Solute Diffusion of Platinum in Rutile Titanium Dioxide

Abstract

195Pt solute diffusion coefficients in undoped single‐crystal rutile TiO2 have been determined parallel to the c‐axis over the temperature range of 1073–1523 K and oxygen partial pressure of 101 kPa. This has yielded the following temperature dependence: D195Pt=1.3±3.2×10−13m2s−1exp(−122.0±13.6italickJmol−1normalRT) On the basis of this result, it has been concluded that 195Pt diffuses via an interstitial mechanism involving rapid transport parallel to the c‐axis through open interstitial diffusion channels. While other divalent cations have also displayed diffusion via the same mechanism, and report diffusion rates that greatly exceed that for cation self‐diffusion, the overall rate of 195Pt diffusion is slow. This has been attributed to the size of Pt2+ (0.80 Å) which is comparative to the dimension of interstitial channels (0.77 Å) through which transport is believed to be taking place.

Preparation of nanosized aluminum nitride powders by the cyanonitridation method

“…1) However, AlN powders are very difficult to sinter without using a sintering aid such as Y 2 O 3 , CaO, or BaO.…”

Use of melamine in the nitridation of aluminum oxide to aluminum nitride

“…Thus, AlN is an attractive material for applications as an electrical packaging material and a component in structural composites. 1) It was recently shown that AlN powder can be used for preparation of alumina particles wrapped in few-layer graphene sheets, which are applicable for improving overall energy-conversion efficiency in dye-sensitized solar cells.…”

Synthesis of AlN: Eu2+ green phosphors by a simple direct nitridation method

“…Traditionally, AlN is used in packaging materials for electronic devices and as a large‐scale integrated circuit heat dissipation substrate, owing to its high thermal conductivity (~ 330 W/mK), low dielectric constant and loss, and high electrical insulation (> 10 14 Ω·cm) . Recently, rare earth‐doped AlN has been studied extensively as a new class of phosphor due to its high chemical stability and wide band gap (~ 6.2 eV) .…”

“…Traditionally, AlN is used in packaging materials for electronic devices and as a large-scale integrated circuit heat dissipation substrate, owing to its high thermal conductivity (~330 W/mK), low dielectric constant and loss, and high electrical insulation (> 10 14 Ω·cm). [4] Recently, rare earth-doped AlN has been studied extensively as a new class of phosphor due to its high chemical stability and wide band gap (~6.2 eV). [5] Several methods have been proposed for the preparation of AlN and AlON-based phosphors, such as high-energy ball milling, [6] spark plasma sintering, [7] gas pressure sintering, [8,9] carbothermal reduction-nitridation, [10,11] and gas reductionnitridation.…”