Study reveals the kinetics of niobium and tantalum with steam at elevated temperatures to determine the suitability of high melting metals for fabrication of equipment for temperature steam environments. Niobium obeyed linear kinetics from 1050 degrees to 1500 degrees C but tantalum followed a paralinear rate law

Kilpatrick, M.

Lott, S. K.

English

NASA Technical Reports Server

June 1968
	
Brief 68-10189 
•	 AEC-NASA TECH BRIEF 
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
I•II1	 IiiTIi 
Reaction Studied of Steam with Niobium and Tantalum 
To determine the suitability of high melting metals 
for fabrication of equipment to be used in high-
temperature steam environments, a study was made of 
the kinetics of the refractory metals, niobium and 
tantalum, with steam at elevated temperatures. An 
insight was also desired into the mechanisms of the 
reactions of steam with metals at high temperatures. 
The results of this study are reported in Reaction of 
Flowing Steam with the Refractory Metals Niobium and 
Tantalum, by Martin Kilpatrick and Stanley K. Lott, 
Journal of the Less-Common Metals, 8, (1965) p. 299-
305. The report includes experimental procedures, 
apparatus, preparation of samples, results, and a com-
prehensive discussion of the experiment. 
In the reactions of niobium and tantalum with 
flowing steam, the experimental method involves (1) 
passing steam over an inductively heated specimen of 
metal, (2) passing the products through a condenser to 
remove water, and (3) measuring the gas evolved at 
suitable time intervals in a gas burette. 
It was found that niobium obeyed linear kinetics 
over the temperature range 10500 to 1500°C after a 
brief induction period; the oxide was identified as 
f3-Nb205. Tantalum, however, followed a paralinear 
rate law at temperatures from 950° to 1300°C, with 
the initial parabolic rate of reaction being followed 
by transition to a linear rate.The parabolic portion can 
be represented by a linear Arrhenius plot, while the
linear portion does not follow an Arrhenius relation-
ship. Tantalum forms /3-Ta205 and, as the transition 
to a-Ta205 takes place around 1300°C, the reaction 
becomes too rapid to measure. 
Notes: 
I. This information may be of interest to mechanical 
and reactor engineers concerned with the design of 
high-pressure steam or water systems. 
2. Inquiries concerning this innovation may be di-
rected to:
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B68-10189 
Source: M. Kilpatrick and S. K. Lott

Chemical Engineering Division
(ARG- 1005 1) 
Patent status: 
Inquiries about obtaining rights for commercial 
use of this innovation may be directed to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439
Category 03 
This document was prepared under the sponsorship of the Atomic liability resulting from the use of the information contained in this 
Energy Commission and/or the National Aeronautics and Space document, or warrants that the use of any information, apparatus, 
Administration. Neither the United States Government nor any per- method, or process disclosed in this document may not infringe pri-
son acting on behalf of the United States Government assumes any vately owned rights.
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Reaction studied of steam with niobium and tantalum

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