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Classified Abstracts

III - - V a c u u m P r o c e s s i n g T e c h n i q u e s - - III Contd

Evaporated Magnesium Fluoride Films

Japan A s tudy was made of the factors which influence the s t ructure of antl-leflectlon films produced by the evaporat ion of magnesium fluoride The magnes ium fluoride was evaporated at about 10-~mm. Hg from a basket - type evaporat ion source and deposited on a small piece of crown glass, placed 8 cm away Half of the subs t ra te was masked during the process. After deposition the transmlsslvxty of the coated and uncoated par ts of the subst ra te were measured wi th monochromat ic light at normal incidence with the help of a selenium cell The optical thickness of the films was approximate ly k X for m a x i m u m transmmslvl ty The rat io of the t ransmlssivl ty of the coated glass to t ha t of the uncoated glass was determined by a formula, given in the article, to have a m a x i m u m value of 1 029 at 6,200 h The refractive index was calculated to be 1 38 If the subs t ra te was kept at room tempera tu re during deposition, the refractive index was found to be the same as t ha t of bulk magnes ium fluoride, ~ e 1 39 But, if the subs t ra te was at a higher temperature , the results were erratic In t ha t case the m a x i m u m value for the ratio of transmlssivlt les was oscillating between 1 033 and 1 031 and the refractive index was 1 37 This seems to indicate t ha t deposits on glass at room tempera ture are free from pores, whereas films deposited on gla~s at elevated t empera tu res are porous due to the formation of a crystalhne s t ructure

Somrnazre Recherche sur les facteurs de t ra l tement mfluengant la s t ructure et la quaht6 de couches antar6- fldchissantes produltes par 6vaporat ion de fluorure de magndsmm

The Application of A l u m m m m Reflecting Films to Glass and Plastics by Thermal Evaporation Canada A s tudy is presented of the fundamenta l principles which govern the deposition of a lumlnmm films upon various materials The article is divided into two par ts Pa r t I deals with films on glass suppor ts and Par t I I (to be published in the next issue) wi th films on plastics The conclusions and notat ions are extended wherever possible to the commercial aspect of evaporat ion (Author)

Somma,re Etude des prlnclpes g6rant le d6p6t d 'Mumlmum sur verre ou plastlques par la m6thode d '6vapora- t ton avec ref6rence partmull~re ~ la product ion ~ l'6chelle lndustrlelle

The Protective Properties of the Natural Oxide Films on A l u m m m m

See Abstract No ' 223/1

Preparation, Properties and Optical Applications of Thin Films of Titanium Dioxide

Umted States The paper presents da ta on the optical properties, s t ructure and oxidation of evaporated t i t an ium films and discusses the structure, propert ies and applications of t i t an ium dioxide coatings prepared by heat oxidation of vacuum deposited t i t an ium and by decomposition of t l t a m u m tetrachlorlde wi th atmos- pherm water vapour I t is shown t h a t the rate of deposition and the pressure in the evaporat ion u m t influence greatly the s t ructure and optical propert ies of evaporated t~tamum films, and of t i t an ium dioxide coatings prepared by heat oxidation of evaporated t i t an ium Pure t i t an ium films can only be deposited by fast evapora- t ion at good vacuum Slow evaporat ion at poor vacuum results in TIO-T1N films with cubic s t ructure The oxidation of pure t i t an ium films in air a t 400 ° to 450°C results in t l t a m u m dioxide films wi th rutile s t ructure and high n-values while ' poorly deposited t i t an ium films ' oxtdlse at the same tempera ture to t i t an ium dioxide films with anatase s t ructure and much lower n-values Rutlle IS especially suitable as a top film in mult i layer combinat ions T l t a m u m dioxide films produced by fulmng t l t a m u m tetrachiorlde on to hot glass are amorphous if the glass t empera ture as kept below 280°C and consist of anatase at higher tempera tures An anod.~ method for applying reflectance-increasing film pairs of a l u m m m m oxide and t i t an ium dioxide and a lunumuu. mirrors is described (Author)

Somma,re Discussion des proprl6t6s optlques, s t ructure et oxydat ton de t l t a m u m evapor6

The Production and Electrical Properties of Thln Metal Films

France The article gives a description of various methods employed to prepare films, the proper tms of which have been subsequent ly investigated f rom the following angles The relation between tbackness and electrical conductivi ty of the films, the effect of the nature of the subs t ra te and the nature of the metal on h im s t ructure and growth, and the influence of tempera ture The metals used in the experiments were gold and copper, the subs t ra tes essentially slhca, plexlglass and monocrysta ls of NaC1, KC1, Kbr and NOsNa

Somma~re Les facteurs lUfluen~auts la conducttvxt6 61ectrlque de couches minces m6talhques out ete etudlds.

Filters for the Infra-Red Region Umted States The authors report on the product ion and performance of infra-red t ransmi t t ing hires deposited

by the vacuum evaporat ion method and prepared from tellurium, bismuth, an t imony and magnes ium oxide Filters of this kind are used for the removal of s t ray radiation and the segregation of narrow bands in radio- metric measurements The films should be opaque In the visible region and should have short wavelength cut-ells in the infra-red The an t imony films were deposited on a l i thium fluoride plate and the b i smuth films on a calcium fluoride plate The former were opaque at 1 ~ and gave a t ransmiss ion of 75~o at 3/z The

Abstract No. and References]

1R7/III

Article by N Morata

J. Se~ Res lnst Japan

45 , Sept. 1952 127-129

188/III

A1 tlcle by Bateson

V'acy, v~m, 2, Oct 1952

365-376

189/III

190/III

Article by G tiass Vacua

2, Oct. 1952 331-346

191/III

:krt~ele G R a : / Ze Vale

7, July-Sept 1952 1211-1219

192/III

October 1052 Vacuum 428 Vcl 1I No 4