Method for fabricating ceramics of silicon carbide toughened by Nano bars of alumina

Abstract

This invention provides a method for producing SiC ceramic tougnened with Al2O3 nanorods. The SiC ceramic utilizes Al2O3 nanorods with a low aspect ratio instead of whiskers or fibers with a high aspect ratio as the toughening component. The rod-like Al2O3 nanoparticles can be uniformly mixed with other raw materials, which can realize uniform toughening. Besides, the rod-like Al2O3 nanoparticles have a low cost, which can reduce the cost of the tougnened SiC ceramic. This invention also considers such advantageous toughening effects as microcrack, crack deflection, crack bridging, pullout and grain refinement.

Description

technical field [0001] The invention relates to a method for manufacturing alumina nanorod toughened silicon carbide ceramics, which belongs to the field of ceramics. Background technique [0002] The problem of brittleness is a common problem for all kinds of ceramics, and silicon carbide ceramics are no exception; how to improve the toughness of silicon carbide ceramics is an important topic of concern in this production field. The linear elastic fracture mechanics developed in the early 1950s was first applied to metal materials, and later Davidge and Wiederhorn found that the theory was equally important for ceramic materials. Since then, people have paid attention to the concept of "microstructural defects" and tried their best to eliminate the defects caused by the process, so as to improve the mechanical properties of structural ceramics. Over the next few years, Lange and Rice observed the interplay between cracks and microstructure and produced a series of highly d...

AI Technical Summary

Problems solved by technology

[0004] The introduction of silicon carbide whiskers or carbon fibers for toughening can indeed greatly improve the toughness of silicon carbide ceramics. However, the preparation cost of silicon carbide whiskers is relatively high, which brings about an increase in the production cost of the entire toughened ceramic product. In particular, the long-term Generally speaking, silicon carbide whiskers and carbon fibers with a high diameter ratio are difficult to mix evenly with other raw materials for silicon carbide ceramics production, and uneven mixing of raw materials will obviously affect the toughening effect of finished silicon carbide ceramics; similarly, using The method of adding alumina whiskers or other oxide whiskers with a high aspect ratio to toughen silicon carbide ceramics also has the problem that the toughening material and other raw materials for silicon carbide ceramics are difficult to mix uniformly.