九州シンクロトロン光研究センター
県有ビームライン利用報告書
課 題 番 号 ： 1901139S

Ｂ Ｌ 番 号 ： 12

（様式第 5 号）

アルミニウムバッファ層上に堆積した超ナノ微結晶ナノダイヤモン
ド膜の機械特性と化学結合構造との相関の解明（英語名）
Study on relationship between mechanical properties and chemical bonding
structures of ultrananocrystalline diamond films deposited on aluminum buffer layer
エ ギ ザ モ ハ メ ド ， ア リ モ ハ メ ド .ア リ , 田 中 佑 樹 , 星 野 光 一 朗 , 吉 武 剛
Mohamed Egiza, Ali M. Ali, Tanaka Yuki, Hoshino Koichiro, and Tsuyoshi Yoshitake
九州大学大学院総合理工学府量子プロセス理工学専攻

Department of Applied Science for Electronics and Materials, Kyushu University※１※２※３※４

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１．概要（注：結論を含めて下さい）
Ultrananocrystalline diamond /amorphous carbon composite (UNCD/a-C) films were depositedby coaxial arc plasma deposition (CAPD) on cemented carbide (WC-Co) substrates directly
and with Al interlayer. The films deposited on Al interlayer achieved evidently enhancement inhardness to 58 GPa and Young’s modulus to 613 GPa comparing with hardness of 50 GPa andYoung’s modulus of 520 GPa of films deposited directly on the substrate. This significant
improvement in the mechanical properties is consistent with enhanced C-C sp 3 fraction in thefilms. The Al interlayer successfully suppres sed the Co catalytic effects that induces films
graphitization and degrades films hardness and Young’s modulus .

２．背景と目的
Diamond and related hard carbon coatings have attracted attention because they are effectively applicable tocutting non-ferrous and abrasive materials due to their unique features such as high hardness and excellent
mold release. The physical properties of carbon materials are strongly influenced by the ratio of sp3(diamond-like) to sp2 (graphite-like) bonds. Ultrananocrystalline diamond/amorphous carbon composite(UNCD/a-C) films deposited on WC-Co at room substrate-temperature exhibit the maximum hardness of 50
GPa and a modulus of 520 GPa [1]. It was demonstrated that low substrate temperature is effective to diamond
growth and suppressing the Co catalytic effects at the interface. Furthermore, the diffusion of Co atoms into thefilms hardly occurs even at the substrate temperature of 550 ºC. To further understand the role of Co catalytic
effects on the properties of the films, Al interlayers were sputtered prior to the film deposition, because it wasreported that the insertion of Al interlayers suppresses the catalytic reactivity of transition metals for inducing
graphitization [2, 3]. The effects of Al interlayer on the films growth, the hardness, and Young’s modulus of thefilms were studied. In addition, the chemical bonding structures of the films were investigated by X-ray
photoemission spectroscopy and near-edge X-ray absorption fine-structure spectroscopies to understand thephysical origin of the films properties due to insertion of Al interlayer.

３．実験内容（試料、実験方法、解析方法の説明）
6

５．今後の課題
In this work, the role of Al interlayers in the suppression of Co
catalytic effects, and the relationship between the films hardness
and C-C sp3 fraction were investigated. From this, we are goingto study the effects of the Al interlayer insertion on the adhesion
strength of the film with the substrates and the film surface
morphologies.
６．参考文献Load [mN]

2000.05

成果）






Hiroshi Naragino et al., Evergreen, 03, 1-5 (2016)
Mohamed Egiza et al., Evergreen, 03, 32-36 (2016)
Hiroshi Naragino et al., Jpn. J. Appl. Phys 55, 030302 (2016)
Hiroshi Naragino et al. Appl. Phys. A, 122, (2016).

0.1

Indentation depth [μm]Fig. 1 Load–displacement curve of UNCD/a-Cfilms deposited on WC-Co substrates (a)without and with Al interlayer.
CC1s
1s(a) Sample 1

OO1s
1s(b) Sample 2C 1s

O 1s

1000500
Binding energy (eV)0Fig. 2 XPS survey of UNCD/a-C films on
WC-Co substrates (a) without and with Alinterlayer.
(a) Sample 1Raw data
Fitted data

sp3 fraction= 64 %sp2 fraction= 36 %sp

3sp
C=OCOOH

2C-O
C-O-C(b) Sample 2sp3 fraction= 71 %sp2 fraction= 29%[1] Hiroshi Naragino et al. Appl. Phys. A, 122, (2016).
[2] Y.S. Li, A. Hirose, J. Appl. Phys. 101, 073503 (2007).
[3] Y.S. Li, A. Hirose, Surf. & Coat. Technol. 202, 280 (2007).
[4] Mohamed Egiza et al. Coatings, 8, 359 (2018)

７．論文発表・特許（注：本課題に関連するこれまでの代表的な(b)4Intensity (arb. unit)

４．実験結果と考察
The films deposited directly on WC-Co substrates exhibit ahardness of approximately 50 GPa and Young’s modulus of 520
GPa. By the insertion of Al interlayers, the hardness and Young’smodulus were improved to 58 GPa and 613 GPa, respectively.
This improvement might be attributed to the suppression of Co
catalytic effects that induces films graphitization and in turn
reduces films hardness and Young’s modulus.
Figure 2 shows the elemental composition of UNCD/a-C
films measured by XPS survey. O 1s and C 1s peaks weredetected, which indicates that the films are free of substratecontaminations. The O 1s peak is attributed to the residual
oxygen in the chamber during the films preparation and exposure
to the environmental air after deposition [4]. Figure 3 shows the
X-ray photoemission spectra of UNCD/a-C films, which weredecomposed to peaks by a software. The estimated sp3/(sp3+sp2)
ratio show an enhancement due to the insertion of Al interlayer,
which show an agreement with the measured hardness andYoung’s modulus. The Al interlayer suppresses the catalytic
reactivity of Co that induces films graphitization.

(a)Intensity (arb. unit)

UNCD/a-C films were deposited on WC-Co substrates withdimensions of 10 mm diameter and 5.5 mm thickness at room
substrate-temperature by CAPD with pure graphite targets. The
inside of a vacuum apparatus was evacuated to base pressures ofless than 10-4 Pa by a turbo molecular pump. An arc plasma gun
equipped with a 720 µF capacitor was operated at an applied
voltage of 100 V. The films were deposited directly and with Al
interlayer sputtered at thickness of 100 nm. The hardness andYoung’s modulus of the deposited films were investigated bynano-indentation as shown in Fig.1. The deposited films werecharacterized by X-ray photoemission spectroscopic at beamline
12 of Kyushu Synchrotron.

Raw data
Fitted datasp

3sp
C=O
COOH

290

2C-O
C-O-C

288286284

282

Binding energy (eV)Fig. 3 C 1s X-ray photoemission spectra ofUNCD/a-C films deposited (a) without and (b)with Al interlayer.

Mohamed Egiza et al. Coatings, 8, 359 (2018)
Ali M. Ali et al. Diamond relat. Mat. 96, 67 (2019)

８．キーワード（注：試料及び実験方法を特定する用語を２～３）
Nanodiamond, Coaxial arc plasma, CAPD, Hardness, XPS, X-ray photoemission spectroscopy, Al interlayer

９．研究成果公開について①

論文（査読付）発表の報告（報告時期：2020 年 3 月）