Analysis of reactions during sintering of CuO-doped 3Y-TZP nano-powder composites

Manipulating microstructure and mechanical properties of CuO doped 3Y-TZP nano-ceramics using spark-plasma sintering

“…The PLS results are described in detail in Ref. 6 An SEM image of a fractured surface and TEM images of an SPSed (spark-plasma sintered) sample are shown in Figs. 2 and 3, respectively.…”

“…5,6,14 Composites of 3Y-TZP doped with 8 mol% of CuO (sample code 3YZ-8C) were prepared by ball-milling followed by subsequent ultrasonic vibration of the milled suspension and drying. For pressureless sintering the composite powder was isostatically pressed into a cylindrical green compact at 400 MPa and a Netzsch 402E dilatometer was used to study sintering behaviour in an oxygen flow as further described in Refs.…”

“…For pressureless sintering the composite powder was isostatically pressed into a cylindrical green compact at 400 MPa and a Netzsch 402E dilatometer was used to study sintering behaviour in an oxygen flow as further described in Refs. 5,6 SPS experiments were performed on a FCT FAST device (Type HP D 25/1, FCT Systeme, Rauenstein, Germany). The SPS procedure contains the following segments.…”

“…[5][6][7] In nanosized CuO doped 3Y-TZP dissolution of CuO in the 3Y-TZP matrix, starting below 600 • C, enhances grain boundary diffusivity and subsequently leads to fast densification in the intermediate sintering stage. At 860 • C a solid-state reaction between CuO and yttria, as segregated to the 3Y-TZP grain boundaries, occurs forming a solid Y 2 Cu 2 O 5 phase which retards densification and induces the formation of the thermodynamic stable monoclinic zirconia phase.…”

“…At 860 • C a solid-state reaction between CuO and yttria, as segregated to the 3Y-TZP grain boundaries, occurs forming a solid Y 2 Cu 2 O 5 phase which retards densification and induces the formation of the thermodynamic stable monoclinic zirconia phase. 6 Obviously, in order to obtain a CuO doped 3Y-TZP ceramic with the desired microstructure and properties, a good control of all these reactions during sintering is necessary.…”