NASA Scientific and Technical Aerospace Reports

are not significantly degraded by the weld repair process. However, both Inconel 718 and CRES 321 exhibited lower apparent
toughness within the weld repair region compared to the parent metal.
Author
Crack Propagation; Inconel (Trademark); Welded Joints; Stainless Steels
20040121004 NASA Langley Research Center, Hampton, VA, USA
Process for Coating Substrates with Catalytic Materials
Klelin, Ric J., Inventor; Upchurch, Billy T., Inventor; Schryer, David R., Inventor; June 22, 2004; 6 pp.; In English; Original
contains black and white illustrations
Patent Info.: Filed 30 Jun. 2000; US-Patent-6,753,293; US-Patent-Appl-SN-607211; No Copyright; Avail: CASI; A02,
Hardcopy
A process for forming catalysts by coating substrates with two or more catalytic components, which comprises the
following sequence of steps. First, the substrate is infused with an adequate amount of solution having a starting material
comprising a catalytic component precursor, wherein the thermal decomposition product of the catalytic component precursor
is a catalytic component. Second, the excess of the solution is removed from the substrate. thereby leaving a coating of the
catalytic component precursor on the surface of the substrate. Third, the coating of the catalytic component precursor is
converted to the catalytic component by thermal decomposition. Finally, the coated substance is etched to increase the surface
area. The list three steps are then repeated for at least a second catalytic component. This process is ideally suited for
application in producing efficient low temperature oxidation catalysts.
Author
Catalysts; Coating; Substrates
20040121009 Defence Science and Technology Organisation, Fishermans Bend, Australia
Fatigue Life Estimate of Centre-Box Lug in Seahawk’s Stabilator
Polanco, Frank G.; Boykett, P. H.; July 2004; 143 pp.; In English; Original contains color illustrations
Report No.(s): DSTO-TR-1590; DODA-AR-013-125; Copyright; Avail: Other Sources
The fatigue failure of a centre-box lug. found in the Seahawk’s stabilator. highlighted deficiencies in the fatigue life
assessment of helicopter airframe structure. Thus a methodology for fatigue life assessment was developed using this cracked
lug as a demonstrator. Indirect measurements from the Flight Loads Survey on the Black Hawk. although not ideal. allowed
the estimation of the amplitude and frequency of the lug’s loading. Of the sixteen assumptions made in this fatigue analysis.
the most restrictive was that a high amplitude and high frequency loading acts for the entire flying time. Three different fatigue
lives were obtained based on different levels of conservatism in the loading estimates. These three loadings were: the
worst-case scenario, a high loading scenario. and a best-case scenario. The worst-case and high-loading scenarios resulted in
low fatigue lives. while the best-case scenario resulted in an unlimited life for the cracked lug. It was surprising to find such
low fatigue lives for two of these scenarios. but these low lives may be due to the conservative assumptions used in the
analysis.
Author
Fatigue Life; Airframes; Helicopters; Lugs; Aerodynamic Loads
20040121104 West Virginia Inst. of Tech., Montgomery, WV, USA
Corrosion Study Using Electrochemical Impedance Spectroscopy
Farooq, Muhammad Umar; 2003 Research Reports: NASA/ASEE Fellowship Program; December 15, 2003, pp. G-1 - G-6;
In English; See also 20040121096; No Copyright; Avail: CASI; A02, Hardcopy
Corrosion is a common phenomenon. It is the destructive result of chemical reaction between a metal or metal alloy and
its environment. Stainless steel tubing is used at Kennedy Space Center for various supply lines which service the orbiter. The
launch pads are also made of stainless steel. The environment at the launch site has very high chloride content due to the
proximity to the Atlantic Ocean. Also, during a launch, the exhaust products in the solid rocket boosters include concentrated
hydrogen chloride. The purpose of this project was to study various alloys by Electrochemical Impedance Spectroscopy in
corrosive environments similar to the launch sites. This report includes data and analysis of the measurements for 304L,
254SMO and AL-6XN in primarily neutral 3.55% NaCl. One set of data for 304L in neutral 3.55%NaCl + 0.1N HCl is also
included.
Author
Corrosion Tests; Electrochemical Corrosion; Electrical Impedance; Impedance Measurement; Spectroscopy; Stainless Steels
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