Українська Русский
DonNTU Masters’ portal

Abstract

Table of contents

Introduction

In connection with development of technique an exceptional value was purchased by the difficult electronic systems for collection, treatment and distribution of information, control of technological processes. Counted on a mass production, they must differ high reliability and not very much high cost. These qualities are determined initial materials and technology of processing them in wares. Basic raw material materials for the receipt of ceramic components of electronic industry are sprinkles of snow, from which sintered ceramics with the special electric, magnetic or optical properties. To this class of raw material materials the sprinkles of snow belong for making of ferroceramics.

Increase of requirements to quality of wares from different materials, in particular ferro-, piezoelectric, ferrite, pulled out the task of finding of methods of the forecast management their parameters on the first plan. Lately an accent is done both on thin Materials Science researches and on optimization of technological parameters of receipt of materials and wares from them. Upgrading is the result of adding up of positive effects of all of the stages of technological process on the basis of deep study and understanding of their physical and chemical nature.

1. Actuality of theme

Without regard to considerable achievements of numerous developments from upgrading materials on the basis of CTS, progress in perfection of the noted materials the last years went down sharply. On the first plan a task comes forward the search of new receptions of perfection of structure of already existent materials, which can decide due to intensification of the separate stages of technological process, increase of activity of reactive components with the purpose of increase of speed of heterogeneous processes. Therefore obvious is importance of development and improvement: methods of receipt of piezomaterials, that is maximally suited production and new application of connections of the system of CTS domains.

2. Purpose and research tasks

A purpose of work is research of influence of some technological factors on electrophysics properties of material of CTS for optimization of technology of production of product. The followings tasks decided thus:

  1. To study influence of the physical and chemical state of raw material on technological parameters and properties of materials.
  2. To set the role of dispersion of charge.
  3. To define the optimum temperature of sintering of ferroelectrichard composition.

3. Production of piezoceramic material

The production process of receipt of materials of the system of CTS includes the followings technological stages (picture 1): choice and preparation of raw material; weighing of initial components and preparation of charge to the synthesis; high temperature synthesis; crushing got as sinters connections; grinding down and separation of powders; averaging and attestation [1].

Technology of making of piezoceramic materials (animation: gif format, size75 KB, 11 frame, 6 repeats, duration 11 seconds)

1 — storage of raw material, 2 — a vacuum drying closet, 3 — shaker, 4 — scales, 5 — selenite the drunk barrel, 6 — a shaker of charge, 7 — tunnel stove, 8 — a hammer crusher, 9 — a shaker of the prepared product, 10 — a magnetic separator, 11 — selenite of the prepared product of type the drunk barrel.

Picture 1 — Technology of making of piezoceramic materials (animation: gif format, size 75 KB, 11 frame, 6 repeats, duration 11 seconds)

Raw material all of the tools dry out on sounding boards from not corrosive material in a vacuum drying closet. Dried carbonates of lead, barium and strontium sieved on vibrating screen with the net of 0,63–0,80 micrometers. Supersieve faction after grinding down and throughs is added to subsieve faction. Other types of raw material rough-dry to the throughs are not added.

Averaged every type of raw material during 1,5–2 hours in the mixers of type the drunk barrel (picture 2). A load makes a not more than 0,8 volume of averager. All of the tools weigh in amounts in obedience to the conducted calculation and poured in a mixer [2].

A mixer of type is the «drunk barel»

Picture 2 — A mixer of type is the drunk barel

A averaged charge is added a grade-mixing in a shaker. Time of grade of 1 hour. The synthesis of materials of CTS is pilot-scale carried out in tunnel stoves of continuous action (picture 3). Charge poured in high-aluminous a kapsel layer in 50–60 mm thick and loaded in turn in tunnel stove. Speed of passing of kapsel through a channel must provide 4th sentinel stay of material in the area of temperatures 880–900 °С [3].

Chart of a tunnel stove

Picture 3 — Chart of a tunnel stove

Material after a synthesis is added crushing in a hammer crusher to the sizes of sinters < 5 mm and to the thin grade in a metallic shaker. Material after grinding down is added magnetic separation on the electromagnetic separator of EMS-2.

At presence of magnetic admixtures material is added by separation repeatedly. After separation finally dried material, will attest, prepare to the dispatch or pass on an area on making of wares [4].

4. Influence of some technological factors on properties of piezoceramic material

4.1. Physical and chemical the states of initial components


The physical and chemical state of components (dispersion, admixture composition, structural features, prehistory of receipt and other) substantially influences on the technological parameters of receipt and property of materials of CTS. Choice of feedstock and level of his quality — one of determinatives of receipt of materials with high electrophysics properties. Variety of qualifications, easily soiled, creates the suppliers of raw material certain complications at working off technological parameters, results frequently in the unproducibility of properties, that is related to the features of solidphase reactions.

Quality of feedstock depends and from the admixtures which substantially influence on a solidphase synthesis and render the negative affecting sinterability of ceramics and its electrophysics properties contained in him [5].

