Kunigahalli L. Vasanth

Naval Surface Warfare Center Carcderock Division · Metals

Scanning Kelvin probe force microscopy was used to investigate the influence of microstructure on the corrosion behavior of nickel aluminum bronzes in ammoniacal and NaCl solutions as well as under potential control in Na2SO4. The results showed an inverse correlation between the measured Volta potential difference and the observed corrosion behavi...

Because of its inherent corrosion resistance and non-magnetic properties, high alloyed austenitic stainless steel is being evaluated by the U. S. Navy for a full-scale ship structure. While other potential issues such as susceptibility to localized corrosion, marine fouling and conditions leading to liquid metal embrittlement have been discussed el...

The performance of thin film inductive magnetic recording heads has been evaluated at high temperature and high humidity conditions with and without saturated sodium chloride solution, in the absence of a Vapor Phase Corrosion Inhibitor (VCI) emitter, and finally, in the presence of a VCI emitter. The performance of inductive recording heads were c...

The Laser Induce Surface Improvement (LISI) process was developed by the University of Tennessee Space Institute and utilizes Nd-Yag lasers to melt selected precursor material with the substrate of interest to form a durable and environmentally resistant surface finish. The LISI process can be tailored to produce a superior surface with minimum, if...

The effect of Volatile Corrosion Inhibitors (VCI's) on the performance of magnetic data storage rigid disks has been studied. This was achieved by comparing the evolution of a disk's morphology and magnetic signals when exposed to harsh environmental conditions with and without a VCI. These conditions were high temperature and humidity originated f...

The effect of beef lipids on the local corrosion resistance of aluminum alloys was investigated. A mixture of chloroform and methanol was employed for the separation of beef from lipids. Electrochemical corrosion studies were also conducted on high purity aluminum sheet. The electrochemical impedance spectroscopic (EIS) experiments were performed a...

Vapor Phase Corrosion Inhibitors (VCIs) are chemical compounds having significant vapor pressures that allow vaporization of the molecules and subsequent adsorption of these on metallic surfaces. The advantage of these vapor phase corrosion inhibitors is that the vaporized molecules can reach hard-to-reach areas commonly found in electronic enclosu...

Rapid developments in computer technology have changed the traditional approach to research in areas of science and engineering, and corrosion is no exception to this. Corrosion affects us all and an enormous amount of savings can be achieved with proper control of corrosion in terms of financial, human and natural resources. It is only natural for...

X ray photoemission spectra of the core and valence levels for crystalline W–Ni–Fe superalloy are presented. Tungsten alloys are referred to as oquotessuperalloyscquotes because of their high density and strength and are important engineering materials for numerous military and industrial applications [see D. J. Jones and P. Munnery, Powder Metall....

The Design Variable Program of NASA/GSFC provided a systematic approach to evaluate the performance of 12 Ampere-Hour Nickel-Cadmium cells of different designs. Design Variables tested in this program included teflonated negative plates, silver treated negative plates, lightly loaded negative plates, positive plates with no cadmium treatment, plate...

Positive grid failure by various corrosion mechanisms is an important life limiting factor in lead-acid secondary batteries. A 5 to 6 year life cycle is currently typical for such batteries in both commercial and military use. Significantly increased ship availability and cost savings to the Navy can be anticipated with the incorporation of batteri...

The corrosion behavior of five tungsten alloys in 3. 5% NaCl has been characterized using electrochemical and gravimetric tests. Laboratory results are compared to results obtained from exposure to natural sea water. The uniform corrosion rates of the alloys were found to be under 2 mils per year. Alloys designated S1 and S2 exhibited preferential...

Broad spectral band data derived from the Nimbus-7 Earth Radiation Budget experiment are analyzed for the top-of-the-atmosphere noon vs. midnight variations in the exitant longwave flux density, spectral variations in the regional albedos, and differences in land and ocean net radiation budgets. The data were studied for a year (June 1979 to May 19...

Sealed Nickel-Cadmium aerospace cells play a very important role in the mission of the satellite. There has been a constant effort to improve the cycle life, energy density, and reliability of these cells by many manufacturers and users. The Design Variable Cell Program is one systematic approach started by NASA in collaboration with General Electr...

The design variable program of NASA is a systematic approach to evaluate the performance of 12Ah aerospace nickel-cadmium cells of 9 important cell designs. These cells were life cycled in a Low-Earth Orbit (LEO) regime for 3 to 4 years. Representative cells taken from the design variable groups after different cycling periods have been examined. T...

Sealed nickel cadmium cells having large number of cycles on them are discharged using Hg/HgO reference electrode. The negative electrode exhibits the second plateau. A SEM of negative plates of such cells show a number of large crystals of cadmium hydroxide. The large crystals on the negative plates disappear after continuous overcharging in flood...

Problems in the solar data generated by the Nimbus 7 satellite are discussed specifically for scientific users. Major and minor data flaws in the Solar and Earth Flux Data Tape (SEFDT) were identified, defined and categorized. Solar channel assembly misalignment, data gaps, and algorithm errors were among the problems described in detail. Solar flu...

The ERB MATRIX tape is generated by an IBM 3081 computer program and is a 9 track, 1600 BPI tape. The gross format of the tape given on Page 1, shows an initial standard header file followed by data files. The standard header file contains two standard header records. A trailing documentation file (TDF) is the last file on the tape. Pages 9 through...

The Naval Weapons Support Center at Crane, Indiana has conducted a large scale accelerated test of 6.0 Ah Ni-Cd cells. Data from the Crane test have been used to develop an equation for the description of Ni-Cd cell behavior in geosynchronous orbit. This equation relates the anticipated time to failure for a cell in synchronous orbit to temperature...

From measurement and analysis of specific retention volumes of four pairs of meta and para isomers at four well controlled temperatures in the liquid-crystalline stationary phase p,p′-dihexoxyazoxybenzene, precise solute free energy, enthalpy and entropy parameters are obtained. It is found that the para isomer is more soluble and is retained longe...

This paper documents a limited literature review on the past, current and proposed use of corrosion inhibitors in naval vessels. A brief discussion of the type of corrosion inhibitors used, mechanisms of corrosion protection and practical methodology of evaluating corrosion inhibitors is given. Wherever, possible, examples of the systems protected...

Void spaces are an inherent part of all ship designs that must balance internal arrangements with hydrodynamic and other ship architecture constraints. These void spaces are for the most part considered to be dry but often they are not as the ship may be using the spaces as ballast. In addition, all void spaces are subject to condensation which con...

A number of binary systems have been investigated with p-n-dodecyloxybenzal-p-n-butoxyaniline—a mesomorphic component exhibiting both smectic and nematic phases—and other non-liquid crystalline solutes. When the transition temperatures of such binary systems are plotted against the mole per cent composition of the liquid crystalline component, two...

A number of binary systems comprising a liquid crystalline Schiff's base, viz. p-acetoxybenzal-p-phenetidine and a non-liquid crystalline Schiff's base are studied. In all these cases, the liquid phase, be it anisotropic or not, is a single homogeneous phase. There is no indication of two distinct liquid phases, one anisotropic and the other isotro...