Tecnologia em Metalurgia, Materiais e Mineração
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original

Addition of hematite as a sintering aid in alumina: effect of concentration on physical, microstructural and mechanical properties

Pedro Henrique Poubel Mendonça da Silveira; Amal Elzubair Eltom; Jheison Lopes dos Santos; Geovana Carla Girondi Delaqua; Carlos Maurício Fontes Vieira; Paulo Roberto Rodrigues de Jesus; Marcelo Henrique Prado da Silva; Alaelson Vieira Gomes

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Hematite (Fe2 O3), or ferric oxide, is a ceramic oxide that, despite being recognized in the field of science and materials engineering, finds limited use as a sintering additive. Therefore, the purpose of this study was to explore the incorporation of hematite as a sintering additive in alumina (AIO3), employing conventional sintering at 1400 °C. Seven compositions were processed, with Fe2 O3 content varying from 0 to 8 wt.%. The samples underwent conventional ceramic processing steps (homogenization, drying, deagglomeration, sieving, and cold uniaxial pressing), followed by sintering at 1400 °C. The physical and mechanical properties of the produced samples were assessed through dilatometry, density measurement using the Archimedes’ method, scanning electron microscopy with energy-dispersive spectroscopy (SEM/ EDS), and flexural and compression tests. The results revealed that the addition of 4 and 6 wt.% of Fe2 O3 resulted in reduced shrinkage of the ceramics, leading to low densification, highly porous surfaces, and diminished flexural strength. On the other hand, lower additions (0.5, 1, and 2 wt.%) of Fe2 O3 improved the sintering of Al2 O3 , yielding samples with increased flexural and compressive strength, linear shrinkage, and densification.


Alumina; Hematite; Flexural resistance; Sintering


1 Baltazar J, Alves MFRP, dos Santos C, Olhero S. Reactive Sintering of Al2O3–Y3Al5O12 Ceramic Composites Obtained by Direct Ink Writing. Ceramics. 2022;5(1):1-12.

2 Piconi C. Alumina. In: Ducheyne P, editor. Comprehensive biomaterials. Amsterdam: Elsevier; 2011. p. 73-94. http://dx.doi.org/10.1016/b978-0-08-055294-1.00016-7.

3 Munz D, Fett T. Ceramics: material properties, failure behavior, materials selection. Berlin: Springer; 1999.

4 Silveira P, Silva T, Ribeiro M, Rodrigues de Jesus P, Credmann P, Gomes A. A brief review of alumina, silicon carbide and boron carbide ceramic materials for ballistic applications. Academia Letters. 2021;3742:1-11.

5 Yang S, Yang S, Zhu Y, Fan L, Zhang M. Flash Sintering of dense alumina ceramic discs with high hardness. Journal of the European Ceramic Society. 2022;42(1):202-206.

6 Wu Y, Zhang Y, Choy KL, Guo J. Liquid-phase sintering of alumina with YSiAlON oxynitride glass. Materials Letters. 2003;57(22-23):3521-3525.

7 Keramat E, Hashemi B. Modelling and optimizing the liquid phase sintering of alumina/CaO–SiO2–Al2O3 ceramics using response surface methodology. Ceramics International. 2021;47(3):3159-3172.

8 German RM, Suri P, Park SJ. Liquid phase sintering. Journal of Materials Science. 2009;44:1-39.

9 Lee JW, Cha JM, Bae BH, Choi SW, Jung HD, Yoon CB. Effects of using MgO, CaO additives as sintering aid in pressureless sintering of M2Si5N8: Eu2+ (M= Ba, Sr) phosphor ceramics for amber LED automotive applications. Journal of Alloys and Compounds. 2021;858:157710.

10 Souto P, Menezes R, Kiminami R. Sintering of commercial mulite powder: Effect of MgO dopant. Journal of Materials Processing Technology. 2009;209(1):548-553.

11 Fabris DCN, Polla MB, Acordi J, Luza AL, Bernardin AM, De Noni A Jr, et al. Effect of MgO· Al2O3· SiO2 glass-ceramic as sintering aid on properties of alumina armors. Materials Science and Engineering A. 2020;781:139237.

12 Pan C, Zhao G, Li S, Wang J, Yin L, Song W, et al. Effect of BaO-2B2O3 sintering aid on the structural and electrical properties of CaBi2Nb2O9 high-temperature piezoelectric ceramic. Journal of Applied Physics. 2021;130(24):244102.

