Investigation of the novel joining dynamics induced by non-equilibrium gas-liquid-solid coexistence state at ceramic joint interface and its application to heat-resistant joint formation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04683
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26030:Composite materials and interfaces-related
• Research Institution: Kyoto Municipal Institute of Industrial Technology and Culture
• Principal Investigator: KOHAMA Kazuyuki 地方独立行政法人京都市産業技術研究所, 京都市産業技術研究所, 次席研究員 (00710287)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 低温接合 / 高温強度 / 接合機構 / 物質移動 / 相変態 / 熱力学 / 自由度

Outline of Final Research Achievements

The principal investigator recently developed the novel composite fillers for low-temperature joining of ceramics that maintained high-temperature joint reliability. The filler composition is specially designed to utilize evaporation and chemical reactions of additive elements in the filler to control the melting point, allowing the filler to melt at relatively-low temperatures during bonding, while the resultant joints can endure even temperatures higher than the bonding temperature. This study aimed to investigate the detailed joining dynamics for practical application of the fillers to formation of heat-resistant ceramic joints. In summary, major ceramics such as alumina, silicon nitride and silicon carbide were joined to themselves using the fillers. The interfacial microstructure characterization and thermo-mechanical property evaluation results revealed some important principles of the filler material design for joining various ceramics.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

ろう付によるセラミックス接合では、通常はフィラーの融点より低温でしか接合体を使用できず、セラミックスの高い耐熱性をいかせない。本研究で提案するフィラーは、接合時には基材元素と添加元素の共晶反応により低い温度で融けるため接合しやすくなる一方、接合後には基材元素の固有の融点まで融けなくなるため耐熱性の高い接合体が得られる。このダイナミクス解明により、各種セラミックスを低温で接合し、かつ接合後の耐熱性を維持できるという、これまでにない画期的な技術的提案につながる。また、フィラー中の添加元素を蒸発させて相変態を誘起するという極めて独創的な原理に基づいており、学術的な波及効果が高い。