Tailoring of functionally graded zirconia–mullite/alumina ceramics

Ewais, Emad M.M.; Besisa, Dina H.A.; Zaki, Zaki Ismail; Kandil, Abd El Hakim Taha

doi:10.1016/j.jeurceramsoc.2012.01.016

Cited by 33 publications

(15 citation statements)

References 53 publications

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“…The recorded value of each test of tailored FGZM/A was nearly equal to the average of the test values of its non-layered composites. This is good evidence of the strength of the interfacial bonding between subsequent layers of the composite as well as the homogeneity and uniformity of the powders in each layer [6,7].…”

Section: Sintering Processmentioning

confidence: 67%

“…Examples of these FGCs are alumina/zirconia, a material used in biomedical and structural applications, mullite/alumina, which is used as a protective coating for SiC components in corrosive environments [2,5]. Zirconia-mullite/alumina FGCs can be used as refractory materials in high temperature applications, as well as being suitable for engineering and tribological applications [6,7].…”

Section: Ceramic/ Ceramic and Glass/ Ceramicmentioning

confidence: 99%

“…• Novel zirconia-mullite/alumina FGC tailored by the reaction sintering method and used in refractory materials that line furnaces, and high temperature applications [6,7].…”

Section: Other Applications Of Functionally Graded Ceramicsmentioning

confidence: 99%

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Advances in Functionally Graded Ceramics – Processing, Sintering Properties and Applications

Besisa¹,

Ewais²

2016

Advances in Functionally Graded Materials and Structures

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In multilayered structures, sharp interface is formed between the layers of dissimilar materials. "t this interface, the large difference in thermal expansion coefficients of the two dissimilar materials generates residual thermal stresses during subsequent cooling. These stresses lead to cracking at the interface, and these cracks lead to the deterioration of mechanical properties, and finally crack propagation leads to the delamination of the multilayered structure. Scientific progress in the field of material technology, and the continuing developments of modern industries have given rise to the continual demand for ever more advanced materials with the necessary properties and qualities. The need for advanced materials with specific properties has brought about the gradual transformation of materials from their basic states monolithic to composites. Recent advances in engineering and the processing of materials have led to a new class of graded multilayered materials called Functionally Graded Materials FGMs . These materials represent a second generation of composites and have been designed to achieve superior levels of performance. This chapter looks at the best processing technologies and the uses and applications of the advanced, high quality products generated, and also presents an extensive review of the recent novel advances in Functionally Graded Ceramics FGCs , their processing, properties and applications. The manufacturing techniques involved in this work have involved many concepts from the gradation, consolidation and different sintering processes. Each technique, however, has its own characteristics and disadvantages. In addition, the FGC concept can be applied to almost all material fields. This chapter covers all the existing and potential application fields of FGCs, such as engineering applications in cutting tools, machine parts, and engine components, and discusses properties of FGCs such as heat, wear, and corrosion resistance plus toughness, and their machinability into aerospace and energy applications.

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Section: Sintering Processmentioning

confidence: 67%

Section: Ceramic/ Ceramic and Glass/ Ceramicmentioning

confidence: 99%

See 1 more Smart Citation

Advances in Functionally Graded Ceramics – Processing, Sintering Properties and Applications

Besisa¹,

Ewais²

2016

Advances in Functionally Graded Materials and Structures

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“…Functionally Graded Ceramics (FGCs) are designed to withstand a variety of severe operative conditions, including high temperatures, corrosive environments, abrasion, mechanical, and thermal‐induced stresses . An overview of the FGC structures already developed and their main application fields is proposed in Table .…”

Section: Introduction To Fgmsmentioning

confidence: 99%

Functionally graded ceramics for biomedical application: Concept, manufacturing, and properties

