scholarly journals Effect of Ca Additions on Ignition Temperature and Multi-Stage Oxidation Behavior of AZ80

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 766 ◽  
Author(s):  
Chunlong Cheng ◽  
Qing Lan ◽  
An Wang ◽  
Qichi Le ◽  
Fan Yang ◽  
...  
Keyword(s):  
High Temperature ◽  
Melting Temperature ◽  
Oxidation Resistance ◽  
Ignition Temperature ◽  
Oxidation Behavior ◽  
Secondary Phase ◽  
Accelerated Oxidation ◽  
Multi Stage ◽  
Incubation Periods ◽  
Before And After

AZ80, AZX801, and AZX802 alloys were prepared to investigate the ignition temperature and multi-stage oxidation behavior in air. Besides, the microstructures of alloys before and after oxidation were compared. The results reveal that AZX802 exhibits the characteristics of higher ignition temperature and best oxidation resistance compared to AZX801 and AZ80, which contributes to the increase of melting temperature of secondary phase in matrix due to the formation and increase of Al2Ca, with the addition of Ca in AZ80. In addition, the incubation periods before accelerated oxidation and the beginning of the accelerated oxidation temperatures of AZ80, AZX801, and AZX802 are different during multi-stage oxidation, which also contributes to the different onset melting temperature of the secondary phase. And the beginning of the accelerated oxidation of Mg alloys at high temperature is always accompanied by the onset melting of the low melting temperature of the secondary phase and the growth of oxide nodule on the surface.

scholarly journals Rare Earth Elements Enhanced the Oxidation Resistance of Mo-Si-Based Alloys for High Temperature Application: A Review

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1144
Author(s):  
Laihao Yu ◽  
Yingyi Zhang ◽  
Tao Fu ◽  
Jie Wang ◽  
Kunkun Cui ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Rare Earth Elements ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Strengthening Mechanism ◽  
Advanced Materials ◽  
Performance Requirements ◽  
Large Numbers ◽  
The One

Traditional refractory materials such as nickel-based superalloys have been gradually unable to meet the performance requirements of advanced materials. The Mo-Si-based alloy, as a new type of high temperature structural material, has entered the vision of researchers due to its charming high temperature performance characteristics. However, its easy oxidation and even “pesting oxidation” at medium temperatures limit its further applications. In order to solve this problem, researchers have conducted large numbers of experiments and made breakthrough achievements. Based on these research results, the effects of rare earth elements like La, Hf, Ce and Y on the microstructure and oxidation behavior of Mo-Si-based alloys were systematically reviewed in the current work. Meanwhile, this paper also provided an analysis about the strengthening mechanism of rare earth elements on the oxidation behavior for Mo-Si-based alloys after discussing the oxidation process. It is shown that adding rare earth elements, on the one hand, can optimize the microstructure of the alloy, thus promoting the rapid formation of protective SiO2 scale. On the other hand, it can act as a diffusion barrier by producing stable rare earth oxides or additional protective films, which significantly enhances the oxidation resistance of the alloy. Furthermore, the research focus about the oxidation protection of Mo-Si-based alloys in the future was prospected to expand the application field.

Pest Resistant and Low CTE MoSi2-Matrix for High Temperature Structural Applications

1994 ◽  
Vol 350 ◽  
Author(s):  
M. G. Hebsur
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Matrix Composition ◽  
Temperature Oxidation ◽  
Accelerated Oxidation ◽  
Structural Applications ◽  
Base Matrix ◽  
Sic Reinforcement

AbstractThe objective of this investigation was to identify a pest resistant MoSi2-base matrix composition having properties suitable for SiC reinforcement. A 30 vol.% addition of fine Si3N4 particulates to MoSi2 significantly improved the low temperature accelerated oxidation resistance and thereby eliminated pest failure. Addition of Si3N4 also improved the high temperature oxidation resistance, strength and more importantly lowered the CTE of MoSi2 such that cracking was eliminated in a hybrid composite consisting of 30 vol.% Si3N4 and 30 vol. % SCS-6 fibers.

Oxidation Behavior of Tantalum Boride Ceramics

2007 ◽  
Vol 124-126 ◽  
pp. 819-822 ◽  
Author(s):  
Junichi Matsushita ◽  
Geum Chan Hwang ◽  
Kwang Bo Shim
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Surface Film ◽  
Oxidation Time ◽  
Oxidation Temperature ◽  
Weight Changes ◽  
Good Oxidation Resistance ◽  
Resistant Layer