With the purpose of study of influence of admixtures on properties of different piezoceramic materials in a charge consciously entered additions — admixtures of silicon, aluminium, iron. The choice of these additions is conditioned their possible presence in a feedstock at his receipt, and also by the features of technological process: on any of the stages the indicated elements can get in material in one or another amount, separately or all together. So, at a vibrograde iron gets in a charge, at calcination in alundum, quartz or high-aluminous kapsel an aluminium and silicon can get in material.

At the receipt of materials with high electrophysics properties quality of feedstock, especially titanic and zirconia, has a decision value. It is possible to suppose that influence of raw material is conditioned mainly his prehistory, determining a crystalline structure, dispersion, cleanness, state of surface, activity of raw material in solid phase processes [6].

4.2. Optimum temperature of synthesis of ferroelectric composition


Compositions of пpiezoceramic materials own the different degree of complication, and it predetermines the features of process of their synthesis to a great extent. Mass of material (gaseous matters are removed) changes at forming of sosoloids, there is his shrinkage, there are thermal effects which characterize passing of reaction in the process of synthesis of material. One of important terms of motion of reactions there is an optimum temperature in hard matters, at which particle acquire mobility, necessary for a exchange placed. With the increase of temperature of their oscillation increased, and active particles which own the large supply of energy and ability to enter into co-operating with other particles appear [7].

For materials of the system of CTS a decline of temperature of synthesis is a not unimportant factor, if to take into account a that circumstance, that volatility of oxide of lead with growth of temperature is considerably increased. One of important terms of motion of reactions there is an optimum temperature in hard matters. In ideal case the temperature of synthesis is chosen high enough, that the reaction of formation of perovskite passed fully, but also low enough, to prevent the losses of volatile component (PBO) and the subsequent grinding down was not complicated.

At the use of technical brands of raw material a monophase product with the structure of perovskite appears at an enough high (1000–1070 °C) temperature, and the electrophysics parameters of materials are notedly worsened here. At the same time application of raw material of reactive cleanness allows to reduce the temperature of synthesis of materials to 900–950 °C and promote their properties [8].


4.3. Dispersion of charge


At the primary mixing and grade-mixing two primary purposes are pursued — the components of charge are mixed up to the high degree of homogeneity and conglomerates collapse, that arrived at most contact between component components. A charge for making of piezoceramic material is made from raw material components in correlation foreseen the formula of composition taking into account the results of the electrophysics measurings of trial parties [9].

For the increase of homogeneity of charge and decline of variation of factious composition of particles of initial components, a premix-averaging and mixing-grinding down of mixture of initial components is foreseen in a flowsheet.

Mixing consists in destruction of conglomerates of particles of powders and achievement of maximal homogenity (degrees of distributing homogeneity) of mixture, by the determined most surface of contacts between by constituents by its initial components. On homogenization of charge diffusive processes depend at an afterbaking (synthesis), structural phasecomposition and electrophysics properties of material [10].

Conclusion


On the basis of the conducted researches it is possible to do the followings conclusions:

— it is rotined that for piezoceramic there must the optimum variant of raw material be matters with the well developed surface, comparatively clean, got at a comparatively not high temperature or by being low temperature modifications;

— it is certain that most influence on the temperature of synthesis and electrophysics properties of piezomaterials is rendered the physical and chemical state of titanias and zirconium;

— it is set that the selected process of mixing must provide the receipt of homogeneous mixture of initial oxides and carbonates with the necessary degree of dispersion, here mixture must contain the least of admixtures and differ high homogeneity and activity.

References

  1. Глозман, И. А. Пьезокерамика / И. А. Глозман. — М.: Энергия, 1967. — 272 с.
  2. Прилипко, Ю. С. Функциональная керамика. Оптимизация технологии: Монография / Ю. С. Прилипко. — Донецк.: Норд-пресс, 2007. — 492 с.
  3. Яффе, Б. Пьезоэлектрическая керамика / Б. Яффе , У. Кук, Г. Яффе. — М.: Мир, 1974. — 288 с.
  4. Смажевская, Е. Г. Пьезоэлектрическая керамика / Е. Г. Смажевская, Н. Б. Фельдман. — М.: Советское радио, 1971.— 200 с.
  5. Технологический регламент получения пьезокерамического материала ЦТСтБС — 2 / Организация П/Я А-7756, 1979. — 23 с.
  6. Фесенко, Е. Г. Новые пьезокерамические материалы / Е. Г. Фесенко. — Изд. Ростовского университета, 1983. — 160 с.
  7. Поляков,  А. А. Технология керамических радиоэлектронных материалов/ А. А. Поляков. —М.: Радио и связь, 1989 —200 с.
  8. Панич, А. Е. Физика сегнетоэлектрической керамики / А. Е. Панич, Т. Г. Левина. — Ростов-на-Дону, 2002 . — 45 с.
  9. Свирская, С. Н. Пьезокерамическое материаловедение. Учебное пособие / С. Н. Свирская. — Ростов-на-Дону, 2009. — 82 с.
  10. Прилипко, Ю. С. Оптимизация технологии получения материалов ЦТС / Ю. С. Прилипко / / Наукові праці ДонНТУ. Сер. хімія і хімічні технологія. — 2007. — Вип. 119 (9). — С. 91 — 100.

In writing this essay master’s work is not yet complete. Final completion: January 2015. Full text of the work and materials on the topic can be obtained by the author or his manager after that date.