{"title":"Phase Equilibrium Relations in the Sc<sub>2</sub>O<sub>3</sub>-Ga<sub>2</sub>O<sub>3</sub> System.","authors":"S J Schneider, J L Waring","doi":"10.6028/jres.067A.003","DOIUrl":null,"url":null,"abstract":"<p><p>The phase equilibrium diagram was determined for the Sc<sub>2</sub>O<sub>3</sub>-Ga<sub>2</sub>O<sub>3</sub> system. A quenching furnace, wound with 60 percent Pt-40 percent Rh wire, was employed for experiments conducted at temperatures up to 1,800 °C. An induction furnace, having an iridium crucible susceptor, was used to obtain higher temperatures. Temperatures in the quenching furnace were measured with both an optical pyrometer and a 95 percent Pt-5 percent Rh versus 80 percent Pt-20 percent Rh thermocouple. The melting point of Ga<sub>2</sub>O<sub>3</sub> was determined as 1,795 ±15 °C. Experiments at temperatures as high as 2,405 °C failed to melt Sc<sub>2</sub>O<sub>3</sub>. Two intermediate binary phases, a compound believed to be 6Sc<sub>2</sub>O<sub>3</sub>·5Ga<sub>2</sub>O<sub>3</sub> and a solid solution occur in the system. The solid solution phase appears as a single phase in the region roughly defined by the compositional limits of 55 to 73 mole percent Ga<sub>2</sub>O<sub>3</sub> at the solidus. The 6:5 compound, stable only at high temperatures, melts incongruently at 1,770 ±15 °C and decomposes below 1,700 ±15 °C. The compound appears to have orthorhombic symmetry with <i>a</i>=13.85 A, <i>b</i>= 9.80 A, and <i>c</i>=9.58 A. The indicated uncertainties in the melting points are a conservative estimate of the overall inaccuracies.</p>","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1963-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324953/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.6028/jres.067A.003","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"1963/2/1 0:00:00","PubModel":"Epub","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The phase equilibrium diagram was determined for the Sc2O3-Ga2O3 system. A quenching furnace, wound with 60 percent Pt-40 percent Rh wire, was employed for experiments conducted at temperatures up to 1,800 °C. An induction furnace, having an iridium crucible susceptor, was used to obtain higher temperatures. Temperatures in the quenching furnace were measured with both an optical pyrometer and a 95 percent Pt-5 percent Rh versus 80 percent Pt-20 percent Rh thermocouple. The melting point of Ga2O3 was determined as 1,795 ±15 °C. Experiments at temperatures as high as 2,405 °C failed to melt Sc2O3. Two intermediate binary phases, a compound believed to be 6Sc2O3·5Ga2O3 and a solid solution occur in the system. The solid solution phase appears as a single phase in the region roughly defined by the compositional limits of 55 to 73 mole percent Ga2O3 at the solidus. The 6:5 compound, stable only at high temperatures, melts incongruently at 1,770 ±15 °C and decomposes below 1,700 ±15 °C. The compound appears to have orthorhombic symmetry with a=13.85 A, b= 9.80 A, and c=9.58 A. The indicated uncertainties in the melting points are a conservative estimate of the overall inaccuracies.