Zirconium is added to a Ni-30 Al (beta) intermetallic alloy in the range of 0.05 w/o to 0.25 w/o. This addition is made during melting or by using metal powders. The addition of zirconium improves the cyclic oxidation resistance of the alloys at temperatures above 1100 C

Barrett, C. A.

Lowell, C. E.

English

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United States Patent I191 1111 Patent Number: 4,610,736 
Barrett et al. 1451 Date of Patent: Sep. 9, 1986 
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NICKEL BASE COATING ALLOY 
Inventors: 
Assignee: 
Appl. No.: 
Filed: 
Int. C1.4 .... 
Charles A. Barrett, Fairview Park; 
Carl E. Lowell, Lakewood, both of 
Ohio 
The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, D.C. 
478,131 
Mar. 23, 1983 
......................................... C22C 19/03 
U.S. Cl. ..................................... 148/429; 420/460 
Field of Search ................. 420/460; 148/409, 429 
References Cited 
U.S. PATENT DOCUMENTS 
2,910,356 10/1959 Grala et al. ......................... 420/460 
3,260,505 7/1966 Ver Snyder .......................... 253/77 
3,494,709 2/1970 Piearcey .............................. 416/232 
3,564,940 2/1971 Thompson et al. ................... 75/134 
3,677,835 7/1982 Tien et al. .......................... 14W32.5 
3,869,284 3/1975 Baldwin ............................ 75/134 F 
4,340,425 7/1982 Frosch ................................ 420/445 
OTHER PUBLICATIONS 
Gmelin, “Handbuch Der Anorganischen Chemie”, 8th 
Ed, System Nr. 35A, Aluminum (1934), pp. 969, 970, 
971, 1004. 
Primaty Examiner-R. Dean 
Attorney, Agent, or Firm-Gene E. Shook; John R. 
Manning 
ABSTRACT 
Zirconium is added to a Ni-30 AI (Beta) intermetallic 
alloy in the range of 0.05 w/o to 0.25 w/o. This addition 
is made during melting or by using metal powders. The I 
addition of zirconium improves the cyclic oxidation 
resistance of the alloy at temperatures above 1100” C. 
1571 
7 Claims, 1 Drawing Figure 
https://ntrs.nasa.gov/search.jsp?R=19870005049 2020-03-23T15:08:04+00:00Z
U.S. Patent Sep. 9,1986 4,610,736 
1 
NICKEL BASE COATING ALLOY 
ORIGIN OF THE INVENTION 
The invention described herein was made by employ- 
ees of the United States Government and may be manu- 
factured and used by or for the Government for govern- 
mental purposes without the payment of any royalties 
thereon or therefor. 
TECHNICAL FIELD 
BRIEF DESCRIPTION OF THE DRAWING 
The objects, advantages, and novel features of the 
invention will be more fully apparent from the follow- 
ing detailed description when read in connection with 
the accompanying drawing. The graph which forms the 
drawing shows specific weight change plotted against 
time for a 3000 hour test having one hour exposure 
cycles at 1200" C. in static air of 2.32 mm thick test 
samples of a Ni-30 A1 (beta) intermetallic alloy to 
which zirconium had been added in accordance with 
the present invention. 
BEST MODE FOR CARRYING OUT THE 
INVENTION 
Small amounts of zirconium were alloyed to a nomi- 
nal nickel-30 aluminum (beta) intermetallic alloy in 
accordance with the invention. This was accomplished 
by melting the metallic alloy in a zirconia lined crucible. 
By joint melting of two separate master heats, the exo- 
thermic reaction caused by combining the two heats 
enables the zirconium to be leached from the zirconia 
liner without melting at an excessively high tempera- 
ture. After melting, the intermetallic alloy contained 
0.20 w/o zirconium. 
The cyclic oxidation resistance of this intermetallic 
alloy was significantly improved by the zirconium addi- 
tion. The scaling rate was found to be essentially para- 
bolic for out to 3000 one hour exposure cycles at 120020 
,736 
2 
C. in static air. A scaling rate parabolic scaling constant 
of just under 0.01 was derived for the sample shown in 
the drawing. 
Based on the tests shown in the drawing it was found 
the oxidation resistance of this alloy to be far superior to 
conventional coating alloys or any other alloy or coat- 
ing in the iron-, nickel-, or cobalt-base systems. This 
includes the best FeCrAl heater alloys. 
The nickel-30 aluminum (beta) alloy without any 
zirconium addition was tested in a similar manner. It 
