Doctoral Dissertations

Abstract

"A static method was used to study the equilibria which exist between the higher sulfides of zirconium and sulfur at temperatures from 700° to 1000 °C. Both disulfide and trisulfide have been identified by chemical analysis and X-ray diffraction. There exists a two-phase region of 'ZrS2' and 'ZrS3'. The composition limit of the homogeneous disulfide phase appears to exist between ZrS1.90 and ZrS2.00. The lower composition limit of the homogeneous region of the trisulfide phase was established as ZrS2.75.

An experimental method of Blitz and co-workers, i.e., the use of evacuated horizontal tubes unequally heated at both ends with a temperature gradient, was adopted for this study. The mixture of sulfur and sulfide was heated until equilibrium was attained. Temperatures from 119° to 445 °C for liquid sulfur were used for the sulfur end of the tube. The resulting zirconium sulfide was then analyzed. The standard free energy change was calculated from the data.

An experimental study has been conducted to determine the equilibrium behavior of the system Sr - S - H2. 'ZrS2' - 'ZrS3' two-phase mixtures were heated in the temperature range from 500° to 700 °C in a circulating type equilibrium apparatus. The system was studied by equilibrating H2 - H2S gas mixtures with the condensed sulfide phases. The equilibrium gas mixtures were analyzed with a Fisher Gas Partitioner.

The standard linear free energy equation for the reaction ZrS2 (s) + H2S (g) = ZrS3 (s) * He (g) was derived from the results and was calculated to be :
ΔF° = - 15.46 T + 11,585

This equation determines the stability of the zirconium sulfide phases when they are subjected to hydrogen reduction. In a dynamic method, hydrogen was circulated over the heated sulfide until equilibrium was attained.

An attempt was made to extend both experimental methods of investigation - the static method of sulfur equilibration in the furnace with temperature gradient and the dynamic method of hydrogen reduction in the circulating type of apparatus - to the Ti - S and the Hf - S systems. The heat of reaction and standard free energy change for the hafnium sulfides were calculated from the experimental results. Limited data were obtained for the titanium sulfides"--Abstract, pp. ii-iii

Advisor(s)

Daniel S. Eppelsheimer

Committee Member(s)

A. W. Schlechten
A. H. Larson

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Metallurgical Engineering

Publisher

University of Missouri at Rolla

Publication Date

1964

Pagination

vii, 173 pages

Note about bibliography

includes bibliographical references (pages 158-161)

Rights

© 1964 Norbert Achilles Vermaut, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 1661

Print OCLC #

5962714

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Metallurgy Commons

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