Browsing by Author "Paterson, Adrian"

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    The flocculation of kaolin with polyacrylamides
    (1982) Paterson, Adrian; Heckroodt, Oelof
    Flocculation occurs when high molecular mass organic molecules form bridges between particles, causing them to aggregate. This modifies the sedimentation properties of the mineral slurry. Thus classical measures of flocculation, among them the settled bed height and the supernatant turbidity, have tended to focus on the properties of the suspension rather than the flocculant. The kaolin - polyacrylamide system is investigated in this study.
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    Processing and properties of silicon nitride ceramics
    (1993) Nel, Jacqueline Margot; Shaw, Martin; Paterson, Adrian; Allen, Colin
    Silicon nitride, Si₃N₄, ceramics were produced using either silicon or silicon nitride powder. The silicon was reaction bonded in nitrogen atmosphere to form reaction bonded Si₃N₄,which was then sintered between 1700°C and 1800°C to form a dense Si₃N₄ ceramic. The silicon nitride powder compacts were also sintered between 1700°C and 1800°C. In order to achieve densification Y₂O₃-A1₂O₃ additive combination was used in both processing routes. The physical and mechanical properties of the Si₃N₄ materials was found to be dependent on the processing conditions. The post sintered reaction bonded Si₃N₄ materials had the highest densities and hardness values, while the sintered Si3N4 materials had the highest strength and toughness values. The microstructure was also influenced to a great extent by the processing conditions, and this in tum influenced the mechanical properties of the ceramics.