13 Silveira PHPM, Jesus PRR, Ribeiro MP, Monteiro SN, Oliveira JCS, Gomes AV. Sintering Behavior of AL2O3 Ceramics Doped with Pre-Sintered NB2O5 and LiF. Materials Science Forum. 2020;1012:190-195.

14 Gomez E, Echeberria J, Iturriza I, Castro F. Liquid phase sintering of SiC with additions of Y2O3, Al2O3 and SiO2. Journal of the European Ceramic Society. 2004;24(9):2895-2903.

15 Shan K, Li R, Liu J. Effect of Y2O3 on the corrosion resistance of two-step sintered Al5Y3O12-MgAl2O4 sidewalls in the aluminum electrolyte. Journal of the European Ceramic Society. 2022;42(4):1815-1821.

16 Carvalho ANC, Sousa Melo JJ, Sales FHS. Medidas elétricas e dielétricas em cerâmicas de BaTiO3 dopadas com SiO2 e Bi2O3. Brazilian Journal of Development. 2022;8(1):6871-6899.

17 Zaki ZI, Alotaibi SH, Alhejji BA, Mostafa NY, Amin MA, Qhatani MM. Combustion synthesis of high density ZrN/ZrSi2 composite: influence of ZrO2 addition on the microstructure and mechanical properties. Materials (Basel). 2022;15(5):1698.

18 Svancarek P, Galusek Gnanasagaran CL, Ramachandran K, Ramesh S, Ubenthiran S, Jamadon NH. Effect of co-doping manganese oxide and titania on sintering behaviour and mechanical properties of alumina. Ceramics International. 2023;49(3):5110-5118.

19 Sktani ZDI, Rejab NA, Ratnam MM, Ahmad ZA. Fabrication of tougher ZTA ceramics with sustainable high hardness through (RSM) optimisation. International Journal of Refractory Metals & Hard Materials. 2018;74:78-86.

20 Liu L, Zachariah MR. Enhanced performance of alkali metal doped Fe2O3 and Fe2O3/Al2O3 composites as oxygen carrier material in chemical looping combustion. Energy & Fuels. 2013;27(8):4977-4983.

21 Jiang Y, Mao Q, Ma T, Liu X, Li Y, Ren S, et al. Facile preparation of Fe2O3 Al2O3 composite with excellent adsorption properties towards Congo red. Ceramics International. 2021;47(10):13884-13894.

22 Yan P, Zhang K, Peng Y. Study of Fe2O3-Al2O3 catalyst reduction parameters and conditions for catalytic methane decomposition. Chemical Engineering Science. 2022;250:117410.

23 Hu J, Li H, Chen S, Xiang W. Enhanced Fe2O3/Al2O3 oxygen carriers for chemical looping steam reforming of methane with different Mg ratios. Industrial & Engineering Chemistry Research. 2022;61(2):1022-1031.

24 Ma Z, Liu G, Lu Y, Zhang H. Redox performance of Fe2O3/Al2O3 oxygen carrier calcined at different temperature in chemical looping process. Fuel. 2022;310:122381.

25 Abyzov A. Aluminum oxide and alumina ceramics (review). Part 1. Properties of Al2O3 and commercial production of dispersed Al2O3. Refractories and Industrial Ceramics. 2019;60:24-32.

26 Bercoff P, Bertorello H. Magnetic properties of hematite with large coercivity. Applied Physics. A, Materials Science & Processing. 2010;100:1019-1027.

27 Muan A, Gee C. Phase equilibrium studies in the system iron oxide-A12O3 in air and at 1 Atm. O2 pressure. Journal of the American Ceramic Society. 1956;39:207-214.

28 Muan A. On the stability of the phase Fe2O3. Al2O3. American Journal of Science. 1958;256:413-422.

29 Dayal R, Gard J, Glasser F. Crystal data on FeAlO3. Acta Crystallographica. 1965;18:574-575.

30 Feenstra A, Sämann S, Wunder B. An experimental study of Fe–Al solubility in the system corundum–hematite up to 40 kbar and 1300 C. Journal of Petrology. 2005;46(9):1881-1892.

31 Dreval L, Zienert T, Fabrichnaya O. Calculated phase diagrams and thermodynamic properties of the Al2O3–Fe2O3–FeO system. Journal of Alloys and Compounds. 2016;657:192-214.

32 Majzlan J, Navrotsky A, Evans B. Thermodynamics and crystal chemistry of the hematite–corundum solid solution and the FeAlO3 phase. Physics and Chemistry of Minerals. 2002;29:515-526.

