INVESTIGATION OF THE GRANULOMETRIC COMPOSITION AND STRUCTURE OF AlN AND SI3N4 POWDERS AFTER HYDROGEN— THERMAL TREATMENT

The dependence of main properties of samples from zirconia stabilized by CaO, on a phosphate binder from orthophosphoric acid on the P2O5 content (0.8, 1.4, 2.0, 2.6 %) and their thermal treatment temperature (200, 400, 1000, 1200, 1400, 1580, 1750, 2000 ОC) has been investigated. The optimal amount of the phosphate binder (2.0 % in P2O5) was established, providing some increase in the strength of refractories made of zirconia stabilized by CaO, at temperatures of ~ 1750—2000 ОC compared with other quantities of P2O5. Using the petrographic and X-ray phase methods, the dependence of phase composition and structure of samples from zirconia stabilized by CaO, on the phosphate binder on the thermal treatment temperature and P2O5 content was investigated. As a result of the carried out studies, the production technology of ramming mass from CaO-stabilized zirconia and products from it on the binder made of orthophosphoric acid, designed for service temperatures up to 2350 ОC, has been improved. Products manufactured according to the improved technology will increase their durability in the service and increase the operation duration of high-temperature industrial units.

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Effect of the thermal treatment mode on the composition and structure of ZrB2-SiC system composites

Glass Physics and Chemistry ◽

10.1134/s1087659613050027 ◽

2013 ◽

Vol 39 (5) ◽

pp. 579-588 ◽

Cited By ~ 3

Author(s):

I. B. Ban’kovskaya ◽

D. V. Kolovertnov

Keyword(s):

Thermal Treatment ◽

Treatment Mode ◽

Composition And Structure

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Impact of Sycamore Maple Thermal Treatment on a Granulometric Composition of Chips Obtained due to Processing on a CNC Machining Mentre

Sustainability ◽

10.3390/su11030718 ◽

2019 ◽

Vol 11 (3) ◽

pp. 718 ◽

Cited By ~ 3

Author(s):

Richard Kminiak ◽

Ladislav Dzurenda

Keyword(s):

Thermal Treatment ◽

Granulometric Composition ◽

Negative Impact ◽

Cnc Machining ◽

Numerical Control ◽

Three Dimensions ◽

Dust Particles ◽

Feed Speed ◽

Mode Iii ◽

Granulometric Analysis

This article deals with a granulometric composition of chips from the milling process of native and thermal treatment maple cuttings on a 5-axial Computer numerical control (CNC) machining center SCM Tech Z5. The aim of this article was to determine the changes in the granulometric composition of chips due to the thermal treatment of wood and to assess the potential risk of the creation of harmful dust fractions. Cuttings were milled with a shank cutter with exchangeable razor blades at feed speed vf = 1 ÷ 5 m·min−1 and material removal e = 3 mm. The thermal treatment in order to modify the color of the maple wood was done with water vapour at temperatures of tI = 112.5 ± 2.5 °C for a period of τ = 5.5 h (Mode I), tII = 127.5 ± 2.5 °C for a period of τ = 6.5 h (Mode II), and tIII = 137.5 ± 2.5 °C for a period of τ = 7.5 h (Mode III). The granulometric composition of the chips was detected by sifting. A granulometric analysis of the chips provided that more than 2/3 of the produced chips are a coarse fraction consisting of flat chips with dimensions over 1 mm. Dust fractions smaller than 500 μm form isometric grains, i.e., chips having approximately the same size in all three dimensions. Inhalable dust particles, smaller than 125 μm, do not exceed a 2.5% share. The granulometric analysis of chips shows that the thermal treatment of maple wood does not create respirable fractions, and therefore, the thermal treatment of the wood does not have a negative impact on the living and working environments.

