CN1239432C

CN1239432C - Process for self-propagating synthesis of alpha-sialon powder with stable rare earth ion

Info

Publication number: CN1239432C
Application number: CN 200410015999
Authority: CN
Inventors: 蒋久信; 王佩玲; 何万保; 陈卫武; 程一兵; 庄汉锐; 严东生
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2004-01-19
Filing date: 2004-01-19
Publication date: 2006-02-01
Anticipated expiration: 2024-01-19
Also published as: CN1569745A

Abstract

The present invention relates to a self-propagating synthetic method of alpha-sialon powder with stable rare earth ions, which is characterized in that Ce<3+>, Pr<3+> and Eu<3+> rare earth ions with large radii are not easy to enter alpha-sialon crystal lattices in common processes, but can enter the alpha-sialon crystal lattices in a larger amount after the synthesis by the high-temperature self-propagating combustion process. In the method, the adopted raw materials comprise not less than 99.0 wt% of silicon nitride (Si3N4) powder, aluminum nitride (AlN) powder, rare earth oxide (RE2O3, RE=Ce, Pr, and Eu) and yttrium oxide (Y2O3) and not less than 98.0 wt% of aluminum (Al) powder and silicon (Si) powder, and x, m and n in the alpha-sialon general formula of Re<x>Si<12-(m+n)>Al<m+n>O<n>N<16-n> are used as parameter ingredients for component selection, wherein m=2n=3x, x=0.3 to 0.6, RE is independently mixed by any one of Ce, Pr and Eu or compounded with element Y according to different proportions.

Description

The A Erfasailong powder that rare earth ion is stable spread synthetic method certainly

Technical field

The present invention relates to be the stable A Erfasailong of a kind of rare earth ion (powder of α-Sialon) spread synthetic method certainly.More precisely provide a kind of with silicon nitride (Si ₃N ₄), aluminium nitride (AlN), rare earth oxide (RE ₂O ₃) and yttrium oxide (Y ₂O ₃), aluminium powder (Al) and silica flour (Si) be main raw material, (preparation method of powder of α-Sialon) belongs to the preparation field of nitrogen based ceramic powder body by the synthetic light rare earth ion stabilized A Erfasailong of self-propagating high-temperature burning process.

Background technology

Sialon is Si ₃N ₄Sosoloid, at first propose in 1972 by people such as people such as K.H.Jack and Y.Oyama.Corresponding to Si ₃N ₄α-and β-two kind of variant, the sosoloid of two kinds of structures of Sialon is called α-Sialon and beta-Sialon.Because the Sialon pottery has high strength, high rigidity, wear-resistant, corrosion-resistant, characteristics such as anti-thermal shock and high-temperature stability and using in high temperature, corrosive atmospheres such as metallurgy, chemical industry, its high strength, high rigidity can also play a role in mechanical industry as cutter and bearing etc.With regard to α-Sialon and beta-Sialon pottery, characteristics are separately arranged again.α-Sialon pottery has very high hardness, but its toughness is lower, thereby is restricted on using; Though the beta-Sialon pottery has low slightly hardness, has obtained popularization because of its toughness is higher.Therefore, can come the microstructure of control material to reach the purpose of the over-all properties of optimizing material by certain technology, increase its toughness such as pattern, bring into play α-Sialon and beta-Sialon over-all properties mutually by forming α-Sialon/ beta-Sialon complex phase ceramic by control α-Sialon crystal grain.

