• Title/Summary/Keyword: Cations

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Effect of Cations on the Sorption and the Tensile Properties of CMC Fibers (CMC섬유내의 양이온이 섬유의 흡습성과 인장 성질에 미치는 영향)

  • 이미식
    • Journal of the Korean Society of Clothing and Textiles
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    • v.18 no.1
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    • pp.113-120
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    • 1994
  • The Purpose of this study was to improve the moisture related properties of viscose rayon fibers. Viscose rayon filament yarns were partially etherified to make CMC fibers. CMC fibers were converted to the sodium, calcium, and ferric salt forms by an ion exchange method. The property changes of ion exchanged CMC fibers were examined. Cation contents of fibers were varied depending on the degree of substitution of CMC fibers. The strength of Na, Ca, Fe-CMC was higher than H-CMC owing to the plasticization by moisture sorption and the crosslinking by cations. The moisture regain was increased by carboxymethylation and that of Fe-CMC showed the highest value. The degree of swelling determined by the water retention value was observed to be Na-CMC > Ca-CMC > H-CMC > Fe-CMC. The solution retention value was decreased in the order . Ca-CMC > Na-CMC > H-CMC > Fe-CMC.

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Selective Carbonization and Nitridation of Titanium in (ZrTi)O2 Powders Synthesized by Copreciptation Method

  • Shin Soon-Gi
    • Korean Journal of Materials Research
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    • v.15 no.10
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    • pp.662-666
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    • 2005
  • Solid solutions of $(Zr/Ti)O_2$ were prepared in powder form by the coprecipitation technique. After mixing with carbon or exposing to nitrogen gas at elevated temperature, titanium cations selectively diffused out from the oxide compound to form titanium carbide (TiC) or titanium nitride (TiN), respectively. TiN formed strong interfacial contacts between the oxide grains. In contrast, TiC formed as small crystallites on oxide grains but did not bind the matrix grains together. TiN therefore played a role in strengthening the interparticle bonding, but TiC weakened the bonding between grains. Partial diffusion of titanium cations also led to nanolayered structure being formed between the oxide grains, which provided weak interfacial layers that fractured in a step-wise fashion.