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Pollutant Identification by Selected Area Electron Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052675 ◽

1974 ◽

Vol 32 ◽

pp. 532-533

Author(s):

R. E. Ferrell ◽

G. G. Paulson ◽

C. W. Walker

Keyword(s):

Thermal Treatment ◽

Electron Diffraction ◽

Sample Preparation ◽

Crystal Structures ◽

Water Samples ◽

Environmental Samples ◽

Short Review ◽

Selected Area Electron Diffraction ◽

Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

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Crystal Structure Analysis of Cu-Zr Alloys by Convergent Beam Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098277 ◽

1981 ◽

Vol 39 ◽

pp. 354-355

Author(s):

A. F. Marshall ◽

J. W. Steeds ◽

D. Bouchet ◽

S. L. Shinde ◽

R. G. Walmsley

Keyword(s):

Crystal Structure ◽

Point Group ◽

Intermetallic Phase ◽

Three Dimensional ◽

Crystal Structure Analysis ◽

Ion Milling ◽

Composition And Structure ◽

Unit Cells ◽

Sputter Deposited ◽

Convergent Beam

Convergent beam electron diffraction is a powerful technique for determining the crystal structure of a material in TEM. In this paper we have applied it to the study of the intermetallic phases in the Cu-rich end of the Cu-Zr system. These phases are highly ordered. Their composition and structure has been previously studied by microprobe and x-ray diffraction with sometimes conflicting results.The crystalline phases were obtained by annealing amorphous sputter-deposited Cu-Zr. Specimens were thinned for TEM by ion milling and observed in a Philips EM 400. Due to the large unit cells involved, a small convergence angle of diffraction was used; however, the three-dimensional lattice and symmetry information of convergent beam microdiffraction patterns is still present. The results are as follows:1) 21 at% Zr in Cu: annealed at 500°C for 5 hours. An intermetallic phase, Cu3.6Zr (21.7% Zr), space group P6/m has been proposed near this composition (2). The major phase of our annealed material was hexagonal with a point group determined as 6/m.

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Development of Crystallinity in Turbostratic Boron Nitride Derived from Polymeric Precursors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089081 ◽

1991 ◽

Vol 49 ◽

pp. 954-955

Author(s):

X. Qiu ◽

A. K. Datye ◽

T. T. Borek ◽

R. T. Paine

Keyword(s):

Thermal Treatment ◽

Boron Nitride ◽

Diffraction Pattern ◽

Polymeric Precursors ◽

Polymer Precursors ◽

Diffuse Ring

Boron nitride derived from polymer precursors is of great interest for applications such as fibers, coatings and novel forms such as aerogels. The BN is prepared by the polymerization of functionalized borazine and thermal treatment in nitrogen at 1200°C. The BN powders obtained by this route are invariably trubostratic wherein the sheets of hexagonal BN are randomly oriented to yield the so-called turbostratic modification. Fib 1a and 1b show images of BN powder with the corresponding diffraction pattern in fig. 1c. The (0002) reflection from BN is seen as a diffuse ring with occational spots that come from crystals of BN such as those shown in fig. 1b. The (0002) lattice fringes of BN seen in these powders are the most characteristic indication of the crystallinity of the BN.

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Off-axis electron holography applied to the study of interfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121624 ◽

1992 ◽

Vol 50 (1) ◽

pp. 244-245

Author(s):

J.K. Weiss ◽

M. Gajdardziska-Josifovska ◽

M. R. McCartney ◽

David J. Smith

Keyword(s):

Electric Fields ◽

Resolution Enhancement ◽

Interfacial Structure ◽

Atomic Scale ◽

Bulk Property ◽

Electron Holography ◽

Specimen Thickness ◽

Composition And Structure ◽

Chemical Segregation ◽

Diffraction Effects

Interfacial structure is a controlling parameter in the behavior of many materials. Electron microscopy methods are widely used for characterizing such features as interface abruptness and chemical segregation at interfaces. The problem for high resolution microscopy is to establish optimum imaging conditions for extracting this information. We have found that off-axis electron holography can provide useful information for the study of interfaces that is not easily obtained by other techniques.Electron holography permits the recovery of both the amplitude and the phase of the image wave. Recent studies have applied the information obtained from electron holograms to characterizing magnetic and electric fields in materials and also to atomic-scale resolution enhancement. The phase of an electron wave passing through a specimen is shifted by an amount which is proportional to the product of the specimen thickness and the projected electrostatic potential (ignoring magnetic fields and diffraction effects). If atomic-scale variations are ignored, the potential in the specimen is described by the mean inner potential, a bulk property sensitive to both composition and structure. For the study of interfaces, the specimen thickness is assumed to be approximately constant across the interface, so that the phase of the image wave will give a picture of mean inner potential across the interface.

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