Theory and practice of making foils by vacuum deposition

MINISTRY OF EDUCATION 
AND SCIENCE OF RUSSIAN FEDERATION  
NATIONAL UNIVERSIT Y OF SCIENCE AND TECHNOLOGY “MISIS”
I.B. Ulanovskiy
THEORY AND PRACTICE  
OF MAKING FOILS  
BY VACUUM DEPOSITION
Moscow  2016

УДК 544.3 
 
У47
Ulanovskiy I.B.
У47  
Theory and practice of making foils by vacuum deposition / 
I.B. Ulanovskiy. - М. : Izdatelskiy Dom ³MISIS´, 2016. - 232 с.
ISBN 978-5-87623-975-4
This book is the ¿rst attempt ever to offer a consistent review of the main stages 
of a new way to produce foil from metals and alloys through  vacuum deposition; 
the author has created physical models adequately describing this process and enabling engineering calculations of its basic parameters. The results of this study 
have laid a scienti¿c foundation for the development of commercial scale process 
of  making ultrathin foils, including those from dif¿cult-to-form titanium alloys, 
as well as for the development of vacuum engineering devices working something 
of semiconductors.
This book aims to draw the attention of materials science experts, students 
and postgraduate students of technical universities. 
ɍȾɄ
,6%1
” I.B. Ulanovskiy, 2016

CONTENT
Foreword 
......................................................................................................... 6
Introduction .................................................................................................. 10
Chapter 1. General regularities of vacuum condensate structure  
formation and basic requirements to industrial thin foil production  
through vacuum deposition 
.......................................................................14
1.1. Mechanisms of condensation from a gas phase and ³original´ 
structure of the condensate 
....................................................................... 15
1.1.1. Critical temperature of condensation ........................................ 17
1.1.2. InÀuence of the substrate temperature on the condensation 
mechanism ........................................................................................... 19
1.1.3. Primary structure formation in thin ¿lms  
................................. 21
1.2. The structure of ³thick´ condensates ................................................ 23
1.2.1. The inÀuence of substrate temperature on the condensate 
structure 
................................................................................................ 24
1.2.2. Textural effects in the structure of vacuum condensates 
........... 29
1.2.3. Speci¿cs of structure formation in the case of condensation  
onto a moving substrate ........................................................................... 33
1.2.4. The inÀuence of vacuum rarefaction, residual  
gas composition, condensation rate and the deposited layer 
 thickness on condensate structure 
....................................................... 36
1.3. Main requirements to the development of foil production  
process by vacuum deposition ................................................................. 39
Chapter 2. Developing a specialized equipment complex  
and mastering the foil production prosess ................................................44
2.1. Development of УВФ -75-1, УВФ -78-1 plants and a foil heat 
treatment plant 
.......................................................................................... 45
2.2. Development of the ¿rst national pilot plant УВ68Л  
for foil production by vacuum deposition ............................................... 47
2.3. Development of high-capacity plant УВФ-2,0 for making  
foil from hard-to-deform alloys and auxiliary facilities. Launching  
foil production process 
............................................................................. 51
Chapter 3. Heat and mass transfer at a high-speed electron beam 
evaporation of metals, and vacuum vapor deposition onto a moving 
substrate ....................................................................................................55
3.1. Calculation of heat and mass transfer between vaporizer  
and substrate ............................................................................................. 57
3

