Effect of molybdenum plus chromium on the corrosion of iron-, nickel-, and cobalt-base alloys in basaltic lava and simulated magmatic gas at 1150/sup 0/C

Abstract By conducting continuous weight-gain measurements from 500 to 1300 C on a variety of Fe-Al, Fe-Cr-Al, Ni-Al and Co-Al alloys in oxygen at 100 torr and examining the reaction products which form, reasons for the enexpected ineffectiveness of preferential aluminum oxidation have been explored. With Fe-4.4 percent Al and Fe-12 percent Al, there are two different regions of parabolic growth- these are associated with the appearance of γ-A12O3 below 900 C and α-Al2O3 above. The latter is normally more protective but possesses a greater tendency for cracking and spalling; adding 24.6 percent chromium promotes its formation at lower temperatures. With Ni-5.0 percent Al, two displaced regions are also found; here, nickel penetrates alumina to provide intermediate NiO · Al2O3 and an outer layer of NiO. With Co-4 percent Al, somewhat less cobalt penetrates γ-Al2O3 to provide CoQ · Al2O3 and an outer layer of Co3O4. When both CoO and α-Al2O3 are stable phases, the latter grows mainly by internal oxidation and offers little protection.

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A comparative study of iron-, nickel-, and cobalt-base weldments exposed in TVA 20-MW and Rocketdyne atmospheric fluidized bed combustors

10.2172/6559930 ◽

1990 ◽

Author(s):

D. Wang ◽

K. Natesan

Keyword(s):

Comparative Study ◽

Fluidized Bed ◽

Iron Nickel ◽

Cobalt Base

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Corrosion of Metals by Liquid Vanadium Pentoxide and the Sodium Vanadates

Journal of Engineering for Power ◽

10.1115/1.3445692 ◽

1973 ◽

Vol 95 (1) ◽

pp. 36-44 ◽

Cited By ~ 8

Author(s):

R. C. Kerby ◽

J. R. Wilson

Keyword(s):

Oxygen Partial Pressure ◽

Partial Pressure ◽

Vanadium Pentoxide ◽

Corrosion Test ◽

Metal Corrosion ◽

Accelerated Corrosion ◽

Corrosion Tests ◽

Accelerated Corrosion Tests ◽

Iron Nickel ◽

Corrosion Of Iron

The rates of liquid vanadate corrosion of iron, nickel and several alloys containing iron, nickel, and chromium have been examined by the use of both static and dynamic accelerated corrosion tests. The dynamic corrosion test involved the rotation of metal disks in the vanadate melts. Corrosion products on the surface of the corroded specimens and in the vanadate melts were examined and identified. The rates of corrosion were found to depend on temperature, oxygen partial pressure, the composition, amount and turbulence of the liquid vanadates, the composition of the metals or alloys in contact with the liquid vanadates, and the duration of the corrosion tests. A mechanism for metal corrosion in the presence of liquid vanadates is proposed.

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Plasma-Arc Studies for Alloy Analysis

Applied Spectroscopy ◽

10.1366/000370267774385687 ◽

1967 ◽

Vol 21 (5) ◽

pp. 300-304 ◽

Cited By ~ 5

Author(s):

James H. Muntz

Keyword(s):

Base Metal ◽

Matrix Effects ◽

Operating Conditions ◽

Spectral Lines ◽

Plasma Arc ◽

Main Disadvantage ◽

Aluminum Iron ◽

Iron Nickel ◽

Cobalt Base ◽

Alloy Analysis

An evaluation of the plasma-arc spectrochemical technique for alloy analysis was made. Matrix effects were studied and found to be present at all concentrations investigated, but were not significant enough to preclude the use of one set of standards for any one particular base metal. The application of the technique for the analysis of aluminum, iron, nickel, and possibly cobalt base alloys has been demonstrated using identical operating conditions and with only three sets of standards. Tungsten was determined with a graphite cap covering the plasma's tungsten transfer electrode to prevent spectral lines from this source. The maintenance required by the nebulizer is the main disadvantage of the technique.

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A Method for Predicting Creep Data for Commercial Alloys on a Correlation Between Creep Strength and Rupture Strength

Journal of Basic Engineering ◽

10.1115/1.3425365 ◽

1972 ◽

Vol 94 (1) ◽

pp. 1-6 ◽

Cited By ~ 11

Author(s):

R. M. Goldhoff ◽

R. F. Gill

Keyword(s):

Rupture Strength ◽

Structural Instability ◽

Data Sets ◽

Creep Data ◽

Time Data ◽

Creep Properties ◽

Long Time ◽

Iron Nickel ◽

Aluminum Base ◽

Cobalt Base

In this paper a method is presented for correlating the creep and rupture strengths of a wide variety of commercial alloys. The ultimate aim of this correlation is to predict design creep properties from rupture data alone. This is of considerable interest because rupture parameter or isothermal rupture curves are frequently the only data available since relatively little creep data is taken today. It is demonstrated in this work that reasonable predictions, useful in design, can be made. The alloys studied range from aluminum base through low alloy and stainless steels and include iron-nickel, nickel, and cobalt-base superalloys. Very long time data for single heats of each of the alloy types has been taken from either the literature or sources willing to make such data available. The construction is simple, and common techniques for determining scatter in the correlation are developed. The predictions include scatter bands of strain-time data developed from the 15 data sets encompassing all the alloys. It is suggested that some refinement might be gained by studying numerous heats of a single specification material where such data is available. A complicating problem of structural instability arises and is discussed in the paper.

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