Petit

Montanaro

Palmero

2018

Int J Applied Ceramic Tech

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Functionally Graded Materials (FGMs) represent a novel approach for the realization of innovative properties and/or functions that conventional homogeneous materials cannot accomplish. In conventional materials, in fact, the composition or the structure is uniform over the volume; on the opposite, in FGMs such features gradually change from layer to layer, with the aim of realizing a gradation of properties over the volume and performing a set of specified functions. Among FGMs, special attention is given today to Functionally Graded Ceramics (FGCs), designed and developed to withstand a variety of severe operative conditions, including high temperatures, corrosive environments, abrasion, mechanical, and thermal induced stresses. An important application field of FGCs is for medical prosthetic devices and artificial tissues, taking inspiration from the several examples of living tissues with graded structures. After an introduction on the rationale for using FGCs in the biomedical field, the 3 main types of graded materials developed today (eg, composition, porosity and microstructural graded ceramics) are here reviewed, highlighting the most innovative technologies used to develop them, their potentials and challenging features in comparison with the monolithic counterparts. K E Y W O R D S

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“…Functionally graded ceramics (FGCs) operate with coherent and semi coherent interfaces between each layer. The intent of FGCs is to provide a composite which pairs the strength and hardness of one constituent, usually at the exposed end, with the toughness of the second constituent; mimicking natural structures such a tree bark or bones [92] [93].…”

Section: Figure 20: Crack Deflection Along a Multi Layered Interface mentioning

confidence: 99%

Mullite Whisker Enhanced Zirconia Toughened Alumina Ceramic Matrix Composite for High Temperature Applications

Robertson¹

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Ceramic Matrix Composites (CMC) are an attractive material for high temperature applications because they possess many of the high temperature capabilities of monolithic ceramics but also have enhanced mechanical properties due to their multi-phase structure. Recent successes with incorporating SiC fibre reinforced high temperature CMCs into advanced gas turbines have caused a renewed interest in applying CMCs to other high temperature applications. In this work, an oxide based CMC is proposed as a more oxidation resistant and cost effective CMC. Zirconia Toughened Alumina (ZTA), as the matrix, has enhanced toughness, strength, and creep resistance over single phase alumina or zirconia. ZTA can further be enhanced by the incorporation of single crystal mullite whiskers due to their stability in oxidizing atmospheres at high temperatures. Mullite whiskers are grown through the molten salt method and incorporated into the ZTA matrix using a colloidal processing route. The composition of the ZTA matrix is 15 wt% yttria stabilized zirconia (YSZ), 85 wt% α-alumina. The mullite whiskers make up 20 vol% of the composite, yielding a final composition of 71.6 wt% α-alumina, 12.7 wt% YSZ, and 15.6 wt% mullite. The green compacts are fired in a two stage sintering process incorporating atmospheric pressure sintering to 92% density (to seal the pore channels) and then hot isostatic pressure sintering to full density. The mechanical test results show that baseline ZTA (ZTA n ) with final porosity of 13.2% has a flexural strength of 61.71 ± 0.99 MPa at room temperature and 52.34 ± 15.72 MPa at 1200°C, a fracture toughness of 5.02 ± 0.21 MPa•m 1/2 and a hardness of 10.73 GPa. ZTA with whisker content (ZTA w ) with final porosity of 3.31% reached a flexural strength of 135.76 ± 1.30 MPa at room temperature, 80.52 ± 13.18 MPa at 1200 °C, a fracture toughness of 8.74 ± 0.24 MPa•m 1/2 and a hardness of 11.99 GPa. The addition of whiskers to ZTA has improved room temperature flexural strength by 120.0%, flexural strength at 1200°C by 53.8%, fracture toughness by 74.1%; but the whiskers have little effect on the hardness. Although high temperature flexural strength was improved by the addition of whiskers, the iv improvement to strength at high temperature was not as significant in ZTA w . Degradation of large whiskers was found during cyclic oxidation of ZTA w 1200 °C. v

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Tailoring of functionally graded zirconia–mullite/alumina ceramics

Cited by 33 publications

References 53 publications

Advances in Functionally Graded Ceramics – Processing, Sintering Properties and Applications

Advances in Functionally Graded Ceramics – Processing, Sintering Properties and Applications

Functionally graded ceramics for biomedical application: Concept, manufacturing, and properties

Mullite Whisker Enhanced Zirconia Toughened Alumina Ceramic Matrix Composite for High Temperature Applications

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