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Most of the structural ceramics having a high melting point, high hardness, good high temperature strength, thermal stability and corrosion resistance, etc., are a class of important practical value material. However, structural ceramics brittle limit some of its applications, preparation of nanocomposite ceramics is an effective way to improve its mechanical properties. The traditional method of preparation of nanocomposite ceramics first need synthetic nano-powder, and then use the powder to be sintered. The nanopowder expensive, difficult to scale preparation. During the sintering process, nano powder specific surface area and high activity, grain growth speed, difficult to obtain small grain size of the composite ceramics. The main purpose of this paper is to find a new sintering technology, used to prepare a small grain size, high performance composite ceramics. This experiment using a two-step method in situ reaction sintering and spark plasma sintering (SPS) prepared composite ceramics, fine microstructure with respect to the one-step preparation of the samples, the grain is finer, better mechanical properties, content is as follows: First a metal Ti powder and commercial micron B4C powders for the preparation of the starting material TiB2/TiC composites. Sintering of different temperatures, different holding times and different sintering method the four groups TiB2/TiC composite, to compare visits from the density, microstructure, the chamber Wen Weishi hardness and fracture toughness, MSP strength. Found that one-step sintered samples using SPS rapidly reduce the temperature of incubation of the two-step method the average grain size of the sintered samples were 1μm, 200nm, its chamber Wen Weishi hardness and fracture toughness similar to 18.3GPa 4.9MPa.m1 / 2, MSP strength were 833MPa, 1095MPa. Visible due to the sintered samples have a finer grain size, the two-step method has a higher strength. Using metal Ti powder and commercial submicron SiC powder the initial raw material preparation Ti5Si3/TiC of composite. Preparation of a different temperature, holding time and sintering method the four groups Ti5Si3/TiC composite, to compare visits from the density, microstructure, the chamber Wen Weishi hardness and fracture toughness, MSP strength. Found that one-step as well as the SPS quickly lower the temperature of incubation the average grain size of the two-step Preparation Samples were 300-400nm ,200-300nm, its chamber Wen Weishi hardness and fracture toughness similar to 12.3GPa and 3.7 MPa, respectively. m1 / 2, MSP intensity similar to, to 460MPa or so. In short, this article uses a two-step in situ reaction sintering and spark plasma sintering (SPS), prepared with fine microstructure and high-performance ceramic composite.
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