3.1.1. Methods of description of spatial distribution of vapor  
and radiation Àows 
............................................................................... 57
3.1.2. Determining local angle coef¿cients of radiation  
from the substrate onto the lunule ....................................................... 68
3.1.3. Calculations of vapor and heat Àow densities  
on the strip surface ............................................................................... 74
3.1.4. Determining the condensate depth,  
the vapor utilization coef¿cient and the grading screen shape 
................ 76
3.2. Mathematical description of heat transfer in a moving substrate  ......78
3.3. Numerical solution of the problem ................................................... 84
3.3.1. The algorithm for calculating the temperature  
¿eld averaged over the strip width and thickness  .............................. 84
3.3.2. The algorithm for calculating  
the temperature ¿eld averaged over the strip width  ........................... 86
3.3.3. The algorithm for calculating the temperature  
¿eld averaged over the strip thickness 
................................................. 90
3.4. Testing the adequacy of the developed mathematical simulation 
.......93
3.5. Application of the developed mathematical simulation to predict  
heat and mass transfer processes during vacuum deposition .................. 96
Chapter 4. Main laws of the evaporation process of multi-component 
alloys out of a continuously fed molten pool  
.........................................104
4.1. The composition of the equilibrium pool of molten metal  
with an arbitrary number of alloy components 
...................................... 105
4.2. The evaporation kinetics for multicomponent alloys ..................... 109
4.3. The evaporation of the melts close to dilute solutions ................... 120
4.4. Determination of the activity and Henry coef¿cients.  
Comparing the calculation methods of the equilibrium pool 
................ 124
Chapter 5. Developing principles for substrate strip and antiadhesive 
material selection and a technology of foil manufacturing process 
........131
Chapter 6. Through porosity of the foil made by the vacuum  
condensation technique 
...........................................................................139
6.1. Vacuum tightness and through porosity of the foil 
......................... 140
6.1.1. A quantitative criterion of the foil vacuum tightness .............. 141
6.1.2. Experimental determination of foil vacuum tightness ............ 143
6.2. The inÀuence of vacuum deposition parameters  
on the characteristics of through porosity in the foil ............................. 146
6.3. The model of through porosity formation in the foil ................. 151
4

6.4. Calculation of the preset vacuum tightness of the foil ................... 158
6.5. Calculation of the gas permeability of porous foil screens  
at high temperatures ............................................................................... 161
Chapter 7. Scienti¿c and practical research to develop the process  
of producing thin foil by vacuum vapor deposition onto a moving 
substrate strip ..........................................................................................170
7.1. The choice of alloys concentration range for practical  
applications 
............................................................................................. 171
7.2. Substrate strip and antiadhesive í materials, structures  
and structural interaction 
........................................................................ 172
 7.3. The inÀuence of vacuum deposition process parameters  
on the condensate structure .................................................................... 174
7.3.1. Substrate strip temperature ...................................................... 174
7.3.2. Residual gases pressure and condensation rate 
....................... 192
7.4. The inÀuence of condensation process parameters  
on condensate mechanical properties .................................................... 196
7.5. The use of heat treatment of condensates ....................................... 200
7.6. The inÀuence of condensation conditions on the foil surface 
........ 206
Chapter 8. Using the work results to adress challenges of industry ....... 211
Conclusion ..............................................................................................218
References 
...............................................................................................219
5

 This work is a tribute to Academician 
 Alexander F. Belov í an architect of the Soviet
 aviation metallurgy, the founder 
of the  National Institute of Light Alloys
Foreword
This monograph is based on the author¶s thesis ³The study of principles 
of formation of the structure of vacuum condensates of titanium-based 
alloys and the development of the process of titanium foil production´ 
submitted for the Doctor of Science in Process degree and successfully 
defended in 1991. The study was made in 1973í1990 at the National Institute of Light Alloys (VILS) í one of major research and process centers of 
the Soviet aviation industry at the time. 
Due to the secrecy policies enforced at the time, this work was classi¿ed ³For Of¿cial Use Only´, which greatly impeded the possibility to 
publish its ¿ndings. Today such formal barriers have become obsolete, but 
it is the author¶s belief that its consistently structured solutions to all the 
problems involved may be still useful for a broad scienti¿c community. 
This is the monograph¶s mission. 
Academician Alexander F. Belov, the founder of the National Institute of 
Light Alloys under the auspices of the Ministry of Aviation Industry of the 
USSR, was enthusiastic concerning about all kinds of new manufacturing 
processes, materials and equipment. In early 1970s, at the International Conference on Vacuum Metallurgy, he learned from a report of American experts 
about allegedly successful development of a breakthrough process of making 
foil from titanium alloys through vacuum evaporation and deposition.
This method works as follows. A titanium alloy ingot, from 
which a foil shall be made, is put into a vacuum chamber. The surface of the ingot is heated by an electron beam gun. It causes the alloy to evaporate and deposit on the surface of substrate strip continuously moving over the vaporizer. Once the coating is formed, 
it is separated from the substrate strip as ¿nished foil. Before the start 
of the process, the surface of the substrate strip is coated with a special 
 
separating/antiadhesive material to provide separation of the condensate 
from the substrate strip.
Leading experts from VILS were quite skeptical concerning this idea 
as the development of such process obviously involved a number of brand 
new challenges. 
6