The oxidation behavior of tantalum diboride (TaB2) powder at high temperature was investigated in order to determine the possibility of the use of advanced high temperature structural materials. Unfortunately, monolithic TaB2 were known to be chemical stability up to high temperatures. To date, there have been few reports regarding the properties of TaB2 ceramics. The samples were oxidized at room temperature to 1273 K for 5 minutes to 25 hours in air. The weight changes were measured to estimate the oxidation resistance. The oxidation of samples oxidized for short oxidation time of 5 minutes started at 873 K, and the weight gain increased with increasing oxidation temperature. On the other hand, at the oxidation time of above 1 hour, a maximum weight gain value at 973 to 1073 K was observed. However, even if the oxidation temperature was increased an additional weight change slightly occurred. The weight gain of the sample oxidized at 1273 K for 5 minutes to 25 hours was about 40 to 20 % of the theoretical oxidation mass change. According to the powder X-ray diffraction date, the oxidized TaB2 sample was changed to Ta2O5 at 873 K. Finally, the TaB2 showed a good oxidation resistance at high temperature, because the surface film of tantalum oxide (Ta2O5) formed by oxidation acted as an oxidation resistant layer.

Isothermal Oxidation Behavior of Ni Base Superalloy DM02 for High Temperature Dies

2007 ◽  
Vol 546-549 ◽  
pp. 1253-1256
Author(s):  
Qing Li ◽  
Jin Xia Song ◽  
Cheng Bo Xiao ◽  
Shi Yu Qu ◽  
Ding Gang Wang ◽  
...  
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Growth Mechanism ◽  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Good Oxidation Resistance ◽  
Base Superalloy

The isothermal oxidation behavior of a new developed Ni base superalloy named DM02 for high temperature dies was studied in this paper. The dynamic curve was achieved by monitoring weight gain of the alloy as a function of time. The results showed that the alloy had fairly good oxidation resistance at 1050°C and 1100°C. The oxidation kinetics at both 1050°C and 1100°C followed parabolic rules in segment. It has been found that the oxidation of the alloy was controlled by multi-oxides of (Ni, Co)O, (Ni, Co)Al2O4, and NiWO4, growth mechanism in the primary stage, and by Al2O3, NiAl2O4 growth mechanism in the following stage. After oxidation at 1050°C for 100h, the oxide scale of the alloy was mainly composed of two areas. Some were thin uniform (Ni， Co)Al2O4(outer)/Al2O3 (inner) composites scale and others were multi-layer oxide scale of ( Ni,Co)O / multi-oxides (mainly NiWO4、NiO and NiAl2O4.) /Al2O3.

A New Gold-Indium Eutectic Bonding Method

1992 ◽  
Vol 264 ◽  
Author(s):  
Chin C. Lee ◽  
Chen Y. Wang ◽  
Goran Matijasevic ◽  
Steve S. Chan
Keyword(s):  
High Temperature ◽  
Diffusion Process ◽  
Thermal Shock ◽  
Melting Temperature ◽  
Acoustic Microscope ◽  
Bonding Quality ◽  
Eutectic Bonding ◽  
Before And After ◽  
Bonding Method ◽  
Scanning Acoustic Microscope

AbstractAu-In eutectic bonding method which needs only a low process temperature (˜200°C) but produces high temperature (450°C) bonds is reported. In this study, multiple layers of Au and In are deposited directly on semiconductor wafers in one vacuum cycle to prevent indium oxidation and then bonded to substrates coated with Au. At 200°C the indium layer melts and dissolves the gold layers to form a mixture of liquid and solid. The diffusion process continues until the bond solidifies. Upon solidification, the bond has a melting temperature of 456.5°C. Scanning Acoustic Microscope was used to determine the excellent bonding quality before and after thermal shock tests and SEM with EDX capability is employed to determine the composition of the resulting bonds.

Sic Reinforced-Mosi2 Alloy Matrix Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
J. J. Petrovic ◽  
R. E. Honnell ◽  
A. K. Vasudevan
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Solid Solutions ◽  
Oxidation Behavior ◽  
Initial Study ◽  
Initial Assessment ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Alloy Oxidation ◽  
Sic Particle

AbstractMoSi2 based composites possess significant potential as high temperature structural materials. The present investigation constitutes an initial study of the fabrication and properties of MoSi2/silicide alloys and SiC particle reinforced-MoSi2 /silicide alloy matrix composites. Alloying disilicides (WSi2, Nb5Si2, Ta5Si2 ) and trisilicides (Mo5 Si3, W5Si3, Nb5Si3, Ta5Si3, Ti5Si3 ) were examined. Results indicated that at the 50/50 mole % alloying level, MoSi2 formed solid solutions with the alloying disilicides. Reaction of the MoSi2 /TaSi2 alloy with SiC was observed. An initial assessment of 50/50 mole % disilicide alloy oxidation behavior suggested an oxidation resistance inferior to that of pure MoSi2.

