Restraining of calcium contamination in near-net shape alumina ceramics during slip casting

Restraining of calcium contamination in near-net shape alumina ceramics during slip casting

Článek WoS

The traditional method for shaping ceramics is by slip casting on gypsum molds; however, its application for near-net shaping of ceramic components is limited due to contamination by calcium ions. The focus of this study is the modification of the mold to limit Ca2+ contamination and to maintain favorable sucking properties. Cement was added to a standard gypsum mold to suppress its erosion, and a decrease in the sucking rate was observed due to its reduced macroporosity. The highest values of green densities were obtained at gypsum/cement weight ratios of 90/10 and 70/30. The microstructure analysis showed that alumina blocks prepared from the molds containing higher quantities of cement (30 or 50 wt%) were resistant to abnormal grain growth caused by Ca2+ contamination from the gypsum. The gypsum/cement mixtures for making molds for slip casting significantly limit mold erosion due to a lower sucking rate and abnormal grain growth of the slip cast samples because of the decreased diffusivity of Ca2+ ions. Therefore, the present modification of the mold renders the slip casting method more suitable for the near-net shaping of ceramics.

The traditional method for shaping ceramics is by slip casting on gypsum molds; however, its application for near-net shaping of ceramic components is limited due to contamination by calcium ions. The focus of this study is the modification of the mold to limit Ca2+ contamination and to maintain favorable sucking properties. Cement was added to a standard gypsum mold to suppress its erosion, and a decrease in the sucking rate was observed due to its reduced macroporosity. The highest values of green densities were obtained at gypsum/cement weight ratios of 90/10 and 70/30. The microstructure analysis showed that alumina blocks prepared from the molds containing higher quantities of cement (30 or 50 wt%) were resistant to abnormal grain growth caused by Ca2+ contamination from the gypsum. The gypsum/cement mixtures for making molds for slip casting significantly limit mold erosion due to a lower sucking rate and abnormal grain growth of the slip cast samples because of the decreased diffusivity of Ca2+ ions. Therefore, the present modification of the mold renders the slip casting method more suitable for the near-net shaping of ceramics.

alumina; contamination; density; microstructure; slip casting

alumina; contamination; density; microstructure; slip casting

DRDLÍK, D.; ROLEČEK, J.; DRDLÍKOVÁ, K.; SALAMON, D.

2019

04.06.2018

1744-7402

International Journal of Applied Ceramic Technology

15

6

Spojené státy americké

1559

1566

8

https://onlinelibrary.wiley.com/doi/10.1111/ijac.13042