Effect of Mn doping on the densification and properties of transparent alumina by high-pressure spark plasma sintering

Jonathan Mottye; Barak Ratzker; Sergey Kalabukhov; Bar Favelukis; Shmuel Hayun; Nachum Frage

doi:10.1016/j.ceramint.2023.06.092

Effect of Mn doping on the densification and properties of transparent alumina by high-pressure spark plasma sintering

Jonathan Mottye, Barak Ratzker, Sergey Kalabukhov, Bar Favelukis, Shmuel Hayun, Nachum Frage

Ben-Gurion University of the Negev, Tel Aviv University

Research output: Contribution to journal › Article › peer-review

Abstract

It is common practice to control the densification and microstructure of alumina using additives or dopants. In the present study, the effect of Mn-doping on the sintering behavior, optical properties, microstructure, and mechanical properties of alumina was examined. Addition of 0.5 at.% Mn was shown to significantly reduce densification rate and grain growth during high-pressure spark plasma sintering (HPSPS). The major effects resulted from the formation of MnAl₂O₄ nano inclusions located at grain boundary triple points. The Mn-doped alumina was highly transparent and had a light-brown tint due to absorption between ∼410 and 580 nm and a cutoff at 300 nm. The MnAl₂O₄ nano-inclusions caused the Young's modulus to decrease from 400 ± 5 GPa for pure alumina to 370 ± 5 GPa for Mn-doped alumina, while the fracture toughness increased from 2.97 to 3.66 MPa m^0.5, and the hardness was the same. Thus, the addition of Mn enables control of the transparent alumina densification process and microstructure development, and it can be used to tailor the optical and mechanical properties for specific applications.

Original language	American English
Pages (from-to)	28369-28375
Number of pages	7
Journal	Ceramics International
Volume	49
Issue number	17
DOIs	https://doi.org/10.1016/j.ceramint.2023.06.092
State	Published - 1 Sep 2023

Keywords

Alumina (AlO)
Galaxite (MnAlO)
Mechanical properties
Optical properties
Spark plasma sintering
Transparent ceramic

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Process Chemistry and Technology
Surfaces, Coatings and Films
Materials Chemistry

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10.1016/j.ceramint.2023.06.092

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@article{d3505bf668394e7ba783c7c5f440c3d6,

title = "Effect of Mn doping on the densification and properties of transparent alumina by high-pressure spark plasma sintering",

abstract = "It is common practice to control the densification and microstructure of alumina using additives or dopants. In the present study, the effect of Mn-doping on the sintering behavior, optical properties, microstructure, and mechanical properties of alumina was examined. Addition of 0.5 at.% Mn was shown to significantly reduce densification rate and grain growth during high-pressure spark plasma sintering (HPSPS). The major effects resulted from the formation of MnAl2O4 nano inclusions located at grain boundary triple points. The Mn-doped alumina was highly transparent and had a light-brown tint due to absorption between ∼410 and 580 nm and a cutoff at 300 nm. The MnAl2O4 nano-inclusions caused the Young's modulus to decrease from 400 ± 5 GPa for pure alumina to 370 ± 5 GPa for Mn-doped alumina, while the fracture toughness increased from 2.97 to 3.66 MPa m0.5, and the hardness was the same. Thus, the addition of Mn enables control of the transparent alumina densification process and microstructure development, and it can be used to tailor the optical and mechanical properties for specific applications.",

keywords = "Alumina (AlO), Galaxite (MnAlO), Mechanical properties, Optical properties, Spark plasma sintering, Transparent ceramic",

author = "Jonathan Mottye and Barak Ratzker and Sergey Kalabukhov and Bar Favelukis and Shmuel Hayun and Nachum Frage",

note = "Funding Information: The microstructure of the 15-min Mn-doped sample was analyzed by TEM at the (transparent) center and (opaque) edge regions. At the edge (Fig. 4a and b), many residual pores (average pore size <100 nm) that appear black in HAADF contrast are found at triple points. The average grain size of the Mn-doped alumina was found to be 130 ± 23 nm. In addition, fine inclusions ranging in size from ∼10 up to ∼100 nm in diameter are detected as a bright phase in the HAADF contrast due to a higher atomic Z number (Fig. 4c and d). According to the XRD analysis, these inclusions consist of the second phase MnAl2O4. This conclusion is supported by analysis of a relatively large second-phase particle (Fig. 5a) by selected area electron diffraction (SAED) (Fig. 5b and c) and EDS (Fig. 5d). As the SAED pattern and elemental analysis reflect the crystal structure and elemental composition of MnAl2O4, respectively. The MnAl2O4 nano inclusions were found to be located at triple points. Moreover, practically all the residual pores found in the specimen seem to be adjacent to MnAl2O4 inclusions. At the center of the sample (Fig. 4c and d), almost all porosity was eliminated, while the MnAl2O4 inclusions remained. It is important to note that the alumina grain size as and inclusions were similar at the edge and center of the sample. Publisher Copyright: {\textcopyright} 2023",

year = "2023",

month = sep,

day = "1",

doi = "10.1016/j.ceramint.2023.06.092",

language = "American English",

volume = "49",

pages = "28369--28375",

journal = "Ceramics International",

issn = "0272-8842",

publisher = "Elsevier Ltd.",

number = "17",

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TY - JOUR

T1 - Effect of Mn doping on the densification and properties of transparent alumina by high-pressure spark plasma sintering

