Alpha--sialon ceramic doping composite rare earth and preparation method thereof

Abstract

The present invention provides alpha-sialon ceramics doped with composite rare earth and a preparation method thereof, and relates to the alpha-sialon ceramics and the preparation method. The present invention solves the problem that the hot pressing and no pressure can not easily prepare Sc-alpha-sialon phase in the existing sintering method, thus restricting the application of scandium oxide. The ceramics has a formula (ScxRy)Si<12-(m+n)>AlOnN<16-n>. The preparation method comprises the following steps: raw materials are mixed in wet environment, dried and then arranged in a mould; under the conditions of protective nitrogen and pressure of 30MPa, the temperature is raised and maintained; thus the ceramics can be prepared. With the common influence of Y<3+>, the preparation method adopts Sc<3+> in the alpha-sialon structure and makes full use of the scandium oxide. The prepared ceramic material has the hardness of 21GPa; and the formation of alpha-sialon grains, which are shaped like a long rod, results in excellent toughness of the ceramic material, which is about 5.3MPm<1 / 2>.

Description

technical field [0001] The invention relates to an α-sialon ceramic and a preparation method thereof. Background technique [0002] α-sialon has the characteristics of high hardness, good thermal and chemical stability, and excellent anti-friction and wear resistance, and has great application potential in harsh environments. During sintering, it can absorb metal cations (Li + , Ca 2+ , Mg 2+ and most rare earth metal ions) into its own structure, thereby reducing the intergranular phase in the material (H. Mandal, J. Eur. Ceram. Soc, 1999, 19, p2349-2357). Among them, Nd 3+ (0.100nm) and Lu 3+ (0.085nm) are considered to be the two largest and smallest rare earth ions that can enter the α-sialon structure, respectively (T.Ekstrom, Mater.Res.Soc.Symp.Proc., 1993, p121 and T.Ohji, Ceram. Eng. Sci. Proc. 22, 2001, p 159). [0003] Recently, it has been found that large-sized rare earth ions, such as Ce 3+ (0.103nm) and La 3+ (0.106nm) etc. into the α-sialon structure ...

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that it is difficult to obtain the Sc-α-sialon phase in the existing sintering methods such as hot pressing and pressureless, thus limiting the application of scandium oxide, and to provide a kind of α-sialon doped with complex rare earth Ceramics and methods for their preparation

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