Densification of silicon nitride with alumina and yttria or ytterbia sintering aids

2003 ◽  
Vol 58 (2) ◽  
pp. 34
Keyword(s):  
Silicon Nitride ◽  
Sintering Aids

Tensile Creep of Y-Si3N4: II. Cavitation

1991 ◽  
Vol 49 ◽  
pp. 972-973 ◽  
Author(s):  
B. J. Hockey ◽  
S. M. Wiederhorn
Keyword(s):  
Silicon Nitride ◽  
Creep Rupture ◽  
Tensile Creep ◽  
Sintering Aids ◽  
Microstructural Changes

ATEM has been used to characterize three different silicon nitride materials after tensile creep in air at 1200 to 1400° C. In Part I, the microstructures and microstructural changes that occur during testing were described, and consistent with that description the designations and sintering aids for these materials were: W/YAS, a SiC whisker reinforced Si3N4 processed with yttria (6w/o) and alumina (1.5w/o); YAS, Si3N4 processed with yttria (6 w/o) and alumina (1.5w/o); and YS, Si3N4 processed with yttria (4.0 w/o). This paper, Part II, addresses the interfacial cavitation processes that occur in these materials and which are ultimately responsible for creep rupture.

Heterogeneous Formation of Oriented Silicon Oxynitride on α-Si3N4 Seed Crystals : Habits And Radiation Stability

1999 ◽  
Vol 5 (S2) ◽  
pp. 778-779
Author(s):  
R.W Carpenter ◽  
W Braue ◽  
M.J. Kim
Keyword(s):  
Silicon Nitride ◽  
Heterogeneous Nucleation ◽  
Radiation Stability ◽  
Silicon Oxynitride ◽  
Minor Constituent ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Nucleation Sites ◽  
Heterogeneous Formation ◽  
A Minor

Lath-like silicon oxynitride crystals have often been observed in the microstructure of silicon nitride based ceramics after processing. They are usually located in glassy regions which are siliceous solidified sintering aid liquid, and usually contain a small (∼100nm) a-Si3N4 crystal. These nitride crystals are considered to be seeds, incompletely dissolved in the melt, that are heterogeneous nucleation sites for the oxynitride crystals. We present here the first observations of morphological and crystallographic habits between the seed nanocrystals and the host oxynitride laths.Fig. 1 shows a typical oxynitride lath containing a nitride seed crystal. The lath is surrounded by glass and ß-Si3N4 particles, and a small cristobalite particle (a minor constituent). This microstructure is from an Si02-Si3N4 ceramic processed with Al2O3 sintering aid. The same oxynitride lath/seed structures were observed when other sintering aids (eg. Y2O3, MgO, ZrO2) were used, so they are independent of sintering aid.

The effect of nano-sized sintering aids on toughening behavior of silicon nitride

2008 ◽  
Vol 43 (8) ◽  
pp. 2799-2805 ◽  
Author(s):  
Sriharsha Pasupuleti ◽  
Ramseshu Peddetti ◽  
Sridhar Santhanam ◽  
Kei-Peng Jen ◽  
Zachary N. Wing ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Sintering Aids

Analysis of Internal Friction on Silicon Nitride with Visco-Elastic Model

2006 ◽  
Vol 317-318 ◽  
pp. 429-432 ◽  
Author(s):  
Shuji Sakaguchi
Keyword(s):  
Relaxation Time ◽  
Silicon Nitride ◽  
Internal Friction ◽  
Temperature Dependence ◽  
Creep Deformation ◽  
Maxwell Model ◽  
Elastic Model ◽  
Sintering Aids ◽  
Characteristic Peak ◽  
Nitride Ceramics

Temperature dependence of internal friction on silicon nitride ceramics with yttria and alumina sintering aids was discussed using 4-elements visco-elastic model. It is known that the internal friction of this ceramic material shows a characteristic peak at around 1040 oC and an exponential increase over 1200 oC. This temperature dependence of internal friction was well approximated with using parallel Maxwell model. The parameters for this model and the relaxation time on this model were obtained. The relaxation time was very short, compared to the transient creep deformation of this ceramics. The analyzed results on internal friction could not be related with the creep deformation.

Non-Oxide Additives As Sintering Aids For Si3N4-Based Ceramics

1992 ◽  
Vol 287 ◽  
Author(s):  
C. Ge ◽  
Y. Xia ◽  
L. Chen
Keyword(s):  
Silicon Nitride ◽  
Sintering Aids ◽  
Combined Use ◽  
Work Done

ABSTRACTThis article is a review of the selected activities since 1979 in using non-oxide additives as sintering aids for silicon nitride. Emphasis was placed on the work done in the authors' laboratory, and it is shown that ZrN and AIN in combined use can result in producing silicon nitride with good properties.

Effects of Sintering Conditions and Additives on Translucent Silicon Nitride Ceramics

2012 ◽  
Vol 724 ◽  
pp. 282-286 ◽  
Author(s):  
Wen Wu Yang ◽  
Miki Inada ◽  
Yumi Tanaka ◽  
Naoya Enomoto ◽  
Junichi Hojo
Keyword(s):  
Silicon Nitride ◽  
Visible Region ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Sintering Additives ◽  
Nitride Ceramics ◽  
Sintering Conditions

Translucent β-Si3N4 sintered ceramics have been fabricated by using AlN-MgO sintering additives. In the present study, the authors employed AlN-MgO as a standard sintering aid, and investigated the effects of sintering conditions on the translucency of Si3N4. Furthermore, various oxides such as HfO2, Sm2O3, Y2O3, Sc2O3, La2O3, Nd2O3, CeO2, CaO, ZrO2 etc. were used as the sintering aids of Si3N4, and the sintered β-Si3N4 ceramics exhibited different transmittances in the visible region. It was found that the transmittance of sintered ceramics was mainly affected by the sintering additives.

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