Conferences

Mechanical behavior and electrical conductivity of zinc-oxideceramics

   
О.О.Bochechka 2,
 
А.І.Chernienko 2,
 
Е.М.Lutsak 2
 

1 I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Kyiv
2 V. Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine, Kyiv
oleynik@ipms.kiev.ua

Usp. materialozn. 2020, 1:114-126
https://doi.org/10.15407/materials2020.01.114

Abstract

Results of an electron microscopic investigation of particles of lonsdaleite powder with additives of cubic diamond and polycrystalline specimens based on it at Р = 7,7 GPa in the temperature range 1700—1900 °С are presented. Lonsdaleite particles are characterized by a predominantly ternary texture [1120] l of different degree of perfection. Structural mechanisms of transformations in lonsdaleite particles, which cause the formation on nanograined structure in sintering, have been established. The initial stage is the mechanical dispersion of particles and dispersion as a result of plastic faulting deformation, which promotes their fragmentation without breakdown of continuity. The indicated processes lead to the destruction of texture in particles. Beginning from 1700 °С, the lonsdaleite →cubic diamond phase transformation with the orientation ratio (111) d || (001) l occurs. It is realized within rods as elements of the substructure of lonsdaleite. At 1900 °С, the size of detected elements of the structure (grains) is 5—15 nm. Beginning from 2000 °С, the self-association of such grains into aggregates with sizes up to 70 nm and the subsequent process of coalescence of grains in aggregates with the formation of the monocrystalline state occur. The next stage of formation of the granular structure is caused by the formation of grain boundaries and development of collective recrystallization. After sintering at Т = 2100 °С, the grain size in specimens does not exceed 100 nm. It has been established that the transformation in lonsdaleite proceeds by structural mechanisms that are characteristic of wurtzite modifications of boron nitride and silicon carbide (strong disordering in the direction of the basal axis, plastic faulting deformation, and formation of multilayer polytypes during the hexagonal-to-cubic phase transformation).


Download full text

COALESCENCE, FRAGMENTATION, GRAIN, LONSDALEITE, PARTICLES, SINTERING

References

1. Liu J., Zhan G., Wang Y., Yan X., Liu F., Wang P., Lei L., Peng F., Kou Z., Xe D. Superstrong micro-grained polycrystalline diamond compact through work hardening under high pressure. Appl. Phys. Lett. 2018. Vol. 112. P. 61901.
https://doi.org/10.1063/1.5016110

2. Oliinyk H.S., Yaroshch V.V., Danylenko M.V. Vplyv udarnoi poperednoi obrobky vykhidnykh poroshkiv almazu na formuvannia mikrostruktury polikrystalichnykh materialiv na yoho osnovi [Influence of the shock pretreatment of initial diamond powders on the formation of the microstructure of polycrystalline materials based on it]. Nadtverdi materialy. 2000. No. 1. P. 12-21 [in Russian].

3. Bochechka O.O. Fizyko-khimichni osnovy spikannia almaznykh poroshkiv pid diieiu vysokoho tysku ta vysokoi temperatury [Physico-chemical fundamentals of sintering of diamond powders under the action of high pressure and high temperature]. Kіev: Nauk. dumka, 2019. 238 p.[in Ukrainian].

4. Oliinyk H.S., Kotko A.V. Samoorhanizatsiia chastynok ultradyspersnoho almazu v umovakh nahrivu pry vysokomu tysku [Self-organization of ultrafine diamond particles under the conditions of high pressure heating]. Lysty v ZhTF. 2008. Vol. 34, No. 15. P. 55-61 [in Russian].

5. Oliinyk H.S., Kotko A.V., Trofimova L.M. Osoblyvosti formuvannia zeren struktury v kompaktnykh materialakh na osnovi vykhidnykh poroshkiv almazu dynamichnoho syntezu [Features of formation of the grain structure in compact materials based on initial diamond powders obtained by dynamic synthesis]. Elektronna mikroskopiia i mitsnist materialiv. Kiev: In-t probl. materialovedeniia NAN Ukrainy. 2006. Issue 13. P. 160-170 [in Russian].

6. Irifune T., Kurio A., Sakamoto S., Inoue T., Samiya H. Ultrahard polycrystalline diamond from graphite. Nature. 2003. Vol. 421. P. 599-600.
https://doi.org/10.1038/421599b

7. Samiya H., Irifune N. Microstructure and mechanical properties of hardness nano-polycrystalline diamonds. Sci. Technical. Rev. 2008. No. 66. P. 85-92.

8. Samiya H., Irifune N., Kurio F., Sakamoto S., Inoue T. Microstructure features of polycrystalline diamond synthesized directly from graphite under static high pressure. J. Mater. Sci. 2004. Vol. 39. P. 445-450.
https://doi.org/10.1023/B:JMSC.0000011496.15996.44

9. Huang Q., Yu D., Xu W., Ma Y., Wang Y. Nanotwinned diamond with unprecedented hardness and stability. Nature. 2014. Vol. 510 (7504). P. 250-243.
https://doi.org/10.1038/nature13381

10. Tang H., Yan X., Yu P., Hu Q., Wang Y., Wu L., Zou Q., Ke Y., Zhao Y. Revealing the formation mechanism of ultrahard nanotwinned diamond from onion carbon. Carbon. 2018
https://doi.org/10.1016/j.carbon.2017.12.027

doi: 190.1016/j. carbon. 2017.123.027.
https://doi.org/10.1152/japplphysiol.00570.2017

11. Oliinyk H.S., Danylenko M.V. Plastychna frahmentatsiia krystaliv 2NBN i 6NSiC pry termobarychnii obrobtsi [Plastic fragmentation of 2HBN and 6HSiC crystals during thermobaric treatment]. Krystalohrafiia. 2002. No. 6. P. 906-913 [in Russian].

12. Oliinyk H.S. Strukturni peretvorennia pry formuvanni nadtverdykh materialiv na osnovi vykhidnykh poroshkiv viurttsytnoho nitrydu boru [Structural transformations in the formation of superhard materials based on the wurtzitic boron nitride initial powders]. Nadtverdi materialy. 2012. No. 1. P. 3-26 [in Russian].

13. Kurdiumov O.V., Sliesariev V.N., Ostrovska N.F. Osoblyvosti struktury ta mekhanizm formuvannia lonsdeilita [Features of the structure and mechanism of formation of lonsdaleite]. Dop. AN SRSR. 1980. Vol. 255, No. 6. P. 1382-1385 [in Russian].