Mechanical properties of ZrB2- and HfB2-based ultra-high temperature ceramics ... at 1400 °C of 660 ± 25 MPa with an oxide layer thickness of 12 ± 1 μm. 2 wt.
Flexural strengths at room temperature, at 1400 °C in air, and at room temperature after 1 h oxidation at 1400 °C were determined for ZrB2- and HfB2-based ultra-high temperature ceramics ((UHTCs)).
Defects caused by electrical discharge machining (EDM) lowered measured strengths significantly and were used to calculate fracture toughness via a fracture mechanics approach.
ZrB2 with 20 vol.% SiC had room temperature strength of 700 ± 90 MPa, fracture toughness of 6.4 ± 0.6 MPa, Vickers hardness at 9.8 N load of 21.1 ± 0.6 GPa, 1400 °C strength of 400 ± 30 MPa, and room temperature strength after 1 h oxidation at 1400 °C of 678 ± 15 MPa with an oxide layer thickness of 45 ± 5 μm.
HfB2 with 20 vol.% SiC showed room temperature strength of 620 ± 50 MPa, fracture toughness of 5.0 ± 0.4 MPa, Vickers hardness at 9.8 N load of 27.0 ± 0.6 GPa, 1400 °C strength of 590 ± 150 MPa, and room temperature strength after 1 h oxidation at 1400 °C of 660 ± 25 MPa with an oxide layer thickness of 12 ± 1 μm.
2 wt.% La2O3 addition to UHTCs slightly reduced mechanical performance while increasing tolerance to property degradation after oxidation and effectively aided internal stress relaxation during spark plasma sintering (SPS) cooling, as quantified by X-ray diffraction (XRD).
Slow crack growth was suggested as the failure mechanism at high temperatures as a consequence of sharp cracks formation during oxidation.
Zirconium Diboride Microparticles
ZrB2 microparticles were coated on Cu metal by the roll-milling process. •. Nano ZrB2 coating was achieved by using the microparticles at room temperature. •. Nano ZrB2 coating has 0–100 ... Keywords. Zirconium diboride. Cu metal surface
.ZrB2 microparticles were prepared by the citric acid gel method.
•ZrB2 microparticles were coated on Cu metal by the roll-milling process.
•Nano ZrB2 coating was achieved by using the microparticles at room temperature.
•Nano ZrB2 coating has 0–100 nm particle size and 15–25 μm thickness.
•Nano ZrB2 coating is an electroactive surface.
In this study, ZrB2 was prepared from ZrOCl2.8H2O, H3BO3, and citric acid by using the gel method.
The gel was dried at 400 °C and then it was calcined at 1500 °C.
The prepared 0.5–1 μm ZrB2 powder was encapsulated into the Cu tube.
For the purpose of coating ZrB2 on Cu metal, the roll-milling of ZrB2 particles inside the cylindrical Cu tube has been performed at room temperature.
The prepared ZrB2 coating on Cu was analyzed by using FE-SEM, EDS, XRD, electrical resistivity, and CV measurements.
The final ZrB2 particle size on the surface of the coating layer was below 100 nm, and the coating thicknesses were about 15–20 μm.
The long nanofiber-like ZrB2 structures were observed.
The coating of nano ZrB2 on Cu was achieved by using this novel roll-milling process which is an environmentally friendly, low cost and practical technique.
Zirconium Diboride Powder Low Price
Zirconium Diboride Powder available in all sizes ranges for research and ... Note: We supply different size ranges of nano and micron size powder as per the ...
Niobium Boride Powder
Niobium boride Powders having NbB, NbB2, and Nb3B4 phases in various amounts and single-phase NbB powders were successfully synthesized by using powder metallurgy methods from related metal oxide raw materials in the presence of a strong reducing agent.
Nb2O5, B2O3, and Mg powder blends were milled at room temperature by a high-energy ball mill for a different time.
Subsequently, an undesired MgO phase was removed from the milled powders by HCl leaching to constitute NbB–NbB2–Nb3B4 as final products, and they were subjected to an annealing process at 1500 °C for 4 h to observe probable boride transformation.
Characterization was carried out by XRD, DSC, PSA, SEM/EDX, TEM, and VSM.
The effects of milling time (up to 9 h) on the formation, microstructure, and thermal behavior of the final products were investigated.
The reduction reaction took place after milling stoichiometric powder blends for 2 h.
Nano-sized NbB–NbB2–Nb3B4 powders in high purity were obtained in the absence of any secondary phase and any impurity via mechanochemistry by milling for 5 h and leaching with 4 mol/L HCl.
After annealing, pure and nano-sized NbB–NbB2–Nb3B4 powders transformed to a single NbB phase without leaving behind NbB2 and Nb3B4 phases.
Zirconium Diboride Nanoparticles
Nano zirconium diboride powder possesses high purity, narrow particle size distribution, large specific surface area
Zirconium diboride nanoparticle has a high melting point (3040 ℃), high hardness, high thermal conductivity, etc., is an excellent high-temperature structural material.
ZrB2 nanoparticle has metallicity which shows fantastic conductivity and its electric resistance is slightly lower than metal zirconium
It is stable in a wide temperature range
Good oxidation resistance in air and anti-corrosion ability
Fabrication, interfacial characteristics, and strengthening mechanisms of ZrB2 microparticles reinforced Cu composites prepared by hot-pressed sintering
Journal of Alloys and Compounds ( IF 4.650 )
1–9 wt% of ZrB2 particles are added to Cu to produce ZrB2/Cu composites by a hot-pressed sintering process.
Microstructures, mechanical and electrical properties of the prepared ZrB2/Cu composites are systematically investigated.
The results indicated that the relative density and electrical conductivity of the composites decrease with increasing ZrB2 content.
However, the microhardness reaches a maximum value of 100.8 HV0.2 as ZrB2 content increases to 7 wt % and then decreases when ZrB2 content further increases.
TEM study reveals that the hexagonal ZrB2 crystals in size of several micrometers are well embedded in the Cu matrix.
The interfacial zone consists of both sharp interfaces and an amorphous transition layer.
Grain refinement strengthening, Orowan strengthening, and coefficients of thermal expansion mismatch strengthening contribute to the increment of microhardness and reduce the electrical conductivity.
Zirconium Boride (ZrB2) Powder Description. A light grey metallic powder, chemically attacked very little by cold HCl, more rapidly by HNO3, and is dissolved by ...
Chemical Properties of Zirconium Boride (ZrB2) Powder
~Hf= 89.195 and B= 10.804
Purities Usually Available 99% to 99.99%
Physical Properties of Zirconium Boride (ZrB2) Powder
a) -140 + 325 mesh powder
b) Minus 325 mesh powder (APS= 10 microns or less)
c) Sputtering targets
Typical Applications of Zirconium Boride (ZrB2) Powder
The material has potential for use in hypervelocity reentry vehicles such as ICBM heat shields or aerodynamic leading-edges, due to its strength and thermal properties.
Zirconium Boride (ZrB2) Powder Packaging
25KG per drum or as required by the customer
Our product is clearly tagged and labeled externally to ensure efficient identification and quality control.
Great care is taken to avoid any damage which might be caused during storage or transportation.
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