BY THE SEVENTEENTH GOLD MEDALIST OF THE JAPAN INSTITUTE OF METALS

Transcription

1 COMMEMORATIVE LECTURE BY THE SEVENTEENTH GOLD MEDALIST OF THE JAPAN INSTITUTE OF METALS The Relation Fusion Entropy Fusion Metallic Their Crystal By Hiroshi or Heat Structure* Sawamura' The present vestigationh been carried out order revise results present author's previousvestigation. For this purpose, new data about heat fusion most metallic have been used. Almost results those previous vestigationhave beenobtaed. In present vestigation,however, a new fact h beenfound that relation question metallic belongg CPHex should be considered two different regions separately, one beg region lower or region higher. The followgpredictions have been deducedfrom present vestigation: (1) The structures liquid phes equilibrium with solid metallic (except Al) belongg FCC at ir s will be with or, dependently species metallic element, because relation entropy fusion or heat fusion se metallic ir is exactly by a straight le or a smooth curve. The thg will be said about metallic belongg or types space lattice. Though spacelattice followg metallic is considered be BCC at present, most m belong probably FCC Zr, V, Ti, Mn, Eu. Though crystal structure followgmetallic is unknown at present, y belong probably FCC or CPHex Pa, Ac, U, Sm, Pm, Nd, Pr, La, Ce, Ra. I. When one mole absorbg Introduction any solid Tm K heat ΔH, ΔH at one element melts atmospheric (ΔH/Tm)=ΔS at its pressure are called stard molar heat fusion stard molar entropy fusion respectively. In present paper, however, we use simplified nomenclatures, heat fusion entropy fusion, stead above-mentioned expressions. In present paper, moreover, words " crystal structure or space lattice solid element" are ten used, which mean crystal structure or space lattice solid element equilibrium with liquid phe element at its. Accordg Kubchewski Evans(1), Crompn (1895) Richards (1897) were first pot out that entropy fusion metals should have * ** (1) O. Commemorative Institute Pressor Kubchewski mochemistry, Trans. Lecture Metals, Emeritus JIM 3rd, Annual Meetg, Tokyo, 4 `6 April, Kyo University, Kyo, Edition, E.L.L. Evans: (1958), p.189. Metalhcrgical nearly constant value about 2.0. It will become clear afterwards that, strictly speakg, this rule is not right. Tammann uched 1913 on relation crystal structure metallic ir entropy fusion. However, he could not obta any concrete conclusion about this problem. In 1943 Scheil utilized periodic table order evaluate entropy fusion C (diamond). There is some question about his method estimatg entropy fusion. In April year 1958, present author(4) vestigated relation among entropy fusion metallic, ir ir crystal structure for purpose estimatg entropy fusion V which unknown at that time, obtaed some very terestg conclusions. The results this research were also reported(5) journal "Suiyokwai-Shi" published September year. For this vestigation two references were Japan G.Tammaｎn: E.Scheil: Japan. Ther- (4)H. Sawamura: (5)H.Sawamura: Z. Phys. Chem.,.85(1913), Z. Elektrochem., JSPS, , Suiyokwai-Shi, (1943), (1958), 242. April. 13(1958), Vol.13

