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N. V. Korobov
N. V. Korobov
Moscow State Technological University «STANKIN»
Russia
Moscow State Technological University «STANKIN»
Russia
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Articles

  • Date submitted
    2018-02-03
  • Date published
    2018-08-26

SELECTION OF THERMO-MECHANIC MODE OF PELLET MOLDING FROM TiO2 POWDER FOR MAGNETRON APPLICATION OF COMPOSITE COATINGS ON PARTS

It is advisable to make film coatings based on titanium dioxide for the details of instrumentation industry to reduce their resistance from compositions with other oxides. It is desirable to prepare the compounds during coating stage by magnetron method. Comparison of the designs of magnetron installations substantiates the rationality of using an installation with a single magnetron, equipped with a pellet from a composition of powders based on titanium. The coating technology using a single magnetron equipped with a composite pellet is described using an example of the application of wear-resistant self-lubricating coatings from a Ti + WS 2 composition. To equip the magnetron with a TiO 2 powder pellet, the task was to ensure the greatest uniformity of the density distribution in the pellet volume, and to achieve the greatest value of this density. As a result of the study of the technology of hot molding of TiO 2 powder described in the article, the efficiency of combining the heating of a powder with its compaction in one operation is shown. During this operation, the dependence of the density of the produced pellet on the molding temperature, pressure, holding time under pressure and grain size was experimentally investigated. The chosen thermomechanical mode of TiO 2 pellet molding is substantiated. By using the following mode (in the studied range) of molding it is possible to produce the pellet with the highest density: temperature 1300 ° С , pressure 40 MPa, holding time under pressure 20 min, and grain size 2.2  μ m.

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A. M. Dmitriev, N. V. Korobova (2018) SELECTION OF THERMO-MECHANIC MODE OF PELLET MOLDING FROM TiO2 POWDER FOR MAGNETRON APPLICATION OF COMPOSITE COATINGS ON PARTS. Journal of Mining Institute. Vol 232. p. 388. DOI: 10.31897/pmi.2018.4.388
  • Date submitted
    2018-03-26
  • Date published
    2019-04-25

DEVELOPMENT AND RESEARCH OF FORMATION TECHNOLOGIES ON SPECIALIZED PRESSES WITH SUBSEQUENT SINTERING OF HIGH-DENSITY DETAILS FROM IRON-BASED POWDERS

Creating shifts of the lyaers in a deforming workpieces improves the quality of the product produced by pressure treatment. qual-channel angular pressing and precipitations of a cylindrical billet with a rotating turnaround were developed by specialists earlier and became basic for scientists engaged in nanotechnology. One of the most modern schemes for creating nanostructures by processing on presses is the «Cyclic Extrusion Compression» scheme (in Russia – «Hourglass»), which has significant drawbacks. To date, research on the creation of layer shifts in compacted metal powders is substantially less than in compaction of compact blanks. The article developed compaction schemes for presses of blanks from iron-based powders that have a certain analogy with the «Hourglass», while lacking the disadvantages inherent in the named scheme and implemented on the created samples of specialized hydraulic presses. The results of the studies of density, strength and microhardness before sintering the samples molded from a number of domestic and imported powders on iron base, including those doped with carbon and other alloying components, are described. It has been established that with the use of the formation schemes for powders providing large shifts between particles, the density of the preforms increases on average by 10-12 %. With an average stress (16.32 MPa) of the transverse section of the molded specimen prior to its sintering, molding with shifts between particles increases this stress by 78 %. The strength after sintering of samples made using the compaction schemes developed by the authors of the article increases approximately by 2 times. Magnetic pulse treatment (MPT) of a molded sample prior to its sintering increases its resistance to shearing before sintering, regardless of the molding pattern. When MPT of both the powder and the molded sample is executed, the most uniform distribution of microhardness in the sample is achieved, and after subsequent sintering, the most uniform distribution of the mechanical characteristics of the product. The results of all studies are described by regression equations.

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A. M. Dmitriev, N. V. Korobov, A. Zh. Badalyan (2019) DEVELOPMENT AND RESEARCH OF FORMATION TECHNOLOGIES ON SPECIALIZED PRESSES WITH SUBSEQUENT SINTERING OF HIGH-DENSITY DETAILS FROM IRON-BASED POWDERS. Journal of Mining Institute. Vol 236. p. 216. DOI: 10.31897/pmi.2019.2.216