Alumina reinforced eucryptite ceramics: Very low thermal expansion material with improved mechanical properties

Abstract

Composite materials formed by a LAS matrix reinforced with second phases are promising materials in many applications where better mechanical properties than those corresponding to conventional low thermal expansion coefficient materials are required. In this study we will show the capability of the design of a LAS-alumina submicron composite. The main scope of this work is to test the sinterability of the composites and to design a composition for a very low thermal expansion submicron composite. For this purpose, Taimei alumina (TM-DAR) powders and an ad hoc synthesized ␤-eucryptite phase were used to fabricate the composite. XRD phase compositions and microstructures are discussed together with data from dilatometries in a wide temperature range. The results obtained show the possibility of designing a submicron composite with a very low thermal expansion coefficient and improved mechanical properties that can be used in oxidizing conditions.

Lithium aluminosilicate reinforced with carbon nanofiber and alumina for controlled-thermal-expansion materials

“…Recent studies have corroborated the compatibility between alumina and the LAS composition studied in this work [24]. The stability of the phases during the sintering process (SPS) is essential for controlling the composition of the final material, and, therefore, its thermal expansion coefficient.…”

“…The incorporation of alumina as a third phase provides an interesting opportunity to optimize some properties of LAS-based materials, as dispersed alumina nanoparticles contribute to the CTE balance and improve the mechanical properties of a composite [24]. Table 2 shows the relative density, fracture strength, fracture toughness and electrical resistivity of the LAS/40 vol.% Al 2 O 3 /20 vol.% CNFs material sintered at different temperatures using SPS.…”

Surface modification of Li(Li0.17Ni0.2Co0.05Mn0.58)O2 with LiAlSiO4 fast ion conductor as cathode material for Li-ion batteries

“…The deterioration of the electrode in the electrolyte is mainly caused by the powerful side reactions between the active material and the electrolyte, which correlate strongly with the thermal stability of LNCMO [27]. The enhanced thermal stability of LAS-2 should be due to that the LAS coating layer which possesses good thermal stability [37,56] and plays an significant role in protecting the active material from side reactions in the electrolyte.…”

Thermal expansion of β-eucryptite in oxide-based ceramic composites

“…12,[27][28][29] Such highly negative values indicate the occurrence of spontaneous micro-cracking due to the ␤-eucryptite thermal expansion anisotropy. 30 The strategy of combining ␤-eucryptite and an oxide like alumina 31,32 or zirconia 33,34 to prepare a near zero CTE material has been already reported. For example, ␤-eucryptite-3 mol% yttria partially stabilized zirconia (3YPSZ) composites (55 wt.% ␤-eucryptite/3YPSZ and 65 wt.% ␤-eucryptite/3YPSZ) processed by slip-casting and conventional sintering (T < 1325 • C) exhibit a very low CTE (1.45 × 10 −6 / • C and −0.52 × 10 −6 / • C respectively) and a relative high bending strength (220 MPa for 55 wt.% ␤-eucryptite/3YPSZ).…”