2 226 The Relation Entropy Fusion or Heat Fusion Metallic adopted; first report(6) published year 1952 by National Bureau Mes, U.S.A. second appendix journal "KzokuButsuri" published year 1958-"Periodic Table recently revised" (7). The results this research present author are summarized follows: (1) Metallic were clsified four groups by type crystal structure. The first group consisted metallic havg body-centred cubic lattice (BCC); second group consisted metallic havg face-centred cubic lattice (FCC); third group consisted metallic havg close-packedhexagonal lattice (CPHex); fourth group consisted havg or space lattice. The relation metallic ir entropy fusion found be by followg formul for first three groups: Their Crystal Structure Fig. 1 Relation heat fusion (Chalmers). group dependent value should be constant follows: its (1) In this med vestigation, wher metallic les equal formul The les. small function Chalmers(8) had 1. (1) BCC, space perature him, he treated followg all solid CPHex by les fusion is pot present results author from shown that respects: if y type not had FCC. belongg type lattice. that group relation solid by a straight entropy space lattice ir heat le. Therefore, fusion solid II. Procedure Investigation Results latter oretical different former. obtaed CPHex (1) se though from formul distance fluence entropy problem research He treated FCC In confirmed author He His present. group, vestigated, adopted, Fig. deter formul les i.e., upon 10-4 be by above vertical dƒ S/dTm x not applicable by that 2.1 certaly higher could or, view, a clation markedly it havg approximately formula The three were parallel however, Seven years have elapsed sce present author published results above mentioned vestigation. Durg this time, new recommended values for heat fusion most solid were given by Kelley(9), while a table cludg crystal structure most solid prepared by Elliott Gleiser(10). Such beg ce, present author tended revise results his previous vestigation, utilizg se new data. it tem- fusion accordg (6) F. D. Rossi, D. D. Wagman, W. H.Evans, S. Leve I. Jaffe: Selected Values ChemicalThermodynamic Properties,(Circular National Bureau Stards,500, 1952). (7) Appendix Kzoku-Butsuri: Periodic Table recentlyrevised,(1958). (8) B. Chalmers: PhysicalMetallurgy,(1959),p. 85. Table 1 shows values heat fusion recommended by Kelley values entropy fusion calculated by present author solid which are grouped families similar crystal structure. In this table, however, several values used previous vestigation are cluded. These values have been considered be available also present vestigation. For example, accordg reference (6), entropy fusion iron is 1.99, while its value is 2.03 when it is calculated usg Kelley's value. As difference se values is negligibly small, it h been decided adopt former value present vestigation. A pot worth noticg about Kelley's publication used present research is that new values many metallic are given re, which have not been cluded reference (6) used previous vestigation. Though it is not clear how accurate se values are, y all have been adopted tact present vestigation. (9) K. K. Kelley: Contributions Data on TheoreticalMetallurgy, Bureau Mes,(1960). (10) J. F. Elliott M. Gleiser: Thermochemistry Steebnahg, Vol.1, (1960),p. 5.

3 Hiroshi Sawamura Table 1 Remarks: *Estimated The heat fusion entropy **F. C. Tetragonal 227 fusion solid.

4 228 The Relation Entropy Fusion or Heat Fusion Metallic As regards crystal structure, that Cr Ca should be poted out present ce. The space lattice former is confirmed be FCC at present, though it considered be BCC at time when previous vestigation carried out. The space lattice latter is confirmed be BCC at present, though it unknown seven years ago. The pots representg relation belongg BCC, FCC CPHex ir entropy fusion have been plotted shown Fig. 2, Fig. 3 Fig. 4 respectively. Then four straight les I II, III IV, V VI, V' VI' have been drawn. The lt two les V VI V' VI' represent above-mentioned relation belongg CPHex. The former relates havg lower. The latter relates those havg a higher cocides with le III IV. Moreover, followg metallic havg higher than 2300 K se figures, it is supposed that experimental errors may be cluded heat fusion se : are omitted somewhat large value Fig. 2 Relation entropy fusion (BCC). Their Crystal Structure Hf, Mo, Nb (Cb), Ir, Ru, Tc Though method drawg se straight les described previous paper, it will now be explaed aga. The relation belongg FCC ir entropy fusion is exactly by a straight le shown Fig. 3. Only Al seems not obey this rule. If this rule really exists, it is eily supposed that or similar rules should also exist metallic belongg BCC CPHex. Under this consideration present author h tended fd first rule question belongg BCC, h drawn a straight le III through two pots, i.e., pot K pot Fe shown Fig. 2. Then, two parallel straight les III IV V VI have been drawn successively. These les are parallel le I II, vertical distance two les III IV V VI h been kept equal that two les I II III IV. The reon why two pots K Fe are selected bis is follows: (1) The values heat fusion given for K Fe seem considerably accurate on account fact that pot former is very low that latter is one very important metals. The crystal structure se is accurately known at all s. To present author's surprise, le III IV drawn above-mentioned procedure exactly represents by chance relation metallic (except Al) belongg FCC ir entropy fusion. The three les dicated by I II, III IV V VI correspond exactly those determed previous vestigation, y are by formul (1), respectively. Naturally le V' VI' is by formula. Therefore, formul representg relation metallic different types space lattice ir heat fusion may be derived from formul (1), follows: (4) Fig. 3 Relation entropy fusion (FCC). (5) (CPHex, region lower ) (6) (CPHex, region higher ) The formula(5) Fig.4 Relation entropy fusion (CPHex). The relation expressed by se formul may be graphically shown Fig. 5, Fig. 6 Fig. 7. Figure 8 shows relation havg various types space lattice or than BCC, FCC CPHex ir entropy fusion. It is worth noticg that pots se (except In) representg

