کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1607881 | 1516238 | 2016 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The role of CaH2 in preventing oxidation for the production of single-phase NiTi alloy in solid state
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Single-phase NiTi synthesized from Ni and TiH2 powders was successfully formed in a solid-state reducing environment of CaH2. A comparison was done with a specimen synthesized in an environment without CaH2. An in-depth investigation on the surface of the specimen sintered without CaH2 revealed a thick layer of oxide with a thickness of 94 μm, whereas the specimen sintered in the reducing environment showed a significant reduction in oxide formation. The decomposition of CaH2 liberates Ca, which effectively reacts with oxygen at 930 °C and consumes available oxygen in the system, thus minimizing oxygen to react with Ti to form TiO2. A significant reduction of this oxidation creates a balanced composition between Ni and Ti. An oxygen-free environment allows unhindered Ni-Ti reaction, which leads to the formation of single-phase NiTi, which is mostly found formed in the middle volume of the specimen. The optimum enthalpy change was observed to occur at the middle of the specimen with ÎHA-M = 26 J/g on cooling and ÎHM-A = 25.5 J/g on heating, and the enthalpy was found to decrease towards the edge of the specimen due to the decreasing volume of transforming B2-NiTi.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 655, 15 January 2016, Pages 364-371
Journal: Journal of Alloys and Compounds - Volume 655, 15 January 2016, Pages 364-371
نویسندگان
Hafizah Hanim Mohd Zaki, Jamaluddin Abdullah,