TY - JOUR A1 - Rudolph, Pascale A1 - Brzezinka, Klaus-Werner A1 - Wäsche, Rolf A1 - Kautek, Wolfgang T1 - Physical chemistry of the femtosecond and nanosecond laser-material interaction with SiC and a SiC-TiC-TiB2 composite ceramic compound N2 - The interaction of nanosecond laser pulses in the ultraviolet wavelength range and femtosecond laser pulses in the near-infrared region with the semiconductor SiC and the composite compound SiC–TiC–TiB2 was investigated. Surface analytical techniques, such as XPS, depth profile (DP), and micro-Raman spectroscopy (?-RS) were used to identify the chemical changes between untreated and laser-treated areas. Single-pulse irradiation led to material modifications in the condensed state in most instances. Multi-pulse results differed depending on the pulse duration. Crystal structure changes were observed as a consequence of laser-induced melting and resolidification. In air contact all components underwent oxidation reactions according to thermodynamic expectations. Exceptions were observed under exclusion of oxygen, SiC was reduced to elemental Si. KW - Femtosecond techniques KW - Nanosecond techniques KW - Ceramics KW - Raman spectra/condensed matter KW - XPS/surface analysis PY - 2003 U6 - https://doi.org/10.1016/S0169-4332(02)01356-9 SN - 0169-4332 SN - 1873-5584 VL - 208-209 SP - 285 EP - 291 PB - North-Holland CY - Amsterdam AN - OPUS4-2791 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klaffke, Dieter A1 - Wäsche, Rolf A1 - Janakiraman, N. A1 - Aldinger, F. T1 - Tribological characterisation of siliconcarbonitride ceramics derived from preceramic polymers N2 - Amorphous SiCN ceramics were prepared in a laboratory scale as disk shaped specimens with 10 mm diameter and 0.3 mm thickness. The friction and wear behaviour was characterised in gross slip fretting tests under unlubricated conditions at room temperature against steel (100Cr6) and ceramic (Al2O3). Tests with a ball-on-disk contact were performed in laboratory air with different content of water vapour. The results show clearly that the relative humidity has a significant effect on friction and wear behaviour. All tests in dry air lead to higher friction and higher wear rate than in normal air. Improved friction and wear behaviour was observed with increasing pyrolysis temperature up to 1100 °C of the SiCN specimens. This is attributed to increasingly better mechanical properties and higher stiffness of the amorphous network due to the evaporation of gaseous organic species and the formation of free graphite like carbon. KW - Ceramics KW - Preceramic polymer KW - Siliconcarbonitride KW - Friction KW - Wear PY - 2006 U6 - https://doi.org/10.1016/j.wear.2005.04.031 SN - 0043-1648 VL - 260 IS - 7-8 SP - 711 EP - 719 PB - Elsevier CY - Amsterdam AN - OPUS4-12302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Paulick, Carl A1 - Steinborn, Gabriele A1 - Richter, V. A1 - Werner, M. T1 - Joining of ceramic components in the green state via LPIM N2 - It has been successfully demonstrated that ceramic materials can be joined in the green state without a second phase by using low pressure injection molded parts. The investigation of the joining interface revealed that a high quality interface can be achieved by carefully adjusting the different manufacturing steps. The use of monomodal particle size distribution in the used powder CT3000SG is inferior to a broader particle size distribution obtained by replacing 33% of the finer alumina powder by coarser CT1200SG. In this way the dewaxing process is significantly improved when the wall thickness of the part exceeds 3 mm. The investigation of the mechanical properties of the joined and sintered parts revealed, that the bending strength of the joined specimens achieved about 80 % of the unjoined, monolithic specimens. T2 - 4th International Conference on Advanced Materials and Processing CY - Hamilton, New Zealand DA - 2006-12-10 KW - Joining KW - Ceramics KW - Green state KW - Interface KW - Bending strength KW - Low pressure injection molding PY - 2005 UR - http://www.scientific.net/3-908453-89-5/207/ SN - 1022-6680 SN - 1662-8985 VL - 29-30 SP - 207 EP - 210 PB - Trans Tech Publ. CY - Zurich AN - OPUS4-19001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -