Phase diagram of the system Al2O3-SiO2

Strelov, K. K.; Kashcheev, I. D.

doi:10.1007/bf02227394

Cited by 18 publications

(6 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…According to the phase diagrams in literature, the sintering process should have produced Al 2 O 3 agglomerated by an Al-rich mullite phase. 57,58 EDS spot scans of each phase showed agreement with the phase compositions suggested by the literature. EDS mapping of the microstructure was used to produce a segmented image of the phases based on Al concentrations (Figure 13B), suggesting volume fractions of 55% Al 2 O 3 , 42% mullite, and 3% porosity.…”

Section: Al-si Ceramic Phase Assemblagesupporting

confidence: 85%

“…Although other researchers have considered the chemical homogeneity of phases in the indentation of OPC samples, 12,18,59 this paper examines the homogeneity in terms of the mechanical response (i.e., continuity). This section presents an exercise to evaluate whether the OPC microstructure would theoretically have large enough regions of homogeneity (i.e., minimal structural compliance) to provide a continuous mechanical response.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

On the role of continuity in statistical nanoindentation of composite microstructures

2022

View full text Add to dashboard Cite

The validity of the statistical nanoindentation (SNI) technique for cementitious materials has been questioned by numerous researchers; however, it is still a commonly used method in literature. This study revisits assumptions pertaining to continuum mechanics of the method by using a well-established selective SNI method to evaluate continuity in the mechanical response of each indent. Ordinary portland cement (OPC) was investigated alongside a two-phase aluminosilicate ceramic (Al-Si). Filtering for continuity of indents eliminated a majority of indents in each sample. The indents meeting continuity requirements in the OPC sample had moduli values in the range of documented calcium silicate hydrates and portlandite-the predominant hydration phases in OPC. In the Al-Si sample, 73% of continuous indents were assigned to a mullite phase, although the chemical analysis showed only 42% mullite. This was attributed to the embedded morphology of the mullite phase, which made it more susceptible to structural compliance. These observations suggest that SNI may be ineffective for measuring the mechanical properties of individual phases in a microstructure if they are not prolific enough to exhibit a continuous indent response. Discontinuous indents due to microstructural interaction between phases were also shown to have a potential influence on the number of clusters (i.e., phases) suggested by the deconvolution algorithms.

show abstract

Section: Al-si Ceramic Phase Assemblagesupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

On the role of continuity in statistical nanoindentation of composite microstructures

2022

View full text Add to dashboard Cite

show abstract

“…It can be concluded that laser treatment primarily promotes ablation of the glass phase, which contains a small amount of Al along with the oxides of Na and Ca and Si. The prevalence of Si content over Al in the surface layer of the channel indicates that the composition corresponds to the SiO 2 ‐Al 2 O 3 compound, which is close to cristobalite‐mullite (SiO 2 ‐ 3Al 2 O 3 • 2SiO 2 ) 40‐42 . Taking into account the XRD data, mullite is mainly in the amorphous state 43‐45 .…”

Section: Resultsmentioning

confidence: 92%

“…The prevalence of Si content over Al in the surface layer of the channel indicates that the composition corresponds to the SiO 2 -Al 2 O 3 compound, which is close to cristobalite-mullite (SiO 2 -3Al 2 O 3 • 2SiO 2 ). [40][41][42] Taking into account the XRD data, mullite is mainly in the amorphous state. [43][44][45] Some weak peaks in the halo can be attributed to mullite nuclei in the glass phase.…”

Section: Sem and Eds Datamentioning

confidence: 99%

Physicochemical processes in the zone of local laser heating of porous aluminosilicate ceramics

Aguilar

Власова

Bernal

et al. 2021

Int J Ceramic Engine & Sci

View full text Add to dashboard Cite

The performed investigations have shown that the basis of the local laser heating/"drilling" of composite coarse-pored ceramics consisting of aluminosilicates and a glass phase is the melting and ablation processes that lead to the formation of a hole. The interaction of the components of the composite in the zone of high-temperature heating is accompanied by the formation of melt of a glass phase of new composition. The motion of the metal to the depth of a sample through pore channelsclusters of the main ceramic material depends on the viscosity of melt (i.e., on the radiation regime) and the cooling rate of the melt (i.e., the thermo physical properties of the ceramics and glass phase). The development of hydrodynamic pressure in the zone of laser heating leads not only to the ejection of a part of the melt from the channel, but also to the densification of the ceramics adjacent to the Accepted Article This article is protected by copyright. All rights reserved walls of the vitrified channel. These effects depend to a great extent on the ceramics/glass phase ratio and on the porosity of the initial ceramics.

show abstract

“…The core of the fiber should be co-doped with several molar percent of alumina to allow incorporation of the high concentrations of thulium ions. However, the alumina concentration over 4mol% is difficult to achieve using conventional solution doping process [13]. Thus, high thulium concentration in the fiber without an adequate level of alumina concentration may cause adverse effects such as reduced lifetime and unwanted energy transfer upconversion (ETU) process [14,15].…”

Section: Introductionmentioning

confidence: 99%

Highly efficient thulium-doped high-power laser fibers fabricated by MCVD

et al. 2019

View full text Add to dashboard Cite

We report a hybrid process by combining both vapor-phase and solution-doping techniques of rare-earth doped preform fabrication in conjunction with the MCVD technique, in order to fabricate highly efficient Tm-doped laser fibers. The proposed fabrication route takes advantage of co-doping silica with high alumina content through the vapor-phase doping process, which is otherwise difficult to achieve using conventional solution doping technique. In addition, by employing the solution doping method, high-purity thulium halide precursors that have low vapor pressures up to several hundred degree Celsius. These highpurity thulium halide precursors can be used to dope the fiber core region with a high thulium concentration that is optimized for an efficient two-for-one cross-relaxation process for 79xnm diode pumped thulium-doped fiber laser. Fibers fabricated using the hybrid approach show more homogeneous and flat-top dopant profiles, compared with the conventional approach, where both aluminum and thulium are incorporated in the core through solution doping. This will ensure that more doped region will take part in the cross-relaxation process. Superior laser performance with a slope efficiency of >70% in the two-micron band has been demonstrated when diode pumped at ~790nm.

show abstract

Phase diagram of the system Al2O3-SiO2

Cited by 18 publications

References 4 publications

On the role of continuity in statistical nanoindentation of composite microstructures

On the role of continuity in statistical nanoindentation of composite microstructures

Physicochemical processes in the zone of local laser heating of porous aluminosilicate ceramics

Highly efficient thulium-doped high-power laser fibers fabricated by MCVD

Contact Info

Product

Resources

About