Spark plasma sintering and characterization of bulk nanostructured fully stabilized zirconia: Part I. Densification studies

Abstract

The sintering of nanosize powders of fully stabilized zirconia was investigated using the spark plasma sintering (SPS) method. The influence of sintering temperature, heating rate, direct current pulse pattern, sintering time, and sintering pressure on the final density and grain size of the product was investigated. The dependence of densification on temperature showed a maximum at 1200 °C, resulting with nearly fully dense zirconia with a crystallite size of about 100 nm. Heating rate (50∼300 °C min−1) and sintering time (5–16 min) had no significant influence on the final density and the crystallite size. Pulsing patterns ranging from 2:2 to 48:2 (on:off) had no influence on the density or the crystallite size. However, the applied pressure had a significant influence on the final density but no apparent effect on crystallite size for a sintering temperature of 1200 °C and a hold time of 5 min.

Microstructure and Properties of Spark Plasma Sintered Aluminum Containing 1 wt.% SiC Nanoparticles

“…However, the rate of increase was significant at 500 and 600 °C and marginal at 550 °C . This agrees with what was reported in [23]. Full densification was achieved in sample sintered at 600 °C for 10 min, as can be seen in the microstructure presented in Figure 6c.…”

“…The rate of this change, at lower pressure range, was higher than that at higher pressure. Such behavior was observed by other researchers [23,36,37]. In spark plasma sintered pure Mo [36], pressure rise between 29 and 67 MPa enhanced densification till a marginal value was reached at 57 MPa.…”

“…The process involves simultaneous application of pulsed DC current and uniaxial pressure. With SPS, high heating rates can be achieved [23], and sintering can be performed at relatively low temperatures for short sintering times. This enables the synthesis of fully dense materials [24].…”

Characterization of densified fully stabilized nanometric zirconia by positron annihilation spectroscopy

“…2͑b͒ for the same samples. 5 It is noted that the marked decrease in the LMF ͑in the range of 900-1200°C͒ coincides with a marked change in density over the same temperature range. In contrast, the change in crystallite size is relatively small over this temperature range, becoming important only when the temperature exceeds 1200°C where the relative density reaches 100%.…”

“…[2][3][4] The technique has been used recently to consolidate nanocrystalline fully stabilized zirconia. 5,6 The method is similar to conventional hot pressing, but in the SPS case all of the energies for the process come from highintensity current pulses applied to a graphite die containing the sample. The primary effect is Joule heating but other effects, such as current-enhanced mass transport and reactivity, are believed to contribute to the process.…”