Dataset Information

The agglomeration, coalescence and sliding of nanoparticles, leading to the rapid sintering of zirconia nanoceramics.

ABSTRACT: Conventional sintering is a time- and energy-consuming process used for the densification of consolidated particles facilitated by atomic diffusion at high temperatures. Nanoparticles, with their increased surface free energy, can promote sintering; however, size reduction also promotes agglomeration, so hampering particle packing and complete densification. Here we show how the ordered agglomeration of zirconia primary crystallites into secondary particle assemblies ensures their homogeneous packing, while also preserving the high surface energy to higher temperatures, increasing the sintering activity. When exposed to intense electromagnetic radiation, providing rapid heating, the assembled crystallites are subjected to further agglomeration, coalescence and sliding, leading to rapid densification in the absence of extensive diffusional processes, cancelling out the grain growth during the initial sintering stages and providing a zirconia nanoceramic in only 2?minutes at 1300?°C.

SUBMITTER: Kocjan A

PROVIDER: S-EPMC5451455 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The agglomeration, coalescence and sliding of nanoparticles, leading to the rapid sintering of zirconia nanoceramics.

Kocjan Andraž A Logar Manca M Shen Zhijian Z

Scientific reports 20170531 1

Conventional sintering is a time- and energy-consuming process used for the densification of consolidated particles facilitated by atomic diffusion at high temperatures. Nanoparticles, with their increased surface free energy, can promote sintering; however, size reduction also promotes agglomeration, so hampering particle packing and complete densification. Here we show how the ordered agglomeration of zirconia primary crystallites into secondary particle assemblies ensures their homogeneous pa ...[more]

PMID: 28566771

Similar Datasets

Project description:It is known that the yttria-stabilized zirconia (YSZ) material has superior thermal, mechanical, and electrical properties. This material is used for manufacturing products and components of air heaters, hydrogen reformers, cracking furnaces, fired heaters, etc. This work is aimed at searching for the optimal sintering mode of YSZ ceramics that provides a high crack growth resistance. Beam specimens of ZrO2 ceramics doped with 6, 7, and 8 mol% Y2O3 (hereinafter: 6YSZ, 7YSZ, and 8YSZ) were prepared using a conventional sintering technique. Four sintering temperatures (1450 °C, 1500 °C, 1550 °C, and 1600 °C) were used for the 6YSZ series and two sintering temperatures (1550 °C and 1600 °C) were used for the 7YSZ and 8YSZ series. The series of sintered specimens were ground and polished to reach a good surface quality. Several mechanical tests of the materials were performed, namely, the microhardness test, fracture toughness test by the indentation method, and single-edge notch beam (SENB) test under three-point bending. Based on XRD analysis, the phase balance (percentages of tetragonal, cubic, and monoclinic ZrO2 phases) of each composition was substantiated. The morphology of the fracture surfaces of specimens after both the fracture toughness tests was studied in relation to the mechanical behavior of the specimens and the microstructure of corresponding materials. SEM-EDX analysis was used for microstructural characterization. It was found that both the yttria percentage and sintering temperature affect the mechanical behavior of the ceramics. Optimal chemical composition and sintering temperature were determined for the studied series of ceramics. The maximum transformation toughening effect was revealed for ZrO2-6 mol% Y2O3 ceramics during indentation. However, in the case of a SENB test, the maximum transformation toughening effect in the crack tip vicinity was found in ZrO2-7 mol% Y2O3 ceramics. The conditions for obtaining YSZ ceramics with high fracture toughness are discussed.

Project description:BackgroundTo explore the effect of adhesive surface with porcelain sintering and different silane coupling agents on adhesive properties of zirconia ceramics.MethodsZirconia blocks (n=72) were randomly divided into two large groups (n=36) according to whether the adhesive surface was treated with sintered porcelain: N (no porcelain sintering), P (porcelain sintering). Then, according to different silane coupling agents, each group was randomly divided into three small groups, six small groups in total (n=12): NN (no porcelain sintering and agent), NM (no porcelain sintering + Monobond-S), NC (no porcelain sintering + Clearfil Repair); PN (porcelain sintering + no agent), PM (porcelain sintering + Monobond-S), PC (porcelain sintering + Clearfil Repair). After surface treatment, RelyX Unicem Cement was used to make ceramic-resin bonding specimens. Then, each of the six small groups was randomly divided into two subgroups; shear bond strength (SBS) was tested and bond failure mode was analyzed before and after thermal cycling 5,000 times.Results(I) SBS analysis: the SBS values of the P groups were significantly higher than those of the N groups (P<0.05). The groups treated with silane coupling agents showed higher SBS values than the control group (P<0.05), and the PC groups showed the highest SBS values (P<0.05). The SBS of each group was significantly decreased after thermal cycling (P<0.05). (II) The microcharacteristics under scanning electron microscopy and energy spectrum analysis: the ceramic blocks being treated by porcelain sintering showed more roughness than the control group. A large amount of silicon (Si) appeared on the surface of the ceramic blocks after porcelain sintering.Conclusions(I) Treating the adhesive surface by porcelain sintering can improve the bonding strength between zirconia and RelyX Unicem Cement, and the effect was better in conjunction with silane coupling agent. (II) The two kinds of silane coupling agent (Monobond-S, Clearfil Repair) can improve the bonding strength between zirconia and resin cement. The effect of Clearfil Repair is better than that of Monobond-S. (III) Thermal cycling had a significant adverse effect on SBS between zirconia and RelyX Unicem Cement. Clearfil Repair is helpful in improving the durability of zirconia bonding strength.

Dataset Information

The agglomeration, coalescence and sliding of nanoparticles, leading to the rapid sintering of zirconia nanoceramics.

Publications

The agglomeration, coalescence and sliding of nanoparticles, leading to the rapid sintering of zirconia nanoceramics.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets