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Silicon nitride based sintered material and method for producing the same, and molten-metal-resistant member and wear-resistant member using the same

A manufacturing method and silicon nitride technology are applied in the fields of silicon nitride sintered body and its manufacture, and wear-resistant components, which can solve the problems of decreased thermal shock resistance, cracks, decreased mechanical strength, etc.

Active Publication Date: 2008-07-30
KYOCERA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the stress-concentrated metal silicide becomes a source of damage, and cracks are generated between the silicon nitride crystal and the metal silicide, and as a result, there is a problem that the mechanical strength decreases.
[0010] On the other hand, there is also a problem of low thermal shock resistance in a material having a large difference in thermal expansion coefficient between a silicon nitride crystal and a plurality of metal silicides contained therein.
For example, when the silicide of W and the silicide of Fe are included as the metal silicide, the difference in thermal expansion coefficient between the crystal of silicon nitride and the silicide of W, or the crystal of silicon nitride and the silicide of Fe is large. Therefore, When thermal stress is applied to the silicon nitride sintered body by thermal shock, cracks are likely to occur between the silicon nitride crystal and the metal silicide, and the thermal shock resistance decreases

Method used

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  • Silicon nitride based sintered material and method for producing the same, and molten-metal-resistant member and wear-resistant member using the same
  • Silicon nitride based sintered material and method for producing the same, and molten-metal-resistant member and wear-resistant member using the same
  • Silicon nitride based sintered material and method for producing the same, and molten-metal-resistant member and wear-resistant member using the same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0115] Water to the powder (P 1 ), a powder composed of a compound of the second metal element (P 2 ) for wet mixing, and the resulting slurry was dried at 100°C to make a pre-mixed powder (P 12 ). From the pre-mixed powder (P 12 ), silicon nitride (Si 3 N 4 ) powder (average particle size 1 μm, gelatinization rate 90%, Fe impurity content 500ppm) and Si powder (average particle size 3 μm, Fe impurity content 800ppm), further mixed and weighed at the ratio shown in Table 1 sintering aid powder. Here, the content of the raw material powder and the sintering aid powder is made 100% by mass in total. Also, the powder of Table 1 (P 1 ), powder (P 2 ) content is the amount converted into the content of the first and second metal elements, respectively.

[0116] Also, when using Fe 2 o 3 as a powder (P 2 ), powder (P 2 ) is the content of Fe contained in Si powder and silicon nitride powder 2 o 3 The total amount of the content is converted into the amount of Fe. Als...

Embodiment 2

[0135] Iron oxide (Fe 2 o 3 ) powder, WO with an average particle size of 1 μm 3 The powder is wet mixed, and the resulting slurry is dried at 100°C to make a pre-mixed powder (P 12 ). In the pre-mixed powder, silicon nitride (Si 3 N 4 ) powder (average particle size 1μm, gelatinization rate 90%, Fe impurity content 100ppm) and Si powder (average particle size 3μm, Fe impurity content 200ppm), mixed as a sintering aid with an average particle size 1μm the Y 2 o 3 powder, and Al with an average particle size of 0.7 μm 2 o 3 The powder was mixed, granulated, and shaped in the same manner as in Example 1 to obtain a plurality of cylindrical shaped bodies with an outer diameter of 60 mm and a thickness of 45 mm. The obtained molded body was degreased by maintaining at 600° C. for 3 hours in a nitrogen atmosphere. In addition, iron oxide powder, WO 3 powder, silicon nitride powder, Si powder, Y 2 o 3 Powder, Al 2 o 3 The mass ratio of the powder is 1:0.8:10.3:69.3:13...

Embodiment 3

[0145] For iron oxide (Fe 2 o 3 ) powder, WO with an average particle size of 0.4 μm 3 The powders were mixed, and the mass conversion ratio of Fe and W was 1:1. The same as in Example 1, preliminary mixing was carried out to prepare preliminary mixed powder. In this preliminary mixed powder, silicon nitride powder and Si powder were mixed in the same manner as in Example 2, and iron oxide powder was weighed at 1 mass %, 1 mass %, 10 mass %, and 70 mass % (subtotal 82 mass %), respectively. 、WO 3 powder, silicon nitride powder, Si powder (Si 3 N 4 Conversion), as the basic composition.

[0146] Next, change Y with an average particle size of 0.5 μm 2 o 3 Powder, Al with an average particle size of 3 μm 2 o 3 Powder, SiO with an average particle size of 2 μm 2 The amount of the powders was subtotaled to 18% by mass, and then added, and all the powders (total 100% by mass) were mixed and granulated in the same manner as in Example 2, and then shaped and degreased to ma...

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Abstract

A silicon nitride based sintered material which comprises crystals of silicon nitride and a grain boundary layer containing at least two of a first metal silicide (a metal silicide comprising a first metal element of at least one of Fe, Cr, Mn and Cu), a second metal silicide (a metal silicide comprising a second metal element of at least one of W and Mo) and a third metal silicide (a metal silicide comprising plural metal components containing the first metal element and the second metal element, wherein the grain boundary layer has an adjacency phase in which at least two of the first to third metal silicides are adjacent to one another.

Description

technical field [0001] The present invention relates to a silicon nitride sintered body excellent in thermal and mechanical properties. In particular, it relates to a silicon nitride sintered body excellent in thermal shock resistance and mechanical strength, and a method for producing the same. Also, it relates to various members using the silicon nitride sintered body, and particularly relates to a molten metal-resistant member most suitable for metal casting and a wear-resistant member most suitable for a pulverizer. Background technique [0002] A silicon nitride sintered body is a member having excellent thermal and mechanical properties, and has been described in various patent publications or documents. [0003] In particular, a silicon nitride sintered body in which metal silicides such as Fe, W, Cr, and Mo are precipitated in the grain boundary layer (grain boundary layer) of the silicon nitride sintered body for the purpose of improving the mechanical properties h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/591
Inventor 大川善裕织田武广
Owner KYOCERA CORP