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ТЕХНОСФЕРА_РИЦ
DOI: 10.22184/1993-8578.2021.14.2.132.134
Fine-grained ceramics based on copper oxide nanopowder was prepared using spark plasma sintering (SPS) method. It is harder (with microhardness of 7.1 GPA) than ceramics obtained by the conventional method.
Fine-grained ceramics based on copper oxide nanopowder was prepared using spark plasma sintering (SPS) method. It is harder (with microhardness of 7.1 GPA) than ceramics obtained by the conventional method.
Теги: copper oxide microhardness powder spark plasma sintering method метод электроискрового спекания микротвердость оксид меди порошок
CERAMICS CREATED BY THE SPS-METHOD FROM COPPER-OXIDE NANOPOWDER
V.I.Lysenko*, Leading Researcher, Doct. of Sci. (Physics and Mathematics)
DOI: 10.22184/1993-8578.2021.14.2.132.134
Получено: 14.12.2020 г.
Fine-grained ceramics based on copper oxide nanopowder was prepared using spark plasma sintering (SPS) method. It is harder (with microhardness of 7.1 GPA) than ceramics obtained by the conventional method.
INTRODUCTION
One of the most important tasks in nanotechnologies is to develop ceramics from nanosized powders where it is possible to preserve very small grain sizes. It is well known that the smaller the ceramics grain size and the more developed the granular structure, the stronger and harder is the ceramics. However, nanopowders used to prepare ceramics contain stable hard-to-break agglomerates of nanoparticles [1], which require non-standard compacting methods (for example, hot pressing). The current state of research in the field of nanoceramics prepared from various nanopowders is sufficiently shown in [2, 3] and others, including the author’s works [4–11].
This paper is devoted to research of the ceramics obtained from copper oxide nanopowder.
Copper nanooxide is a widely used material. It is applied as a chemical and propellant fuel combustion catalyst. Besides, copper oxide is used in superconducting and thermoelectric materials and also as a dye for glasses, ceramics and enamels. Moreover, this material is applied in anti-corrosion coatings, various antifouling paints preventing biofouling of sea and river vessel hulls. Copper oxide is used in electrical industry. In addition, nanosized copper-containing powders impart effective biocidal properties to traditional medical materials and are suitable for creating materials of medical or other applications (varnishes, paints, etc.) with antibacterial properties [12].
The aim of this work was to obtain ceramics from copper oxide nanopowder by the SPS (Spark Plasma Sintering) method. The obtained ceramics were studied and their properties compared with the characteristics of ceramics obtained earlier by the traditional method (dry pressing with several load-unloading cycles and subsequent sintering).
EXPERIMENTAL METHODS AND RESULTS
Microhardness of ceramic samples obtained earlier by the traditional method is equal to 6.5 GPa at Tmax = 800 °С.
In the experiments we used a powder created by the Russian company "PlasmoTerm" (powders are synthesized in a thermal plasma flow generated in an electric discharge) with an average size of spherical particles of 80 nm and a specific surface area Sуд = 20 m2/g. CAS number is 1317-38-0, purity is 99+ %, black color.
Phase composition: a mixture of copper oxide CuO and copper oxide Cu2O. Polydisperse powder. The particle size distribution function is close to logarithmic-normal.
Figure 1 shows a photograph of the initial copper oxide nanopowder sample obtained by electron microscopy.
In this work, sintering was carried out on a Labox "Sinter Land" facility of the Lavrentyev Institute of Hydrodynamics of the Siberian Branch of the Russian Academy of Sciences by the electrospark sintering (hot pressing using a sintering spark plasma) SPS method, in which electric current pulses pass through a pre-compressed powder (in these experiments, the current reached 2 kA at voltage of 3–4 V).
The main difference between SPS and traditional pressing (sequential pressing and sintering) is the supply of a pulsed electric current directly to the sample, which contributes to the rapid heating of the powder and the preservation to a large extent of its microstructural parameters in the consolidated material. Pressing was carried out at a maximum temperature Tmax = 900 °С and a pressure of 40 MPa. The heating rate was 100° / min, and the samples were not kept at the maximum temperature.
On a ZEISS EVO-50WDS-XVP-BU scanning electron microscope of the ITAM SB RAS, ceramic chips were studied after a gold layer was deposited on them. The microhardness of all ceramic samples was investigated using a PMT-3 microhardness tester.
According to the data of X-ray phase analysis, the copper oxide CuO phase predominated in the obtained ceramics.