AU - Mottye, Jonathan

AU - Ratzker, Barak

AU - Kalabukhov, Sergey

AU - Favelukis, Bar

AU - Hayun, Shmuel

AU - Frage, Nachum

N1 - Funding Information: The microstructure of the 15-min Mn-doped sample was analyzed by TEM at the (transparent) center and (opaque) edge regions. At the edge (Fig. 4a and b), many residual pores (average pore size <100 nm) that appear black in HAADF contrast are found at triple points. The average grain size of the Mn-doped alumina was found to be 130 ± 23 nm. In addition, fine inclusions ranging in size from ∼10 up to ∼100 nm in diameter are detected as a bright phase in the HAADF contrast due to a higher atomic Z number (Fig. 4c and d). According to the XRD analysis, these inclusions consist of the second phase MnAl2O4. This conclusion is supported by analysis of a relatively large second-phase particle (Fig. 5a) by selected area electron diffraction (SAED) (Fig. 5b and c) and EDS (Fig. 5d). As the SAED pattern and elemental analysis reflect the crystal structure and elemental composition of MnAl2O4, respectively. The MnAl2O4 nano inclusions were found to be located at triple points. Moreover, practically all the residual pores found in the specimen seem to be adjacent to MnAl2O4 inclusions. At the center of the sample (Fig. 4c and d), almost all porosity was eliminated, while the MnAl2O4 inclusions remained. It is important to note that the alumina grain size as and inclusions were similar at the edge and center of the sample. Publisher Copyright: © 2023

PY - 2023/9/1

Y1 - 2023/9/1

N2 - It is common practice to control the densification and microstructure of alumina using additives or dopants. In the present study, the effect of Mn-doping on the sintering behavior, optical properties, microstructure, and mechanical properties of alumina was examined. Addition of 0.5 at.% Mn was shown to significantly reduce densification rate and grain growth during high-pressure spark plasma sintering (HPSPS). The major effects resulted from the formation of MnAl2O4 nano inclusions located at grain boundary triple points. The Mn-doped alumina was highly transparent and had a light-brown tint due to absorption between ∼410 and 580 nm and a cutoff at 300 nm. The MnAl2O4 nano-inclusions caused the Young's modulus to decrease from 400 ± 5 GPa for pure alumina to 370 ± 5 GPa for Mn-doped alumina, while the fracture toughness increased from 2.97 to 3.66 MPa m0.5, and the hardness was the same. Thus, the addition of Mn enables control of the transparent alumina densification process and microstructure development, and it can be used to tailor the optical and mechanical properties for specific applications.

AB - It is common practice to control the densification and microstructure of alumina using additives or dopants. In the present study, the effect of Mn-doping on the sintering behavior, optical properties, microstructure, and mechanical properties of alumina was examined. Addition of 0.5 at.% Mn was shown to significantly reduce densification rate and grain growth during high-pressure spark plasma sintering (HPSPS). The major effects resulted from the formation of MnAl2O4 nano inclusions located at grain boundary triple points. The Mn-doped alumina was highly transparent and had a light-brown tint due to absorption between ∼410 and 580 nm and a cutoff at 300 nm. The MnAl2O4 nano-inclusions caused the Young's modulus to decrease from 400 ± 5 GPa for pure alumina to 370 ± 5 GPa for Mn-doped alumina, while the fracture toughness increased from 2.97 to 3.66 MPa m0.5, and the hardness was the same. Thus, the addition of Mn enables control of the transparent alumina densification process and microstructure development, and it can be used to tailor the optical and mechanical properties for specific applications.

KW - Alumina (AlO)

KW - Galaxite (MnAlO)

KW - Mechanical properties

KW - Optical properties

KW - Spark plasma sintering

KW - Transparent ceramic

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U2 - 10.1016/j.ceramint.2023.06.092

DO - 10.1016/j.ceramint.2023.06.092

M3 - Article

SN - 0272-8842

VL - 49

SP - 28369

EP - 28375

JO - Ceramics International

JF - Ceramics International

IS - 17

ER -

Effect of Mn doping on the densification and properties of transparent alumina by high-pressure spark plasma sintering

Abstract

Keywords

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