Fabrication of Alumina-Based Toughened Nanocomposites

Matsunaga, Takuya; Leela-adisorn, Uraiwan; Kobayashi, Yoshitomo; Choi, Seong Min; Araki, Hideo

doi:10.2109/jcersj.113.123

Cited by 18 publications

(10 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Then, we fabricate monolithic alumina and alumina-nickel nanocomposites, and estimate the strength, fracture toughness, and CFPZ size of these materials. 13) The results show that materials with larger CFPZ size have higher fracture toughness. In the present paper, the term 'CFPZ size' refers to a macroscopically defined CFPZ size, calculated from the macroscopically defined fracture toughness and strength.…”

Section: Introductionmentioning

confidence: 92%

“…Ceramic-based nanocomposites have been fabricated using high-speed sintering techniques, such as pulse electric current sintering (PECS) or hot pressing, 22) but the second-phase particles tend to segregate to the matrix boundaries. A soaking method 13) was developed as a new technique for fabricating intra-type nanocomposites. The present paper uses an alumina-nickel nanocomposite system to explain the soaking method.…”

Section: )mentioning

confidence: 99%

“…Upon sintering, we easily obtained intra-type nanostructured alumina-nickel nanocomposites. Because the experimental procedure of the soaking method was reported elsewhere, 13) we describe it only briefly here. Using the commercially available -alumina powder (AKP-G015, Sumitomo Chemical, Japan) and nickel nitrate (Osaka Chemistry, Japan) solution, -alumina powder containing nano-sized nickel was prepared.…”

Section: )mentioning

confidence: 99%

See 2 more Smart Citations

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

2006

Self Cite

View full text Add to dashboard Cite

In order to improve the fracture toughness of inherently brittle ceramics, a new material design concept must be developed. One suitable concept involves the use of dislocation activities. Intra-type ceramic-based nanocomposites use dislocation activities to enhance strength and fracture toughness. The dislocations are generated by residual stresses induced during sintering process around the second-phase nanoparticles dispersed within the matrix grains. In this paper, first, we proposed an indirect technique for estimating a critical frontal process zone (CFPZ) size for ceramics and clarified the relation between the strength, fracture toughness, and CFPZ size. The fracture toughness of ceramics is closely related to the CFPZ size because ceramics with larger CFPZ size consume higher fracture energy during crack extension and consequently have higher fracture toughness. Second, we fabricated toughened alumina-nickel nanocomposites using a soaking method to construct an intra-type nanostructure, and found that the appropriate annealing conditions after sintering could achieve toughened nanocomposites. Finally, we discussed the relation between the experimentally obtained fracture toughness and the CFPZ size of monolithic alumina, as-sintered nanocomposites, and annealed nanocomposites. The results revealed that nanocomposites showed the largest CFPZ size and the highest fracture toughness after appropriate annealing: the sessile dislocations ahead of a crack tip in a nanocomposite are thought to serve as stress concentration, create many nanocracks in the CFPZ, and expand the CFPZ size.

show abstract

Section: Introductionmentioning

confidence: 92%

Section: )mentioning

confidence: 99%

Section: )mentioning

confidence: 99%

See 1 more Smart Citation

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

2006

Self Cite

View full text Add to dashboard Cite

show abstract

“…[2][3][4][5][6][7][8][9] In nanocomposite systems, nano-Ni dispersed Al 2 O 3 hybrid materials (nano-Ni/Al 2 O 3 ) have been investigated well concerning mechanical properties such as bending strength, hardness and fracture toughness. [4][5][6][7][8][9] However, when their nanocomposites are applied at high temperatures, oxidation behavior of dispersed metals must be understood to design their lifetime.…”

Section: Introductionmentioning

confidence: 99%

Influence of Si-Doping of Nano-Ni Dispersed Al<SUB>2</SUB>O<SUB>3</SUB> Composites on High-Temperature Oxidation

Maruoka

Nanko

2010

Mater. Trans.

View full text Add to dashboard Cite

The oxidation kinetics of 5 vol% nano-Ni dispersed Al 2 O 3 with Si-doping (nano-Ni/Al 2 O 3 -Si) was studied in the present paper. The starting powder mixture was prepared by drying aqueous slurry consisting of alumina with nickel nitrate and Si (OCH 3 ) 4 . The powder mixture was reduced at 600 C for 12 h in a stream of Ar-1%H 2 gas mixture. Nano-Ni/Al 2 O 3 -Si was densified by pulsed electric current sintering. The oxidation test was conducted at 1200-1350 C for 1-14 d in air. Oxidized zone consisted of Al 2 O 3 matrix and NiAl 2 O 4 as the oxidation product. Growth of the oxidized zone followed a parabolic manner. A thin NiAl 2 O 4 layer was also observed on the sample surface. Si-doping decreases growth rate of oxidized zone effectively at lower temperatures such 1200 C.

show abstract

“…In this research, samples were prepared by the Pulsed Electric Current Sintering (PECS) method, using mixed powder created by the soaking method, 8) in order to create a Ni dispersed alumina matrix nanocomposite. The two types of commercially available alumina, γ -alumina (AKP-G015, Sumitomo Chemical Co., purity: 99.99%, average coagulated particle diameter: 2.6 μm) and α-alumina (AKP-53, Sumitomo Chemical Co., average particle diameter: 0.3 μm), were used as starting material matrices.…”

Section: Starting Materialsmentioning

confidence: 99%

Relation between functional properties of alumina-based nanocomposites and locations of dispersed particles

Nishimura

Choi

Hashimoto

et al. 2009

J. Ceram. Soc. Japan

Self Cite

View full text Add to dashboard Cite

We previously proposed the toughening and strengthening mechanisms of alumina-based nanocomposites on the basis of dislocation activities, assuming that nano-sized particles were embedded within the alumina grains. In this research, we fabricated both intragranular dominant and intergranular dominant nanocomposites of alumina/nickel(Ni) system. In order to fabricate intragranular dominant nanocomposites, γ-alumina powder with many nanopores was used as a starting material through a soaking method. Intergranular dominant nanocomposites were prepared using α-alumina powder as a starting material. Monolithic alumina samples were also sintered for comparison. Mechanical, thermal, and electrical properties were estimated for those specimens. The results showed that the intragranular nanocomposites had a higher mechanical strength and fracture toughness than the intergranular nanocomposites. The values of thermal expansion and thermal conductivity were slightly high in the intragranular nanocomposites compared to the intergranular one. The intergranular nanocomposites indicated a low dielectric breakdown voltage. Relations between the functional properties of the nanocomposites and the location of the dispersed Ni particles were discussed based on dislocation activities and the percolation model.

show abstract

Fabrication of Alumina-Based Toughened Nanocomposites

Cited by 18 publications

References 5 publications

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

Relation between Strength, Fracture Toughness, and Critical Frontal Process Zone Size in Ceramics

Influence of Si-Doping of Nano-Ni Dispersed Al<SUB>2</SUB>O<SUB>3</SUB> Composites on High-Temperature Oxidation

Relation between functional properties of alumina-based nanocomposites and locations of dispersed particles

Contact Info

Product

Resources

About