Carbide

About: Carbide is a research topic. Over the lifetime, 36331 publications have been published within this topic receiving 503586 citations.

Transition metal carbide-based materials: synthesis and applications in electrochemical energy storage

Abstract: Transition metal carbides have attracted vast interest over the past years due to their appealing properties such as high conductivity, high chemical stability and thermal stability. With the rapid development of nanotechnology, more and more novel transition metal carbide structures have been prepared and investigated in various areas. In the present review, we summarize the current very recent progress in the synthesis and applications of transition metal carbides in the fields of capacitors and batteries. We also present critical issues, challenges, and perspectives with the hope of providing a fuller understanding of the associated electrochemical processes. Such an understanding is critical for tailoring and designing transition metal carbides with desired activity and stability.

In Situ Growth of Three‐Dimensional MXene/Metal‐Organic Framework Composites for High‐Performance Supercapacitors

Abstract: In this study, we propose a versatile method for synthesizing uniform three-dimensional (3D) metal carbides, nitrides, and carbonitrides (MXenes)/metal–organic frameworks (MOFs) composites (Ti3C2TX/Cu-BTC, Ti3C2TX/Fe,Co-PBA, Ti3C2TX/ZIF-8, and Ti3C2TX/ZIF-67) that combine the advantages of MOFs and MXenes to enhance stability and improve conductivity. Subsequently, 3D hollow Ti3C2TX/ZIF-67/CoV2O6 composites with excellent electron- and ion-transport properties derived from Ti3C2TX/ZIF-67 were synthesized. The specific capacitance of the Ti3C2TX/ZIF-67/CoV2O6 electrode was 285.5 F g−1, which is much higher than that of the ZIF-67 and Ti3C2TX/ZIF-67 electrode. This study opens a new avenue for the design and synthesis of MXene/MOF composites and complex hollow structures with tailorable structures and compositions for various applications.

Microstructure of Long-Term Aged IN617 Ni-Base Superalloy

Abstract: The microstructure of the Ni-base superalloy IN617 that had undergone prolonged aging (approximately 65,000 hours) at a series of temperatures from 482 °C to 871 °C has been characterized by microhardness measurements, optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) Cr23C6, Mo-rich eta-M6C, and Ti(C,N) constitute the major primary coarse precipitates both within the grains and along the grain boundaries The secondary carbides were mostly fine Cr23C6, which had a cube-on-cube orientation relationship (OR) with the fcc matrix, and at long times were present in cuboidal and plate-shape forms within the grains and as films along the grain boundaries Fine, eta-M6C carbides were also observed at low to intermediate temperatures with an OR given by [011] carbide//[011] matrix, \( \left( {\bar{1}\bar{1}1} \right) \) carbide//\( \left( {\bar{1}\bar{1}1} \right) \) matrix The coarse eta-M6C carbides increased in extent at 871 °C, whereas the counterpart fine carbides were absent The γ′ phase was found to be present at all aging temperatures up to 871 °C, with a volume fraction ranging from very low to approximately 5 pct at 593 °C, where the peak in microhardness occurs The observations have also suggested that the presence of a very small amount of γ′ at temperatures as high as 871 °C at long times may be associated with a reaction between the fine eta-carbides and the γ matrix Ultrafine precipitates of the intermetallic phase Ni2(Cr,Mo) with the Pt2Mo-type structure was observed in addition to γ′ in samples aged for 28,300 hours at the lowest aging temperature of 482 °C These precipitates were absent in samples aged at higher temperatures The various observations made have suggested that the long-term thermal stability of the IN617 alloy is reasonably good over a wide temperature range of 538 °C to 704 °C, whereas at higher temperatures (871 °C), the substantial decrease in the volume fraction of γ′ and coarsening and clustering of the carbides lead to a large drop in the microhardness A modified time-temperature-transformation (TTT) diagram was constructed based on the results of this study and comparison with previous reports