The effect of rare-earth oxide addition on the hot-pressing of magnesium silicon nitride

2002 ◽  
Vol 22 (5) ◽  
pp. 777-783 ◽  
Author(s):  
Shukiko Tanaka ◽  
Kiyoshi Itatani ◽  
Hiroshi Uchida ◽  
Mamoru Aizawa ◽  
Ian J Davies ◽  
...  
Keyword(s):  
Rare Earth ◽  
Silicon Nitride ◽  
Hot Pressing ◽  
Rare Earth Oxide ◽  
Oxide Addition

ChemInform Abstract: Hot Pressing of Silicon Nitride with Mixed Rare-Earth Oxide Additives

ChemInform ◽  
1988 ◽  
Vol 19 (33) ◽  
Author(s):  
E. RAPOPORT ◽  
C. BRODHAG ◽  
F. THEVENOT
Keyword(s):  
Rare Earth ◽  
Silicon Nitride ◽  
Hot Pressing ◽  
Rare Earth Oxide

scholarly journals Effects of rare earth oxide addition on NdFeB magnets.

1987 ◽  
Vol 11 (2) ◽  
pp. 235-238 ◽  
Author(s):  
K. Ohashi ◽  
T. Yokoyama ◽  
Y. Tawara
Keyword(s):  
Rare Earth ◽  
Rare Earth Oxide ◽  
Ndfeb Magnets ◽  
Oxide Addition

Fracture Toughness of Si3N4 Based Ceramics with Rare-Earth Oxide Sintering Additives

2009 ◽  
Vol 409 ◽  
pp. 377-381 ◽  
Author(s):  
Peter Tatarko ◽  
Štefánia Lojanová ◽  
Ján Dusza ◽  
Pavol Šajgalík
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Aspect Ratio ◽  
Rare Earth Oxide ◽  
Rare Earth Oxides ◽  
Crack Deflection ◽  
Indentation Fracture ◽  
Toughening Mechanisms ◽  
Sintering Additives

Fracture toughness of hot-pressed silicon nitride and Si3N4+SiC nanocomposites prepared with different rare-earth oxides (La2O3, Sm2O3, Y2O3, Yb2O3, Lu2O3) sintering additives have been investigated by Chevron Notched Beam, Indentation Strength and Indentation Fracture techniques. The fracture toughness values of composites were lower due to the finer microstructures and the lack of toughening mechanisms. In the Si3N4 with higher aspect ratio (Lu or Yb additives) crack deflection occurred more frequently compared to the Si3N4 doped with La or Y, which was responsible for the higher fracture toughness.

Fabrication and Properties of Si3N4 with Rare Earth Apatite Grain Boundary Phases

1992 ◽  
Vol 287 ◽  
Author(s):  
Terry N. Tiegs ◽  
Stephen D. Nunn ◽  
Kristin L. Ploetz ◽  
Paul A. Menchoffer ◽  
Claudia A. Walls
Keyword(s):  
Rare Earth ◽  
Silicon Nitride ◽  
Grain Boundary ◽  
Ambient Temperature ◽  
Rare Earth Oxide ◽  
High Toughness ◽  
The Rare Earth

ABSTRACTThe rare earth-oxide and nitride apatites were examined as grain boundary phases in silicon nitride to assess their potential for developing high toughness materials using gas-pressuresintering. Densification was dependent on the quantity of additives used with high densities achieved at equivalent oxygen contents of ∼8%. Fracture toughnesses (KIc) up to 8-10 MPa√m were obtained for some compositions. Ambient temperature flexural strengths were in the range of 400-720 MPa; however, the strengths atelevated temperatures (1200ºC) were reduced from these values.

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