TY - JOUR
T1 - Syntheses of full-density nanocrystalline titanium nitride compacts by plasma-activated sintering of mechanically reacted powder
AU - Sherif El-Eskandarany, M.
AU - Omori, M.
AU - Konno, T. J.
AU - Sumiyama, K.
AU - Hirai, T.
AU - Suzuki, K.
N1 - Funding Information:
Part of the present work was achieved when the first author was at his former address. The authors thank the referee for the critical suggestions. We also thank Messrs. Y. Murakami and S. Ito for their kind technical support during the SEM and TEM observations. One of the authors (MSE) thanks Ms. Mitsuko El-Eskandarany for her kind support during the metallographical preparations. This work was partially supported by a Grant-in-Aid for Co-operative Research (07305033), given by the Ministry of Education, Science, Sports and Culture, Japan.
PY - 1998
Y1 - 1998
N2 - Nearly equiatomic nanocrystalline titanium nitride'(Ti56N44) powder with an average grain size of 5 nm has been synthesized by ball milling elemental Ti powder under nitrogen gas flow at room temperature. During the first stage of reactive ball milling (RBM) (time < 3.6 ks), the metallic Ti powder tends to agglomerate to form powder particles with a larger diameter. At the second stage (3.6 to 22.0 ks), the agglomerated particles of Ti fragment to form smaller particles. These smaller particles that have new or fresh surfaces begin to react with the milling atmosphere (nitrogen) during the third stage of milling (22 to 86 ks) to form TiN powder coexisting with unreacted Ti powder. Toward the end of milling (86 to 173 ks), a single phase of nanocrystalline TiN (NaCl structure) is obtained. The powder of this end-product has a spherical-like morphology with an average particle size of about 0.4 μm diameter. A sintering procedure using plasma activation has been employed to consolidate the powder particles at several stages of the RBM. The as-milled and as-consolidated powders have been characterized as a function of the RBM time by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), optical metallography, and chemical analyses. Density measurements of the consolidated samples show that after 86 to 173 ks of the RBM time, the compacted samples are essentially fully dense (above 96 pct of the theoretical density for TiN). The results also show that the consolidated TiN compacts still maintain their unique nanocrystalline properties with an average grain size of about 65 nm. The hardness and some mechanical properties of the consolidated TiN compacts have been determined as a function of the RBM time.
AB - Nearly equiatomic nanocrystalline titanium nitride'(Ti56N44) powder with an average grain size of 5 nm has been synthesized by ball milling elemental Ti powder under nitrogen gas flow at room temperature. During the first stage of reactive ball milling (RBM) (time < 3.6 ks), the metallic Ti powder tends to agglomerate to form powder particles with a larger diameter. At the second stage (3.6 to 22.0 ks), the agglomerated particles of Ti fragment to form smaller particles. These smaller particles that have new or fresh surfaces begin to react with the milling atmosphere (nitrogen) during the third stage of milling (22 to 86 ks) to form TiN powder coexisting with unreacted Ti powder. Toward the end of milling (86 to 173 ks), a single phase of nanocrystalline TiN (NaCl structure) is obtained. The powder of this end-product has a spherical-like morphology with an average particle size of about 0.4 μm diameter. A sintering procedure using plasma activation has been employed to consolidate the powder particles at several stages of the RBM. The as-milled and as-consolidated powders have been characterized as a function of the RBM time by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), optical metallography, and chemical analyses. Density measurements of the consolidated samples show that after 86 to 173 ks of the RBM time, the compacted samples are essentially fully dense (above 96 pct of the theoretical density for TiN). The results also show that the consolidated TiN compacts still maintain their unique nanocrystalline properties with an average grain size of about 65 nm. The hardness and some mechanical properties of the consolidated TiN compacts have been determined as a function of the RBM time.
UR - http://www.scopus.com/inward/record.url?scp=0032115183&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032115183&partnerID=8YFLogxK
U2 - 10.1007/s11661-998-0023-3
DO - 10.1007/s11661-998-0023-3
M3 - Article
AN - SCOPUS:0032115183
VL - 29
SP - 1973
EP - 1981
JO - Metallurgical Transactions A (Physical Metallurgy and Materials Science)
JF - Metallurgical Transactions A (Physical Metallurgy and Materials Science)
SN - 1073-5623
IS - 7
ER -