【公開日：2023.07.31】【最終更新日：2023.05.16】
課題データ / Project Data
課題番号 / Project Issue Number
22UT0283
利用課題名 / Title
ホウ化物コーティング膜の断面観察
利用した実施機関 / Support Institute
東京大学 / Tokyo Univ.
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）マルチマテリアル化技術・次世代高分子マテリアル/Multi-material technologies / Next-generation high-molecular materials（副 / Sub）-
キーワード / Keywords
電子顕微鏡/Electron microscopy,集束イオンビーム/Focused ion beam,電子回折/Electron diffraction,3D積層技術/ 3D lamination technology
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Plucknett Kevin
所属名 / Affiliation
Dalhousie University
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
福川 昌宏,森田 真理,木村 鮎美
利用形態 / Support Type
（主 / Main）技術補助/Technical Assistance（副 / Sub）,機器利用/Equipment Utilization
利用した主な設備 / Equipment Used in This Project
UT-102：高分解能走査型分析電子顕微鏡
UT-152：CADデータ連動3次元機能融合デバイス評価用前処理システム
UT-004：環境対応型超高分解能走査透過型電子顕微鏡
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
The research that was conducted was based around the use of electron microscopy techniques to analyse a variety of advanced structural materials. Specifically, this work involved the use of high-resolution scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and conventional transmission electron microscopy (CTEM). In each case, associated energy dispersive X-ray spectroscopy was applied to assess the chemical compositions of each of the materials on a micro and/or nano length scale. Furthermore, for selected sample preparation for STEM/CTEM examination, a Ga+ ion focused ion beam (FIB) system was also employed to make the associated thin film samples.Three sets of materials were assessed in seven-month period of collaborative research work, each to varying degrees:A. Surface-borided titanium carbide-316 stainless steel composites, also known as ‘cermets’, and subsequently referred to a TiC-316,B. Laser directed energy deposition (DED) processed TiC-Ni3Al based coatings (or clads), deposited onto AISI D2 tool steel substrates,C. Surface-borided AISI H13 tool steel samples prepared through laser DED processing.
実験 / Experimental
Through the combined use of SEM, STEM, and CTEM, the crystalline surface phases were identified on a sub-micron and nano-scale resolution. Specifically, STEM and CTEM were applied to the surface-borided titanium carbide (TiC)-316 stainless steel composites, with EDS utilized for detailed chemical analyses. FIB was used for excising surface regions of the borided TiC-316 stainless steel composites. SEM/EDS were only used for the laser directed energy deposition (DED) processed TiC-Ni3Al based coatings and surface-borided AISI H13 tool steel samples.
結果と考察 / Results and Discussion
The core of the efforts undertaken at the University of Tokyo were based around material (A) above, namely the borided TiC-316 cermets. These materials were assessed in four distinct process conditions, namely: (i) The ‘as-sintered’ state (vacuum sintered at 1,550 °C/1 hour),(ii) Surface borided in vacuum at 850 °C/4 hours after following the same sintering treatment as in (i),(iii) Surface borided in vacuum at 950 °C/4 hours after following the same sintering treatment as in (i),(iv) Surface borided in vacuum at 1,050 °C/4 hours after following the same sintering treatment as in (i).The use of SEM, STEM, and CTEM were found to be highly beneficial in elucidating the boriding mechanism itself. The boriding technique utilises a boron source, which when heat, facilities the diffusion of boron into the surface of the material being borided. While this approach has been applied to ferrous- and titanium-based alloys, this is believed to be the first time it has been applied to such a TiC-based cermet system. Preliminary studies of the mechanical behaviour had shown benefits, with both the Vickers hardness and scratch hardness increased by surface boriding.Through the combined use of SEM, STEM, and CTEM, the crystalline surface phases were identified on a sub-micron and even nano-scale. In particular, while the formation of iron borides (FeB and Fe2B) was anticipated from prior studies on surface boriding of ferrous alloys, the use of STEM/CTEM highlighted further subtle microstructural changes. For example, nano-scale (~100 nm diameter) TiB2 precipitates (analysed to be very close in stoichiometry to TiB2, and therefore extremely likely to be this phase from the Ti-B phase diagram) were observed to form on the TiC crystals when borided at intermediate temperature (i.e., 950 °C/4 hours); these precipitates were analysed to be very close in stoichiometry to TiB2, and therefore extremely likely to be this phase from the Ti-B phase diagram, however some alloying with components from the 316 steel cannot be ruled out. In contrast, at the higher boriding temperature (i.e., 1,050 °C/4 hours) the TiB2 precipitates were no longer apparent. However, very fine scale sub-surface porosity was apparent, which is deleterious to the mechanical properties.In terms of materials (B) and (C) noted above, the laser DED processed TiC-Ni3Al clads and borided tool steel, due to time constraints, these studies were restricted to the use of high-resolution SEM and associated EDS analysis. Again, this work highlighted fine details regarding the evolution of the surface structure that had not been available using the facilities at the Fellowship recipient’s home institution.
図・表・数式 / Figures, Tables and Equations
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件