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Carbide

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


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TL;DR: In this article, the corrosion properties of cemented carbides with cobalt binder phase have been examined in HCl and H 2 SO 4 solution at room temperature, and the effect of magnetic saturation property on corrosion behavior is described.
Abstract: The corrosion properties of cemented carbides with cobalt binder phase have been examined in HCl and H 2 SO 4 solution at room temperature. Potentiodynamic polarization technique with saturated calomel reference electrode was employed in this study. Air and inert argon were used as a circulating media. The effect of magnetic saturation property of cemented carbide on corrosion behavior is described. Specimens were prepared in industrial sinter furnaces under various conditions to obtain different magnetic saturation at various binder contents. According to aerated experiment, there was a difference of anodic behavior of cemented carbides between HCl and H 2 SO 4 solution. The specimen in H 2 SO 4 solution shows lower current density than in HCl by up to two orders of magnitude. This can be explained by the effect of anion on corrosion behavior of cemented carbides. A large difference between aerated and deaerated acidic solution was not observed. There was a small change of polarization curve in cathodic regime due to different extent of cathodic reaction. In addition, free corrosion potential was slightly shifted to more noble values in aerated solution. In anodic polarization, both curves were almost identical. This shows that dissolved oxygen has small influence on anodic behavior of cemented carbides. Chronoamperometric measurement as well as electrochemical investigations showed that pseudopassivity is caused by a diffusion controlled process, which is in contradiction to literature where coverage of surface is claimed. Unstable precipitates are formed in cemented carbides with high tungsten containing binder during anodic dissolution.

123 citations

Journal ArticleDOI
TL;DR: In this article, a simple hydrothermal method was used to synthesize high surface area tungsten carbide microspheres (TCMSs) and the performance of the Pt electrocatalyst supported on the as-prepared TCMSs towards the oxygen reduction reaction (ORR) is investigated.
Abstract: In the present work, the preparation of high surface area (256 m2 g−1) tungsten carbide microspheres (TCMSs) by the aid of a simple hydrothermal method is realized and the performance of the Pt electrocatalyst supported on the as-prepared TCMSs towards the oxygen reduction reaction (ORR) is investigated. The SEM micrographs indicated that both the synthesized carbon microspheres (CMSs) and TCMSs showed perfect microsphere structure and uniform size. The EDX measurements confirmed that when the C/W mass ratio is ∼2.5/1, tungsten and carbon coexist in the microspheres. Moreover, from the XRD results, it can be found that both W2C and WC are detected and W2C exists as the main phase. It was found that the Pt particles are uniformly dispersed on the supports, while the corresponding average particle size is ∼3.7, 4.1 and 4.3 nm for Pt/C, Pt/CMSs and Pt/TCMSs, respectively. It was also found that in terms of ORR onset potential and mass activity, the Pt/TCMSs catalyst exhibits superior performance to that of Pt/CMSs and Pt/C, enhancing the ORR catalytic activity by more than 200%. The above behavior could be attributed to its higher electrochemical surface area (ESA), as well as to the synergistic effect between Pt and tungsten carbides.

123 citations

Journal ArticleDOI
TL;DR: In this paper, the microstructure of high velocity oxy-fuel (HVOF) sprayed Cr 3 C 2 -NiCr coatings was characterized by scanning electron microscopy, and the apparent average size and volume fraction of carbide particles in the coatings were estimated through quantitative imaging analysis.
Abstract: Cr 3 C 2 –NiCr coatings were deposited by high velocity oxy-fuel (HVOF) process with different spray parameters to examine dominant microstructural factors in abrasive wear of the coatings. The microstructure of the HVOF sprayed Cr 3 C 2 –NiCr coatings was characterized by scanning electron microscopy and transmission electron microscopy (TEM). The apparent average size and volume fraction of carbide particles in the coatings were estimated through a quantitative imaging analysis. The formation of carbide phases in the coating was discussed based on the TEM observation results. The abrasive wear behavior of the coating was evaluated by the dry rubber wheel abrasive wear test and the wear mechanisms were elucidated. Influences of apparent size and volume fraction of carbide particles on the abrasive wear weight loss were examined through correlating the proposed relation with the experimental results. Results showed that Cr 3 C 2 particle size was significantly reduced after the spraying and Cr 7 C 3 carbide was present around Cr 3 C 2 particles, and Cr 23 C 6 carbide was dispersed in NiCr alloy matrix with a nano-crystalline structure. The three carbides were formed in the coating through different mechanisms. The removal of carbide particles in the coating was mainly responsible for the abrasive wear of the coating. The content and particle size of the Cr 3 C 2 carbides were the two key factors controlling the abrasive wear of the HVOF sprayed Cr 3 C 2 –NiCr coatings.

123 citations

Journal ArticleDOI
TL;DR: In order to extend the service life of carbide components and enhance their efficiency for rock drilling under various conditions, the recent research efforts have focused on their failure mechanisms and developing nanostructured, functionally graded and Co-free cemented carbides as mentioned in this paper.
Abstract: Cemented carbide is an old and well-known WC-based hardmetal, which has been widely applied in geo-engineering as drill buttons and various wear-resistant parts. In order to extend the service life of cemented carbide components and enhance their efficiency for rock drilling under various conditions, the recent research efforts have focused on their failure mechanisms and developing nanostructured, functionally graded and Co-free cemented carbides. With the advance in synthesizing nanosized powders and advent of electric field assisted fast sintering techniques, the consolidation of nanostructured and Co-free cemented carbides and even pure WC materials has been possible; and because of their high hardness and wear resistance, they are much promising in geo-engineering drilling. Functionally graded cemented carbide provides a combination of high wear resistance and toughness in a single component, which is also much favorable for geo-engineering drillers. In addition, by replacing the binder phase Co with Ni or carbide binder, and even without binder phase, the corrosion and oxidation of the resultant materials can be significantly improved without considerable deterioration of fracture toughness.

123 citations

Journal ArticleDOI
TL;DR: In this article, the fatigue properties of two types of cold-work tool steels tempered at various temperatures were evaluated and the microstructure and fracture surface morphology were correlated to the fatigue behavior.
Abstract: The fatigue properties of two types of cold-work tool steels tempered at various temperatures were evaluated. The microstructure and fracture surface morphology were correlated to the fatigue behavior. Cold-work tool steels using this study were a conventional tool steel (JIS SKD11; 1.4C-11Cr-0.8Mo-0.2V) and its modified steel (M-SKD11; 0.8C-8Cr-2Mo-0.5V). The fatigue strength of the M-SKD11 steel increased 20 pct over that of the SKD11 steel for any number of cycles. This is attributed to the refinement of primary M7C3 carbides. These M7C3 carbides fractured during fatigue and were found at the sites of fatigue crack initiation. Change in crack initiation behavior was confirmed by acoustic emission testing. The S-N curves of the steels are similar to those of most structural steels. However, the subsurface fatigue crack initiation was dominant at lower alternating stresses. This study points to a general approach of carbide refinement that can be used for the enhancement of fatigue properties.

122 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,218
20222,462
2021994
20201,277
20191,413
20181,471