A resistor furnace, with some preliminary results up to 2,000 degrees C

A phase equilibrium diagram for t he system BaO-B, 0 3-S iO, has bee n co n s~ru c te d fr·om data, o btained esse ntiall y by th e quenching met hod, o n 178 te rnary co mpOS it IOn s . One ne w co mpo und, 3Ba· 03B, 9 3· 28 i9" melt in g .at 1,009: C a n.d pos~ess in g an ext~·e m e l y ,t1at primary fi e ld appears, and Its op t ical prope rt ies and X-ray dIffractIOn data a re ~I ve n . [he BaO· 4B,0 3 and 8 iO, prima r y phase areas lllclude alm ost 70 perce nt of t he diagram , a nd o ver these areas exis ts a large region of t wo-liquid immiscibili ty. Limi ted da ta indi cates t hat t he immiscibi lity ga p dec reases wi t h increasing te mpe rat ure. The solid so lu t io n regio n betwee n 2BaO · 38 iO, and BaO·2SiO, ex te nds in to t he in te ri o r of t he diagram a nd is co mplex in nat ure. An isofr-a ct diagram fo r t he quenc hed glasses is s hown . F or precise te mpe rat ure con t ro l of a qu enchin g furn ace, a self-adjustin g, bridge-ty pe con t roll er is desc r ibed briefly .

Section: Very Rare_ ___ _ __ _ ________________________ _ ------_ --mentioning

confidence: 99%

The system barium oxide-boric oxide-silica

Levin¹,

Ugrinic²

1953

“…F rom th ese disks, th e specim ens for solidus and liquidus determinations wer e ground in th e form of small fo ur-sided pyramids, grooved on each side [7] . The tests were condu cted in a thoria resistor-type furnace [8,9]. The specimens wer e placed in the furnace on a disk of a platinum-rhodium alloy for temperatures below 1,900° C. For tempera t ures high er than thi s value, t he samples were placed on an iridium disk.…”

Section: Sample Preparation and Test Methodsmentioning

confidence: 99%

Phase equilibrium relations in the systems Lime-Titania and Zirconia-Titania

Coughanour¹,

Roth²,

DeProsse³

1954

W . Coughanour, R. S. Roth, a nd V. A. DeProsseThe systems CaO-Ti02 and Zr0 2-Ti 02 were studied by means of solid-sta te reactions and by the observation of fu sion characteristics. The existence of t wo bin a r y co mpound s in the CaO-Ti02 system was con firmed . One co mpound was fo und to exist in the Zr02-1 i02 system. This co mpound , Zr02· Ti 02, has been found to ha ve orthor hombi c sy mm etry wi th t he following pa ra meters at roo m te mperature : a = 4.806 A, b= 5.032 A, c= 5.447 A. Solidsolu tion development was obse rved in t he Zr02-Ti 02 system , bu t not in t he CaO-Ti 0 2 system. Fro m t he d ata o btained , an equilibr ium di agram is suggested fo r each system. IntroductionA study of phase relationships in th e systems CaOTi02 and ZrOz-Ti02 h as been condu cted as a par t of a program of fundam en tal stud ies of cerami c dielect rics . l B oth of these systems have been investigated by prev ious workers. The res ul ts of these investigat ions were ra ther d ivergen t, however , so i t was cons idered essen tial that the systems b e reinvestigated.The number of com po unds proposed fo r th e CaO-T i02 system h as varied from one [1] 2 to three [2]. Some previous studi es of the Zr02-Ti02 system [3,4] h avo ind icated th e a bsence of any compounds in the system and th e presence of part ial solid solu t ions. The possibili ty of the stabili zation of th e tetragonal form. of Zr02 by Ti02 has . also been suggested [5]. Brown and Duwez [6] from X -ray and thermal-ex pa nsion meas urem ents proposed a phase diagram ind icating the comp ound Zr02· TiOz. Their d iagram , although no t suppor ted by fusion-poin t data, is simil ar to th e one determined in the present investigation.The determina tion of the meltin g poin ts of the com po und s, and of the solidus and liquidus temperat uros at various points across the two systems, have s upp li ed data from which a revised equilibrium diagr am h as been constructed for th e systems CaOTi02 and Zr02-Ti02. Sample Preparation and Test MethodsThe following materials were used as th e source of componen ts in th e samples fo r this study: CaOEimer Amend Co. reagen t-grade calcium carbonate of 99.5-percen t purity; Zr02-dense Zr02 of nominal 99-per cen t purity, ob tained from the Ti tanium Alloy Manufacturing Co.; Ti02-highly purified titania of purity over 99.9-per cent, ob tained from the Ti tanillm Division of the N a tional Lead Co.Calculations of weigh t composition wer e m ade to ± 0.0l p ercen t, no correction being m ade for t he p ercentage purity of the r aw materials.I 'rhis study was sponsored by the Office of Ordnance Research, Department oCthe Army.2 :J<'igures in brackets indicate literature references at the end of this paper.

“…This eutectic wa determined , however , by a meLhod of optical pyrometry: The furnace, sampl e preparation, and procedure are described in R esearch Papers 1443 and 1703 [19] . The specimen upon which th e optical pyrometer was fo cused was a small four-sided pyramid about %6 in .…”

Section: Apparatus and Methodsmentioning

confidence: 99%

The system BaO-B2O3

Levin¹,

McMurdie²

1949

A phase equilibrium diagram of the system BaO-B20 3 has been constructed fr om data obtained essentiall y by the quenching method. Four congruently m elting compounds were identifi ed: BaOAB20 3, melting at 879° ± 5° C; BaO.2B20 3, melting at 900° ± 5° C; BaO.B20 3, melting at 1,095° ± 5° C; and 3BaO.B20 3, melting at 1,383° ± 5° C . Some optical properties of these compounds were determined with the petrographic microscope, and X-ray d.ffraction data suitable for their id entification were obtained. Barium m etaborate, BaO.B20 3, s howed an inversion occurring between 100° and 400° C. Mixtures contain ing less than 30 p ercent of BaO were found to eparate on fu sion into two li quid layers, one of which contained 30 p ercent of BaO, wherea t he other was nearly pure 1320 3• A curve showing indices of refraction of the quenched glasses is also presc ntcd.