Effect of Porosity on Hertzian Contact Damage in Silicon-Nitride Ceramics

2008 ◽  
pp. 65-70
Author(s):  
J.H. She ◽  
J.F. Yang ◽  
Y. Beppu ◽  
T. Ohji
Keyword(s):  
Silicon Nitride ◽  
Hertzian Contact ◽  
Contact Damage ◽  
Nitride Ceramics

Hertzian contact damage in silicon nitride ceramics with different porosity contents

2015 ◽  
Vol 35 (8) ◽  
pp. 2269-2276 ◽  
Author(s):  
N. Azeggagh ◽  
L. Joly-Pottuz ◽  
D. Nélias ◽  
J. Chevalier ◽  
M. Omori ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Hertzian Contact ◽  
Contact Damage ◽  
Nitride Ceramics

STRENGTH DEGRADATIONS FROM HERTZIAN CONTACT DAMAGES IN NITRIDED PRESSURELESS SINTERED SILICON NITRIDE CERAMICS

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1819-1826 ◽  
Author(s):  
KIL HO GUAHK ◽  
IN SUB HAN ◽  
KEE SUNG LEE
Keyword(s):  
Silicon Nitride ◽  
Hard Spheres ◽  
Continuous Process ◽  
Theoretical Models ◽  
Strength Loss ◽  
Indentation Load ◽  
Hertzian Contact ◽  
Pressureless Sintering ◽  
Nitride Ceramics ◽  
Number Of Cycles

Strength degradations in silicon nitride ceramics subject to damage from contact with hard spheres are investigated. Strengths against indentation load, number of cycles in contact, or stress-rate parameter are reported and compared with theoretical models. Silicon nitride ceramics are prepared by nitride pressureless sintering (NPS) process, which process is the continuous process of nitridation reaction of Si metal combined with subsequent pressureless sintering. Microstructure characterizations reveal silicon nitride fabricated by NPS process exhibits a quasi-plastic mode, with continuous strength loss beyond a load above the onset of yield, and falloff at high number of cycles, > 105 at contact load, P = 950 N , using WC sphere r = 1.98 mm . The strength degradation is substantially faster by dynamic fatigue. Failures originated from contact damages, quasi-plastic microcrack zones, with developing radial cracks during strength test. The implication is that quasi-plastic damage of NPS silicon nitride itself can preserve benefits from the inherent higher damage tolerance at lower number of cycles of contacts, but fatigue susceptibility at multicycle contacts and lower stressing rate.

Hertzian contact damage in a highly porous silicon nitride ceramic

2003 ◽  
Vol 23 (8) ◽  
pp. 1193-1197 ◽  
Author(s):  
Jihong She ◽  
Jian-Feng Yang ◽  
Yoshihisa Beppu ◽  
Tatsuki Ohji
Keyword(s):  
Silicon Nitride ◽  
Porous Silicon ◽  
Hertzian Contact ◽  
Contact Damage ◽  
Silicon Nitride Ceramic ◽  
Highly Porous

Effect of microstructural coarsening on Hertzian contact damage in silicon nitride

1995 ◽  
Vol 30 (4) ◽  
pp. 869-878 ◽  
Author(s):  
Hockin H. K. Xu ◽  
Lanhua Wei ◽  
Nitin P. Padture ◽  
B. R. Lawn ◽  
R. L. Yeckley
Keyword(s):  
Silicon Nitride ◽  
Hertzian Contact ◽  
Contact Damage ◽  
Microstructural Coarsening

Contact Damage and Strength Degradation in Nitrided Pressureless Sintered (NPS) Silicon Nitrided Ceramics

2007 ◽  
Vol 353-358 ◽  
pp. 102-105
Author(s):  
Chang Gyu Kang ◽  
Chul Kim ◽  
Tae Woo Kim ◽  
In Sub Han ◽  
Kee Sung Lee
Keyword(s):  
Silicon Nitride ◽  
Cost Effective ◽  
Strength Degradation ◽  
Pressureless Sintering ◽  
Contact Damage ◽  
Damage Resistance ◽  
Plastic Damage ◽  
Nitride Ceramics ◽  
Damage Response ◽  
Bend Tests

A study is made of the damage resistance and strength degradation of nitrided pressureless sintered (NPS) silicon nitride ceramics. The silicon nitride is prepared by cost-effective NPS process combining by nitridation and consecutive pressureless sintering. Contact testing with spherical indenters is used to characterize the damage response. Examination of the indentation sites indicates a quasi-plastic damage modes are observed. Bend tests on specimens containing quasi-plastic contact damages reveal those materials to be not susceptible to strength degradation.

Effect of Grain Boundary Phase on Contact Damage Resistance of Silicon Nitride Ceramics

2005 ◽  
Vol 287 ◽  
pp. 421-426 ◽  
Author(s):  
Chul Seung Lee ◽  
Kee Sung Lee ◽  
Shi Woo Lee ◽  
Do Kyung Kim
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Grain Morphology ◽  
Boundary Phase ◽  
Contact Damage ◽  
Damage Resistance ◽  
Intergranular Phase ◽  
Nitride Ceramics ◽  
Damage Response ◽  
Different Types

Contact damage resistances of silicon nitride ceramics with various grain boundary phases are investigated in this study. The grain boundary phases are controlled by the addition of different types of sintering additives, or the crystallization of intergranular phase in a silicon nitride. We control the microstructures of materials to have similar grain sizes and the same phases to each other. Contact testing with spherical indenters is used to characterize the damage response. The implication is that the grain boundary phase can be another controllable factor against contact damage and strength degradation even though it is not critical relative to the effect of grain morphology.

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