Knudsen effusion mass spectrometry alloys

The emphasis of this article is on the gaseous species observed in equilibrium high-temperature vapors and their dissociation energies. The fundamentals of Knudsen effusion mass spectrometry and recent methodic developments are described in Sect. 2. The results obtained by this method for metals and alloys, oxides, metal halides, and technical materials are reviewed in the following four sections. The results are discussed considering, in addition, relevant studies by... 

Thermodynamic data of alloys, such as mixing properties, can additionally be evaluated from the data obtained for the gaseous species over these alloys. A comprehensive bibhography of the studies by Knudsen effusion mass spectrometry up to the year 1974 is given by Chatillon et al. [12]. 

The activities for the Li-Pb alloys determined by Knudsen effusion mass spectrometry by Neubert agree well with those from EMF measurements [229]. The results obtained by Rammensee and Fraser [241] for solid Fe-Co alloys and the melt of the Fe-Ni system are not consistent with the investigations by Tomiska [242, 243] on these alloys also given in Table 7. The chemical activities determined by Hilpert et al. [252] for the nickel-rich part of the Ni-Al system (x i = 0.7 to 0.92) are not very consistent with those obtained for only two compositions of this concentration range by Oforka and Argent s investigations... 

An account of the gaseous species observed by Knudsen effusion mass spectrometry in the eqilibrium vapor of metals, alloys, oxides, halides, and technical systems is given. The fundamentals and recent developments of this method are briefly reported. Dissociation and atomization enthalpies of selected gaseous species are tabulated. Accounts of the equilibrium studies by Knudsen effusion mass spectrometry in order to obtain thermodynamic properties for condensed phases from gas phase data are additionally given for the aforementioned materials. Table 8 shows as an example the enthalpies and Gibbs energies of formation for different solid intermetallic compounds. A special section (Sect. 

In the field of metals or alloys gaseous complex Zintl compounds were identified for the first time. The combination of the results of all electron ab initio computations and Knudsen effusion mass spectrometry have made the determination of improved values for bond energies possible. Moreover, bond energies for transition metal trimers were obtained for the first time. 

Most of the vaporization studies by Knudsen effusion mass spectrometry, carried out for the determination of thermodynamic data of condensed phases, refer to alloys and to a smaller extent to oxide systems as shown by this article. In comparison to this only a few metal halide systems have been investigated. In addition to the study of elements and binary oxides or halides by far most of the... 

The present study was carried out to determine for the first time the thermodynamic activities of Ti and Al over the complete composition range 0 < xAI < 1 in the temperature range from 1200 to 1600K. A detailed presentation of the results obtained will be reported in Ref. [15], The study reported here is part of our systematic investigations on the influence of ternary addiditives to the Ti/Al alloys. Vaporization studies by Knudsen effusion mass spectrometry are used for the thermodynamic investigations. The results obtained by this method for many alloy systems are summarized in a review article by Hilpert [ 16]. The measurements reported in this work complement... 

Hil] Hilpert, K., Miller, M., Study of the Vapori2ationofNi-Cr-Aland Fe-Cr-Al Base Alloys by Knudsen Effusion Mass Spectrometry , Z. Metallkd., 83(10), 739-743 (1992) (Experimental, Thermodyn., 15)... 

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