Question

For the Ba0-Ti0   phase diagram show, using sketches and reac­tions, the heating path (beginning at room temperature) and cooling path (be­ ginning with a single-phase liquid) for the following compositions:

                                                   38 mole% Ti02

                                                   79 mole% Ti02

                                                   73 mole% Ti02

In the case of cooling, also sketch what the microstructure might look like after reaching room temperature. Then, choose one of the three compositions above for which you think nonequilibrium cooling could take place, and discuss how that path would differ from the equilibrium path. How would you determine from either: (a) the distribution of phases in the microstructure; and/or (b) the phase content (e.g., by x-ray diffraction) if nonequilibrium cooling had occurred?

een 1800 T-1860° Ba O-TYO2 1830 Ba2TiO4 + 1700 liquid , Нех. ВаТiOз dg 1612% 16000 1600 TiO2 1563° Liquid Вa TIOД liquid + 1500 Нех. ВаTiOз 1460° Cubic BaTiO3 1428° eiloe eriuoa Вао 1400 + liquid 1357° BaTi4Og+ liquid Вa-TiOд 1322 1317 BaTi409 1300 Cubic BaTiO3 Ba2TiO4 BaTi205 TiO2 reot + Soletas BaTi2O5 cubic BaTiO3 BBATI3O7 1210° Cubic BaTiO3+BaTi307 60 1200 TIO2 90 80 70 BaO 30 50 40 Mol % Fio nl intermediate compounds of both con- Ba2Ti04 BaTiO3 BaTi205 BaTi307

Answer 1

A too Liguid Her BaTios (612 T:02 (S63 4460 Culic Bao 44 60 1428 t L raTi0u 1357 aTiDy 1322 1317 TaT;03 BaTyOe Cubic Pais al r 1216 ( 1200 TiO AD otiO,t OacCana Un Bal 30 40 Go T:0 BaTiO PBai307

eaui brum stata Cenystallizton In A 30-1. T,0 with Fiss derrean nmpatu. to intc e:0L Cuve cost s tom melt Moves dava Hhe Cunve moce TO t atla T:0yBT0 fat decti ath phos cyallies exheuted ) Cystali satir mwth T:0, ndsetd l Fisd T.0 L cuxve ctallseon To2 fm me down th muwe P polnl uhich cuAve a yeactan eactswith Lid poin Hene TO toum T t0 1-ids Ba rch Now oin ich isge down cach mouy Cunve Sa0ction Pint Eact qid to with Now T BoO rich more PTi exhaudad um To .his conteru v eaction Eutecte Pein y betwen move Foxth +st T RTi,0, smullann Cmagmo wth 73T: simp wth T,0, entete Cmystulaltn 's coystati zan merily t th TO 0, smutloncasly ig cytatis muu

Pnphy'socart Jua'r Buljo, Payby Bo Ti0s NMOLndroy for inuibum Canditon Could rm inibium cyctallnelan he tghay move cactron Phoes cndilin inegui libm OLcous uhen a veactin Phur rs this ppers fhun fred have seaie mineru Suffici en omoun of Henc would harr un vonio Teetn stut lyfms faturn al 2t ponly eatelr alho ben fh -Th Prenn ef voniou of mreale phaw 4 th elat teytuey cou ld be evidin!d in uilibum Condit