1-20 of 253 Search Results for

ionization potential

Follow your search
Access your saved searches in your account

Would you like to receive an alert when new items match your search?
Close Modal
Sort by
Series: ASM Handbook
Volume: 6
Publisher: ASM International
Published: 01 January 1993
DOI: 10.31399/asm.hb.v06.a0001340
EISBN: 978-1-62708-173-3
...Properties of shielding gases used for welding Table 1 Properties of shielding gases used for welding Gas Chemical symbol Molecular weight Specific gravity (a) Density Ionization potential g/ft 3 g/L aJ (b) eV Argon Ar 39.95 1.38 0.1114 1.784 2.52 15.7 Carbon...
Series: ASM Handbook
Volume: 6A
Publisher: ASM International
Published: 31 October 2011
DOI: 10.31399/asm.hb.v06a.a0005597
EISBN: 978-1-62708-174-0
...Properties of shielding gases used for welding Table 1 Properties of shielding gases used for welding Gas Chemical symbol Molecular weight Specific gravity (a) Density Ionization potential g/L g/ft 3 aJ (b) eV Argon Ar 39.95 1.38 1.784 0.1114 2.52 15.7 Carbon...
Series: ASM Handbook Archive
Volume: 10
Publisher: ASM International
Published: 01 January 1986
DOI: 10.31399/asm.hb.v10.a0001772
EISBN: 978-1-62708-178-8
... Milling Figure 7 shows a simplified one-dimensional potential-energy diagram that illustrates field ionization near a metal surface. The potential well of the gas atom is distorted by the externally applied electric field and is affected by the image potential near the sample surface. Therefore...
Series: ASM Handbook
Volume: 13A
Publisher: ASM International
Published: 01 January 2003
DOI: 10.31399/asm.hb.v13a.a0003620
EISBN: 978-1-62708-182-5
..., and noble metal alloys dealloying. The current-potential behavior of a binary alloy undergoing selective dissolution is reviewed. The article highlights the four mechanisms required for the formation of porous metals: ionization-redeposition, surface diffusion, volume diffusion, and percolation model...
Series: ASM Handbook
Volume: 13A
Publisher: ASM International
Published: 01 January 2003
DOI: 10.31399/asm.hb.v13a.a0003681
EISBN: 978-1-62708-182-5
... processes, such as amalgamation or thermal diffusion. Two different modification methods are discussed. The first, ion implantation, is the introduction of ionized species (usually elements, for example, Ti + ) into the substrate using kilovolt to megavolt ion accelerating potentials. The second method...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006651
EISBN: 978-1-62708-213-6
... with lower ionization potentials are formed more efficiently than those with high ionization potentials (e.g., chlorine, iodine, fluorine, etc.), which have ionization potentials near or higher than that of argon. Different zones within the plasma contribute to the ionization process. Desolvation...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006653
EISBN: 978-1-62708-213-6
... in Fig. 1 , the presence of sufficient energy to generate an atomic vapor may also promote the generation of the singly-charged ion of that species (i.e., the energy available exceeds the first ionization potential for the element). When a significant fraction of the metal vapor exists as ions within...
Series: ASM Handbook Archive
Volume: 10
Publisher: ASM International
Published: 01 January 1986
DOI: 10.31399/asm.hb.v10.a0001738
EISBN: 978-1-62708-178-8
... imparted is sufficient only to release an electron. This energy is termed the ionization potential. However, as the electron energy is increased above the ionization potential, enough energy can be transferred to the molecule to release additional electrons ( Eq 2 and 3 ) or to cause bonds to be broken...
Series: ASM Handbook Archive
Volume: 10
Publisher: ASM International
Published: 01 January 1986
DOI: 10.31399/asm.hb.v10.a0001728
EISBN: 978-1-62708-178-8
... with a steady, high concentration of an element having desirable ionization properties. The high concentration of the buffer in the arc column controls the arc voltage and current. The effect of changes in the concentrations of other species with varying ionization potentials is comparatively small. Control...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006648
EISBN: 978-1-62708-213-6
... efficiency of these elements is low in an argon plasma. Helium appears to be a strong candidate to improve the ionization of the aforementioned elements, because it has a first-ionization potential of 24.5 eV and two metastable levels at 19.82 and 20.62 eV. However, due to the low mass of the helium atoms...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006641
EISBN: 978-1-62708-213-6
..., cold-plasma analysis only works for low-mass elements that have relatively lower first-ionization potential. Elements with relatively high first-ionization potential cannot be ionized by such a weak plasma. As a result, a sample must be analyzed at least two times under both hot- and cold-plasma...
Series: ASM Handbook
Volume: 6
Publisher: ASM International
Published: 01 January 1993
DOI: 10.31399/asm.hb.v06.a0001445
EISBN: 978-1-62708-173-3
.... As shown in Fig. 6 , helium seems to improve beam transmission whereas argon can cause severe beam blockage ( Ref 19 ). This is probably due to the lower ionization potential of argon (15 eV) compared to that of helium (25 eV). The effects of air and CO 2 on beam transmission lie between the extremes...
Series: ASM Handbook
Volume: 2
Publisher: ASM International
Published: 01 January 1990
DOI: 10.31399/asm.hb.v02.a0001117
EISBN: 978-1-62708-162-7
... Standard Electrode Potential At 25 °C, 0.87 V versus standard hydrogen electrode Ionization Potentials Degree of ionization Potential, eV I 8.296 II 23.98 III 37.75 IV 258.1 V 338 Semiconductor Properties p -type dopant for silicon and germanium...
Series: ASM Handbook
Volume: 6A
Publisher: ASM International
Published: 31 October 2011
DOI: 10.31399/asm.hb.v06a.a0005641
EISBN: 978-1-62708-174-0
... by trapping the beam inside the hole by total internal reflection. However, the absorption during the initial transient period is dependent on wavelength and surface conditions. There are several techniques to enhance the initial absorption ( Ref 42 ). They include: The ionization potential...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006640
EISBN: 978-1-62708-213-6
... in the collision results in the ionization of the target atom, resulting in optical emission from both the ion and atomic species in cascade reactions. Penning ionization occurs when the target atom has an ionization potential lower than the excited energy of the metastable atom or molecule. Another important...
Series: ASM Handbook
Volume: 6
Publisher: ASM International
Published: 01 January 1993
DOI: 10.31399/asm.hb.v06.a0001356
EISBN: 978-1-62708-173-3
... for shielding gas-tungsten arc welds, which is only partially responsible for its widespread use. Argon has a low ionization potential (2.52 × 10 −18 J, or 15.7 eV), making it easier to form an arc plasma than with other shielding gases. Argon is approximately 1.4 times heavier than air, so it displaces air...
Series: ASM Handbook
Volume: 2A
Publisher: ASM International
Published: 30 November 2018
DOI: 10.31399/asm.hb.v02a.a0006502
EISBN: 978-1-62708-207-5
... plasma. The higher the power, the more clearly the phenomenon can be observed. This negative effect of plasma can be reduced by diluting it with injection of high-ionization-potential gas, such as helium, argon, nitrogen, and mixtures of these gases. Shielding gas may also be required to protect the hot...
Series: ASM Handbook
Volume: 6
Publisher: ASM International
Published: 01 January 1993
DOI: 10.31399/asm.hb.v06.a0001336
EISBN: 978-1-62708-173-3
... in the plasma column. The arc appears to become a broader and more isothermal heat source. The lower peak temperature is reasonable, because a combination of the high ionization potential of helium and relatively low currents of welding arcs gives an arc column that is only slightly ionized. Figure 7 showed...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006647
EISBN: 978-1-62708-213-6
... areas. The atomization process mainly occurs in the preheating zone. The initial radiation zone covers predominantly the excitation and ionization, and the normal analytical zone comprises the emission collected by the spectrometer. The upper part of the plasma corresponds with the recombination zone...
Series: ASM Handbook
Volume: 6A
Publisher: ASM International
Published: 31 October 2011
DOI: 10.31399/asm.hb.v06a.a0005590
EISBN: 978-1-62708-174-0
... widespread use. Argon has a low ionization potential (2.52 × 10 −18 J, or 15.7 eV), making it easier to form an arc plasma than with other shielding gases. Argon is approximately 1.4 times heavier than air, so it displaces air, resulting in excellent shielding of the molten weld pool. Helium has...