Filters

Settings

Now showing1 - 2 of 2
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    The role of milling liquids in processing of metal-ceramic-precursor powders
    (Wiley Interscience, 2013)
    Holstein, Nadja
    ;
    Wiegandt, Katharina
    ;
    Holleyn, Florian
    ;
    Kriegesmann, Jochen
    ;
    Kunze, Michael R.
    Reaction bonding of aluminum oxide (RBAO) and the reactive sintering of metal-alumina composites (s-MAC) are encouraging concepts for the preparation of highly dense components exhibiting specific properties. Precursor powders should be adapted for conventional powder metallurgical (PM) techniques. Thus, the focus is on the preparation of precursor powders for RBAO and s-MAC processing, exemplified by Al-Al2O3 and Cr-Al 2O3 powders, respectively. For both variants, a fine grained, homogenous precursor is the essential prerequisite - particularly, if the goal for reactive synthesis routes is complete densification by pressureless sintering. The precursor powders had been wet grinded in an attrition mill. Organic milling liquids with different properties were investigated. The characterization is based on stability considerations of the milling suspensions. The comparison of the particle size distributions with the results of the sedimentation trails indicates the existence of different hard agglomerate structures build up in the milling process. According to the solvent properties the milling results can be classified not only to polar and nonpolar, but rather to polar protic, polar aprotic and nonpolar solvents. In addition, the influences of the powder characteristics on the corresponding reaction bonding or reaction sintering mechanism are examined.
    Publicationtype: Conference Paper
      113
  • Some of the metrics are blocked by your 
    consent settings
    Item type:Publication, Access status: without files ,
    Calcium phosphate ceramics as substrate for cartilage cultivation
    (Wiley Interscience, 2004-12-01)
    Janßen, Rolf
    ;
    Nagel-Heyer, Stephanie
    ;
    Göpfert, Christiane
    ;
    Pörtner, Ralf
    ;
    Toykan, Derya
    Hip, knee and shoulder joints are complex structures that bear a combination of articular cartilage, bone and synovial fluid. Articular cartilage is a shock-absorbing tough, connective tissue that covers the ends of bones in joints and enables the bones to glide over one another. Since there are no nerves or blood vessels in cartilage, once it is damaged it has a reduced ability to repair or restore itself. Thus, there has been continuous research on the regeneration of cartilage by tissue engineering. Our investigation is focussed on a tissue engineered cartilage-carrier-construct, where the cartilage is grown on top of a ceramic carrier as bone equivalent. Calcium phosphates are widely used as bioceramics due to their biocompatibility and bioactivity. Former in vivo (mini pig) investigations have demonstrated the potential of this concept for local cartilage repair. But still the properties of the carrier have to be optimised. In this study different types of calcium phosphate ceramics with different surface properties were investigated in order to generate cartilage on their surfaces. The results indicate that the adhesion of cartilage/calcium phosphate is a critical parameter for reliable implants.
    Publicationtype: Conference Paper
      8