التفاصيل البيبلوغرافية
| العنوان: |
High-Pressure Synthesis of Bulk Cobalt Cementite, Co 3 C |
| المؤلفون: |
Paul V. Marshall (11593199), Zeynep Alptekin (11593202), Scott D. Thiel (11593205), Dean Smith (3115575), Yue Meng (1635511), James P. S. Walsh (9924989) |
| سنة النشر: |
1753 |
| المجموعة: |
Smithsonian Institution: Digital Repository |
| مصطلحات موضوعية: |
Biophysics, Medicine, Space Science, Biological Sciences not elsewhere classified, Chemical Sciences not elsewhere classified, promising magnetic properties, promising new route, energy stoichiometric phases, dimensional thin film, 237 gpa (<, type cobalt carbide, type ) consistent, experimental bulk modulus, bulk cobalt cementite, p , calculated formation enthalpy, c decreases steadily, 3 , 2 , ambient pressures <, results using high, 0 , dimensional phases, situ <, route toward, results offer, pnnm <, pnma <, metastable cementite, k < |
| الوصف: |
Transition metal carbides find use in a wide range of advanced high-resilience applications including high-strength steels, heat shields, and deep-earth drills. However, carbides of the mid-to-late transition metals remain difficult to isolate and characterize on account of their metastability, which precludes the preparation of high-quality bulk single crystal samples using traditional solid-state methods. Herein, we report a combined computational and experimental survey of the cobalt–carbon binary system under high pressures and demonstrate that pressure offers a route toward the bulk synthesis of the metastable cementite-type cobalt carbide, Co 3 C, which under ambient conditions can only be prepared in low-dimensional thin film or nanoparticle forms. First-principles calculations reveal two competitive low-energy stoichiometric phases under ambient pressures Pnnm -Co 2 C (Fe 2 C-type) and Pnma -Co 3 C (Fe 3 C-type)consistent with the known low-dimensional phases that have been studied for their promising magnetic properties. However, the calculated formation enthalpy of Pnma -Co 3 C decreases steadily with the applied pressure, while that of Pnnm -Co 2 C increases. We pursue these results using high-pressure laser-heated synthesis methods coupled with in situ X-ray diffraction and observe the formation of Pnma -Co 3 C above 4.8 GPa. We determine the experimental bulk modulus of Co 3 C to be K 0 = 237 GPa ( K p = 4.0). First-principles calculations of the phonon modes in Co 3 C reveal dynamical instabilities at ambient pressure that are absent under compression. These results offer a promising new route for the synthesis of rare-earth-free magnets. |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
unknown |
| العلاقة: |
https://figshare.com/articles/journal_contribution/High-Pressure_Synthesis_of_Bulk_Cobalt_Cementite_Co_sub_3_sub_C/16850531Test |
| DOI: |
10.1021/acs.chemmater.1c03092.s001 |
| الإتاحة: |
https://doi.org/10.1021/acs.chemmater.1c03092.s001Test |
| حقوق: |
CC BY-NC 4.0 |
| رقم الانضمام: |
edsbas.B1921BDF |
| قاعدة البيانات: |
BASE |
