Microstructural Characterization of Silicon Nitride Ceramics Processed by Pressureless Sintering, Overpressure Sintering, and Sinter HIP

2008 ◽  
pp. 603-615 ◽  
Author(s):  
K. R. Selkregg ◽  
K. L. More ◽  
S. G. Seshadri ◽  
C. H. McMurty
Keyword(s):  
Silicon Nitride ◽  
Microstructural Characterization ◽  
Pressureless Sintering ◽  
Nitride Ceramics

Characterization of porous silicon nitride ceramics using bentonite as binder and sintering additive

2009 ◽  
Vol 60 (5) ◽  
pp. 456-460 ◽  
Author(s):  
Guang-Peng Jiang ◽  
Jian-Feng Yang ◽  
Ji-Qiang Gao ◽  
Koichi Niihara
Keyword(s):  
Silicon Nitride ◽  
Porous Silicon ◽  
Sintering Additive ◽  
Nitride Ceramics

Vacuum Heat Treatment of MgO -Densified Pressureless Sintered Silicon Nitride Ceramics

2007 ◽  
Vol 554 ◽  
pp. 107-112 ◽  
Author(s):  
V. Demir ◽  
Derek P. Thompson
Keyword(s):  
Heat Treatment ◽  
Silicon Nitride ◽  
Pressureless Sintering ◽  
Vacuum Heat Treatment ◽  
Sem Images ◽  
Edx Analysis ◽  
Heat Treated ◽  
Nitride Ceramics ◽  
Different Temperatures ◽  
Sintered Silicon

Silicon nitride samples were pressureless sintered with up to 5 w/o MgO to give densities in the range 98-99% of theoretical. After pressureless sintering, selected samples were placed in a vacuum heat treatment furnace surrounded by a carbon bed in a carbon crucible at a pressure of less than 4x10-4 mbar, and vacuum heat treated at different temperatures and times to remove grainboundary glass. The results showed that this was substantially achieved at 1575oC for 3h and that increasing the time to 5 hours gave still further improvement. SEM images, EDX analysis and oxidation tests provided additional evidence for the removal of Mg from the samples.

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.

CHARACTERIZATION OF SUBSURFACE DAMAGE OF EXPLOSIVELY INDENTED SILICON NITRIDE CERAMICS

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1504-1509
Author(s):  
JONG HO KIM ◽  
HANEUL KIM ◽  
DO KYUNG KIM ◽  
SOON NAM CHANG
Keyword(s):  
Silicon Nitride ◽  
Subsurface Damage ◽  
Boundary Phase ◽  
Damage Behavior ◽  
Nitride Ceramics ◽  
Damage Response ◽  
Grain Size And Shape ◽  
Different Grain Size ◽  
Dynamic Damage

In this study, explosive indentations were used to characterize the dynamic damage behavior of silicon nitride ceramics with different microstructures. Three grades of silicon nitrides with different grain size and shape were prepared. Subsurface damage of specimens was characterized extensively using optical and electron microscopy. It was found that the dynamic damage response depends strongly on the microstructure of specimens, particularly on the glassy grain boundary phase.

The preparation of silicon nitride ceramics by gelcasting and pressureless sintering

2016 ◽  
Vol 42 (10) ◽  
pp. 11593-11597 ◽  
Author(s):  
Wenmiao Zeng ◽  
Xueping Gan ◽  
Zhiyou Li ◽  
Kechao Zhou
Keyword(s):  
Silicon Nitride ◽  
Pressureless Sintering ◽  
Nitride Ceramics

Low temperature pressureless sintering of silicon nitride ceramics for circuit substrates in powder electronic devices

2018 ◽  
Vol 44 (4) ◽  
pp. 4375-4380 ◽  
Author(s):  
Yusen Duan ◽  
Jingxian Zhang ◽  
Xiaoguang Li ◽  
Ying Shi ◽  
Jianjun Xie ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Low Temperature ◽  
Electronic Devices ◽  
Pressureless Sintering ◽  
Nitride Ceramics
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