Experimental study on the feasibility of using liquid-assisted processing in fabrication of Mo-Si-B alloys

• Published in: Materials letters Vol. 253; pp. 13 - 17
• Main Authors: Bruzda, Grzegorz, Polkowski, Wojciech, Polkowska, Adelajda, Nowak, Rafał, Kudyba, Artur, Sobczak, Natalia, Karczewski, Krzysztof, Giuranno, Donatella
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.2019; Elsevier BV
• Subjects: Alloys; Binary alloys; Binary systems; Boron alloys; Borosiliconizing; Eutectic alloys; Feasibility studies; Feature recognition; High temperature; High temperature tests; Interfaces; Intermetallic alloys and compounds; Liquid assisted processing; Liquid phases; Materials science; Mo-Si-B alloys; Molybdenum base alloys; Molybdenum disilicides; Optimization; Porosity; Process parameters; Sessile drop method; Structural analysis; Substrates; Thickness; Interfaces; Liquid assisted processing; Borosiliconizing; Sessile drop method; Mo-Si-B alloys; Intermetallic alloys and compounds
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2019.06.024

•Experimental assessment of a novel liquid-assisted borosiliconizing process.•A new technological approach for a fabrication of Mo-Si-B materials.•Wetting, spreading and reactivity in Si-B/Mo system.•Reactively formed molybdenum silicides, borosilicides and borides. In this work, we used a sessile drop experiment to assess a feasibility of novel processing design engaging liquid-phase assisted fabrication of multi-phase materials from Mo-Si-B system. For this purpose, binary eutectic silicon-boron alloy (Si-3.2B wt%) was subjected to contact heating with polycrystalline molybdenum substrate at temperature up to 1385 °C. It was in-situ observed that molten Si-3.2B alloy wets and rapidly spreads over the Mo surface. After the high temperature test, the solidified couple was subjected to structural characterization by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray diffraction methods. The obtained results revealed that the direct interaction between examined materials under applied testing conditions results in the reactively formed product layer having a thickness of ∼80 µm. The following structural features were recognized starting from the surface side: (I) the main product layer composed of columnar-like MoSi2 phase and Mo5Si3 phase; (II) an intermediate layer made of MoB and Mo5SiB2 phases. Although these results give the first indication for designing a novel liquid-assisted fabrication method of Mo-Si-B materials, an existence of porosity in the product layer clearly suggests that a further optimization of the process parameters is necessary.