Premium
Viscosity and Density of Boron Trioxide
Author(s) -
NAPOLITANO ALBERT,
MACEDO PEDRO B.,
HAWKINS EARL G.
Publication year - 1965
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1965.tb14690.x
Subject(s) - viscometer , arrhenius equation , thermodynamics , viscosity , volume (thermodynamics) , atmospheric temperature range , chemistry , reduced viscosity , relative viscosity , activation energy , boron , temperature dependence of liquid viscosity , curvature , mineralogy , analytical chemistry (journal) , materials science , geometry , physics , organic chemistry , mathematics
Extensive and accurate viscosity values for molten B 2 O 3 are reported over the continuous range from 20 poises (at 1400°C) to 10 10 poises (at 318°C). The measurements were made with a wide‐range rotating‐cylinder viscometer. The melts were pretreated by bubbling superdry nitrogen through them to ensure a minimum water content. Above 800°C the temperature dependence of the viscosity curve obeyed the Arrhenius equation; below 800°C the curvature was smooth showing no breaks. At the low temperatures, although its curvature decreased, the viscosity curve did not obey the Arrhenius equation. Densities were determined between 411° and 1400°C. Over this range the volume expansion coefficient changed by 1 order of magnitude from 3.35 × 10 −4 /°C to 3.34 × 10 −5 /°C. The liquid volume expansion coefficient above 1200°C was smaller than that of the glass below the glass transition temperature, indicating some type of structural rearrangement in B 2 O 3 .