Journal of The Less Common Metals最新文献

{"title":"Exchange interaction in rare-earth compounds of the type RCo4B","authors":"J. Liu, F. D. Boer, K. Buschow","doi":"10.1016/0022-5088(91)90358-B","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90358-B","url":null,"abstract":"","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"39 1","pages":"137-141"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82834124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SiS2-isostrukturelle Anionen [SiP22−], [GeAs22−] und [SnAs22−] in Alkaliverbindungen","authors":"B. Eisenmann, J. Klein","doi":"10.1016/0022-5088(91)90355-8","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90355-8","url":null,"abstract":"","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"35 1","pages":"109-117"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86503426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The ternary system Co-Ga-As at 800 °C","authors":"Ingrid Lindeberg,&nbsp;Yvonne Andersson","doi":"10.1016/0022-5088(91)90360-G","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90360-G","url":null,"abstract":"<div><p>Solid state phase equilibria at 800 °C in the Co-Ga-As system have been investigated by X-ray powder diffraction methods. GaAs forms equilibria with CoGa₃, CoGa, CoAs₃, CoAs₂ and CoAs. The presence of a ternary phase with a homogeneity range around the composition Co₃Ga_0.5As_1.5 has been established.</p></div>","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"175 1","pages":"Pages 155-162"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-5088(91)90360-G","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71731011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation and hydriding properties of magnesium-containing hydrogen storage materials chemically deposited from a homogeneous phase","authors":"Hayao Imamura,&nbsp;Yoshihiro Usui,&nbsp;Masaharu Takashima","doi":"10.1016/0022-5088(91)90362-8","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90362-8","url":null,"abstract":"<div><p>Use of the dissolution of magnesium metal in liquid ammonia enabled novel magnesium-containing hydrogen storage materials to be prepared. The dispersion of magnesium atoms in ammonia matrices at 77 K using a metal vapour technique gave rise to a homogeneous solution of dissolved magnesium metal in liquid ammonia. Hydrogen storage materials prepared using the solvent power of ammonia are of two types. (i) Magnesium was crystallized out of the solution of dissolved magnesium in liquid ammonia; the crystallization was carried out in the presence or absence of catalytically active nickel powders (respectively Mg-Ni or Mg); (ii) Magnesium was highly dispersed on an active carbon (AC) support by impregnating the AC with the solution (referred to as <span><math><mtext>Mg</mtext><mtext>AC</mtext></math></span>). Using AC on which catalytically active nickel had been previously supported, the preparation of samples was further extended to include binary systems (<span><math><mtext>Mg-</mtext><mtext>Ni</mtext><mtext>AC</mtext></math></span>). These samples were investigated in connection with the preparation methods. The magnesium samples were extremely active toward hydrogen absorption. For the Mg-Ni and <span><math><mtext>Mg-</mtext><mtext>Ni</mtext><mtext>AC</mtext></math></span> samples an increase in nickel markedly accelerated the initial hydriding rates of the parent magnesium metal.</p></div>","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"175 1","pages":"Pages 171-176"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-5088(91)90362-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71731012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic structures of TbMn6Sn6 and HoMn6Sn6 compounds from neutron diffraction study","authors":"B.Chafik El Idrissi,&nbsp;G. Venturini,&nbsp;B. Malaman,&nbsp;D. Fruchart","doi":"10.1016/0022-5088(91)90359-C","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90359-C","url":null,"abstract":"<div><p>Neutron diffraction measurements have been performed on the ternary stannides TbMn₆Sn₆ and HoMn₆Sn₆ of HfFe₆Ge₆ type structure (space group, <em>P</em>6/<em>mmm</em>). This structure can be described as a filled derivative of the CoSn B35-type structure. Each of the rare earth and manganese atoms is successively distributed in alternate layers stacked along the <em>c</em> axis with the sequence Mn-R-Mn-Mn-R-Mn. Owing to the manganese atom coordination of the rare earth, this structure appears closely related to the CaCu⁶- and ThMn₁₂-type structures. This study confirms that both the rare earth and the manganese sublattices order simultaneously above room temperature. In the whole temperature range studied (2–300 K), TbMn₆Sn₆ and HoMn₆Sn₆ exhibit a collinear ferrimagnetic arrangement. At 300 K, the magnetic structure consists of a stacking of ferromagnetic (001) layers of rare earth and manganese with the coupling sequence Mn(+)R(−)Mn(+)Mn(+)-R (−)Mn(+) (<em>μ</em>_<em>Mn</em> ≈ 2.0(1)<em>μ</em>_<em>B</em>, <em>μ</em>_<em>Tb</em> = 4.9(1)<em>μ</em>_<em>B</em>, <em>μ</em>_<em>Ho</em> = 4.7(1)<em>μ</em>_<em>B</em>). For HoMn₆Sn₆, the magnetic moments lie in the (001) plane while in TbMn₆Sn₆, they deviate by <em>φ</em> = 15° from the <em>c</em> axis. Below 300 K, the two compounds exhibit a spin rotation process and at 2 K the magnetic moments are along [001] and at 50° from this axis for TbMn₆Sn₆ and HoMn₆Sn₆ respectively <em>μ</em>_<em>Mn</em> = 2.4(1)<em>μ</em>_<em>B</em>, <em>μ</em>_<em>Tb</em> = 8.6(1)<em>μ</em>_<em>B</em>, <em>μ</em>_<em>Ho</em> = 8.4(1)<em>μ</em>_<em>B</em>).</p><p>The results are discussed in terms of Ruderman-Kittel-Kasuy-Yoshida exchange interactions and compared with those obtained previously for the parent RFe₆Al₆ and RCo₆ compounds.