New ultrahigh hardness material realized by octahedral coordinated SiN and partial ordering of atomic arrangement

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K18979
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Materials engineering and related fields
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Suzuki Tsuneo 長岡技術科学大学, 工学研究科, 准教授 (00313560)
• Project Period (FY): 2017-06-30 – 2019-03-31
• Keywords: 硬質薄膜 / エピタキシャル成長 / 積層不整 / 酸窒化物

Outline of Final Research Achievements

Cr-Si-N-O thin films were epitaxially grown on MgO substrates by pulsed laser deposition. The composition of these films was analyzed by Rutherford backscattering spectroscopy. X-ray diffraction analysis and transmission electron microscopy revealed them to be single-crystal-like (Cr,Si)(N,O) thin films. In addition, the diffraction of D51 observed in the selected area electron diffraction patterns indicated the presence of stacking faults. Therefore, it was concluded that the (Cr,Si)(N,O) thin films exhibited solid-solution hardening due to the addition of Si, and stacking faults induced by the addition of oxygen. Measurements by the nanoindentation method determined that the hardness of the Cr-Si-N-O thin films was about 35 GPa. The hardness did not vary with oxygen content.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

金属の切削加工は、もの作りの重要な基本工程の１つである。そこで使われるドリル等の切削工具には、硬質材料が薄膜として被覆されている。この被覆材料がより硬い物質になれば、省エネや生産性の向上に直結する。本研究では、全く新しい学術的な考察を基本に、これまで世の中に無かった新しい物質を合成した。その結果、これまでの材料と比較して極めて高い硬度が達成され、その要因が特殊な原子の配列であることが確認できた。