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.

Influences of Different Calcinations Ambience on Phase Composition and Morphologies of Ceramic Coatings on Ti Alloy by Micro-Arc Oxidation

2010 ◽  
Vol 97-101 ◽  
pp. 1554-1557
Author(s):  
Guo Dong Hao ◽  
Nai Wu Zhang ◽  
Tao Yun ◽  
Jin Wang ◽  
Bo Lian ◽  
...  
Keyword(s):  
Phase Composition ◽  
High Temperature Oxidation ◽  
Ceramic Coatings ◽  
Ti Alloy ◽  
Temperature Oxidation ◽  
Weight Gains ◽  
Micro Arc Oxidation ◽  
Oxidation Properties ◽  
Α Al2o3

Compound ceramic coatings with the main crystalline of Al2TiO5 (as-coated samples) were prepared in situ on the surface Ti-6Al-4V alloy by means of pulsed bi-polar micro-arc oxidation (MAO) in a NaAlO2 solution. The coated samples were calcined in argon and air at 1000 oC, respectively. The phase composition, surface morphology of the ceramic coatings were investigated by XRD, SEM and XRF. The samples were treated in argon and the as-coated ones were calcined in air at 1000 oC to study the anti-oxidation properties of the samples. The results show that Al2TiO5 was decomposed very soon and transformed into α-Al2O3 and rutile TiO2 in air. However, Al2TiO5 was decomposed very slowly in argon and the final coating surface was completely α-Al2O3. Also, the morphology of the ceramic coatings after the calcination was different. The coatings calcined in argon were fined; grains and pores were smaller than those in air. High temperature oxidation occurred very strongly in the TC4 substrate, the weight gains of the as-coated ceramic coatings and the treated ones in argon were nearly changing in the form of parabola, and the weight gains of the coated samples treated in argon were comparatively lower than those of the as-coated samples.

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.

EFFECTS OF YTTRIUM NITRATE ON MICROSTRUCTURE AND HIGH TEMPERATURE RESISTANCE OF ZrO2–Y2O3 CERAMIC COATINGS PREPARED BY A MODIFIED PEO PROCESS ON AN Al–12Si ALLOY

2017 ◽  
Vol 24 (Supp02) ◽  
pp. 1850026
Author(s):  
WANG PING ◽  
ZHOU LIGUO ◽  
HAN JING ◽  
GUO YONGCHUN
Keyword(s):  
High Temperature ◽  
Salt Solution ◽  
High Temperature Oxidation ◽  
Fine Particles ◽  
Heat Insulation ◽  
Ceramic Coatings ◽  
Coated Sample ◽  
Yttrium Nitrate ◽  
Temperature Oxidation ◽  
Weight Gains

A ZrO2–Al2O3 ceramic coating and YSZ–Al2O3 coating were prepared on ZAlSil2Cu3Ni2 alloys by a modified plasma electrolytic oxidation (PEO) in zirconium salt solution. The microstructure, heat-insulating and high temperature oxidation properties were investigated by SEM, XRD and a fabricated heat insulation temperature testing device. The results showed that the surface of the YSZ–Al2O3 coating was composed of fine particles and had lower roughness. Yttrium partially stabilized the zirconia solid solution (Y[Formula: see text]Zr[Formula: see text]O[Formula: see text] which was formed in zirconium yttrium salt solution with a higher reaction temperature. The growth rate of the YSZ–Al2O3 coating was greater than the ZrO2–Al2O3 coating. Especially, the outward growth obviously improves. Furthermore, the heat insulation property of the coating enhances. The curves of the weight gains in the sample with YSZ–Al2O3 coating showed a logarithmic shape under the high temperature oxidation treatment of 400[Formula: see text]C. The weight gains of the sample with YSZ–Al2O3 coating were relatively lower than that of the as-coated sample. The ceramic layer had good high temperature stability.

High-Temperature Oxidation Resistant Nanocoatings on Austenitic Stainless Steels

2009 ◽  
Vol 1243 ◽  
Author(s):  
Hugo F. Lopez
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
High Efficiency ◽  
Elevated Temperatures ◽  
Clean Energy ◽  
Ceramic Coatings ◽  
Energy Utilization ◽  
Weight Changes ◽  
Temperature Oxidation

ABSTRACTIn recent years, the increasing energy costs have lead to power utility industries to seek/develop high efficiency systems of production and of energy utilization. In addition, environmental concerns regarding greenhouse gas emissions are playing a major role in the development of clean energy systems. The development of metallic materials that can withstand elevated temperatures is among the viable alternatives to increase energy efficiency. Nevertheless, for this to happen, the corrosion and oxidation resistance of Fe- and Ni-based alloys needs to be significantly improved. Among the possible ways to enhance the life of high temperature alloys is the application of protective ceramic coatings. Conventional coatings are expensive and the protective effects controversial at times. An alternative which offers a great potential is the application of nano-ceramic coatings. Hence, in this work nanocrystalline coatings based on nano-CeO2 are applied to an austenitic stainless steel 304L and then exposed to elevated temperatures. Weight changes are monitored as a function of time and the results are compared with uncoated alloys tested under similar conditions. In addition, computer simulations of possible rate limiting diffusion mechanisms are carried out. It is found that the nanocoatings provided remarkable high-temperature oxidation resistance and improved scale adhesion. In particular, it is found that the smaller the nanoparticles are, the more effective the nanocoatings in providing oxidation resistance.

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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