MilliporeSigma
  • TiO2 effect on crystallization mechanism and physical properties of nano glass-ceramics of MgO-Al2O3-SiO2 glass system.

TiO2 effect on crystallization mechanism and physical properties of nano glass-ceramics of MgO-Al2O3-SiO2 glass system.

Journal of nanoscience and nanotechnology (2013-07-19)
Sinae Jo, Seunggu Kang
ABSTRACT

The effect of TiO2 on the degree of crystallization, thermal properties and microstructure for MgO-Al2O3-SiO2 glass-ceramics system containing 0-13 wt% TiO2 and 0-1.5 wt% B2O3 in which the cordierite is the main phase was studied. Using Kissinger and Augis-Bennett equations, the activation energy, 510 kJ/mol and Avrami constant, 1.8 were calculated showing the surface-oriented crystallization would be preferred. The alpha-cordierite phase was generated in the glass-ceramics of containing TiO2 of 0-5.6 wt%. However, for the glass-ceramics of TiO2 content above 7 wt%, an alpha-cordierite disappeared and micro-cordierite phase was formed. The glass-ceramics of no TiO2 added had spherical crystals of few tens nanometer size spread in the matrix. As TiO2 content increased up to 5.6 wt%, a lump of dendrite was formed. In the glass-ceramics containing TiO2 7-13 wt%, in which the main phase is micro-cordierite, the dendrite crystal disappeared and a few hundred nanometer sized crystal particles hold tightly each other were generated. The thermal conductivity of glass-ceramics of both a-cordierite and micro-cordierite base decreased with TiO2 contend added. The thermal conductivity of glass-ceramics of 1.5 wt% TiO2 added was 3.4 W/mK which is 36% higher than that of glass-ceramics of no TiO2 added. The sintering temperature for 1.5 wt% TiO2 glass-ceramics was 965 degrees C which could be concluded as to apply to LTCC process for LED packaging.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Titanium(IV) oxide, rutile, 99.995% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, rutile, ≥99.98% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, contains 1% Mn as dopant, nanopowder, <100 nm particle size (BET), ≥97%
Sigma-Aldrich
Titanium(IV) oxide, mixture of rutile and anatase, nanoparticles, <150 nm particle size (volume distribution, DLS), dispersion, 40 wt. % in H2O, 99.5% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, nanopowder, 21 nm primary particle size (TEM), ≥99.5% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, rutile, nanopowder, <100 nm particle size, 99.5% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, rutile, <001>, (single crystal substrate), ≥99.9% trace metals basis, L × W × thickness 10 mm × 10 mm × 0.5 mm
Sigma-Aldrich
Titanium(IV) oxide, mixture of rutile and anatase, nanopowder, <100 nm particle size (BET), 99.5% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, ReagentPlus®, ≥99%
Sigma-Aldrich
Titanium(IV) oxide, puriss., meets analytical specification of Ph. Eur., BP, USP, 99-100.5%
Sigma-Aldrich
Titanium(IV) oxide, rutile, powder, <5 μm, ≥99.9% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, anatase, powder, 99.8% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, anatase, powder, −325 mesh, ≥99% trace metals basis
Sigma-Aldrich
Titanium(IV) oxide, anatase, nanopowder, <25 nm particle size, 99.7% trace metals basis