</p></div>","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"175 1","pages":"Pages 143-154"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-5088(91)90359-C","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71731600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Demixing of U-Zr alloys under a thermal gradient","authors":"T. Ogawa,&nbsp;T. Iwai,&nbsp;M. Kurata","doi":"10.1016/0022-5088(91)90349-9","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90349-9","url":null,"abstract":"<div><p>Redistribution of the components in U-Zr and U-Pu-Zr alloys occurs under a steep temperature gradient. The phenomenon was analysed as a thermal diffusion process accompanying phase separation. A unique combination of thermodynamic and transport properties was found to be responsible for the pronounced demixing of these alloys under thermal gradient.</p></div>","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"175 1","pages":"Pages 59-69"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-5088(91)90349-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71731601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the structural and hydrogen desorption properties of the Zr(Cr1 − xCux)2 alloys","authors":"A. Dras̆ner,&nbsp;Z̆. Blaz̆ina","doi":"10.1016/0022-5088(91)90354-7","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90354-7","url":null,"abstract":"<div><p>X-ray powder diffraction studies of the Zr(Cr_{1 − <em>x</em>}Cu_<em>x</em>)₂ system revealed the existence of a single-phase region up to the composition Zr(Cr_0.5Cu_0.5)₂. All the ternary alloys crystallize with a Friauf-Laves structure of the MgCu₂ type, differing from the binary compound ZrCr₂ which exhibits polymorphism and crystallizes with the hexagonal structure of the MgZn₂ type and the cubic structure of the MgCu₂ type. It was also found that single-phase alloys react readily with hydrogen to form hydrides having 2–3 hydrogen atoms per formula unit under a hydrogen pressure of 1.0 MPa at room temperature. Pressure—composition hydrogen desorption isotherms were determined over the temperature range 296–473 K. In general, the dissociation equilibrium pressure increases and hydrogen capacity decreases with increasing copper content. The hydrogen sorption properties of the systems described in this paper and of similar systems based on ZrCr₂ are briefly discussed.</p></div>","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"175 1","pages":"Pages 103-108"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-5088(91)90354-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71731612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigations in the boron-carbon system with the aid of electron probe microanalysis","authors":"Karl A. Schwetz,&nbsp;P. Karduck","doi":"10.1016/0022-5088(91)90345-5","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90345-5","url":null,"abstract":"<div><p>For boron carbide the limit of the homogeneity range at the carbon-rich side has not yet been firmly established. During the last 20 years carbon-rich limiting compositions have been reported corresponding to B₄₃C (<em>i.e.</em> “B₁₃C₃”), B_4.0C (i.e. “B₁₂C₃”) and B_3.6C (<em>i.e.</em> “B₁₁C₃”). By means of quantitative electron probe microanalysis (EPMA) the composition of the boron carbide phase in the following samples has been determined: </p><ul><li><span>1.</span><span><p>(i) boron-carbon diffusion couples, prepared by hot isostatic pressing (HIP) of the pure elements at above 2000 °C;</p></span></li><li><span>2.</span><span><p>(ii) fused, regular boron carbide, obtained by carbothermic reduction of boric oxide at above 2500 °C (ESK electrofurnace process);</p></span></li><li><span>3.</span><span><p>(iii) dense boron carbide compacts made by pressureless sintering of carbothermic boron carbide powder or by HIP of magnesiothermic boron carbide powder at above 2000 °C.</p></span></li></ul><p>In each sample the carbon-rich limiting composition has been determined as B_4.3C (18.8 at.% C) which corresponds to B₁₃C₂·C and is probably a solid solution of carbon in B₁₃C₂. The B₁₂C₃ and B₁₁C₃ compositions could not be found. For quantitative analysis a standard sample has been used, which was obtained by arc melting the pure elements with a <em>B</em>: <em>C</em> atomic ratio of 4.39. Also indirect <em>B</em>: <em>C</em> atomic ratio determinations via chemical analyses of crushed samples have produced evidence to support the limit 4.3 found by EPMA.</p></div>","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"175 1","pages":"Pages 1-11"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-5088(91)90345-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71731674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The structure of LiCu2O2 with mixed-valence copper from twin-crystal data","authors":"R. Berger, A. Meetsma, S. Smaalen, M. Sundberg","doi":"10.1016/0022-5088(91)90356-9","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90356-9","url":null,"abstract":"","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"67 1","pages":"119-129"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76390013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The crystal structure of the low temperature form of Co2As","authors":"Ingrid Lindeberg,&nbsp;Yvonne Andersson","doi":"10.1016/0022-5088(91)90361-7","DOIUrl":"https://doi.org/10.1016/0022-5088(91)90361-7","url":null,"abstract":"<div><p>The low temperature (α) form of Co₂As has been investigated by single-crystal X-ray methods. It crystallizes in a hexagonal unit cell. The space group is <span><math><mtext>P</mtext><mtext>6</mtext><mtext>2m</mtext></math></span> (number 189), with lattice parameters <span><math><mtext>a = 11.9821(7) </mtext><mtext>A</mtext><mtext>̊</mtext></math></span> and <span><math><mtext>c = 3.5822(5) </mtext><mtext>A</mtext><mtext>̊</mtext></math></span> and <em>Z</em> = 12. The crystal structure is closely related to, but distinctly different from, the high temperature Fe₂P-type structure.</p></div>","PeriodicalId":17534,"journal":{"name":"Journal of The Less Common Metals","volume":"175 1","pages":"Pages 163-169"},"PeriodicalIF":0.0,"publicationDate":"1991-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0022-5088(91)90361-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71731010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}