On the processing of nanocrystalline and nanocomposite ceramics

Kear, B. H.; Colaizzi, James; Mayo, W. E.; Liao, Shih‐Chieh

doi:10.1016/s1359-6462(01)00884-3

Cited by 98 publications

(42 citation statements)

References 5 publications

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“…For example, it is currently extremely difficult to produce bulk forms of many metals and ceramics with nano-crystalline micro-structure [5,6]. Nevertheless, they can be readily produced in thin foils and small cubes or cylinders with dimensions less than 1 mm [7]. Further, advanced technologies such as microelectromechanical and/or nano-electromechanical systems (MEMS, NEMS) require knowledge of the mechanical properties of the materials used to fabricate such systems [8].…”

Section: Introductionmentioning

confidence: 99%

The design of accurate micro-compression experiments

Zhang¹,

Schuster²,

Wei³

et al. 2006

Scripta Materialia

393

208

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Section: Introductionmentioning

confidence: 99%

The design of accurate micro-compression experiments

Zhang¹,

Schuster²,

Wei³

et al. 2006

Scripta Materialia

393

208

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“…The contour line pattern of density is like in case of without ultrasonic vibration, the density distribution is substantially less if considers the color gradient closely. Figure 5 shown the quality green compact with maximum density of 0.00315 g/cm 3 and minimum density of 0.00265 g/cm 3 . Density dispersion can be measured using statistics principal (variance) from the following formula.…”

Section: Comparison Of Results Of Density Distributionmentioning

confidence: 99%

“…Figure 3 shown density distribution due to pressing without ultrasonic vibration, found that the maximum density occurs at the upper edge of green compact of 0.007-0.0085 g/cm 3 because it has higher friction force on the edges, the minimum density occurs in the middle portion at the bottom of green compact of 0.00255 g/cm 3 . Considering on the lower edge of green compact found that low density of 0.00255 g/cm 3 but rather higher in the middle at the bottom of green compact of 0.0032 g/cm 3 . If compare the maximum density at the top and the bottom of green compact found that the maximum density at the top is greater than the maximum density at the bottom of green compact.…”

Section: Comparison Of Results Of Density Distributionmentioning

confidence: 99%

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The Comparison of the Characteristics of Displacement Isolines in the Cylindrical Green Compact under Ultrasonic Vibration

Prakorb¹,

Anan²,

Somchai³

et al. 2015

International journal of advanced smart convergence

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“…[13][14][15] Among these methods, pressureless sintering is still a most promising one because of its low cost and easy technique. In this work, Y-TZP nanoceramics were prepared by gelcasting-pressing and pressureless sintering, while the microstructure, the pore distribution and sintering behavior of the green body were studied.…”

mentioning

confidence: 99%

Preparation of Y‐TZP Nanoceramics by Gelcasting‐Pressing Method and Pressureless Sintering

Zhang

Chen

et al. 2006

Adv Eng Mater

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There is worldwide interest in the Y-TZP (tetragonal zirconia polycrystals stabilized by yttria) nanoceramics, which are believed to have some special characteristics such as superplasticity at low temperature. [1] However, fabrication of dense bulk nanocrystalline ceramics is very challenging since inevitable grain growth occurs at relatively high sintering temperatures needed for densification. The fabrication process usually involves forming and sintering. Duran and other researchers [2][3][4][5][6] have shown that green compacts with homogeneous microstructure, small pore size and narrow pore size distribution are necessary to ensure the low temperature sintering. Therefore, one main objective in a forming process is to produce uniform green body with homogeneous microstructure, small pore size and narrow pore size distribution. Previous studies have indicated that microstructural defects such as delamination, microcracks and large pores in the product are caused at drying forming. Recently, colloidal forming processes such as gelcasting [7] and direct coagulation casting (DCC), [8] in which ceramic powder is dispersed in a water-based suspension and held in a gel network, have attracted great interest. Among these methods, the gelcasting has significant advantages over the other processes, in terms of dimensional accuracy, the uniform structure and high strength of the green bodies, simplicity, and as well reduced manufacturing cost. Gelcasting has rapidly developed in the past decade as a promising colloidal in situ forming technique. It has been utilized in the forming of many sorts of ceramic material systems. [9][10][11][12] However, few reports about the use of this method for nanoceramics are found in the literature.Though gelcasting forming processes can improve the uniformity of green bodies and reduce structural defects but because of some characteristics of the nano powders itself, it is very difficult to preparation of a concentrated suspension with high solid volume loading in gelcasting, therefore the density of the green body is unsatisfactory. An optimal approach would be a combination of gelcasting and dry pressing processes, bringing together their advantages. Based on this concept, a new ceramics-forming process, gelcastingpressing, is developed by the authors.In addition, lots of methods, including hot-pressing, sinter-forging, hot-isostatic pressing and spark plasma sintering, have been used to fabricate nano-ceramics. [13][14][15] Among these methods, pressureless sintering is still a most promising one because of its low cost and easy technique. In this work, Y-TZP nanoceramics were prepared by gelcasting-pressing and pressureless sintering, while the microstructure, the pore distribution and sintering behavior of the green body were studied.Characteristics of powders and green bodies. Characteristics of nano-powders: The X-ray diffraction (XRD) patterns of nanopowders calcinated at different temperatures for 2 h are shown in Figure 2. It is seen that there is no diffraction peaks and t...

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On the processing of nanocrystalline and nanocomposite ceramics

Cited by 98 publications

References 5 publications

The design of accurate micro-compression experiments

The design of accurate micro-compression experiments

The Comparison of the Characteristics of Displacement Isolines in the Cylindrical Green Compact under Ultrasonic Vibration

Preparation of Y‐TZP Nanoceramics by Gelcasting‐Pressing Method and Pressureless Sintering

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