Comparison of Fluorination Treatments to Improve the High Temperature Oxidation Resistance of TiAl Alloys in SO2 Containing Environments

2010 ◽  
Vol 638-642 ◽  
pp. 1374-1378 ◽  
Author(s):  
Patrick J. Masset ◽  
Rossen Yankov ◽  
Andreas Kolitsch ◽  
Michael Schütze
Keyword(s):  
High Temperature ◽  
Sulfur Dioxide ◽  
Ion Implantation ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Titanium Aluminides ◽  
Temperature Oxidation ◽  
Tial Alloys ◽  
Plasma Immersion Ion Implantation

Surfaces of titanium aluminides were treated by fluorine either physically using Plasma Immersion Ion Implantation (PI³) or chemically with a F-based polymer. By controlling the fluorination parameters, both treatments improve the oxidation resistance even in the presence of sulfur dioxide (0.1 vol%). No sulfur was detected in the oxide scale although thermodynamic calculations predict the formation of sulfides. The inward diffusion of oxygen and nitrogen in the alloy was found to be reduced in the presence of SO2.

AlN formation and enhancement of high-temperature oxidation resistance by plasma-based ion implantation

2003 ◽  
Vol 169-170 ◽  
pp. 359-362 ◽  
Author(s):  
Yoshihito Hara ◽  
Tetsuji Yamanishi ◽  
Kingo Azuma ◽  
Hitoshi Uchida ◽  
Mitsuyasu Yatsuzuka
Keyword(s):  
High Temperature ◽  
Ion Implantation ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation

Review of Several Studies on High Temperature Oxidation Behaviour and Mechanism of Austenitic Stainless Steels

2011 ◽  
Vol 312-315 ◽  
pp. 1097-1105
Author(s):  
Hisao Fujikawa
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Stainless Steels ◽  
High Temperature Oxidation ◽  
Austenitic Stainless Steels ◽  
Oxidation Behaviour ◽  
Oxide Interface ◽  
Temperature Oxidation

Three studies on the oxidation behaviour of austenitic stainless steels were described in the present paper. (1) High temperature oxidation behaviour and its mechanism in austenitic stainless steels with high silicon: Sulfur contained as impurity in steel showed a harmful influence to the oxidation resistance of 19Cr-13Ni-3.5Si stainless steels. It was found that the abnormal oxidation was caused from the surroundings of MnS inclusions. (2) Effect of a small addition of yttrium on high temperature oxidation resistance of Si-containing austenitic stain less steels: The oxidation resistance of 19Cr-10Ni-1.5Si steels was improved remarkably even with only 0.01%Y addition, which is the same concentration as added for de-oxygenation. Y was enriched at the grain boundary of oxide scale and metal-oxide interface. It was suggested that Y-containing steels shoed good oxidation resistance, because the enriched Y at the grain boundary and metal-oxide interface prevented the diffusion of iron and oxygen ions through the oxide scale. (3) Effect of grain size on the oxidation behaviour of austenitic stainless steels: Type 304, 316 and 310 steels with finer grain size showed better oxidation resistance than those with coarser grain size at 850°C. The oxide scale of steels with coarser grain size easily spalled during the cooling process.

Effect of B on the Microstructures and High Temperature Oxidation Resistance of a Nb-Si System In Situ Composite

2007 ◽  
Vol 546-549 ◽  
pp. 1489-1494 ◽  
Author(s):  
Ai Qin Liu ◽  
Shu Suo Li ◽  
Lu Sun ◽  
Ya Fang Han
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Arc Melting ◽  
The Matrix

Nb-16Si-24Ti-6Cr-6Al-2Hf-xB(x=0, 0.5, 1, 2, 4, 6) in situ composites were prepared by arc-melting. Microstructure and the effect of boron on 1250C oxidation resistance of the composites were investigated by scanning electron microscopy(SEM) and X-ray energy disperse spectrum(EDS) as well as X-ray diffraction(XRD). The experimental results showed that the high temperature oxidation resistance of the alloy was remarkably improved by adding proper amount of boron. This may be resulted from several beneficial roles of boron, i.e., boron improves the resistance of Nb5Si3 by solid solution strengthening, inhibits the diffusion of oxygen in the matrix, improves the adherence between the oxide scale and the substrate and increases the cracking resistance of the oxide scale.

High Temperature Oxidation Properties of Cr/C Coating on 4Cr10Si2Mo Steel by Plasma Immersion Ion Implantation and Deposition

2011 ◽  
Vol 239-242 ◽  
pp. 2306-2309
Author(s):  
Yun Peng Chang ◽  
Hui Zhi Xi ◽  
Shu Ai Shao
Keyword(s):  
High Temperature ◽  
Ion Implantation ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Antioxidant Properties ◽  
Temperature Oxidation ◽  
Uncoated Sample ◽  
Air Atmosphere ◽  
Chromium Plating ◽  
Plasma Immersion Ion Implantation

Thin Cr/C film was synthesized on 4Cr10Si2Mo steel substrates by Plasma Immersion Ion Implantation and Deposition (PIIID). The high-temperature oxidation behavior of Cr/C Coating at 900°C for 100 hours in air atmosphere was investigated. The results show that the Cr/C coating on 4Cr10Si2Mo steel by PIIID process has excellent high-temperature resistance and antioxidant properties. After the oxidation behavior for 100 hours, the surface of coated specimen maintains completely and the Cr/C coating has a good bonding force with substrates. The composition of the oxidation scale and the surface morphology were studied by using XRD and SEM. An uncoated sample and a hard chromium plating sample with same substrate took part in the experiment in same condition for comparing.

High Temperature Oxidation Protection of Multi-Phase Mo-Containing TiAl-Alloys by the Fluorine Effect

2012 ◽  
Vol 1516 ◽  
pp. 95-100 ◽  
Author(s):  
Alexander Donchev ◽  
Raluca Pflumm ◽  
Svea Mayer ◽  
Helmut Clemens ◽  
Michael Schütze
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Titanium Aluminides ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Temperature Oxidation ◽  
Tial Alloys ◽  
Β Phase ◽  
Multi Phase ◽  
The Impact

ABSTRACTIntermetallic titanium aluminides are potential materials for application in high temperature components. In particular, alloys solidifying via the β-phase are of great interest because they possess a significant volume fraction of the disordered body-centered cubic β-phase at elevated temperatures ensuring good processing characteristics during hot-working. Nevertheless, their practical use at temperatures as high as 800°C requires improvements of the oxidation resistance. This paper reports on the fluorine effect on a multi-phase TiAl-alloy in the cast and hot-isostatically pressed condition at 800°C in air. The behavior of the so-called TNM material (Ti-43.5Al-4Nb-1Mo-0.1B, in at %) was compared with that of two other TiAl-alloys which are Nb-free and contain different amounts of Mo (3 and 7 at%, respectively). The oxidation resistance of the fluorine treated samples was significantly improved compared to the untreated samples. After fluorine treatment all alloys exhibit slow alumina kinetics indicating a positive fluorine effect. Results of isothermal and thermocyclic oxidation tests at 800°C in air are presented and discussed in the view of composition and microstructure of the TiAl-alloys investigated, along with the impact of the fluorine effect on the oxidation resistance of these materials.

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