ions and the large ions are Oxygen ions. a) Determine the number of atoms per unit cell. b) Determine the chemical formula for the compound. c) Determine the coordination number for both ions.

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PROBLEM 5: A hypothetical AX type of ceramic material is known to have a density of 2.65 g/cm3
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Unformatted text preview: and a unit cell of cubic symmetry with a cell edge length of 0.43 nm. The atomic weights of the A and X elements are 86.6 and 40.3 g/mol, respectively. On the basis of this information, which of the following crystal structures is (are) possible for this material: rock salt, cesium chloride, or zinc blende? Justify your choice (s). PROBLEM 6: TiCaO 3 has the perovskite structure. On this basis calculate the size of the unit cell of TiCaO 3. PROBLEM 7: Determine whether or not a cylindrical specimen of aluminum oxide having a flexural strength of 300 MPa (43,500 psi) and a radius of 5 mm will fracture when subjected to a load of 7500 N in a three-point bending test. Assume the support point separation to be 15 mm. PROBLEM 8: Explain why crystalline ceramics are harder, yet more brittle than metals?...
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## This note was uploaded on 09/04/2011 for the course ME 311 taught by Professor Meyers during the Spring '08 term at University of Texas.

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HW11-new - and a unit cell of cubic symmetry with a cell...

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