Heating and Electrical Holder
Electric-field assisted sintering of ZrO2
Sintering is the process of forming a solid mass of material without melting the material. It often leaves voids and pores, which compromises material strength. Sintering by temperature alone occurs at high temperatures (~80% of the melting point) and can take several hours.
Electrical current is often used in addition to temperature to lower the required temperature and reduce the length of the sintering process. However, the role of this current is still largely unknown at the nanoscale.
Until recently there was not a commercially available solution that could heat and apply current to a sample within the electron microscope. Researchers in the van Benthem group at University of California Davis studied sintering mechanisms in yttria-stabilized ZrO2 (3YSZ), using TEM and STEM images to monitor the microstructural evolution of the agglomerates during densification.
When they used Protochips’ Fusion to apply 900 °C to the sample, the structure remained unchanged for 106 minutes. They then raised the temperature to 1200 °C, at which point the pores shrank.
To see the effect of electrical current, the researchers applied a field of 500V/cm and a temperature of 900 °C. After just 4 minutes, pore shrinkage and coalescence occurred, confirming the field-assisted sintering.