Members

• Caterina Eberl
• Annette Sans
• Marie-Luise Schreiber
• Fanny Schurz
• Jakob Wilfert

Former Members

Research

Amorphous networks, consisting of the elements Si, B, N and C are surprisingly highly durable: in an inert atmosphere, the onset of weight loss starts between 1800 and 2000 °C, depending on the molecular precursor employed. Unparalleled among nitride materials are the resistivity against oxidation and crystallization. Particularly promising is the application of these novel materials as ceramic fibers in ceramic fiber reinforced ceramics (CFCs) for the aerospace industry.

In a novel synthesis strategy, three-dimensional covalently bonded nitride and/or carbide networks are built up in a ternary or quaternary system. The high degree of cross-linking in such random networks, which is due to the presence of nitrogen and carbon in the network, may lessen the crack propagation inside a workpiece. Moreover, the material properties may be optimized by varying the elemental composition.

Single source precursors

Pre- ceramic polymers and their pyrolytic conversion to ceramics

Applications of Si/B/N/(C) ceramics

Ceramic coatings and infiltrations

Fibers

Phosphors for LEDs

Equipment

• GC/MS (GCMS-QP2010 Plus, Shimadzu)
• NMR
  • Liquid-state (300 MHz Avance DPX- 300 SB - Bruker)
  • Solid-state (400 MHz, DSX-400 WB - Bruker
• Powder X-ray Diffractometers
• Single Crystal Diffactometers
• High-temperature DTA/TG (STA 409 C – Netzsch, equipped with a water-cooled chamber oven up to 2000 °C)
• DTA/TG/MS (up to 1350 °C, STA 409 C – Netzsch, equipped with Q421 – Balzer – mass spectrometer)
• Elemental analysis
  • Hot gas extractor (TC-436 and C-200, Leco)
  • ICP-OES (ARL 3580 B, EcuBlens and Vista Pro Simultaneous, Varian
• SEM (XL 30 TMP - Philips) – EDX (EDAX)
• Helium Pycnometer (AccuPyc II 1340, Micromeritics)
• Gel Permeation Chromatography (S 1122, Sykam)
• Microwave furnace (Start-1500 Mikrowellen System, MLS)
• Glove-boxes (MT 200, MB 150BG-II, MB 200B, M.Braun)
• Furnaces
  • tube furnaces up to 1200 °C (LOBA, HTM Reetz)
  • tube furnaces up to 1800 °C (LORA, HTM Reetz and TRH 100-600/18, Gero)
  • chamber furnace (8 GR/22-1G, Gero)
• Fume hoods with Schlenk line
• Fluorescence spectrometer (Fluorolog-3 FL3-22, Horiba Jobin Yvon)

Selected publications

• M. Jansen, J. C. Schön, L. Wüllen van: The Route to the structure Determination of Amorphous Solids: A Case Study of the Ceramic Si₃B₃N₇
  Angew. Chem.Int. Ed. 45 (2006) 4244-63
• B. Jäschke, T. Jäschke, M. Jansen: Amorphous Multinary Ceramics in the Si-B-N-C System
  Struct. Bond. 101 (2002) 138 Berlin, Springer
• J. Löffelholz, J. Engering, M. Jansen: Sol-Gel Process in the Ammono-System - A Novel Access to Silicon Based Nitrides
  Z. Anorg. Allg. Chem. 626 (2000) 963-968
• P. Baldus, M. Jansen, D. Sporn: Ceramic Fibres for Matrix Composites in High-Temperature Engine Applications
  Science 285 (1999) 699-703
• H.-P. Baldus, M. Jansen: Novel High-Performance Ceramics - Amorphous Inorganic Networks from Molecular Precursors
  Angew. Chem. Int. Ed. 36 (1997) 328

Contact: Prof.Dr.Dr.h.c. M. Jansen

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