As a result of sintering by hot pressing from a nanosized copper oxide powder, a ceramic with a fine-grained structure was obtained, the average particle size of which did not exceed 100 nm.
The microhardness of the obtained ceramics (Hv = 7.1 GPa) turned out to be somewhat higher than that of the ceramics obtained by the traditional method (with Hv = 6.5 GPa). ■
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
V.I.Lysenko*, Leading Researcher, Doct. of Sci. (Physics and Mathematics)
DOI: 10.22184/1993-8578.2021.14.2.132.134
Получено: 14.12.2020 г.
Fine-grained ceramics based on copper oxide nanopowder was prepared using spark plasma sintering (SPS) method. It is harder (with microhardness of 7.1 GPA) than ceramics obtained by the conventional method.
INTRODUCTION
One of the most important tasks in nanotechnologies is to develop ceramics from nanosized powders where it is possible to preserve very small grain sizes. It is well known that the smaller the ceramics grain size and the more developed the granular structure, the stronger and harder is the ceramics. However, nanopowders used to prepare ceramics contain stable hard-to-break agglomerates of nanoparticles [1], which require non-standard compacting methods (for example, hot pressing). The current state of research in the field of nanoceramics prepared from various nanopowders is sufficiently shown in [2, 3] and others, including the author’s works [4–11].
This paper is devoted to research of the ceramics obtained from copper oxide nanopowder.
Copper nanooxide is a widely used material. It is applied as a chemical and propellant fuel combustion catalyst. Besides, copper oxide is used in superconducting and thermoelectric materials and also as a dye for glasses, ceramics and enamels. Moreover, this material is applied in anti-corrosion coatings, various antifouling paints preventing biofouling of sea and river vessel hulls. Copper oxide is used in electrical industry. In addition, nanosized copper-containing powders impart effective biocidal properties to traditional medical materials and are suitable for creating materials of medical or other applications (varnishes, paints, etc.) with antibacterial properties [12].
The aim of this work was to obtain ceramics from copper oxide nanopowder by the SPS (Spark Plasma Sintering) method. The obtained ceramics were studied and their properties compared with the characteristics of ceramics obtained earlier by the traditional method (dry pressing with several load-unloading cycles and subsequent sintering).
EXPERIMENTAL METHODS AND RESULTS
Microhardness of ceramic samples obtained earlier by the traditional method is equal to 6.5 GPa at Tmax = 800 °С.
In the experiments we used a powder created by the Russian company "PlasmoTerm" (powders are synthesized in a thermal plasma flow generated in an electric discharge) with an average size of spherical particles of 80 nm and a specific surface area Sуд = 20 m2/g. CAS number is 1317-38-0, purity is 99+ %, black color.
Phase composition: a mixture of copper oxide CuO and copper oxide Cu2O. Polydisperse powder. The particle size distribution function is close to logarithmic-normal.
Figure 1 shows a photograph of the initial copper oxide nanopowder sample obtained by electron microscopy.
In this work, sintering was carried out on a Labox "Sinter Land" facility of the Lavrentyev Institute of Hydrodynamics of the Siberian Branch of the Russian Academy of Sciences by the electrospark sintering (hot pressing using a sintering spark plasma) SPS method, in which electric current pulses pass through a pre-compressed powder (in these experiments, the current reached 2 kA at voltage of 3–4 V).
The main difference between SPS and traditional pressing (sequential pressing and sintering) is the supply of a pulsed electric current directly to the sample, which contributes to the rapid heating of the powder and the preservation to a large extent of its microstructural parameters in the consolidated material. Pressing was carried out at a maximum temperature Tmax = 900 °С and a pressure of 40 MPa. The heating rate was 100° / min, and the samples were not kept at the maximum temperature.
On a ZEISS EVO-50WDS-XVP-BU scanning electron microscope of the ITAM SB RAS, ceramic chips were studied after a gold layer was deposited on them. The microhardness of all ceramic samples was investigated using a PMT-3 microhardness tester.
According to the data of X-ray phase analysis, the copper oxide CuO phase predominated in the obtained ceramics.
As a result of sintering by hot pressing from a nanosized copper oxide powder, a ceramic with a fine-grained structure was obtained, the average particle size of which did not exceed 100 nm.
The microhardness of the obtained ceramics (Hv = 7.1 GPa) turned out to be somewhat higher than that of the ceramics obtained by the traditional method (with Hv = 6.5 GPa). ■
Declaration of Competing Interest. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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