It was not without good reason that skeptics would argue that even the 
traditional process of crystallization of alloys from the liquid phase has not 
been thoroughly studied over many decades of researches. The processes related to foil structure formation during subsequent thermomechanical 
processing also were not clear in detail. Moreover, the process of titanium 
alloy crystallization from vapor phase was not studied at all, to say nothing 
of the absence of any information on the resulting structure and physical 
and mechanical properties of the foil obtained. 
Another challenge was making the foil of a given chemical composition with the even distribution of alloying elements along width, thickness 
and length of the foil. The thing is that titanium alloys contain alloying 
elements characterized by respective vapor pressures varying hundredfold 
or thousandfold. Agents with a higher vapor pressure evaporate from the 
molten metal before other agents. Therefore it was necessary to study kinetics and thermodynamics of the evaporation process for alloys containing components having different vapor pressures. 
Besides, the foil should have a given thickness with minimum deviations throughout its width and length. It is known that the thickest part of 
the foil forms directly over the center of the vaporizer while away from the 
center it becomes thinner. Therefore, the challenge was to ensure proper 
spatial distribution of the vapor Àow during highly intensive electron beam 
evaporation.
It was dif¿cult to select a proper antiadhesive agent and adjust the parameters of its application on the substrate strip. In fact, if the condensate 
would be peeled off the substrate strip over the vaporizer too early a part 
of the foil will melt down due to the lack of heat removal through the substrate strip. Besides, the condensate must not peel off the coiled substrate 
strip in the process of coiling since the foil peeled too early will be damaged. The condensate must peel off the substrate strip free in the form of 
¿nished foil once the process is over. 
However, despite any understandable dif¿culties, the suggested process 
looked very promising, because it allowed to produce the ¿nished product - a thin foil in one run, while the traditional rolling process of making foil from hard alloys required many processes, not to say that thin and 
wide strip of foil cannot be made from titanium alloys is virtually impossible. Therefore, Academician A.F. Belov decided to develop at VILS the 
process of making titanium foil from hard titanium alloys through metal 
evaporation and deposition in a vacuum.
7

At the time of the Cold War, we were still unaware that the development of new production processes by our counterparts overseas hinged on 
their proprietary organizational and economic know-how. A successful invention would be no longer mentioned in any scienti¿c, technical literature 
and international conference reports. However, a failed invention would be 
widely publicized in scienti¿c and technical literature and highlighted in 
reports made at international conferences alleging a success of a new production process. 
What was the reason for this" As the money put into the development 
of such ³dead-end´ process was gone, they tried to lure their counterparts 
into the development of such process thus causing them substantial ¿nancial losses as well. 
This monograph was inspired by this know-how. We did succeed in developing a new production process. 
In 1972, the author of this book, a graduate of the Department of Physical Chemistry, Moscow Institute of Steel and Alloys, quite young employee 
at VILS, successfully defended his PhD thesis on ³Hydrogen diffusion and 
development of porosity in aluminum.´ The thesis addressed the most topical scienti¿c issues and offered solutions to a number of practical problems 
in VILS¶ major ¿eld of research. Previously, VILS would organize annual 
conferences on the interaction of hydrogen with aluminum causing porosity in aluminum semi-products. The author¶s PhD thesis virtually exhausted 
this subject, having 
addressed its main issues, thus making any 
further conferences on 
this topic unnecessary. 
A good knowledge 
of physical chemistry, 
obtaining fundamentally important scienti¿c results and their 
successful application 
to industries, apparently, prompted Academician A.F. Belov to 
appoint the author as 
Academician A. F. Belov and I. B. Ulanovskiy

