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thermochemical reaction rates

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Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005193
EISBN: 978-1-62708-187-0
... Abstract This article provides an overview of exogenous and indigenous inclusions. It discusses the general concepts of phase diagrams, thermochemical relationships, and reaction rates, along with their practical significance. The article describes the most common techniques for controlling...
Series: ASM Handbook
Volume: 4B
Publisher: ASM International
Published: 30 September 2014
DOI: 10.31399/asm.hb.v04b.a0005927
EISBN: 978-1-62708-166-5
... in the thermochemical treatment. The selection is based on the desired coating and its reaction with the fluidizing gas. The fluidized media could be a combination of inert particles with reactive powders, inert particles coated with the element to be diffused into parts, or only composed of reactive powders...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005206
EISBN: 978-1-62708-187-0
... change of state of a chemical system following the laws of thermodynamics is called chemical thermodynamics. The thermodynamic properties of individual phases can be used for evaluating their relative stability and heat evolution during phase transformations or reactions. Traditionally, the most common...
Series: ASM Handbook
Volume: 5
Publisher: ASM International
Published: 01 January 1994
DOI: 10.31399/asm.hb.v05.a0001225
EISBN: 978-1-62708-170-2
... unavailable in any other cleaning medium. The chemistry involved during various cleaning applications ranges from simple dissolution of contaminants to more complex reactions involving the thermochemical oxidation of organics and the electrolysis of molten salts. Applications As with any cleaning...
Series: ASM Handbook
Volume: 5A
Publisher: ASM International
Published: 01 August 2013
DOI: 10.31399/asm.hb.v05a.a0005707
EISBN: 978-1-62708-171-9
... interaction of a surface with its environment. As with all chemical reactions, the reaction rates that determine the severity of surface degradation due to corrosion are a function of a number of variables, including, for example, the composition and structure of the surface, the composition of the corrodant...
Series: ASM Handbook
Volume: 4A
Publisher: ASM International
Published: 01 August 2013
DOI: 10.31399/asm.hb.v04a.a0005772
EISBN: 978-1-62708-165-8
.... The nucleation rate of the particles at the surface is a function of the boriding time and temperature. This produces a thin, compact boride layer. The subsequent second reaction is diffusion controlled, and the total thickness of the boride layer growth at a particular temperature can be calculated...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003218
EISBN: 978-1-62708-199-3
... Abstract Chemical vapor deposition (CVD) involves the formation of a coating by the reaction of the coating substance with the substrate. Serving as an introduction to CVD, the article provides information on metals, ceramics, and diamond films formed by the CVD process. It further discusses...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006436
EISBN: 978-1-62708-192-4
... Abstract This article describes the surface modification treatments used to modify the tribological properties of titanium alloys. These include physical vapor deposition and thermochemical conversion treatments. The physical vapor deposition includes ion implantation, sputtering, evaporation...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005189
EISBN: 978-1-62708-187-0
... is concerned with how and at what rate the system is transformed from the initial to the final state. The practical importance of chemical kinetics implies that systems often fail to reach the most stable condition and that the path taken plays a major role in determining the speed of the reaction. In general...
Series: ASM Handbook
Volume: 4F
Publisher: ASM International
Published: 01 February 2024
DOI: 10.31399/asm.hb.v4F.a0007013
EISBN: 978-1-62708-450-5
... is usually performed at elevated pressures and is therefore mostly referred to as high-pressure gas quenching (HPGQ). During HPGQ, previously austenitized or thermochemically treated parts are quenched in an inert gas flow in a pressure range between 1 bar and 20 bar, with gas velocities between 0.5 and 20m...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006787
EISBN: 978-1-62708-295-2
... deviate from these rate-law kinetics, or the high-temperature reactions can be a combination of more than one rate. Linear kinetics are typically associated with either a surface reaction step or a nonprotective scaling step being rate controlling. Parabolic kinetics describe high-temperature corrosion...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005434
EISBN: 978-1-62708-196-2
... In this equation, ν ik is the net stoichiometric coefficient of species i in gas-phase reaction k , the net molar reaction rate of which is R k g . The mass fraction (ω i ) and the mole fraction ( x i ) of species i in the mixture are defined as: (Eq 41a) ω i = ρ i ρ...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005348
EISBN: 978-1-62708-187-0
...DOI: 10.31399/asm.hb.v15.a0005348 Abbreviations and Symbols a crystal lattice length along the a axis; cpt critical preheating temperature FM full mold activity CRE carbon removal ef ciency FM (process) fnote mince (thin iron) process CRR carbon removal rate FRC free radical cure A ampere CS...
Series: ASM Handbook
Volume: 13A
Publisher: ASM International
Published: 01 January 2003
DOI: 10.31399/asm.hb.v13a.a0003579
EISBN: 978-1-62708-182-5
... at each electrode at equal rates ( r 1 = r 2 ), as shown in (b), which illustrates copper atoms being oxidized to cupric ions and, at other areas, cupric ions being reduced to metallic copper. Source: Ref 3 This reaction takes place spontaneously, because the standard free energy change...
Series: ASM Handbook
Volume: 24
Publisher: ASM International
Published: 15 June 2020
DOI: 10.31399/asm.hb.v24.a0006561
EISBN: 978-1-62708-290-7
... in anisotropy within the build itself. Additionally, each build is dependent on the starting feedstock material (powder or wire). The rate of layer deposition and cooling kinetics for each layer also have a distinct effect on the internal stress in the build and build plate. Therefore, as-built products...
Series: ASM Handbook
Volume: 2A
Publisher: ASM International
Published: 30 November 2018
DOI: 10.31399/asm.hb.v02a.a0006505
EISBN: 978-1-62708-207-5
... and yield values of rods of 99.7 and 99.99% purities extruded under identical conditions and related observed properties to structural characteristics. Iida et al. ( Ref 23 ) found an anomalous strain-rate sensitivity of yield stress in 99.99 and 99.999% purity metal at fractional values...
Series: ASM Handbook
Volume: 13A
Publisher: ASM International
Published: 01 January 2003
DOI: 10.31399/asm.hb.v13a.a0003588
EISBN: 978-1-62708-182-5
... react chemically when exposed to air or to other more aggressive gases. The reaction rate of some metals is so slow that they are virtually unattacked, but for others, the reaction can be violent. As with most chemical processes, elevated-temperature service is more severe because of the exponential...
Series: ASM Handbook
Volume: 2
Publisher: ASM International
Published: 01 January 1990
DOI: 10.31399/asm.hb.v02.a0005549
EISBN: 978-1-62708-162-7
... steel, temperature BE blended elemental at which cementite completes specimen) solution in austenite B.F. bright field illumination d day d used in mathematical expressions AC1 temperature at which austenite begins (BH)max maximum energy product to form on heating involving a derivative (denotes rate...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003169
EISBN: 978-1-62708-199-3
..., the temperatures required for decomposition of carbonates or hydroxides range from 1000 to 1500 °C (1832 to 2732 °F). A typical decomposition reaction at 1000 °C (1832 °F) and 1 atm pressure is: (Eq 1) CaCO 3 ( s ) ↔ CaO ( s ) + CO 2 ( g ) The rate...
Series: ASM Handbook
Volume: 2
Publisher: ASM International
Published: 01 January 1990
DOI: 10.31399/asm.hb.v02.a0001083
EISBN: 978-1-62708-162-7
..., and thermochemical processing. The article talks about the applications of titanium P/M products, namely, BE and PA products. It concludes with a short note on the future trends in titanium P/M technology. applications blended elemental compacts heat treatment mechanical properties prealloyed compacts...