Method of manufacture and oxidation resistance of a graphite material with zirconium diboride, silicon, and vanadium additions

1978 ◽  
Vol 17 (6) ◽  
pp. 460-463 ◽  
Author(s):  
D. A. Krivoshein ◽  
M. A. Maurakh ◽  
V. S. Dergunova ◽  
Yu. N. Petrov ◽  
Yu. N. Lebedev
Keyword(s):  
Oxidation Resistance ◽  
Zirconium Diboride ◽  
Graphite Material

Improved Oxidation Resistance of Zirconium Diboride by Tungsten Carbide Additions

2008 ◽  
Vol 91 (11) ◽  
pp. 3530-3535 ◽  
Author(s):  
Shi C. Zhang ◽  
Greg E. Hilmas ◽  
William G. Fahrenholtz
Keyword(s):  
Tungsten Carbide ◽  
Oxidation Resistance ◽  
Zirconium Diboride

EFFECT OF COATING CONTENT ON THE PROPERTIES OF A1(OH)3–Y(OH)3/ZrB2 COMPOSITE PARTICLES

2007 ◽  
Vol 14 (03) ◽  
pp. 445-449 ◽  
Author(s):  
JIE-GUANG SONG ◽  
LIAN-MENG ZHANG ◽  
JUN-GUO LI ◽  
JIAN-RONG SONG
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Oxidation Resistance ◽  
Zirconium Diboride ◽  
Resistance Ratio ◽  
Composite Particles ◽  
High Temperature Materials

Zirconium diboride is widely applied to high-temperature materials, but it is easily oxidized at high temperature. To increase the oxidation resistance of zirconium diboride at high temperature, the A 1( OH )3– Y ( OH )3 is coated on the ZrB 2 surface to prepare A 1( OH )3– Y ( OH )3/ ZrB 2 composite particles. In this paper, the effect of coating content on the properties of A 1( OH )3– Y ( OH )3/ ZrB 2 composite particles is investigated. It is analyzed that the particle size and particle size distribution of A 1( OH )3– Y ( OH )3/ ZrB 2 composite particles is increased with the coating content. The dispersion of ZrB 2 particles is largely increased with the coating content of 0%–20%; the dispersion of ZrB 2 particles is similar when the coating content is from 20% to 30%. The oxidation resistance ratio of the ZrB 2 particles with 30% coating content is the best than that of other conditions—it is about three times more than that of the original ZrB 2 particles.

Fabrication and Oxidation-Resistance Property of Coated ZrB2-YAG-Al2O3 Multi-Phase Ceramics

2013 ◽  
Vol 544 ◽  
pp. 347-350
Author(s):  
Jie Guang Song ◽  
Fang Wang ◽  
Ming Han Xu ◽  
Shi Bin Li ◽  
Gang Chang Ji
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Protective Layer ◽  
Zirconium Diboride ◽  
Oxidation Temperature ◽  
Al2o3 Content ◽  
Precipitation Method ◽  
Composite Powders ◽  
Co Precipitation ◽  
Multi Phase

Zirconium diboride is widely applied because of some excellent performances. The results show the A1(OH)3-Y(OH)3/ZrB2 composite powders is prepared by a co-precipitation method, the shell-core structure A12O3-Y2O3/ZrB2 composite powders is prepared by sintering A1(OH)3-Y(OH)3/ZrB2 composite powders. The coating and density ZrB2-YAG-Al2O3 multi-phase ceramics is sintered at 1700°C, 20MPa for 4min by using Al2O3-Y2O3-80wt%ZrB2 composite powders, the oxidation weight is increased with increasing the oxidation temperature, however, the oxidation weight is decreased with increasing the YAG-Al2O3 content. ZrB2 reacted with O2 to form B2O3, and B2O3 is reacted with Al2O3 to form Al18B4O33, which is melted and coated on the surface of ceramics to form a protective layer for the oxidation resistance of ceramics at high temperature.

The addition of lanthanum hexaboride to zirconium diboride for improved oxidation resistance

2007 ◽  
Vol 57 (11) ◽  
pp. 1036-1039 ◽  
Author(s):  
Xing-hong Zhang ◽  
Ping Hu ◽  
Jie-cai Han ◽  
Lin Xu ◽  
Song-he Meng
Keyword(s):  
Oxidation Resistance ◽  
Zirconium Diboride ◽  
Lanthanum Hexaboride

The Oxidation Behavior of ZrB2-Based Mixed Boride

2008 ◽  
Vol 403 ◽  
pp. 253-255 ◽  
Author(s):  
Seung Jun Lee ◽  
Do Kyung Kim
Keyword(s):  
Silicon Carbide ◽  
Phase Separation ◽  
Oxidation Resistance ◽  
Hot Pressing ◽  
Oxidation Behavior ◽  
Zirconium Diboride ◽  
Oxidation Test ◽  
Oxidation Performance ◽  
Sic Composites ◽  
Surface Silica

Zirconium diboride based composites containing silicon carbide with relative densities in excess of 99 % were produced by hot-pressing. Oxidation test was conducted in air at 1500 °C. ZrB2-SiC composite showed relatively low oxidation resistance due to the non-uniform surface silica-rich layer. But in case of mixed boride-SiC composites further improvement of the oxidation performance were observed due to the phase separation in the surface silica-rich layer.

scholarly journals Oxidation resistance of zirconium diboride powder.

1998 ◽  
Vol 10 (2/3) ◽  
pp. 94-96 ◽  
Author(s):  
Jun-ichi MATSUSHITA ◽  
Takashi ENDO
Keyword(s):  
Oxidation Resistance ◽  
Zirconium Diboride

Morphologies of Nonadherent Al2O3 and Matching Substrate Surfaces

1972 ◽  
Vol 30 ◽  
pp. 524-525
Author(s):  
C. S. Giggins ◽  
J. K. Tien ◽  
B. H. Kear ◽  
F. S. Pettit
Keyword(s):  
Electron Microscopy ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Substrate Surface ◽  
Morphological Features ◽  
Thermally Induced ◽  
Oxide Spallation ◽  
Oxidation Resistant ◽  
Induced Stresses ◽  
Substrate Surfaces

The performance of most oxidation resistant alloys and coatings is markedly improved if the oxide scale strongly adheres to the substrate surface. Consequently, in order to develop alloys and coatings with improved oxidation resistance, it has become necessary to determine the conditions that lead to spallation of oxides from the surfaces of alloys. In what follows, the morphological features of nonadherent Al2O3, and the substrate surfaces from which the Al2O3 has spalled, are presented and related to oxide spallation.The Al2O3, scales were developed by oxidizing Fe-25Cr-4Al (w/o) and Ni-rich Ni3 (Al,Ta) alloys in air at 1200°C. These scales spalled from their substrates upon cooling as a result of thermally induced stresses. The scales and the alloy substrate surfaces were then examined by scanning and replication electron microscopy.The Al2O3, scales from the Fe-Cr-Al contained filamentary protrusions at the oxide-gas interface, Fig. 1(a). In addition, nodules of oxide have been developed such that cavities were formed between the oxide and the substrate, Fig. 1(a).

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

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