Continuous Observations With the Electron Microscope on the Formation of Evaporated Films of Silver, Gold, and Tin

McLauchlan, T. A.; Sennett, R. S.; Scott, G. D.

doi:10.1139/cjr50a-043

Cited by 30 publications

(3 citation statements)

References 2 publications

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“…The genera1 features of the products in all cases show close similarities. Where adequate precautions were taken to exclude moisture, particles usually consisted of cubic crystals of 0.01-5 p diam.9-11 Exposure to moist air resulted in rapid re-crystallization and sintering of particles,7-11 with at least partial modification of the cubic habit, although in one investigation 13 recrystallization and growth of NaC1 particles exposed to moist air apparently produced cubes of greater perfection.…”

Section: Mechanism Of Solidification and The Growth And Evaporation O...mentioning

confidence: 97%

Phase changes in salt vapours

Buckle¹

1960

Discuss. Faraday Soc.

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A high-temperat ure cloud chamber technique devised for studying the freezing of supercooled ionic melts also provides data on phase changes involving salt vapours. Descriptions are given of the condensation, growth and evaporation of liquid and solid particles in clouds of alkali halides. Comparison is made with other work on salt aerosols and the results are examined in the light of recent knowledge of vapour constitution and the theory of nucleation in condensation and crystal growth.A method for studying the spontmeous freezing of ionic melts has recently been described.1 In this method molten salt is prepared in a state of fine subdivision by condensing the vapour. Salt vapour at the saturation pressure is generated, in the presence of argon, by heating the solid in the central chamber of a resistance furnace lined with carbon. A salt bead formed on a small platinum heater coil in the roof of the chamber functions as a supersaturating device. On passing a current of about 2 A through the coil the temperature of the bead is raised by 3QQ-4QOo@ and the vapour in its vicinity rapidly becomes supersaturated. Clouds of solid or liquid particles are formed, depending on the furnace temperature, and these are studied as they circulate in the supporting gas (fig. 1). Movement of individual particles is followed by examining the strongly-illuminated clouds with a telescope, the presence of crystalline particles being revealed by twinkling. By studying clouds at various furnace temperatures below the melting point Q, a point is located where twinkling first becomes apparent during the lifetime of a cloud. In this way, values are obtained for the threshold of freezing Ts and the critical supercooling 8 = Tf-.Ts. A full account of the method together with results for alkali halides will be given elsewhere? An interpretation of the observed supercoolings, based on the theory of homogeneous crystal nucleation, is also in progress.3 Certain qualitative information concerning the condensation, growth and evaporation of cloud particles was obtained during the course of these experiments which received only brief discussion in previous papers. In the present paper this is set out more fully, together with additional evidence, and compared with other work relating to alkali halide aerosols. The results are discussed with reference to recent studies on the constitution of alkali halide vapours and the theory of nucleation in condensation and crystal growth. RESULTS OF OBSERVATIONS ON CLOUDSThe most profound changes in the characteristics of cloud particles for any salt were brought about by changes in the furnace temperature. This provides a convenient basis for the description of clouds, FURNACE TEMPERATURES ABOVE TsAt furnace temperatures above the freezing threshold the Airy diffraction patterns seen in the telescope consisted of a bright central disc of about 0 . 5 m diam. with occasionally a faint concentric ring separated from the disc by a dark

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Section: Mechanism Of Solidification and The Growth And Evaporation O...mentioning

confidence: 97%

Phase changes in salt vapours

Buckle¹

1960

Discuss. Faraday Soc.

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“…The use of TEM to make in situ study of the growth processes, and thus understand the underlying mechanisms, dates back to McLauchlan, Sennett, and Scott. 4 At that time, fundamental issues of metal epitaxy were of interest, and much valuable work was done under relatively poor vacuum conditions, but with in situ deposition. [5][6][7][8][9][10][11] The molecular beam epitaxy technique has emerged since then as a powerful method for controlled growth of semiconductor films, but requires ultrahigh vacuum ͑UHV͒ conditions and excellent control of surface structure and deposition conditions.…”

Section: Introductionmentioning

confidence: 99%

A new surface science in situ transmission and reflection electron microscope

Marshall

McDonald

Tong

et al. 1998

Review of Scientific Instruments

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“…Such a property presents problems in the design of capsules for the 137 CsCl source, because a sufficient volume must be allowed for expansion caused by the phase transformation. Since KC1 may be one of the major impurities in 13 'CsCl, its effects on the phase behavior and other physical properties of CsCl must be determined.…”

Section: Introductionmentioning

confidence: 99%

Anomalous behavior in the kinetics of phase transformation in CsCl--KCl system

Lin¹,

Braski²

1973

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Continuous Observations With the Electron Microscope on the Formation of Evaporated Films of Silver, Gold, and Tin

Cited by 30 publications

References 2 publications

Phase changes in salt vapours

Phase changes in salt vapours

A new surface science in situ transmission and reflection electron microscope

Anomalous behavior in the kinetics of phase transformation in CsCl--KCl system

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