was evident that the small zirconium addition resulted 
in an improvement of several orders of magnitude. 
DESCRIPTION OF THE ALTERNATE 
EMBODIMENTS 
After the nickel-30 aluminum (beta) intermetallic 
alloy having the small zirconium addition had proved 
itself in the cyclic oxidation testing shown in the draw- 
ing, the alloy was also produced as metal powder. A 
0.17 W/B zirconium addition was made to the powder 
2o which was hot extruded to a dense alloy. This same 
dense alloy was produced from the powder by hot 
isostatic pressing. The resulting alloy showed the same 
superior cyclic oxidation resistance as the melted alloy. 
While several embodiments of the invention have 
25 been disclosed and described, it will be apparent that 
various modifications may be made to these alloys with- 
out departing from the spirit of the invention or the 
scope of the subjoined claims. 
1. An improved oxidation resistant nickel base alloy 
an intermetallic (beta) alloy containing about 30 
between about 0.05 weight percent to about 0.25 
This invention is concerned with a coating alloy con- 
taining nickel and aluminum. The invention is particu- 
larly directed to a beta phase intermetallic alloy having 
improved oxidation resistance. 
oxidation resistance of a Ni-30 AI (beta) alloy at temper- 
atures above 1 100" C. Such an alloy has no basic alloy 
additives because of the difficulties encountered when it 
is attempted to add small controlled amounts of ele- 
ments to the beta intermetallic alloy. 
Protective coatings of A1203 have been used in the 
prior art. It has been found in cyclic testing above 1100" 
C. that such protective coatings would tend to spa11 or 
flake off when cooled. 
BACKGROUNDART 
Thompson et a1 U.S. Pat. NO. 3,564,940 discloses a 
high strength, eutectic alloy directionally solidified or 
as high strength whiskers. A nickel-aluminum-chromi- 
um-zirconium alloy described in this patent contains 30 consisting essentially of 
many other elements. The nickel content can be as high 
as 35.2 atomic percent, and the zirconium content can 
be as low as 0.005 weight percent. 
DISCLOSURE OF INVENTION 
This invention is directed to an alloy which contains 
nickel and about 30 weight percent aluminum forming a 
p phase intermetallic alloy to which zirconium is added. 
The zirconium addition is in the range of 0.05 w/o to 
0.25 w/o. This addition improves the cyclic oxidation 
resistance of the alloy at temperatures above 1100" C. 40 
It has been found desirable to improve the cyclic l5 
weight percent aluminum, 
weight percent zirconium, and 
35 the remainder being nickel. 
2. a nicke1-30 w/o aluminum (beta) intermetallic 
the addition of between about 0.05 w/o to about 0.25 
w/o zirconium to improve the cyclic oxidation 
resistance at elevated temperatures. 
3. A method of improving the cyclic oxidation resis- 
tance of a nickel-30 weight percent aluminum (beta) 
intermetallic alloy at temperatures above about 1100" C. 
comprising 
adding small amounts of zirconium between about 
0.05 w/o to about 0.25 w/o to the alloy thereby inhibit- 
ing spalling at high temperatures. 
4. A method of improving the cyclic oxidation resis- 
tance of a (beta) intermetallic alloy as claimed in claim 
3 wherein the intermetallic alloy is heated to the melting 
alloy, the improvement comprising 
45 
50 temperature, and 
the zirconium is added to the melted alloy. 
5. In a method of improving the cyclic oxidation 
resistance of a nickel-30 weight percent aluminum 
(beta) intermetallic alloy at temperatures above about 
mixing predetermined amounts of nickel and alumi- 
adding about 0.17 w/o zirconium powders to said 
6. A method of improving the cyclic oxidation resis- 
tance of a (beta) intermetallic alloy as claimed in claim 
5 wherein the mixed powders are hot extruded to form 
a dense alloy. 
7. A method of improving the cyclic oxidation resis- 
65 tance of a (beta) intermetallic alloy as claimed in claim 
5 wherein the mixed powders are hot isostatically 
pressed to form a dense alloy. 
55 1100" C., the improvement comprising the steps of 
num powders, and 
mixture. 
60 
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Nickel base coating alloy

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