High-Temperature Oxidation of WC-20%TiC-10%Co Carbides

2013 ◽  
Vol 811 ◽  
pp. 93-97 ◽  
Author(s):  
Yeon Sang Hwang ◽  
Dong Bok Lee
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Large Weight ◽  
Oxidation Characteristics ◽  
Weight Gains ◽  
Poor Oxidation Resistance

The oxidation characteristics of WC-20%TiC-10%Co sintered carbides were studied by oxidizing at 700, 800 and 900 °C for 3 h in air. The samples oxidized fast with large weight gains, displaying quite poor oxidation resistance. The formed oxide scales that consisted primarily of CoWO4, WO3, and TiO2 were porous, and prone to cracking.

Influences of Calcination Ambiences on Phase Composition and High Temperature Oxidation Resistance Property of Ceramic Coatings on Ti–6Al–4V Alloy by Micro-Plasma Oxidation

2007 ◽  
Vol 336-338 ◽  
pp. 2481-2483 ◽  
Author(s):  
Guo Dong Hao ◽  
Zhao Hua Jiang ◽  
Zhong Ping Yao ◽  
Heng Ze Xian ◽  
Yan Li Jiang
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Ceramic Coatings ◽  
Plasma Oxidation ◽  
Temperature Oxidation ◽  
Complete Decomposition ◽  
Weight Gains ◽  
High Temperature Calcination

Compound ceramic coatings with the main crystalline of Al2TiO5 (as-coated samples) were prepared on Ti-6Al-4V alloy by pulsed bi-polar micro-plasma oxidation (MPO) in NaAlO2 solution. The coated samples were calcined in Ar and air at 1000oC, respectively. The phase composition, morphology and element content of the coatings were investigated by XRD, SEM and XRF. The samples treated in Ar and the as-coated ones were calcined in air at 1000oC to study the oxidation resistance of the samples. The results showed that Al2TiO5 decomposed and transformed into corundum and rutile TiO2 during the high temperature calcination. Al2TiO5 decomposed very quickly in air and the proportion of Al2O3 to TiO2 was 44:55 after a complete decomposition. On the contrary, Al2TiO5 decomposed very slowly in argon with the final proportion of Al2O3 to TiO2 of 81:18 on the coating surface. The morphology of the ceramic coatings after the calcination was also different. The coatings calcined in argon were fined: the grains and pores were smaller than those of the coatings calcined in air. The weight gains of both coatings changed in the form of parabola law, and the weight gains of the coated samples treated in argon were comparatively lower than that of the as-coated samples. During the high temperature calcination, the samples treated in argon cannot distort easily, compared with the as-coated ones.

The Investigation of the Interdiffusion Barrier in TiAl/MCrAlY System

2010 ◽  
Vol 654-656 ◽  
pp. 1920-1923 ◽  
Author(s):  
Wen Wang ◽  
Yu Xian Cheng ◽  
Sheng Long Zhu ◽  
Fu Hui Wang ◽  
Li Xin
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Diffusion Barrier ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
The Poor ◽  
Structural Applications ◽  
Nicraly Coating ◽  
Overlay Coatings ◽  
Poor Oxidation Resistance

TiAl based alloys are promising candidates for structural applications at high temperature. However, the poor oxidation resistance above 800oC obviously restrains their applications. Although NiCrAlY overlay coatings can remarkably improve the high temperature oxidation resistance of TiAl, serious inward diffusion of Ni from the coating to the substrate occurs which could reduce the lifetime of the coating/substrate system. Apparently, the development of interdiffusion barrier could overcome the disadvantage of the NiCrAlY/TiAl system. In this work, Ta, TiN and Cr2O3 interlayers were deposited between NiCrAlY coating and γ-TiAl substrate as diffusion barrier (DB). The interdiffusion behavior of the TiAl/DB/NiCrAlY system was investigated at 1000°C. The results showed that the metallic and nitride interlayers cannot retard the interdiffusion of Ni effectively. As an active diffusion barrier, the oxide interlayer obviously suppressed the inward diffusion of Ni from the coating to the substrate by the formation of alumina-rich layers at both the TiAl/DB and DB/NiCrAlY interfaces.

High Temperature Oxidation of Ti45.4Al4.8Nb and Ti46Al2Mo2Nb Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 801-804
Author(s):  
J.W. Kim ◽  
Dong Bok Lee
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Middle Layer ◽  
Tio2 Layer ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
Oxidation Characteristics ◽  
Dissolved Ions

The Ti46Al2Nb2Mo and Ti45.4Al4.8Nb alloys were oxidized isothermally and cyclically in air between 800 and 1000oC, and their oxidation characteristics were investigated. Nb and Mo were beneficial to oxidation resistance. The initially formed thin TiO2-rich scale changed to an outer, superficial TiO2 layer, a thick Al2O3-rich middle layer, and an inner (TiO2-rich, Al2O3-deficient) layer, as the extent of oxidation progressed. The dissolved ions of Mo and Nb had a tendency to be expelled from the outer TiO2 layer, which was formed by the outward diffusion of Ti ions, to the inner (TiO2-rich, Al2O3-deficient) layer, which was formed by the inward transport of oxygen, owing to the nobility of Mo and Nb when compared to Ti and Al.

High Temperature Oxidation of Ti39.4Al10V Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 813-816 ◽  
Author(s):  
Dong Bok Lee ◽  
Y.D. Jang
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Mixed Layer ◽  
High Temperature Oxidation ◽  
Oxide Scales ◽  
Temperature Oxidation ◽  
Outward Diffusion

Alloys of Ti39.4Al10V (at.%) that consisted mainly of ordered β-Ti, γ-TiAl and α2-Ti3Al phases were oxidized at 700, 800, 900, and 1000oC in air. The oxide scales formed consisted largely of an outermost, thin TiO2 layer, an outer, thin Al2O3 layer, and an inner, very thick (TiO2+Al2O3) mixed layer. Vanadium, which was uniformly distributed throughout the oxide scale, harmfully decreased oxidation resistance, and made thick, nonadherent scales owing to the formation of low melting compounds of V-oxides. The oxidation progressed via the outward diffusion of Ti, Al and V ions, and the concurrent inward transport of oxygen.

AK STEEL 441

Alloy Digest ◽  
2006 ◽  
Vol 55 (6) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Ferritic Stainless Steel ◽  
High Temperature Oxidation ◽  
High Temperature Strength ◽  
Temperature Oxidation ◽  
Temperature Performance

Abstract AK Steel 441 has good high-temperature strength, an equiaxed microstructure, and good high-temperature oxidation resistance. The alloy is a niobium-bearing ferritic stainless steel. This datasheet provides information on composition, hardness, and tensile properties as well as deformation. It also includes information on high temperature performance and corrosion resistance as well as forming and joining. Filing Code: SS-965. Producer or source: AK Steel.

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