Effects Of ZrC Research Articles

Study on the effect of ZrC and CNTs particles on Inconel 625 coatings fabricated by coaxial-wire-feed laser cladding

In order to investigate the effect of coaxial-feed laser cladding with the addition of ZrC and CNTs reinforcing particles, a four-split-beam coaxial-wire-feed system was used for the first time to fabricate the cladding layers. Specifically, the effects of the reinforcing particles on the microstructure, mechanical and corrosion properties of the cladding layers were investigated. On 316L substrates, three types of cladding layers were created: pure Inconel 625, Inconel 625 with ZrC, and Inconel 625 with ZrC-CNTs. The testing findings revealed that the cladding layer with reinforcement particles added possessed the ideal geometrical features of large melt width and low dilution rate. Due to the coaxial action of the laser and the wire, the grains on both sides of the single-bead cladding layer transited from columnar crystals to equiaxial crystals along the temperature gradient, and the grains in the middle of the single-bead cladding layer showed the competing growth of columnar crystals and equiaxial crystals at the fusion line. The addition of ZrC and CNTs particles produced a heterogeneous nucleation effect that refined the grain size and homogenized the grain orientation, which CNTs accentuated. Compared with the pure Inconel 625 cladding, the tensile strength of the ZrC/Inconel 625 cladding increased from 731Mpa to 783Mpa, the hardness increased by 29%, and the electrochemical corrosion rate decreased by 53.6%. The elongation of the ZrC-CNTs/Inconel 625 cladding increased from 13.4% to 24%, but the corrosion resistance decreased significantly.

Effect of ZrC on the Microstructure and Properties of CrMnFeCoNi High-Entropy Alloy Coatings Prepared by a Plasma Transferred Arc Process.

The low strength caused by the single FCC structure of the CrMnFeCoNi high entropy alloy (HEA) limits its application in the field of coating. Here, we prepared high-entropy alloy coatings of CrMnFeCoNi with different ZrC contents on Q235 steel by a plasma transferred arc process. The effects of ZrC on the microstructure and properties of the CrMnFeCoNi HEA coating were investigated by optical microscopy, scanning electron microscope, and X-ray diffraction and by employing a potensiostat/galvanostat. The results showed that ZrC mainly existed in the coatings as a second phase, having little influence on the main crystal structure and micromorphology of the CrMnFeCoNi HEA coating. The hardness of the CrMnFeCoNi HEA coating increased with the ZrC content. ZrC can effectively improve the corrosion resistance of the CrMnFeCoNi HEA coating. In a 1 mol/L NaCl solution with 4 wt% ZrC, the annual corrosion rate was only 5.997% of that of the HEA coating. Nevertheless, the improvement in the wear resistance of CrMnFeCoNi high-entropy alloy coatings was not apparent with the addition of ZrC. Consequently, the addition of ZrC to the FeCoCrNiMn high-entropy alloy coating holds promise for applications in corrosion resistance, particularly in oceanic environments.

Effect of ZrC and ZrO2 Additions on the Microstructure and Properties of ZrB2–SiC Ceramics

We have studied the effect of ZrC and ZrO2 additions on the microstructure and properties of ceramic composites based on ZrB2???5% SiC, produced by pressure-sintering mechanically activated powders at a temperature of 1600??C. The results demonstrate that the addition of ZrO2 increases the density, hardness, and fracture toughness of ceramic composites based on ZrB2???5% SiC. In particular, the KIc of the ZrB2???5% SiC ceramic is 4.6 ?? 0.3 MPa m1/2 and that of the composite containing 20% ZrO2 is 7.3 ?? 0.4 MPa m1/2.

Mechanical properties and grain orientation evolution of zirconium diboride-zirconium carbide ceramics

The effect of ZrC on the mechanical response of ZrB2 ceramics has been evaluated from room temperature to 2000°C. Zirconium diboride ceramics containing 10vol% ZrC had higher strengths at all temperatures compared to previous reports for nominally pure ZrB2. The addition of ZrC also increased fracture toughness from ∼3.5MPam for nominally pure ZrB2 to ∼4.3MPam due to residual thermal stresses. The toughness was comparable with ZrB2 up to 1600°C, but increased to 4.6MPam at 1800°C and 2000°C. The increased toughness above 1600°C was attributed to plasticity in the ZrC at elevated temperatures. Electron back-scattered diffraction analysis showed strong orientation of the ZrC grains along the [001] direction in the tensile region of specimens tested at 2000°C, a phenomenon that has not been observed previously for fast fracture (crosshead displacement rate=4.0mmmin−1) in four point bending. It is believed that microstructural changes and plasticity at elevated temperature were the mechanisms behind the ultrafast reorientation of ZrC.

