The team from Central South University has revealed the crucial influence of magnesium oxide and calcium carbonate on the properties of porous alumina ceramics.

Central South University Team Reveals Key Effects of Magnesium Oxide and Calcium Carbonate on the Performance of Porous Alumina Ceramics

A research team from the Hunan Key Laboratory of Mineral Materials and Application at Central South University, together with the Technology Center of China Tobacco Hunan Industrial Co., Ltd., has made significant progress in the study of mineralizers for porous alumina ceramics. Their findings, entitled "Effects of Magnesium Oxide and Calcium Carbonate Mineralizers on the Performance of Porous Alumina Ceramic," have been published in the August 2023 issue of *Materials Science and Engineering of Powder Metallurgy*.

Porous alumina ceramics are extensively used in applications such as aerospace engines, casting, and high-end equipment manufacturing thanks to their excellent high-temperature resistance and corrosion resistance. The research team employed TiO₂, magnesium oxide (MgO), and calcium carbonate (CaCO₃) as mineralizers, and systematically investigated the influence of different contents and holding times of mineralizers on the properties of the ceramics using an atmospheric pressure sintering process.

The study reveals that the addition of magnesium oxide and calcium carbonate significantly reduces the sintering shrinkage rate and density of porous alumina ceramics while substantially increasing the apparent porosity and dissolving efficiency. Notably, samples with MgO can be fully dissolved in alkali solution within just 24 hours, demonstrating superior dissolve-ability; meanwhile, CaCO₃ provides a more notable increase in porosity, and also achieves high dissolving efficiency when co-solvents are used. Furthermore, appropriately prolonging the sintering holding time helps to improve the density and mechanical properties of the material.

Professor Jing Ouyang, the team leader, noted that this research offers new ideas for the fine tuning of structure and properties in porous alumina ceramics, and provides a technological basis for efficient removal of ceramic cores and the development of high-performance ceramic materials. Looking ahead, the research team will continue to explore the combined effects of multiple mineralizers on ceramic properties, aiming to support the application of advanced functional ceramics in high-end manufacturing sectors.

This work was supported by the National Natural Science Foundation of China and other funding programs.

Reference:

CHEN Guang, WANG Wei, LIANG Lixing, PENG Yonghui, ZHOU Wentao, OUYANG Jing, WANG Zhiguo. Effects of magnesium oxide and calcium carbonate mineralizers on the performance of porous alumina ceramic [J]. Materials Science and Engineering of Powder Metallurgy, 2023, 28(4): 347-360. DOI:10.19976/j.cnki.43-1448/TF.2023028

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