Effect of a Low-Concentration H3PO4 Solution Application on High-Temperature Behaviour of Ti and Ti-Al Alloys

S.Y. Brou; G. Bonnet; Jean Luc Grosseau-Poussard

doi:10.4028/www.scientific.net/DDF.289-292.69

Paper Titles

Diffusion in Metallic Elements and Intermetallics
p.15

Selected Observations in Phase Constituents, Growth Kinetics and Microstructural Development of Aluminides in U-Mo vs. Al and 6061 Diffusion Couples Annealed at 600°C
p.41

Diffusion in Metal Dusting Processes
p.51

Isotope Fractionation due to Sedimentation of Atoms in Centrifuged Indium-Lead Alloy
p.63

Effect of a Low-Concentration H₃PO₄ Solution Application on High-Temperature Behaviour of Ti and Ti-Al Alloys
p.69

Structural Investigations of Solidification and Heat Treatments Influence on High Alloyed Cast Irons Grades with Nb-V-Ti Additions
p.77

Influence of Beta Stability on Hydrogen Diffusion in Various Beta Titanium Alloys
p.87

Grain Boundary Diffusion of Ni in Ultra-Fine Grain Copper-Lead Alloy Produced by Equal Channel Angular Pressing
p.95

Verification of a Commercial CALPHAD Database for Re and Ru Containing Nickel-Base Superalloys
p.101

HomeDefect and Diffusion ForumDefect and Diffusion Forum Vols. 289-292Effect of a Low-Concentration H3PO4 Solution...

Effect of a Low-Concentration H₃PO₄ Solution Application on High-Temperature Behaviour of Ti and Ti-Al Alloys

Abstract:

TiAl, TA6V and titanium coupons were treated by a phosphoric acid solution by dipping. They were then submitted to a heat treatment and, in the case of TiAl and TA6V, to high temperature discontinuous oxidation under laboratory air. The H3PO4 treatment allowed to decrease the mass gains for TiAl and TA6V, in particular during the first 100 hours. XRD analyses demonstrated for the three substrates the formation of a pyrophosphate layer during the heating period. This pyrophosphate evolved towards TiO2 with oxidation time increase, quicker for smaller aluminium content (or higher titanium content) in the metallic substrate. The decrease of mass gains was attributed to a diffusion barrier effect of the pyrophosphate layer as long as it was present.