Ordered coalescence of nanocrystallites contributing to the rapid anisotropic grain growth in silicon nitride ceramics

2013 ◽  
Vol 69 (3) ◽  
pp. 270-273 ◽  
Author(s):  
Jianfeng Hu ◽  
Zhijian Shen
Keyword(s):  
Silicon Nitride ◽  
Grain Growth ◽  
Nitride Ceramics

Influence of additives on anisotropic grain growth in silicon nitride ceramics

2006 ◽  
Vol 422 (1-2) ◽  
pp. 85-91 ◽  
Author(s):  
P.F. Becher ◽  
G.S. Painter ◽  
N. Shibata ◽  
R.L. Satet ◽  
M.J. Hoffmann ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Grain Growth ◽  
Nitride Ceramics

Sintering of Dense Silicon Nitride Ceramics at Low Temperature

2006 ◽  
Vol 45 ◽  
pp. 1717-1722 ◽  
Author(s):  
José Carlos Bressiani ◽  
Luis Antonio Genova
Keyword(s):  
Silicon Nitride ◽  
Low Temperature ◽  
Grain Growth ◽  
Apparent Density ◽  
Theoretical Density ◽  
Efficient Separation ◽  
Nitride Ceramics

Densification curves of silicon nitride specimens with varying composition were determined with the aid of a dilatometer and these curves are presented in this paper. A novel procedure has been used to determine the densification curves as well as the temperature at which the rate of densification was highest. From these data, sintering profiles have been proposed to produce silicon nitride based ceramics with high apparent density (above 96% of theoretical density) at temperatures as low as 1520º C, with incipient grain growth. This procedure also enabled efficient separation of the densification and grain growth phenomena and it can be used in other two-step sintering studies.

Grain growth in millimeter wave sintered silicon nitride ceramics

2004 ◽  
Vol 24 (12) ◽  
pp. 3337-3343 ◽  
Author(s):  
M. Hirota ◽  
M.C. Valecillos ◽  
M.E. Brito ◽  
K. Hirao ◽  
M. Toriyama
Keyword(s):  
Silicon Nitride ◽  
Grain Growth ◽  
Millimeter Wave ◽  
Nitride Ceramics ◽  
Sintered Silicon

Grain boundary glassy phase and abnormal grain growth of silicon nitride ceramics

2001 ◽  
Vol 27 (5) ◽  
pp. 603-605 ◽  
Author(s):  
Haitao Yang ◽  
Lin Gao ◽  
Gangqin Shao ◽  
Runze Xu ◽  
Peiyun Huang
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Grain Growth ◽  
Glassy Phase ◽  
Abnormal Grain Growth ◽  
Nitride Ceramics

Fabrication of Nanocrystalline Dense Silicon Nitride Ceramics

2012 ◽  
Vol 715-716 ◽  
pp. 738-738
Author(s):  
Hai Doo Kim ◽  
Seong Hyeon Hong
Keyword(s):  
Grain Size ◽  
Silicon Nitride ◽  
Grain Growth ◽  
Oxygen Content ◽  
High Surface ◽  
Full Density ◽  
Microstructural Development ◽  
Nitride Powder ◽  
Nitride Ceramics ◽  
Silicon Nitride Powder

Since the properties of the bulk ceramics are dependent on the grain size the ceramic materials with nanoscale grain size is of interest. Sintering of nanosized powder compacts to full density with minimum grain growth is a difficult task to achieve due to its high surface energy. Two step sintering methode was developed to enhance densification with minimum grain growth for silicon nitride ceramics with liquid phase. Starting with nano-sized silicon nitride powder two step sintering methode gives rise to a very fine-grained b-Si3N4 matrix with large agglomerated Si2N2O grains due to its high surface oxygen content. Addition of Y2O3 shifts the composition point to a primary phase field with no Si2N2O, gives rise to b-Si3N4 with nano scale grain size and near full density. Carbothermal reduction method was employed to reduce the oxygen content in nano-sized silicon nitride powder to give nanocrystalline dense silicon nitride ceramics without Si2N2O formation. Use of SPS was effective to suppress the grain growth and to give near full density. Microstructural development and mechanical properties will be reported.

Grain Growth Behavior of Fine-Grained Silicon Nitride Ceramics

1996 ◽  
Vol 204-206 ◽  
pp. 515-520 ◽  
Author(s):  
H. Hirotsuru ◽  
Mamoru Mitomo ◽  
Toshiyuki Nishimura
Keyword(s):  
Silicon Nitride ◽  
Grain Growth ◽  
Growth Behavior ◽  
Fine Grained ◽  
Nitride Ceramics ◽  
Grain Growth Behavior

Microstructural Design and Control of Silicon Nitride Ceramics

MRS Bulletin ◽  
1995 ◽  
Vol 20 (2) ◽  
pp. 38-41 ◽  
Author(s):  
Mamoru Mitomo ◽  
Naoto Hirosaki ◽  
Hideki Hirotsuru
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Grain Growth ◽  
Processing Parameters ◽  
Microstructural Development ◽  
Nitride Ceramics ◽  
Microstructural Design ◽  
And Control

The improvement of mechanical properties by microstructural control has been one of the main topics of interest in the development of silicon nitride ceramics. Toughening, by developing an in situ composite or self-reinforced microstructure, has attracted particular attention.Microstructural design is a key factor in the optimization of processing parameters. The microstructures of sintered materials are composed of silicon nitride grains and grain boundaries, which can be either crystalline, amorphous, or partially crystalline, depending on the composition, amount of sintering additives, and processing parameters. Silicon nitride ceramics have been fabricated with an addition of metal oxides and rare-earth oxides that form a liquid phase during sintering and accelerate grain boundary diffusion. The effect of composition of the glassy phase on the mechanical properties of ceramics is presented by Becher et al. and Hoffmann elsewhere in this issue. This article focuses specifically on the design and control of grain size.As it is well recognized, many processing parameters affect grain growth behavior and the resulting microstructure. During sintering, the α- to β-phase transformation leads to a self-reinforcing microstructure on account of the anisotropic grain growth of the stable hexagonal β- Si3N4 phase. Therefore, α-rich powders are widely used for starting materials. Phase transformation accelerates anisotropic grain growth, resulting in an increase in the fracture toughness of Si3N4 ceramics. Kang and Han discuss the effect of phase transformation on nucleation and grain growth in an article in this issue. The effect of the grain-size distribution on microstructural development is described in this article, based on studies conducted mostly with β-Si3N4 powders.

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