Method for producing silicon nitride reaction sintered body

• US 5,928,601 A
• Filed: 10/17/1997
• Issued: 07/27/1999
• Est. Priority Date: 02/28/1994
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Hamazaki, Kagehisa, Toyoda, Hitoshi, Miyake, Kazumi
• Primary Examiner(s): Fiorilla, Christopher A.
• Application Number:
  US08/953,317
• Time in Patent Office: 648 Days
• Field of Search: 264/647, 264/659, 264/683, 501/97.1
• US Class Current: 264/659
• CPC Class Codes: C04B 35/591 obtained by reaction sintering

Abstract

A silicon nitride reaction-sintered body having a high mechanical strength without surface working can be produced by (1) forming a silicon powder mixture of at least two types of silicon powders having substantially independent particle size distribution ranges into a green body, the silicon powder mixture having an average particle size ranging from 5 μm to 300 μm; (2) heating the green body in a nitrogen-containing atmosphere for nitrogenation; and (3) sintering the nitrogenated green body at a temperature of 1900° C. or higher.

Claims

1. A method for producing a silicon nitride reaction-sintered body comprising the steps of (1) mixing a silicon powder mixture having an average particle size of 5 μ

m to 300 μ

m with a sintering aid;

(2) forming the resultant powder mixture into a green body;

(3) nitrogenating said green body in an atmosphere of nitrogen and 20% or less of hydrogen for nitrogenation; and

(4) sintering the nitrogenated green body;

wherein said silicon powder mixture comprises a first silicon powder and a second silicon powder having substantially independent particle size distribution ranges which do not substantially overlap with each other, such that said first and second silicon powders when mixed form a bimodal particle size distribution.

2. The method according to claim 1, wherein said first silicon powder possesses an average particle size ranging from 20 μ

m to 50 μ

m, said second silicon powder possesses an average particle size ranging from 2 μ

m to 5 μ

m, and said first and second powders are mixed to form said silicon powder mixture.