DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder

Tungsten carbide–cobalt (WC–Co) agglomerated powder is widely used for additive manufacturing and spray coating, and a reduction in internal gaps in the powder is required to obtain a product of high quality. In this paper, we investigate plasma effects on agglomerated powder when WC–12%Co powder is...

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Main Authors: Hirotomo Itagaki, Taisei Yachi, Hisato Ogiso, Harumichi Sato, Yorihiro Yamashita, Junichi Yasuoka, Yoshinori Funada
Format: Article
Language:English
Published: MDPI AG 2020-07-01
Series:Metals
Subjects:
Online Access:https://www.mdpi.com/2075-4701/10/7/975
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author Hirotomo Itagaki
Taisei Yachi
Hisato Ogiso
Harumichi Sato
Yorihiro Yamashita
Junichi Yasuoka
Yoshinori Funada
author_facet Hirotomo Itagaki
Taisei Yachi
Hisato Ogiso
Harumichi Sato
Yorihiro Yamashita
Junichi Yasuoka
Yoshinori Funada
author_sort Hirotomo Itagaki
collection DOAJ
description Tungsten carbide–cobalt (WC–Co) agglomerated powder is widely used for additive manufacturing and spray coating, and a reduction in internal gaps in the powder is required to obtain a product of high quality. In this paper, we investigate plasma effects on agglomerated powder when WC–12%Co powder is directly subjected to direct current (DC) arc plasma treatment to reduce gaps in the WC–Co powder. We obtain a plasma-treated powder with reduced gaps among WC particles. Furthermore, plasma-treatment improves the sphericity of the powder particles, due to the spheroidization effect, so that the percentage of plasma-treated particles exceeding 95% sphericity is 50%, which is 1.7 times that of raw powder. Concern regarding the possible generation of W<sub>2</sub>C by plasma treatment is unfounded, with W<sub>2</sub>C levels kept very low according to X-ray diffraction (XRD) analysis, showing a value of 0.0075 for the area ratio W<sub>2</sub>C(002)/WC(100). XRD analysis also reveals that plasma treatment relaxes residual strains in the powder. From these results, the DC plasma treatment of WC agglomerated powder produces a spherical powder with fewer gaps and strains in the powder, making it more suitable for additive manufacturing while suppressing decarburization.
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spelling doaj.art-64dfe95e23a3424a8fe04454a1a6b9f82023-11-20T07:19:41ZengMDPI AGMetals2075-47012020-07-0110797510.3390/met10070975DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated PowderHirotomo Itagaki0Taisei Yachi1Hisato Ogiso2Harumichi Sato3Yorihiro Yamashita4Junichi Yasuoka5Yoshinori Funada6Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8564, JapanMachinery and Material Division, Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa 920-8203, JapanAdvanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8564, JapanAdvanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8564, JapanMachinery and Material Division, Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa 920-8203, JapanPowlex Co., Ltd, Taito-ku, Tokyo 110-0002, JapanMachinery and Material Division, Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa 920-8203, JapanTungsten carbide–cobalt (WC–Co) agglomerated powder is widely used for additive manufacturing and spray coating, and a reduction in internal gaps in the powder is required to obtain a product of high quality. In this paper, we investigate plasma effects on agglomerated powder when WC–12%Co powder is directly subjected to direct current (DC) arc plasma treatment to reduce gaps in the WC–Co powder. We obtain a plasma-treated powder with reduced gaps among WC particles. Furthermore, plasma-treatment improves the sphericity of the powder particles, due to the spheroidization effect, so that the percentage of plasma-treated particles exceeding 95% sphericity is 50%, which is 1.7 times that of raw powder. Concern regarding the possible generation of W<sub>2</sub>C by plasma treatment is unfounded, with W<sub>2</sub>C levels kept very low according to X-ray diffraction (XRD) analysis, showing a value of 0.0075 for the area ratio W<sub>2</sub>C(002)/WC(100). XRD analysis also reveals that plasma treatment relaxes residual strains in the powder. From these results, the DC plasma treatment of WC agglomerated powder produces a spherical powder with fewer gaps and strains in the powder, making it more suitable for additive manufacturing while suppressing decarburization.https://www.mdpi.com/2075-4701/10/7/975cemented carbidetungsten carbideplasma treatmentDC arc plasmaspheroidization
spellingShingle Hirotomo Itagaki
Taisei Yachi
Hisato Ogiso
Harumichi Sato
Yorihiro Yamashita
Junichi Yasuoka
Yoshinori Funada
DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder
Metals
cemented carbide
tungsten carbide
plasma treatment
DC arc plasma
spheroidization
title DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder
title_full DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder
title_fullStr DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder
title_full_unstemmed DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder
title_short DC Arc Plasma Treatment for Defect Reduction in WC-Co Granulated Powder
title_sort dc arc plasma treatment for defect reduction in wc co granulated powder
topic cemented carbide
tungsten carbide
plasma treatment
DC arc plasma
spheroidization
url https://www.mdpi.com/2075-4701/10/7/975
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