Abstract

Organomagnesiumoxane alumoxane siloxane oligomers with different Al:Mg and Al:Si molar ratio have been synthesized through ethylacetoacetate alkoxyhydroxyalumoxane oligomers co-condensation with magnesium acetylacetonate and oligoethoxysiloxanes in organic solvents (alcohol, toluene) at a temperature of 70–100 °С within 3–6 h with the following solvent distillation. The physicochemical properties of the synthesized oligomers were studied. It is shown that with a molar ratio of Al:Mg ≈ 2 and Al:Si ≈ 1, oligomers have fiber-forming properties. The process of thermotransformation of organomagnesiumoxane alumoxane siloxanes into ceramic phases is investigated. It is found that pyrolysis results in the formation of multicomponent ceramics based on magnesium, aluminum, and silicon oxides, in particular, ceramics with a composition close to that of cordierite 2MgO·2Al2O3·5SiO2 (Mg2Al4Si5O18) or a mixed composition: magnesium-aluminum spinel and mullite. Therefore, the synthesized organomagnesiumoxane alumoxane siloxanes are preceramic oligomers and can be used as precursors for the preparation of various components (binders, impregnating compositions, fibers, ceramic powders) of high-purity ceramic composites based on magnesium, aluminum and silicon oxides.

Highlights

  • Among the various ceramic materials, three-component ceramics based on magnesium, aluminum and silicon oxides, in particular mixed spinel-mullite composition ((MgAl2O4 +According to conventional technology, cordierite is produced from oxides, which requires high temperatures for the synthesis of ceramic powders and a narrow sintering range (1520 °C)

  • We are the first to synthesize hydrolytically stable and soluble in organic solvents organomagnesiumoxane alumoxane siloxane oligomers, the thermal transformation of which leads to the formation of highly pure fine crystalline multicomponent ceramics based on aluminum, magnesium and silicon oxides [10]

  • We were faced with the task of synthesizing pre-ceramic oligomers, the pyrolysis of which allows the preparation of cordierite ceramics Mg2Al4Si5O18

Read more

Summary

Introduction

Cordierite is produced from oxides, which requires high temperatures for the synthesis of ceramic powders (above 1250 °C) and a narrow sintering range (1520 °C). This technology does not allow obtaining dense fine crystalline ceramics, expensive finely dispersed and ultrafine powders are used, which limits their widespread practical application [4,5]. We are the first to synthesize hydrolytically stable and soluble in organic solvents organomagnesiumoxane alumoxane siloxane oligomers, the thermal transformation of which leads to the formation of highly pure fine crystalline multicomponent ceramics based on aluminum, magnesium and silicon oxides [10]

Methods
Results
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.