Wettability and interfacial reactions in Al/TiO₂

Abstract

The effects of temperature and testing procedure on the wetting properties of molten Al on polycrystalline TiO 2 substrates were studied by a sessile drop method in vacuum at 1173-1373 K. For the common contact heating procedure, oxidized molten Al wets titania at T > 1210 K. The removal of the oxide film from the Al drop by means of a capillary purification procedure makes the Al/TiO 2 couple wettable at 1173 K. The structure and chemistry characterization of Al/TiO 2 interfaces shows that molten Al reacts with TiO 2 to form fine alumina particles and Ti, which subsequently is dissolved in the Al drop. However, this reaction is remarkable at 1373 K only and much higher temperatures are required for successful reactive synthesis of Al/Al 2 O 3 composites.

High-temperature wetting and interfacial interaction between liquid Al and TiB2 ceramic

“…8 for the temperature of 1400°C. This is in line with the reports on high-temperature interactions between liquid Al and TiO 2 [28][29][30][31][32][33] and formation of Al 2 O 3 particles and Ti dissolved in Al by the reduction reaction:…”

“…For example, Avraham and Kaplan [28] reported the contact angle of about 150°for liquid Al on TiO 2 at 700°C, which decreased to about 85°by heating up to 1000°C. Sobczak et al [29] found that the contact angle for capillary-purified molten Al on TiO 2 equals to 80°at 900°C. In our study, liquid Al on TiB 2 substrates (Figs.…”

Formation of Corundum, Magnesium Titanate, and Titanium(III) Oxide at the Interface between Rutile and Molten Al or AlSi7Mg0.6 Alloy

“…[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] As products of the reduction process, titanium suboxides like Ti 3 O 5 , Ti 2 O 3 , TiO, and concurrently released metallic titanium were reported. [9,10,12,17,19,21] Ti is initially dissolved in the melt.…”

“…[5,6,9,10,[13][14][15][16][17][18][19][20][21] Titanium dissolved in the Al melt is incorporated into the face-centered cubic Al lattice during solidification. [9][10][11]13] Oxygen from reduced TiO 2 forms Al 2 O 3 with Al from the melt. [5,6,9,10,[13][14][15][16][17][18][19][20][21] The kind of the alumina formed depends on the temperature, at which the reduction takes place.…”

On Liquid Metal Wetting of Casting Rings for DC Casting

“…The wettability measurements clearly show that a droplet of molten aluminum cannot wet the TiO 2 nanowire structure, Figure 4, which means the contact angle is >> 90° and the droplet can be removed from the substrate without any damage to the structure, Figure 1. However, it is reported [25] that planar TiO 2 substrates can be wetted by and react with molten aluminum at temperatures above 1100°C [25][26][27] [26]. This oxide, in contact with a tip, may prevent the attachment of aluminum.…”