research manager and administrator of a new unit in VILS aiming to solve 
the above problem. 
The ¿rst specimens of titanium alloy foil were obtained just a few 
months after the appointment, despite overwhelming skeptical attitude. 
But that was only the beginning, only the foretaste of the actual complexity of future problems. 
Our main experiments and invention of new production processes 
aimed to make a foil from titanium alloys. However, process patterns and 
solutions to technological problems discovered during this work are rather 
general and can be applied to processes of foil making by vacuum evaporation and deposiyion of other metals and alloys.
Along with the development of scienti¿c platform of the process, 
we developed technological parameters of the foil production and created 
all necessary equipment for its manufacture. 
This monograph also shows a practical application of the resulting foil 
for making heavy-duty products. Based on our theory of gas-permeable 
screens consisting of multi-layered titanic foil with a preset through-thickness porosity pattern, we developed a vacuum device resembling electronic semiconductors. 
Such screening device is gas-permeable at a moderate temperature and 
it ensures the pumping of all remaining gases through pores in the layers 
of foil, while at a higher temperature it becomes selectively impermeable 
for gases and prevents the access of ³harmful´ components of remaining 
gases to the product placed under the screens. 
It is noteworthy that during this work the author met outstanding scientists and specialists who greatly contributed to successful implementation of this project. First of all, I would like to acknowledge the input 
from the Head of SKB ³Vacuum Coatings´ unit (currently Sidrabe company, Riga), a prominent scientist and designer, PhD in Technical Sciences, 
Edgar V.  Yadin; Director of the E. O. Paton Institute of Electric Welding (Kiev), Academician Boris Paton and Head of the Department of E. 
O. Paton Institute of Electric Welding, Academician Boris A. Movchan; 
Chief Engineer of Vekshinsky Research Institute (Moscow) Vladimir 
Vladimirovich Ivanov; Head of Laboratory of E. O. Paton Institute of 
Electric Welding Mikhail Ivanovich Vinogradov and Leading Specialist 
Vladimir Fedorovich Ulyanov; Director of Kharkov Institute of Physics 
and Process, Academician Viktor Vladimirovich Ivanov; specialists of 
9

ANTK Tupolev: Head of Department of New Equipment Implementation 
(one of the main units of the complex) a successful Design Engineer Oleg 
Nikolayevich Sankov, Chief Technologist Vladimir Vasilyevich Sadkov, 
Head of Laboratory, Phd in Technical Sciences, Yury Viktorovich Gorshkov, Chief Specialist of the Ministry of Aviation Industry Lev Isidorovich 
Karseladze, and VILS employees - Deputy Director of the Institute, Prof. 
Nikolai Fedorovich Anoshkin, Head of Unit, Phd in Technical Sciences, 
Vyacheslav Petrovich Mitin, Head of Research and Production Complex, 
Phd in Technical Sciences, Vladimir Mikhailovich Lovtsov, Scienti¿c Secretary, Phd in Technical Sciences, Lev Khaskelevich Roytberg, Senior Fellow, Phd in Technical Sciences, Boris Abramovich Kopeliovich.
My special acknowledgements go to the specialists who worked under my direct supervision: Evgeny Stepanovich Zhiltsov, Alexander 
Vladimirovich Bushuev, Valentin Fedorovich Eliseev, Georgy Isaakovich 
Dubnik, Alexander Fedorovich Sorokin, Alexander Dmitrievich Dolmatov, 
Viktor Stepanovich Zhukovsky, Tikhon Sergeyevich Tretyakov to name 
but a few. 
I am especially grateful to my teacher í Head of Department of Physical Chemistry of MISiS, Honored Scientist of the RSFSR, Professor, Doctor of Chemistry, Alexander Abramovich Zhukhovitsky.
I would also like to thank Mikhail Soloveitchik, PhD, and Vladimir 
Soloveitchik, PhD, for help in ful¿lling this work.
Finally, I would like to thank Irina Vladimirovna Apykhtina for her 
comprehensive assistance in preparing this monograph, as well as the 
Head of the Department of Physical Chemistry of NITU ³MISiS´, Doctor 
of Chemistry, Professor Mikhail Vasilyevich Astakhov, Doctor of Sciences in Physics and Mathematics Yuri Rakhmilyevich Nemirovskiy for their 
kind attention towards this work.
Introduction
The development of new material and processes is an integral part of 
scienti¿c and technological processes. The evolution of aviation and space 
engineering, modern acceleration devices, vacuum process and a number 
of other industries needs unique foil materials, including ultra thin ones 
made from dif¿cult-to-deform metals, alloys of complex chemical composition, as well as multilayer foil, a foil with high strength, ductility, heat 
resistance, and preset through-thickness porosity, etc. 
10