Silicon carbide powder, compositions using the same, and methods for producing silicon carbide powder

Abstract

A silicon carbide powder according to the present invention is an aggregate of silicon carbide particles containing the element nitrogen. If the powder is measured in a region down to the depth of 12 nm from an outermost surface by X-ray photoelectron spectroscopy, an integral value of a ratio of a detection intensity of the element nitrogen to a total detection intensity of the element carbon and the element silicon is 0.05 or greater. Moreover, the slope of a change in the ratio thereof is -0.0008 or less. A specific surface area measured using nitrogen is preferably 5 m2 / g to 40 m2 / g. Furthermore, the 50% particle diameter D50 in a quantity distribution measured by observation with a scanning electron microscope is preferably 50 nm to 1000 nm. The present invention also provides a method for manufacturing the silicon carbide powder.

Claims

1. A silicon carbide powder consisting of an aggregate of silicon carbide particles containing the element nitrogen, When measured by X-ray photoelectron spectroscopy in the region from the outermost surface to a depth of 12 nm of the silicon carbide powder, the integral value of the ratio of the detection intensity of nitrogen element P2 to the total detection intensity P1 of carbon and silicon elements (P2 / P1) is 0.05 nm or more and 4.5 nm or less, and the slope of the change in the ratio (P2 / P1) is -0.065 nm -1 or more and -0.0008 nm －１ The following is silicon carbide powder.

2. The silicon carbide powder according to claim 1, wherein the 50% particle size D50 in the particle size distribution based on the number of particles measured by scanning electron microscopy is 50 nm or more and 1000 nm or less.

3. Specific surface area S1 is 5 m ２ / g or more 40m ２ The silicon carbide powder according to claim 1 or 2, wherein the amount is less than or equal to / g.

4. The ratio of nitrogen element content A1 in silicon carbide powder to specific surface area S1 (A1 / S1) is 0.01 (mass %·(g / m²)). ２ )) or more 0.5 (mass%・(g / m ２ )) The silicon carbide powder according to any one of claims 1 to 3, wherein the powder is as follows:

5. A composition comprising silicon carbide powder according to any one of claims 1 to 4 and a dispersion medium.

6. A ceramic material comprising a fired product of the composition described in claim 5.

7. The process involves continuously supplying a mother powder containing silicon and carbon elements, along with a plasma gas, to a plasma flame generated in a chamber using a DC plasma torch to gasify the mother powder, and then cooling the gasified mother powder with a cooling gas to produce silicon carbide powder. The process is performed while nitrogen gas is present in the chamber and the pressure inside the chamber is maintained at a negative pressure lower than atmospheric pressure. The plasma frame is in a laminar flow state where, when observed from the side where the frame width is observed to be the widest, the aspect ratio of the frame length to the frame width is 3 or more. The aforementioned plasma gas is a mixture of nitrogen gas and argon gas. The cooling gas is nitrogen gas at 0°C or higher and 30°C or lower, in a method for producing silicon carbide powder. A method for producing silicon carbide powder, wherein, when measured by X-ray photoelectron spectroscopy in a region from the outermost surface to a depth of 12 nm, the integral value of the ratio of the detection intensity of nitrogen element P2 to the total detection intensity P1 of carbon and silicon elements (P2 / P1) is 0.05 nm or more and 4.5 nm or less, and the slope of the change in the ratio (P2 / P1) is -0.065 nm -1 or more and -0.0008 nm -1 or less.

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