Розробка технологічних основ виготовлення пористих і порошкових металевих матеріалів методом їх вакуумного осадження у парі галогенідів лужних металів

На этой основе был предложен новый метод получения инкапсулированных в солевую матрицу порошковых материалов (чистых металлов, сплавов та соединений на их основе) с размерами частиц наноразмерного масштаба путем одновременного осаждения паровых фаз этих материалов и солей на подложку при их одновременном испарении в вакуумной камере при условии перемешивания их паровых потоков в соотношении не ниже 0,5 и температуре подложки ниже температуры плавления соли и металла. Показано, что этот метод инкапсуляции частиц предотвращает их агломерацию и защищает их от взаимодействия с атмосферой, что позволяет длительно хранить нанопорошки металлов без окисления.

Ключевые слова: электронно-лучевое излучение и осаждение; пористая структура; открытая пористость; фактор формы; структурные зоны, нанопорошки, рентгеноструктурный анализ, электронная микроскопия, магнитные свойства, суперпарамагнетизм.

SUMMARY

Liapina K.V. Development of technological fundamentals of producing porous and powderlike metallic materials by the method of their vacuum deposition in vapours of alkali metal halogens

Thesis for the scientific degree of Candidate of Sciences in Engineering in speciality 05.16.02 - Metallurgy of ferrous and non-ferrous metals and special alloys. - E.O.Paton Electric Welding Institute of the NAS of Ukraine, Kiev, 2009.

The work is devoted to establishing the features of the influence of the conditions of vacuum deposition of metals in the presence of alkali metal halogenides on microstructural features of the condensates and development on their basis of methods to produce porous and unconsolidated (powderlike) materials for functional purposes.

Proceeding from the conducted investigations of microstructural characteristics of metal condensates at their simultaneous deposition with alkali metal halogenides, depending on substrate temperature, ratio of vapour flows and deposition rate, it was established that metal condensates with a porous structure form at the ratio of salt/vapour flows smaller than 0/5 and substrate temperature above that of salt melting. In the case of metals, which have no polymorphous transformations, the characteristics of the porous structure of the condensates have a non-monotonic dependence on substrate temperature, and metals with polymorphous transformations have a monotonic dependence. A method is proposed to produce materials with controllable characteristics of the porous structure (type of porosity (closed or open), pore shape, average size and total porosity). Such a method can be used in producing materials for implants (for instance, a stent), or their coatings, the porous structure of which can ensure absorption of the necessary volume of pharmacological preparation, and its gradual release into the biological environment, thus improving the process of their implantation.

It is shown that at the ratio of salt/metal vapour flows greater than 0.5 and substrate temperature lower than that of salt and metal melting, it is possible to form encapsulated into the salt matrix metal powder with a small dispersion of dimensions of nano-scale particles resistant to agglomeration and interaction with the environment. A method is proposed of producing nano-sized powders of metals and their compounds, allowing their long-term storage under atmospheric conditions.

Keywords: electron beam deposition; porous structure; open porosity; form factor; structural zones, nanopowders, X-ray structural analysis electron, microscopy, magnetic properties, superparamagnetism

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