Method for synthetizing Ti3SiC2 high-purity powder

Abstract

The invention relates to a method for synthetizing Ti3SiC2 high-purity powder. The method comprises the following steps: 1) proportioning: selecting Ti powder, SiC powder and TiC powder as raw materials and Al powder as a synthesizing accelerator wherein the molar ratio of Ti to SiC to TiC to Al is (4-4.1): (2-2.1): (1-1.1): (0.2-0.3); mixing the Ti powder, SiC powder, TiC powder and Al powder to obtain a mixture; 2) performing wet grinding on the mixture, sieving, washing to obtain a mixed suspension; 3) standing the mixed suspension, pouring out the supernatant, performing vacuum drying to obtain pretreated mixed powder; and 4) placing the pretreated mixed powder in a vacuum furnace to heat to 1250-1300 DEG C in a heating rate of 15-20 DEG C / min, treating under the condition that the vacuum degree is 1*10<-3>-1*10<-2>Pa, keeping the temperature for 1-2 hours, and obtaining the Ti3SiC2 high-purity powder under the condition that the furnace temperature is reduced to the room temperature. The Ti3SiC2 powder synthetized by the method has high purity and does not require purification treatment; the process is greatly simplified, the technological parameters are stable, the cost is low, the growth of grains is good; and the method is very suitable for mass production.

Description

technical field [0001] The invention relates to a synthetic Ti 3 SiC 2 High-purity powder method. Background technique [0002] In 1960, Hans Nowotny's research group discovered more than 100 new carbides and nitrides, among which there are more than 30 "H-phase compounds". Among these "H-phase compounds" is a cermet called MAX's new ternary compound, in which M is a transition metal, A is mostly Group III and IV elements, and X is carbon or nitrogen. This type of compound not only has the high thermal conductivity, high electrical conductivity, and ease of processing of metals, but also has the properties of hardness, light weight, oxidation resistance, thermal shock resistance, and wear resistance of ceramics. MAX-like compounds are a new class of solids that behave as true layers at the nanoscale; they are thermodynamically stable at high temperatures (even up to 2300 °C); metal chemical bonds, delamination propensity, and dislocation mobility endow them with Unique d...

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Problems solved by technology

[0005] (1) Among the commonly used synthetic raw materials, such as Ti / Si / C, Ti / TiC / Si, the direct reaction of Ti and C or Si during the reaction process will lead to a sudden concentration of heat, and the sintering temperature is too high will make some Si powder is too late to react and is lost by evaporation, which will lead to changes in the molar ratio of raw materials, which is not conducive to Ti 3 SiC 2 Synthesis of high-purity phases, usually TiC, SiC and TiSi x The existence of impurity phases such as; and the evaporation of Si powder may also cause damage to the components of the sintering furnace, resulting in an increase in synthesis costs;

[0006] (2) The price of Ti powder in raw materials is relatively high, and the cost of raw materials will affect Ti powder to a certain extent. 3 SiC 2 Large-scale production of high-purity powders;

[0007] (3) Ti 3 SiC 2 Both block and powder synthesis methods have certain defects

However, the price of the raw material Ti in the 3Ti / Si / 2C formula is high, which is not conducive to reducing production costs; at the same time, the evaporation loss of Si can easily lead to the formation of impurities such as TiC

The 2Ti / Si / TiC formula can replace part of the Ti metal raw material with the lower priced TiC, which is beneficial to reduce the cost, but the volatilization of Si with a low melting point in the raw material will lead to impurities such as TiC on the one hand, and on the other hand, it is easy to dissolve at low temperature. Volatilize to the sintering element (such as heating element) of the sintering equipment, thereby corroding the equipment and accelerating the aging of the equipment

However, there is Si powder in the raw materials of the two patents, and the existence of Si powder will volatilize during the heating process, which not only causes the molar ratio of the raw materials to change, thereby affecting the purity of the product; and the volatilized gaseous Si is easy to pollute the sintered original, making Its service life is reduced; the three-step process of mixed powder pretreatment, powder pressing and sintered block crushing into powder in the above patent greatly increases the production cycle and difficulty, and at the same time, it is easy to introduce impurity powder such as ball milling balls or tank materials, which is not conducive to process parameters The stability of large-scale industrial production is relatively high; the synthesis temperature is relatively high, which is not conducive to the reduction of production cycle and cost

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