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

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.

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Improvement of High-Temperature Oxidation of Titanium Alloys by Dipping in a Phosphoric Acid Solution

Materials Science Forum ◽

10.4028/www.scientific.net/msf.595-598.17 ◽

2008 ◽

Vol 595-598 ◽

pp. 17-22 ◽

Cited By ~ 1

Author(s):

S.Y. Brou ◽

G. Bonnet ◽

Jean Luc Grosseau-Poussard

Keyword(s):

High Temperature ◽

Phosphoric Acid ◽

High Temperature Oxidation ◽

Isothermal Oxidation ◽

Superficial Layer ◽

Phosphoric Acid Solution ◽

Acid Solutions ◽

Heating Period ◽

Temperature Oxidation ◽

Titanium Pyrophosphate

Gamma-TiAl samples were treated by phosphoric acid solutions at different concentrations. With 15 mol/dm3, a viscous deposit was left on the surface leading, after drying and high temperature oxidation, to a very heterogeneous surface aspect. Concentrations below 0.5 mol/dm3 were then used and allowed to greatly ameliorate the homogeneity of the superficial layer. After heating from ambient to oxidation temperature, however, cracks were always observed, due to the departure of gaseous molecules. Isothermal oxidation tests come out at 800°C and 900°C under reconstituted air showed that weight gains were strongly reduced when TiAl had been treated. A compound containing titanium, oxygen and phosphorus was detected at the end of the heating period, identified as titanium pyrophosphate, TiP2O7. This compound remained the only one detected for 100 h when oxidation was come out at 800°C, but evolved towards TiO2 when oxidation time was increased. In the case of oxidation at 900°C, the evolution from TiP2O7 to TiO2 also happened but appeared to go faster.

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High pressure and high temperature behaviour of ZnO

10.1063/1.4872501 ◽

2014 ◽

Cited By ~ 1

Author(s):

Nilesh A. Thakar ◽

Apoorva D. Bhatt ◽

Tushar C. Pandya

Keyword(s):

High Pressure ◽

High Temperature ◽

Temperature Behaviour

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High-temperature behaviour of LPCVD ZrB2 coatings subjected to intense radiative flux

Surface and Coatings Technology ◽

10.1016/0257-8972(94)02361-1 ◽

1995 ◽

Vol 73 (1-2) ◽

pp. 60-65 ◽

Cited By ~ 4

Author(s):

A. Wang ◽

M. Lebrun ◽

G. Male ◽

C.H.S. Dupuy

Keyword(s):

High Temperature ◽

Radiative Flux ◽

Temperature Behaviour

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High temperature thermal and mechanical stability of high-strength nanotwinned Al alloys

Acta Materialia ◽

10.1016/j.actamat.2018.11.011 ◽

2019 ◽

Vol 165 ◽

pp. 142-152 ◽

Cited By ~ 15

Author(s):

Qiang Li ◽

Jaehun Cho ◽

Sichuang Xue ◽

Xing Sun ◽

Yifan Zhang ◽

...

Keyword(s):

High Temperature ◽

Mechanical Stability ◽

High Strength ◽

Al Alloys

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Investigation of High-Temperature Oxidation in Steam for Ni–Al Alloys Using the Combination of a Hydrogen Sensor and an Oxygen Pump–Sensor

Oxidation of Metals ◽

10.1007/s11085-017-9791-8 ◽

2017 ◽

Vol 89 (3-4) ◽

pp. 357-373

Author(s):

Michihisa Fukumoto ◽

Yasumasa Kawamori ◽

Hiroshi Sonobe ◽

Motoi Hara ◽

Hiroyuki Kaneko

Keyword(s):

High Temperature ◽

High Temperature Oxidation ◽

Hydrogen Sensor ◽

Al Alloys ◽

Temperature Oxidation ◽

Oxygen Pump

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High Temperature Behaviour of a New Mg-Ca-Zn Alloy

Magnesium ◽

10.1002/3527603565.ch20 ◽

2005 ◽

pp. 134-139 ◽

Cited By ~ 2

Author(s):

A. Zilberov ◽

G. R. Goren-Muginstein ◽

M. Bamberger

Keyword(s):

High Temperature ◽

Temperature Behaviour ◽

Zn Alloy

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Effect of Time and Temperature when Removing PVA from a PET/PVA Nonwoven Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.821-822.188 ◽

2013 ◽

Vol 821-822 ◽

pp. 188-194

Author(s):

Sizo Ncube ◽

Chu Yang Zhang ◽

Edison Omollo ◽

Li Liu

Keyword(s):

High Temperature ◽

Polyvinyl Alcohol ◽

Pore Size ◽

Water Solubility ◽

Nonwoven Material ◽

Water Bath ◽

Heating Period ◽

Needle Punching ◽

Needle Punching Machine

The study examined the effect of heat and time on fabrics made from polyester (PET) and polyvinyl alcohol (PVA) fibres which have different aerial densities and composed of 90% and 10% of PET and PVA respectively. PVA is included in the fabric due to its water solubility and this will allow the PVA to be removed thereby leaving a more porous fabric. The fabrics were passed through needle punching machine and PVA removed by heating in a water bath. The nonwoven fibre was then heated in water at temperatures of 75, 85 and 100 °C in an effort to remove the PVA fibres and leave a more porous fabric. While removing the PVA through heating in a water bath, the effect of heating period and the temperature on the fabric properties was investigated. The strength, elongation and structure of the fabric were investigated and the changes analysed. It was found that there was a significant removal of PVA at longer periods of time when at a high temperature. The effect on the properties was found to be higher with higher temperatures as well with a decrease in strength ranging between 40% and 60% being experienced while an increase in elongation, between 60% and 90% was experienced. Fibre spacing and pore size was found to have increased as well.

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