Silicon carbide carbonized complex phase ceramic sealing material and preparation method thereof

Abstract

The invention relates to a silicon carbide carbonized complex phase ceramic sealing material, which comprises the following component in portion by weight: 100 portions of silicon carbide powder, 0.1 to 1 portion of boron carbide, 5 to 30 portions of carbon powder, 0.5 to 3 portions of binding agent PVA, and 0.5 to 1.5 portions of dispersing agent. A preparation method comprises the following steps in turn: (1) blending the raw materials in proportion and then adding the mixture into deionized water, and after ball milling and mixing, preparing the mixture into a water-based silicon carbide composite slurry of which the solid phase weight content is between 40 and 60 percent; (2) adopting a spraying granulating process to perform spray drying on the slurry to obtain silicon carbide granulated powder; (3) adopting a two-step mode of 140 MPa dry pressing pre-compaction and 200 MPa isostatic cool pressing final compaction to carry out forming on the granulated powder to obtain a high-density sealing material blank; and (4) putting the blank into a vacuum pressureless sintering furnace, raising the temperature to between 2,000 and 2,100 DEG C, keeping the temperature for 1 to 1.5 hours, and sintering the blank to obtain the silicon carbide carbonized complex phase ceramic sealing material.

Description

technical field [0001] The invention relates to a silicon carbide plus carbon (SiC / C) composite ceramic sealing material and a preparation method thereof. Background technique [0002] In order to meet the special requirements of mechanical seals such as zero leakage, low wear, long life, torque and followability, the mechanical seal material must have high strength, high elastic modulus (stiffness), high hardness, excellent thermal properties, and corrosion resistance. properties and tribological properties. Silicon carbide ceramics is a new type of mechanical seal material with superior performance. It has light weight, high specific strength and strong radiation resistance; it has certain self-lubricating properties and small friction coefficient; it has high hardness, wear resistance and excellent assembly performance. Good; high chemical stability, corrosion resistance; good thermal conductivity, good thermal shock resistance. As a new generation of mechanical sealing...

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Problems solved by technology

[0005] (2) Due to the large difference in the specific gravity of metal, graphite and silicon carbide, and the different dispersion mechanisms, it is difficult to obtain a composite powder with uniform composition by conventional mechanical ball milling, which leads to the non-densification of ceramic sintering and affects the final powder. Excellent mechanical properties, friction properties and high wear rate

[0006] (3) After graphite and metal elements are weak phases relative to silicon carbide, the strength and fracture toughness of metal or graphite silicon carbide ceramics will be reduced