Nickel base coating alloy

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

The identification of cloud types in LANDSAT MSS images

The author has identified the following significant results. Five general families of clouds were identified: cumulonimbiform, cumuliform, stratiform, stratocumuliform, and cirriform. Four members of this five-fold primary division of clouds were further divided into a number of subgroups. The MSS observed and recorded earth radiation in four different wavebands. Two of these bands (4 and 5) image in the visible portion of the electromagnetic spectrum, while the others (6 and 7) image the short wave portion, or just into the infrared. The main differences between the appearances of clouds in the four wavebands are related to the background brightness of land and sea surfaces

Comparisons of cloud cover evaluated from LANDSAT imagery and meteorological stations across the British Isles

The author has identified the following significant results. This stage of the study has confirmed the initial supposition that LANDSAT data could be analyzed to provide useful data on cloud amount, and that useful light would be thrown thereby on the performance of the ground observer of this aspect of the state of the sky. This study, in comparison with previous studies of a similar nature using data from meteorological satellites, has benefited greatly from the much higher resolution data provided by LANDSAT. This has permitted consideration of not only the overall performance of the surface observer in estimating total cloud cover, but also his performance under different sky conditions

Mesoscale Assessments of Cloud and Rainfall over the British Isles

There are no author-identified significant results in this report

Resistance of nickel-chromium-aluminum alloys to cyclic oxidation at 1100 C and 1200 C

Nickel-rich alloys in the Ni-Cr-Al system were evaluated for cyclic oxidation resistance in still air at 1,100 and 1,200 C. A first approximation oxidation attack parameter Ka was derived from specific weight change data involving both a scaling growth constant and a spalling constant. An estimating equation was derived with Ka as a function of the Cr and Al content by multiple linear regression and translated into countour ternary diagrams showing regions of minimum attack. An additional factor inferred from the regression analysis was that alloys melted in zirconia crucibles had significantly greater oxidation resistance than comparable alloys melted otherwise

Analyses of the cloud contents of multispectral imagery from LANDSAT 2: Mesoscale assessments of cloud and rainfall over the British Isles

The author has identified the following significant results. It was demonstrated that satellites with sufficiently high resolution capability in the visible region of the electromagnetic spectrum could be used to check the accuracy of estimates of total cloud amount assessed subjectively from the ground, and to reveal areas of performance in which corrections should be made. It was also demonstrated that, in middle latitude in summer, cloud shadow may obscure at least half as much again of the land surface covered by an individual LANDSAT frame as the cloud itself. That proportion would increase with latitude and/or time of year towards the winter solstice. Analyses of sample multispectral images for six different categories of clouds in summer revealed marked differences between the reflectance characteristics of cloud fields in the visible/near infrared region of the spectrum

High temperature cyclic oxidation furnace testing at NASA Lewis Research Center

A standardized method of testing the cyclic oxidation resistance of various alloys in static air to 1200 C was developed and is routinely used at NASA Lewis Research Center. Test samples are automatically raised and lowered into a resistance wound furnace for a series of fixed interval heating and cooling cycles. Spall catchers collect the accumulated spall from each sample. The samples are weighed intermittently to generate specific weight change/time data. At various test times the samples and the accumulated spall are analyzed by X-ray diffraction. A computer program uses this gravimetric and X-ray data as input to print out the oxidation curves and specific weight change/time and X-ray results in a published format, organizes, and indexes the data. So far, several hundred Fe, Ni, and Co base alloys were tested using this same basic procedure and results form the basis of a series of cyclic oxidation handbooks to be published by NASA. Such specific weight change/time data were used to estimate the oxidative metal consumption by several computer modeling techniques to rank alloys and for use in life testing estimates

Comparison of isothermal and cyclic oxidation behavior of twenty-five commercial sheet alloys at 1150 C

The cyclic and isothermal oxidation resistance of 25 high-temperature Ni-, Co-, and Fe-base sheet alloys after 100 hours in air at 1150 C was compared. The alloys were evaluated in terms of their oxidation, scaling, and vaporization rates and their tendency for scale spallation. These values were used to develop an oxidation rating parameter based on effective thickness change, as calculated from a mass balance. The calculated thicknesses generally agreed with the measured values, including grain boundary oxidation, to within a factor of 3. Oxidation behavior was related to composition, particularly Cr and Al content

Nicral ternary alloy having improved cyclic oxidation resistance

NiCrAl alloys are improved by the addition of zirconium. These alloys are in the Beta or gamma/gamma' + Beta region of the ternary system. Zirconium is added in a very low amount between 0.06 and 0.20 weight percent. There is a narrow optimum zirconium level at the low value of 0.13 weight percent. Maximum resistance to cyclic oxidation is achieved when the zirconium addition is at the optimum value

Mesoscale assessments of cloud and rainfall over the British Isles

There are no author-identified significant results in this report