Effects of ZrC and SiC addition on the microstructures and mechanical properties of binderless WC

ZrC-added WC ceramics and SiC-added WC–2mol% ZrC ceramics were sintered at 1800°C using a resistance-heated hot-pressing machine. Dense WC ceramics containing 0–1mol% ZrC and WC–2mol% ZrC ceramics containing 1–6mol% SiC were obtained. The reaction products W2C, ZrO2 and ZrC-based solid solutions were formed in the ZrC-added WC ceramics during sintering. The relative amount of W2C reached zero at 2mol% ZrC, increased in the range of 2–6mol% ZrC, and decreased again above 6mol% ZrC. The average WC grain size decreased from 0.49μm for the WC ceramic to 0.24μm at 4mol% ZrC. The SiC addition of 1–2mol% to the WC–2mol% ZrC ceramics caused abnormal growth of WC grains. The Vickers hardness of the ZrC-added WC ceramics decreased to 17GPa at 2mol% ZrC. The hardness of the SiC-added WC–2mol% ZrC ceramics increased from 12.4 at 2mol% SiC to 21.5GPa at 6mol% SiC. The fracture toughness of the ZrC-added WC ceramics decreased from 6.2MPam0.5 for the WC ceramic to 5.2MPam0.5 at 4mol% added ZrC. The fracture toughness of the WC–2mol% ZrC ceramics with 6mol% SiC were relatively high at 6.7MPam0.5. The addition of SiC to WC-based ceramics thus improved both hardness and fracture toughness.

Sound absorption properties of spiral vane electrospun PVA/nano particle nanofiber membrane and non-woven composite material

In this research, we fabricated a series of PVA membranes loaded with 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.% ZrC and 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.% TiO2 using a spiral vane electrospun machine respectively. There were 2 sizes of TiO2 nano particles: 10 nm and 200 nm. We tested sound absorption properties of needle-punched nonwovens as well as the composite of nano membranes and needle-punched nonwovens by an impedance tube at the frequency range from 500 Hz to 6500 Hz. Besides, we tested morphological characterization of nano membranes by scanning electron microscope (SEM) and crystalline properties by X-ray diffraction (XRD). We investigated the sound absorption properties of composites as well as the effect of ZrC, TiO2, nano particle sizes and cavity depth on sound absorption properties. Results showed that sound absorption properties of composites increased at the whole range of frequency compared to those of needle-punched nonwovens. When loaded with ZrC nano particles, sound absorption properties of composite shifted to a higher frequency region, and with increasing content of ZrC, sound absorption properties were better above 2500 Hz. However, when loaded with TiO2, sound absorption properties were better at lower frequency. With 3 wt.% TiO2, sound absorption coefficient reached the best at the frequency range from 500 Hz to 1500 Hz. Besides, 200 nm TiO2 was more conductive to the increase of sound absorption properties at lower frequency region compared to 10 nm TiO2. Sound absorption properties of composites with air back cavity shifted to a lower frequency region, too. SEM showed that there was nano particle aggregation when loaded TiO2 nano particles. XRD showed that ZrC nano particles loaded in PVA nano fiber retained their crystalline structure while TiO2 didn’t. It appeared from the results that nano particles had an effect on sound absorption materials, with different kinds and different sizes, sound absorption properties will improve in different ranges of frequency

Effects of ZrC on microstructure, mechanical properties and thermal shock resistance of TiC–ZrC–Co–Ni cermets

TiC–ZrC–Co–Ni cermets with different ZrC contents were prepared by vacuum sintering. Microstructure, mechanical properties and thermal shock resistance were investigated. The results show that bright spherical grains in the microstructure are observed and their relative amounts increase with increasing ZrC addition. X-ray diffraction and energy-dispersive spectrometry results indicate that bright spherical grains are (Zr, Ti)C solid solution with more Zr content. The relative density, hardness and transverse rupture strength decrease with the increase of ZrC content. The fracture toughness, however, increases a little and then decreases. Thermal shock resistance of the cermets with 10%ZrC is the best and then declines with more ZrC addition. The parameter Rst of the cermets is also calculated on the basis of the physical parameters of the constituents to interpret the thermal shock of the cermets.

Doping effects of ZrC and ZrB2 in the powder-in-tube processed MgB2 tapes

We have investigated the effects of ZrC and ZrB2 doping on the superconducting properties of the powder-in-tube processed MgB2/Fe tapes. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX), transport and magnetic measurements. We confirmed the following quite different roles of ZrC and ZrB2 in MgB2. ZrC doping was found to decrease the transport critical current density (Jc) at 4.2 K, while the critical temperature (Tc) kept constant. In contrast, the Jc values in magnetic fields were enhanced greatly by the ZrB2 addition, which resulted in a decrease in Tc by only 0.5 K. The reason for different effects of two dopants is also discussed.