33 Wang ZF, Wang JS, Chen YJ, Yu LX, Bu JL, Wang RL. Effect of molar ratio of Al2O3 to Fe2O3 on the sintering and thermal shock resistance of Al2O3-Fe2O3 composite. Advanced Materials Research. 2011;194:1745-1748.

34 Cao Z, Qin M, Jia B, Gu Y, Chen P, Volinsky AA, et al. One pot solution combustion synthesis of highly mesoporous hematite for photocatalysis. Ceramics International. 2015;41(2):2806-2812.

35 Maca K, Pouchly V, Boccaccini A. Sintering densification curve: a practical approach for its construction from dilatometric shrinkage data. Science of Sintering. 2008;40(2):117-122.

36 Associação Brasileira de Normas Técnicas. NBR 16661:2017: Material refratário denso conformado – determinação de volume aparente, volume aparente da parte sólida, densidade da massa aparente, densidade aparente da parte sólida, porosidade aparente e absorção. 2. ed. Rio de Janeiro: ABNT; 2017.

37 Associação Brasileira de Normas Técnicas. NBR ISO 6872: Odontologia – Materiais Cerâmicos. Rio de Janeiro: ABNT; 2023.

38 Awaju H, Watanabe T, Nagano Y. Compressive testing of ceramics. Ceramics International. 1994;20(3):159-167.

39 Pouchly V, Maca K. Master sintering curve: a practical approach to its construction. Science of Sintering. 2010;42(1):25-32.

40 Ribeiro GC, Fortes BA, Silva L, Castro JÁ, Ribeiro S. Evaluation of mechanical properties of porous alumina ceramics obtained using rice husk as a porogenic agent. Cerâmica. 2019;65(1):70-74. http://dx.doi. org/10.1590/0366-6913201965s12604.

41 Zygmuntowicz J, Piątek M, Miazga A, Konopka K, Kaszuwara W. Dilatrometric sintering study and characterization of alumina-nickel composites. Processing and Application of Ceramics. 2018;12(2):111-117.

42 García DE, Schicker S, Bruhn J, Janssen R, Claussen N. Processing and mechanical properties of pressureless-sintered niobium-alumina-matrix composites. Journal of the American Ceramic Society. 1998;81(2):429-432.

43 Jesus PRR, Silveira PHPM, Ribeiro MP, Silva TT, Arantes VL, Gomes AV. Fabrication of al2o3-nb2o5-lif-zro2 fgms by sps method: microstructural evaluation, dynamic and sintering behaviour. Processing and Application of Ceramics. 2022;16(3):251-258.

44 Taktak R, Baklouti S, Bouaziz J. Effect of binders on microstructural and mechanical properties of sintered alumina. Materials Characterization. 2011;62(9):912-916.

45 Lakshmanan A. Sintering of ceramics: new emerging techniques. Rijeka: Books on Deman; 2012.

46 Ortega FS, Paiva AEM, Rodrigues JÁ, Pandolfelli VC. Propriedades mecânicas de espumas cerâmicas produzidas via. Cerâmica. 2003;49(309):1-5. http://dx.doi.org/10.1590/s0366-69132003000100002.

47 Gomes A, Louro L, Costa C. Ballistic behavior of alumina with niobia additions. Journal de Physique. IV. 2006;134:1009-1014.

48 Ren XZ, Zhang W, Zhang Y, Zhang PX, Liu JH. Effects of Fe2O3 content on microstructure and mechanical properties of CaO–Al2O3–SiO2 system. Transactions of Nonferrous Metals Society of China. 2015;25(1):137-145.

49 Medvedovski E. Alumina–mullite ceramics for structural applications. Ceramics International. 2006;32(4):369-375.

50 Teng X, Liu H, Huang C. Effect of al2o3 particle size on the mechanical properties of alumina-based ceramics. Materials Science and Engineering A. 2007;452:545-551.

51 Yoon BH, Choi WY, Kim HE, Kim JH, Koh YH. Aligned porous alumina ceramics with high compressive strengths for bone tissue engineering. Scripta Materialia, Elsevier. 2008;58(7):537-540.

52 Castillo-Villa PO, Baró J, Planes A, Salje EK, Sellappan P, Kriven WM, et al. Crackling noise during failure of alumina under compression: the effect of porosity. Journal of Physics Condensed Matter. 2013;25(29):292202.

53 Miyake K, Hirata Y, Shimonosono T, Sameshima S. The effect of particle shape on sintering behavior and compressive strength of porous alumina. Materials, MDPI. 2018;11(7):1137.

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