Al-21Ti-23Cr High-Temperature Protective Coating on TiAl Intermetallic Compounds by RF Magnetron Sputtering

1996 ◽  
Vol 460 ◽  
Author(s):  
J. Y. Park ◽  
H. N. Lee ◽  
S. W. Park ◽  
M. H. Oh ◽  
D. M. Wee
Keyword(s):  
High Temperature ◽  
Magnetron Sputtering ◽  
Tensile Test ◽  
Protective Coating ◽  
Cyclic Oxidation ◽  
Oxidation Behavior ◽  
Tensile Deformation ◽  
Rf Magnetron Sputtering ◽  
Deformation Properties ◽  
Before And After

ABSTRACTTi-48A1 specimens were coated with Al-21Ti-23Cr film at 200 W, 0.8 Pa and 573 K by RF magnetron sputtering. The oxidation behavior of the coated specimens was investigated through isothermal and cyclic oxidation tests, and the tensile deformation properties of the coated specimens were also investigated before and after oxidation. The isothermal and cyclic oxidation curves showed that the Al-21Ti-23Cr film was very effective in decreasing the oxidation rate of Ti-48A1. This excellent oxidation resistance is attributable to the formation of a protective Al2O3 layer on the surface of the Al-21Ti-23Cr film. It was found from the results of the tensile test that the protective Al2O3 layer on the surface of the Al-21Ti-23Cr film enabled the Ti-48A1 to maintain its tensile properties in an oxidizing environment.

Effect of TiC Content on Oxidation Behavior of Sintered WC-TiC-TaC Alloys

2007 ◽  
Vol 534-536 ◽  
pp. 1173-1176 ◽  
Author(s):  
Hiroki Tanaka ◽  
Shigeki Mouri ◽  
Kenji Nakahara ◽  
Hideaki Sano ◽  
Guo Bin Zheng ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Mass Change ◽  
Composition Analysis ◽  
Oxidation Test ◽  
Before And After ◽  
Main Component ◽  
Map Analysis ◽  
Oxidation Scale

The effect of TiC content on oxidation behavior of the sintered WC-TiC-TaC alloys with 2 mass% TaC and different TiC amount of 3-45 mass% was investigated through oxidation tests in air at 973K in order to clarify their oxidation mechanism at high temperature. Based on the results of mass change, SEM observation, elemental map analysis and composition analysis of the samples before and after the oxidation test, it was revealed that with increasing TiC content in the alloys, mass changes from oxidation and thickness of the oxidation scale decreased. Thus, it is considered that the main component of the scales changed from WO3 to TiO2 gradually with increasing TiC content in the alloys, and oxygen diffusing through the oxidation scale to the alloys was inhibited more and more.

Preparation and Property of Ceramic Matrix Coating of Anti-Oxidation for Stainless Steel at High Temperature by Slurry Method

2010 ◽  
Vol 105-106 ◽  
pp. 448-450
Author(s):  
Peng Liu ◽  
Lian Qi Wei ◽  
Shu Feng Ye ◽  
Xun Zhou ◽  
Yu Sheng Xie ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Melting Temperature ◽  
Oxidation Resistance ◽  
High Performance ◽  
Ceramic Coating ◽  
Ceramic Matrix ◽  
Sem Images ◽  
Temperature Oxidation ◽  
Slurry Method

In this paper, the new high temperature ceramic matrix coating of anti-oxidation for stainless steel was prepared by slurry method. With the research about oxidation resistance of ceramic matrix coating formed on stainless steel, the effect of initial melting temperature, melting temperature range and thermal expansion coefficients of ceramic sintering change on protective properties of high temperature coating prepared at 1250°C is investigated, and then high temperature sintering ceramic with high-performance is gained through optimization. Through the test of TG-DTA and XRD to the coating, study on high temperature oxidation resistance of ceramic coating and the structure changing of the scale with coating from SEM images and photos, it is shown that the ceramic coating has excellent oxidation resistant properties, the weight loss with coating decrease more than 85%.

Effect of Yttrium Addition on High Temperature Oxidation Resistance of Co-10Cr-5Al Alloys

2011 ◽  
Vol 391-392 ◽  
pp. 606-610 ◽  
Author(s):  
Huai Shu Zhang ◽  
Hong Hua Zhang ◽  
Jun Huai Xiang ◽  
Shan Wang ◽  
Di Wu
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Temperature Oxidation ◽  
Linear Rate ◽  
Rate Law ◽  
Yttrium Addition ◽  
Parabolic Rate

The oxidation behavior of Co-10Cr-5Al-0.3Y alloy in 1 atm of pure O2 at 700°C was investigated. The addition of 0.3 at.%Y significantly increased the oxidation rate of the alloy and changed the oxidation behavior from the approximate parabolic rate law to linear rate law. The scale grown on the surface at 700°C was porous with many small voids and cracks, and was composed of an outer CoO layer and an inner complex layer rich in Al2O3 and Cr2O3 which were intermingled with yttric oxide and spinel Co(Cr, Al)2O4.

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