5 Hiroshi Sawamura Fig. 5 Relation heat fusion (BCC). Fig. 6 Relation heat fusion (FCC). Fig. 7 Relation heat fusion (CPHex). relation question are scattered les V VI V' VI'. III. field above Discussion It can be confirmed Fig. 3 that relation metallic ele- 229 Fig. 8 Relation entropy fusion (Or). ments (except Al) belongg FCC ir entropy fusion is exactly by a straight le. Wher Al obeys this rule is not evident. As it is sure that Al belongs FCC from various pots view, reon why pot Al is far away from le III IV Fig. 3 may be existence some characteristic property Al, or some great experimental error that arose meurement heat fusion Al. As mentioned before, present author h proposed that if an exact lear relation exists belongg FCC ir entropy fusion, similar relation should be found havg different-types space lattice. This idea is probably right light results Chalmers'(8) oretical research already referred. Under this consideration present author h determed relation metallic belongg BCC ir entropy fusion by drawg a straight le 111 shown Fig. 2. The pots several metallic cludg Zr, V, Ti, Mn, Eu shift upwards from le I II, yet exist regularly on les III IV V' VI' found for metallic belongg FCC CPHex respectively, or neighbourhood se les. When fact is taken consideration that relation such that FCC CPHex does not exist FCC BCC or CPHex BCC, it is sure that le I II represents relation metallic belongg BCC, ir entropy fusion, most metallic above poted out have probably crystal structure type FCC no ce h yet been found which a metallic element belongg BCC is transformed state CP Hex at creg, though se metallic are considered those belongg BCC at present. The reon why pot Be belongg CPHex exists far below le V' VI' shown Fig. 4 is unknown. The pots followg metallic,

6 230 The Relation Entropy Fusion or Heat Fusion Metallic Pa, Ac, U, Sm, Pm, Nd, Pr, La, Cc, Ra, are dicated Fig. 8, ir crystal structure beg unknown at present. The types space lattice se are predicted be FCC or C PHex, because pots se exist on or a little apart from les III IV V' VI'. The reon why relation FCC CP Hex h been uched above will be here explaed. The relation metallic belongg CPHex ir entropy fusion remarkably differs from that regardg metallic belongg BCC or FCC shown Fig. 4. It is by le V VI region lower by le V' VI' region higher. The le V' VI' cocides with le III IV, latter representg relation metallic belongg FCC ir entropy fusion. FCC is essentially different from CPHex type space lattice, though m h close-packed structure. When y are heated high, especially high near ir, it seems become difficult distguish one from anor. The fact that relation mentioned above with respect metallic belongg CPHex differs by ces lower or higher, is probably attributable above-mentioned phenomenon. As shown Fig. 3 or Fig. 6, relation metallic (except Al) belongg FCC ir entropy fusion or ir heat fusion is exactly by a straight le or a smooth contuous curve. From this fact it may be supposed that structure liquid phe equilibrium with solid at ir will be regardless species, because orwise relation mentioned above should be by an irregular discontuous Their Crystal Structure curve. The thg will be said about metallic belongg BCC or CPHex. IV. Conclusions The present vestigation on relation among metallic, ir entropy fusion or ir heat fusion ir crystal structure h been carried out order revise results previous vestigation present author by usg new data afterwards published. Almost results have been obtaed previous vestigation. In present vestigation, however, new phenomenon h been found that formula representg relation metallic belongg CPHex ir entropy fusion or ir heat fusion is different two regions lower higher s. The important results predicted present vestigation may be summarized follows: (1) Though followg metallic are considered belong BCC at present, most m belong probably FCC. Zr, V, Ti, Mn, Eu. Though crystal structure followg metallic are unknown at present, y belong probably FCC or CPHex. Pa, Ac, U, Sm, Pm, Nd, Pr, La, Cc, Ra. The structure liquid phe equilibrium with solid metallic belongg FCC at ir may be considered be regardless species. The phenomenon will be found metallic belongg BCC or CPHex.