Solid-state diffusion bonding in an inert-gas atmosphere forms high-strength joints between butting or overlapping surfaces of thoriated nickel. This method eliminates inert-phase agglomeration

Bales, T. T.

Manning, R. C., Jr.

English

NASA Technical Reports Server

August 1965	 Brief 65-10220 
NASA TECH BRIEF 
i& 
NASA Tech Briefs are issued by the Technology Utilization Division to summarize specific 
technical innovations derived from the space program. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical information, Springfield, Virginia, 22151. 
Thoriated Nickel Bonded by Solid-State Diffusion Method 
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LABORATORY APPARATUS FOR DIFFUSION BONDING OF OVERLAPPED SPECIMENS 
The problem: To develop a method of forming 
high-strength joints between butting or overlapping 
surfaces of thoriated nickel (a dispersion of 2 by 
weight of thoria in a matrix of nickel). Thoriated 
nickel combines the properties of good workability 
(ductility) with adequate strength and resistance to 
corrosion at elevated temperatures (up to 2,300,F). 
This material cannot be satisfactorily joined by con-
ventional welding methods, however, because the inert 
thoria particles agglomerate in the weld area. 
The solution: Solid-state diffusion bonding of the 
material in an inert-gas atmosphere. This method 
eliminates inert-phase agglomeration and produces a 
high-strength metallic bond.
How it's done: The areas of the specimens to be 
bonded are first cleaned with acetone and water and 
then brought into contact (overlapped as shown in the 
illustration of a laboratory setup). The contacting 
specimens (tack-welded by capacitor discharge at the 
corners of the overlap to maintain them in the proper 
relative position) are then placed in the bonding ap-
paratus. Bonding is effected by means of direct resist-
ance heating and application of a compressive load to 
the overlapping areas of the specimens. An atmos-
phere of argon gas is maintained in the apparatus dur-
ing the bonding process in order to prevent oxidation 
of the base metal in the specimens. Compressive loads 
of 12,500 psi and 8,000 psi maintained for 1 minute at 
(continued overteafl 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern-
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19650000218 2020-03-11T17:19:18+00:00Z
temperatures of 2,000° F and 2,150° F, respectively, 
produced joints capable of withstanding room-temper-
ature shear stresses of up to 52,000 psi. 
Notes: 
I. The results of tests on thoriated nickel strips 
bonded by this method indicate that the joint 
strength is a linear function of the bonding pres-
sure. Specimens bonded at 2,000° F, using a bond-
ing pressure of 8,000 psi, exhibited a shear strength 
of 52,000 psi (approximately 93 percent of the base 
metal strength). 
2. This method, using somewhat different processing 
parameters, also produced satisfactory bonding 
between thoriated nickel and a precipitation-
strengthened nickel superalloy. 
3. Bonding of the nickel composites subjected to me-
chanical pressure in a vacuum furnace requires 7 
to 10 hours, as compared to a time of only 1 min-
ute using the resistance-heating method in an 
argon atmosphere.
4. The resistance-heating method of bonding nickel 
composites should find industrial application in the 
production of components and structures for vac-
uum heat-treatment furnaces, heat exchangers, gas 
turbines, and other equipment which must operate 
at elevated temperatures. 
5. Information concerning the properties of thoriated 
nickel is given in NASA TN D-1944, "An Investi-
gation of a New Nickel Alloy Strengthened by Dis-
persed Thoria", by Charles R. Manning, Jr., Dick 
M. Royster, and David N. Braski, July 1963, avail-
able from the Clearinghouse [or Federal Scientific 
and Technical Information, Springfield, Virginia, 
22151; price $1.00. Inquiries may also be directed 
to:
Technology Utilization Officer 
Langley Research Center 
Langley Station 
Hampton, Virginia, 23365 
Reference: B65-10220 
Patent status: NASA encourages commercial use 
of this innovation. No patent action is contemplated. 
Source: T. T. Bales and R. C. Manning, Jr.
(Langley- I 16) 
Brief 65-10220	 Categories No. 03 and 05


Thoriated nickel bonded by solid-state diffusion method

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