Coatings for the Protection of Refractory Metals from Oxidation PDF Download

Author: Carol Alnoth Krier
Publisher:
ISBN:
Category : Heat resistant alloys
Languages : en
Pages : 248

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Author: W. A. Gibeaut
Publisher:
ISBN:
Category : Heat resistant alloys
Languages : en
Pages : 104

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Book Description
This report summarizes the information generated since the middle of 1961 on the chemical, physical, and mechanical properties of refractory metals that are coated with oxidation-resistant coatings of advanced-experimental or commercial status. It is a supplement to DMIC Report 162, Coatings for the Protection of Refractory Metals from Oxidation, dated November 24, 1961. Recent data on specific silicide- and aluminide- type coatings for columbium, molybdenum, tantalum, and tungsten and their alloys reflect general advances in coating quality and performance, understanding of the behavior of coated systems, and more complete realization of the problems associated with the use of coated hardware.

Author: National Research Council (U.S.). Committee on Coatings
Publisher: National Academies
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 236

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Book Description

Author: National Research Council (U.S.). Committee on Coatings
Publisher: National Academies
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 246

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Book Description

Author: MATERIALS ADVISORY BOARD (NAS-NRC) WASHINGTON DC.
Publisher:
ISBN:
Category :
Languages : en
Pages : 123

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Book Description
The Coating Subpanel of the Refractory Metals Sheet Rolling Panel reviews and evaluates the current state of the art of coatings for the refractory metals columbium, molybdenum, tantalum, and tungsten. It concludes that a satisfactory technology exists to coat columbium and molybdenum for short-time oxidizing applications where temperatures are as high as 2800 to 3000 F. Coatings for tantalum are in an early stage of development. Satisfactory coatings are not available for protecting tungsten above 3500 F.A coating system, however, must be selected and optimized for each alloy, component design, and for the mission it is to perform. Detailed conclusions are presented for all aspects of coating technology. The conclusions serve as a basis for twelve recommendations concerned with advancing the state of the art. (Author).

Author: William D. Klopp
Publisher:
ISBN:
Category : Heat resistant alloys
Languages : en
Pages : 10

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Author: B. F. Brown
Publisher:
ISBN:
Category : Metallurgy
Languages : en
Pages : 34

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 68

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An investigation of the oxidation behaviour and related characteristics of bulk silicides and silicide coatings of molybdenum and tungsten was conducted. The study included (a) the growth kinetics of disilicide coatings, (b) marker experiments to identify diffusing species during disilicide coating formation, (c) a thermochemical analysis of halide enhanced silicon vapor transport during coating processing, (d) the growth rates of intermediate silicides in the MoSi2/Mo and WSi2/W systems using an electron microprobe technique, (e) the microstructure of protective oxide films grown on MoSi2 and the nonprotective oxidation products formed at low temperatures, (f) an analysis of the oxidation process and the resultant chemistry of the oxidation products based on thermochemical and diffusion rate data, (g) an experimental and analytical treatment of oxidation of molybdenum silicides at high temperatures, to 1600C, and reduced oxygen pressures, and (h) a correlation of experimental coating failure times, in normal oxygen atmospheres, with the required time to transform primary disilicide coatings to lower nonprotective silicide phases. (Author).

Author: B. F. Brown
Publisher:
ISBN:
Category :
Languages : en
Pages : 46

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The vapor pressure of each of the niobium-zinc compounds was measured as a function of temperature. The kinetics of formation of the niobiumzinc compounds on pure niobium from zinc vapor were investigated, and oxidation tests were made on several coatings applied with zinc vapor. The mechanisms involved and the kinetics of the removal of interstitial impurities from niobium by the niobium-zinc compounds were also studied. Further studies of the effects of alloying elements added to the zinc bath used to coat niobium by the dip process confirmed that small amounts of nickel and aluminum in the proper combination are beneficial. (Author).

Author: W. A. Gibeaut
Publisher:
ISBN:
Category : Coatings
Languages : en
Pages : 26

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Four coating processes have been scaled up to coat components of aerospace vehicles: (1) slurry, (2) atmospheric-pressure pack cementa tion, (3) vacuum pack cementation, and (4) fluidized bed. The principal advantage of the slurry process is its ability to coat limited access areas such as the interior channels of built-up corrugated panels. This makes the process ideal for coating spot-welded corrugated panels after they have been welded. The other three coating processes, which are vapor-deposi tion processes, are not so suitable for coating limited-access areas. When they are used for parts such as built-up corrugated panels, the individual parts (including rivets) are coated, then riveted together, and then the entire assembly is recoated. This shortcoming is off set by the fact that the coatings applied by the vapor-deposition processes are more protective at higher temperatures than are the slurry coatings.