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Plasma technology of inorganic compounds

Since the mid 1960s the Latvian Institute of Inorganic Chemistry of the Latvian Academy of Sciences has been carrying out an extensive research in the field of plasma chemistry and plasma technology. Research results gave an opportunity to work out a range of new technological methods for the production of different hard-to-melt compounds (nitride, carbide, boride, oxide, carbonitride and their compositions) in the form of ultra fine powders with the size of separate particles being smaller than 100 nm. Comprehensive investigation of nanosize powders produced in this way made it possible to create materials and coatings characterized by very high maintenance qualities (hardness, mechanical strength, chemical, thermal and wear resistance, specific electrophysical and optical qualities etc.)

The developed technology differs from the traditional ones by the fact that the compound synthesis proceeds from the molecular, atomar or ione state of the substance and the condensed phase forming in a very short while at a very high temperature. Thus particles of a very small size and specific properties are formed.

From 1971 to 1990 the Institute of Inorganic Chemistry was the leading organization in USSR co-ordinating research on the synthesis of hard-to-melt compounds in plasma.

Main authors:

The technology is used in:

  • the production of ultra fine powders of different compounds (see U.Cielens, T.Millers)
  • the production of different materials on the basis of ultra fine powders or for an essential improvements of its properties (see T.Millers):
  • metal-cutting instruments, incl. superhard instruments (SKM, korinit, silinit) that were manufactured in three plants (picture 1);
  • ceramic construction materials with elevated crashworthiness, hardness and mechanical lasting, incl. those for individual and technical protection against concentrated shock and for operation in space (picture 2);
  • ceramic functional materials with high and stable electro- and heat- physical properties (picture 3);
  • polymer materials with ultra fine powder additives to increase cold and wear resistance, incl. those for the needs of aviation;
  • composite materials with specific properties of size change etc., incl. those for control devices of sophisticated systems;
  • metals (aluminium, crude iron, nickel alloys) with small ultra fine powder additive for the improvement of their structure and properties (picture 4);
  • thermal and galvanic coatings with high mechanical and wear resistance, specific electrical and optical properties, incl. those for space machines (picture 5,6).

Implementation of technological methods:

In 1976 the Institute of Inorganic Chemistry formed a Special Design Office of Inorganic Materials with several technological branches providing the production of 3-5 tons of powder a year. Several production enterprises utilizing the plasma technology were later formed also in Russia and Ukraine. In Latvia this technology now is used by "Plasma & Ceramic Technologies" Ltd. and "Neomat" Ltd. In the 80-ties the technology of plasma coating production was used in 14 plants and production departments under methodical guidance of the above-mentioned Special Design Office. Some of them still continue their work today. The biggest amount of work in this field is carried out by the individual enterprise "Terpa" that was formed on the basis of the correspondent department of the Design Office. Materials and products on the basis of ultra fine powders were produced by several organizations in Oblinsk, Leningrad, Noginsk, Kiev, Karsnojarsk, Jakutsk, Kaliningrad, Omsk, Moscow, Podolsk, Zaporozye etc. In Latvia this work is carried on by "Plasma & Ceramic Technology" Ltd. in co-operation with several institutes and companies in Germany, France etc.

Patents:

About 90 authors' certificates of USSR and 3 foreign patents have been received.

Foreign patents:

V.Petrunicus, V.Mihailovs, J.Korolova, J.Grabis, T.Millers, G.Heidemane, J.Zalite, V.Troickis, S.Panfilovs, J.Cvetkovs, O.Grebcova, J.Kijanskis, L.Stafeckis, A.Uelskis. Plasmochemical method for the production of fine powders.

Patent of Germany DE Nr. 333940.

The invention is registered also in France (patent B1 Nr.8318307, 1987) and Hungary.

Articles

  • T.N.Millers, A.A.Kuzjukevics. Micromonocrystals of refractory compounds: composition, structure and properties. - Progr.Crystal Growth and Charact., 1988, vol.16, pp.367-438
  • T.Millers. Materials synthesis on the basis of ultrafine refractory compound powders. - Materials Science and Engineering, 1993, A168, pp.171-176
  • A.Kuzjukevics, K.Ischizaki, J.Grabis, T.Millers, I.Kondo. Hot pressing of TiN-alumina composites. - J.Cer.Soc.Japan, 1994, 102(3), pp.225-230
  • A.Vitola, J.Ronis, V.Avotins, T.Millers. Structure of inorganic phosphorus-nitrogen tetrahedral compounds. - Latvian Journal of Chemistry, 1997, Nr.1, pp.52-59.
  • L.Cera, M.Berzins, T.Millers. Charge development at the interface in Si-C-N composite aqueous suspensions. Latvian Journal of Chemistry, 1997, Nr.2, pp.643-71.
  • T.Millers, J.Ronis, A.VÄ«tola. Synthesis, structure and properties of materials in the system P-N-O. - Phoshorus Research Bulletin, 1999, vol.10, pp.690-695.
  • T.Millers. Plazma, chemistry, and advanced materials. - Proceedings of Latvian Academy of Sciences, B, 2004, vol.58, Nr.2, pp.76-80.
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Picture 1.
Ceramic materials SILINIT-R that are used as metal-cutting instruments (manufactured at the Yugoslavian plant ELEKTROBOSNA)
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Picture 2.
Ceramic construction material that has been used also in space technics (in the spacecraft "Buran")
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Picture 3.
Parts for the gasturbine engine made of ceramic materials
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Picture 4.
Modification of metal and their alloy structure and properties with ultra fine powder additive: the sample on the right hand side is produced with a small powder additive
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Picture 5.
Machine parts restored by means of plasma technology
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Picture 6.
Ceramic materials – machine parts for engineering and other branches