The effect of lanthanum on the fabrication of ZrB2–ZrC composites by spark plasma sintering

Kim, Kyoung Hun; Shim, Kwang Bo

doi:10.1016/s1044-5803(03)00055-x

Cited by 71 publications

(20 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fully dense samples are then obtained at very high temperature and/or by using sintering aids such as metallic elements [19]. As a consequence of the high temperature used, the microstructures of the samples so obtained are generally coarse and contain noticeable residual porosity.…”

Section: Shaping Of Pellet-type Bulk Materials and Comparison With Pomentioning

confidence: 99%

Novel insight into the chemical analysis of light elements in oxycarbides

et al. 2018

View full text Add to dashboard Cite

Pure powders of TiCxO(1-x) solid solution were synthesized through the carbothermal route. The chemical analysis of the light elements in the as-obtained TiCxO(1-x) oxycarbides powders were performed by Instrumented Gas Analysis (IGA). The cell parameters of the samples were determined with an accuracy of about 2% by means of X-ray powder diffraction and the internal standard method. As a result, a model correlating the cell parameters to the chemical composition was established. These reference TiCxO(1-x) oxycarbides powders were then sintered in order to obtain pellets of dense ceramics. After having determined that the sintering process does not change the chemical composition of the starting powder, chemical analysis of the different samples of the solid solution were successfully undertaken by Ion Beam Analysis techniques (IBA). The Nuclear Reaction Analysis (NRA) method -that was used to analyse light elements with very high sensitivity -was coupled with Rutherford Back Scattering (RBS) analysis in order to accurately determine the metallic over light elements ratio and to determine the stoichiometry of the phase on massive samples. Exhaustive simulations of the NRA spectra were performed and demonstrated that discrete compositions of the TiCxO(1-x) can be efficiently measured locally for bulk samples. Compared to IGA results, the relative amounts of carbon and oxygen of bulk materials were determined with a bias lower than 5%. This protocol being implemented for the TiCxO(1-x) system was then tested on HfCxO(1-x)with the same success.3

show abstract

Section: Shaping Of Pellet-type Bulk Materials and Comparison With Pomentioning

confidence: 99%

Novel insight into the chemical analysis of light elements in oxycarbides

et al. 2018

View full text Add to dashboard Cite

show abstract

“…It should be noted that ZrB 2 doping has densification effect. For instance, the addition of ZrB 2 into the ZrC compound enhanced the sintering and produced ZrC with low porosity levels during processing [7] . As were proved by several researchers, the high density MgB 2 samples have high superconducting homogeneity and strong intergranular current flow as determined by magneto-optical studies [8] .…”

Section: Resultsmentioning

confidence: 99%

“…It should be noted that the transitionmetals ZrC and ZrB 2 are potential ceramic materials highly resistant to high temperatures, wear, oxidation and corrosion. They have a very good thermal and electrical conductivity [7] . In this study, we show how ZrC and ZrB 2 affect the properties of MgB 2 tapes made by powder-in-tube technique.…”

mentioning

confidence: 99%

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

2006

CHINESE SCI BULL

View full text Add to dashboard Cite

We have investigated the effects of ZrC and ZrB 2 doping on the superconducting properties of the powder-in-tube processed MgB 2 /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 ZrB 2 in MgB 2 . ZrC doping was found to decrease the transport critical current density (J c ) at 4.2 K, while the critical temperature (T c ) kept constant. In contrast, the J c values in magnetic fields were enhanced greatly by the ZrB 2 addition, which resulted in a decrease in T c by only 0.5 K. The reason for different effects of two dopants is also discussed.Extensive research efforts have been made to improve the performance of MgB 2 materials since the discovery of superconductivity at 39 K in this compound [1] . However, a rapid decrease in critical current density (J c ) at magnetic fields in MgB 2 is the principal limitation to their technological applications. This limitation is strongly correlated to poor grain connection and lack of pinning centers. Hence, chemical doping using different elements/compounds seems to be the best and most practical route [2][3][4][5][6] . Of all the chemical dopings undertaken, Zr and C doping have been successful in enhancing both the irreversibility field (Hirr) and J c (B). The remarkable improvement of J c (B) behavior in the above-doped samples can be explained by the densification effect and the improved pinning [2,4] . The intention of the present work is to study the effect of ZrC and ZrB 2 additions on the phase formation and microstructures of MgB 2 as well as their roles in the J c enhancement. It should be noted that the transitionmetals ZrC and ZrB 2 are potential ceramic materials highly resistant to high temperatures, wear, oxidation and corrosion. They have a very good thermal and electrical conductivity [7] . In this study, we show how ZrC and ZrB 2 affect the properties of MgB 2 tapes made by powder-in-tube technique. We have found quite different behaviors between ZrC and ZrB 2 in MgB 2 .

show abstract

“…1430 • C) must be reached for the eutectic composition (57 mol% of ZrB 2 ) 17 confirming the previous data in the literature. 18 Whatever the ceramic composition, the using of SPS technique leads to high densification levels; around 98% of the theoretical value for the composites and slightly less (96%) for pure zirconium carbide (Fig. 7b).…”

Section: Zirconium Diboride Powdermentioning

confidence: 93%