Ceramic Engineering 103 Final Exam (5/16/03) 1) Arrange each set of oxides in order from most basic to most acidic (3 points each):

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2 Cer 103 Final Exam/WS03 (2) Test ) Sketch a TTT curve for a system containing 0.1 vol% of crystalline material. Add a second curve for 1 vol% crystallinity. Label both curves and label each axis. Identify on one axis the approximate crystal melting temperature and the glass transition temperature. (10) 4) The nose of a TTT curve occurs at 10 minutes and 750ºC for a composition whose crystallization temperature is 1100ºC and glass transition temperature is 475ºC. What is the critical cooling rate for glass formation for this material? Show your work (8) Critical Cooling Rate:

3 Cer 103 Final Exam/WS03 (3) Test ) Calculate the weight of batch materials required to produce 100 grams of a glass with the composition (in mole%): 20K 2 O 10Al 2 O 3 70B 2 O 3. Show your work. (10) Molecular weights: K 2 O = 94.2 g/mole B 2 O 3 = 69.6 g/mole Al 2 O 3 = g/mole K 2 CO 3 = g/mole H 3 BO 3 = 61.8 g/mole Wt. K 2 CO 3 : Wt. Al 2 O 3 : Wt. H 3 BO 3 : What is the composition of this glass in wt% oxides? Show your work. (6 points)

4 Cer 103 Final Exam/WS03 (4) Test ) Consider the glass composition (mole%) 25Na 2 O 15CaO 60SiO 2. Determine the fraction of silica tetrahedra represented by each of the listed Q n types, assuming the simplest structural model. What fraction of the oxygens are NBO s? Show your work. (12) f(q 4 ) f(q 3 ) f(q 2 ) f(q 1 ) f(nbo) 7) Estimate the viscosities for glass melts described in the following situations and describe a method to measure that viscosity (6 points each) Stresses relax in several minutes: Pa-sec Samples deform under their own weight: Pa-sec

5 Cer 103 Final Exam/WS03 (5) Test ) List three oxides that, if added to a soda-lime silicate glass, will increase its refractive index without changing its color. (2 points each) 9) List three oxides that, if added to soda lime silicate glass, will change its color. (2 points each) 10) List three modifying ions that are larger than Na + ; assume constant coordination numbers for each ion. (2 points each) 11) Circle the most appropriate answer (2 points each) a) The addition of B 2 O 3 to an alkali silicate glass (increases/decreases) the thermal expansion coefficient. b) In a chalcogenide glass, Ge usually has a coordination number of (two/three/four). c) The addition of 20 mole% Na 2 O to B 2 O 3 (increases/decreases) the glass transition temperature. d) Assuming the simplest structural model, the network of a 40Na 2 O 60P 2 O 5 glass consists of (Q 3 +Q 4, Q 2 +Q 3, Q 2 +Q 1 ) tetrahedra.

6 Cer 103 Final Exam/WS03 (6) Test e) The more acidic oxide is (P 2 O 5, ZrO 2 ) f) The more basic oxide is (MgO, ZnO) g) Glass with the greater thermal expansion coefficient: Silica glass or Pyrex h) The higher temperature: annealing point or melting point i) Lower initial viscosity on re-heating: 'quenched' glass or 'annealed' glass j) Higher T g : 15Na 2 O 10CaO 75SiO 2 or 25Na 2 O 75SiO 2 k) Greater ionic conductivity: 25K 2 O 75SiO 2 or 12.5Na 2 O 12.5K 2 O 75SiO 2 l) Adding soda to a silicate glass generally (increases/decreases) the density. m) A glass with a high theoretical strength will generally possess a (low/high) elastic modulus. n) Ion exchange strengthening of window glass should be done below T g using a (LiNO 3 /KNO 3 ) molten salt bath. o) Thermally tempered glass will break into (small/big) pieces. p) The type of optical glass with the lower refractive index is (Crown/Flint) glass. q) The type of optical glass with the lower Abbe number is (Crown/Flint) glass. r) Circle the refractive index that will be highest (n D /n F /n C ). s) TiO 2 additions generally (increase/decrease) refractive index. t) Phase separation occurs (above/below) the consolute temperature. u) Circle the colorant ion: Mg 2+ Mn 3+ Ti 4+

7 Cer 103 Final Exam/WS03 (7) Test v) The chemical formula for limestone is (NaHCO 3, CaCO 3, CaO). w) Nucleation is more likely to occur in (high viscosity, low viscosity) melts. x) The ion that absorbs at the longer wavelength: (Fe 2+, Fe 3+ ). y) The CTE of soda lime silicate glass is near (5x10-7 /ºC, 50x10-7 /ºC, 100x10-7 /ºC) z) You ll have to wait longest for flow to occur at the (working point, softening point) Bonus1: You make a new glass and after annealing, discover that it has turned milky white. What could have happened? What experiment(s) can you do to test your hypothesis? (5 points) Bonus 2: (5 points, if it makes a difference): I deserve a for my grade in this course because: