In-situlaser synthesis of Nd–Al–O coatings: the role of sublattice cations in eutectic formation

Abstract

# 2015 International Union of Crystallography Neodymium aluminate coatings have been prepared in-situ by the laser zone melting (LZM) method, using a CO 2 SLABtype laser emitting at 10.6 mm. Polycrystalline Al 2 O 3 commercial plates have been used as substrates, and coatings were prepared from the corresponding mixtures of powdered neodymium and aluminium oxides as starting materials. Microstructure, studied by SEM and phase composition, studied by XRD, proved the in-situ formation of a NdAlO 3 / NdAl 11 O 18 eutectic. As a result, a well integrated composite coating was formed. Nanoindentation tests are consistent with excellent integration between coating and substrate. Structural similarities between the eutectic components within the coating, as well as between these and the substrate, are consistent with the crystallographic concepts proposed by Vegas (Ramos-Gallardo & Vegas, 1997), where cation subarrays play an important role governing metal oxide structures. These structure sublattices are suggested as the driving force behind eutectic oxide formation.

Laser‐induced coloration of ceramic tiles covered with magnetron sputtered precursor layers

“…In a second approach, we used a continuous CO 2 laser incorporated in a laser furnace set‐up . In comparison with conventional thermal procedures for processing ceramic, bricks, and similar materials, this laser‐furnace method is advantageous because processing temperatures can be relatively lower and can provide alternative finishing effects . Overall, the wide range of colors obtained in this work proves the feasibility of using laser‐induced solid‐sate reactions between oxide layers and tile substrates for endowing new esthetic effects to ceramic materials.…”

From Simple to Complex: Design of Inorganic Crystal Structures with a Topologically Extended Zintl–Klemm Concept

“…The DFT calculations have revealed no new stable phases besides the known pcu , svn , and bcu topologies (Figure S2). ,, The pcu → bcu phase transitions are observed for all MX phases except MgSe, for which the pcu phase is transformed to the svn phase at high pressures. This observation is in good agreement with previous experimental and computational results; however, our modeling has not confirmed the hypothetical svn → bcu transition for MgSe at 472 GPa .…”