Ce is thought in research in the past ³⁺Owing to can not enter the room in α-Sialon lattice too greatly.People such as C.M.Wang in recent years ^{(C.M.Wang, M.Mitomo, F.F.xu, N.Hirosaki and Y.Bando, " Synthesis of Ceriom α-sialon with nuclei addition, " J.Am.Ceram.Soc., 84[6] 1389-91 (2001))}Y α-the Sialon that adds 1wt% has synthesized Ce α-Sialon as crystal seed with plasma reactive sintering (PAS) technology.They think that the formation of Ce α-Sialon is what to be subjected in the lip-deep one-tenth nuclear control of the α that has existed-Sialon phase, because can not form Ce α-Sialon phase when not adding crystal seed.And Z.J.Shen ^{(Z.Shen (Z.shen and M.Nygren, " Implications of kinetically promoted formation of metastable α-Sialon phases, " J.Eur.Cearm.Soc., 21 611-15 (2001))}Research work Deng human plasma sintering (SPS) prepared Ce α-Sialon shows that α-Sialon is the principal crystalline phase in the sintered compact mutually.They think that the reason that Ce α-Sialon forms is that plasma sintering is the process of a rapid temperature rise and drop.Heat up fast and make Ce ³⁺Can enter α-Sialon lattice, cooling fast makes the Ce that enters α-Sialon lattice ³⁺Be suppressed in the lattice, and such Ce α-Sialon is metastable mutually.In view of heat up fast and cooling aspect the similarity of SHS and SPS, we have synthesized the stable Sialon powder of light rare earth ion Ce with the self-propagating high-temperature combustion synthesis process.

Although the report of more research to Ce α-Sialon material is arranged in recent years, but seldom to the research of Pr and Eu α-Sialon material.Reported the half-full or full up trivalent rare earth ions of some 4f tracks, for example Yb ³⁺, Eu ³⁺And Sm ³⁺, at Si ₃N ₄Be reduced into divalent ion easily in the sintering process of base pottery.Though Eu ³⁺Ionic radius be 0.095nm, compare Nd ³⁺Ionic radius little, can enter α-Sialon lattice, still, Eu ²⁺Ionic radius but than Nd ³⁺Much bigger, be 0.116nm, can not enter α-Sialon lattice.People such as Z.J.Shen ( ^{Z.Shen and M.Nygren, " Implications of Kinetically promoted fprmation of metastable α-Sialon phases, " J.Eur.Cearm.Soc., 21 611-15 (2001))}Synthesized Eu α-Sialon material with SPS technology, contained α-Sialon in the material, beta-Sialon and P-be (EuSi mutually ₉Al ₁₉ON ₃₁), and be principal crystalline phase with α-Sialon.People such as R.J.Xie ( ^{R.J.Xie, M.Mitomo, K.Uheda.F.F.Xu and Y.Akimune, " Preparation and luminescence spectra of calcium-and Rare-earth (R=Eu; Tb and Pr)-codoped α-sialon ceramics; " J.Am.Ceram.Soc., 85 [5] 1229-34 (2002))}Synthesized Eu with heat pressing process ₂O ₃/ Pr ₂O ₃With the stable α-Sialon material of CaO compound ion.In that (Eu, Ca) in α-Sialon system, during less than 70at.%, can obtain with α-Sialon is the material of principal crystalline phase at Eu/Ca, wherein also contains the β-Si of trace ₃N ₄Perhaps beta-Sialon phase, and in that (Pr, Ca) in α-Sialon system, when Pr/Ca=50at.%, α-Sialon is a principal crystalline phase, also has a spot of β to generate mutually.Therefore, we have also synthesized rare earth ion Pr and the stable Sialon powder of Eu with the self-propagating high-temperature combustion synthesis process.

Summary of the invention

The object of the present invention is to provide the stable A Erfasailong of a kind of rare earth ion (powder of α-Sialon) spread synthetic method certainly.

The objective of the invention is to implement: use existing RE by following manner ₂O ₃-Si ₃N ₄-AlN-Al ₂O ₃The knowledge of α in the multicomponent system-Sialon phase plane is not less than 99% silicon nitride (Si with mass percent ₃N ₄), aluminium nitride (AlN), rare earth oxide (RE ₂O ₃) and yttrium oxide (Y ₂O ₃) and mass percent is not less than 98% aluminium powder (Al) and silica flour (Si) is a main raw material, by the ion stabilized A Erfasailong of the self-propagating high-temperature burning process synthesizing rare-earth (powder of α-Sialon).

Specifically:

(1) according to existing Ln ₂O ₃-Si ₃N ₄-AlN-Al ₂O ₃The knowledge of α in the multicomponent system-Sialon phase plane is with α-Sialon general formula R E _xSi _12-(m+n)Al _M+nOnN _16-nIn x, m, n for selecting the parameter of component point, m=2n=3x, x=0.3～0.6.RE be among Ce, Pr and the Eu any independent doping or with Y composite mixed by different ratios.

(2) raw material: comprise that mass percent is not less than 99% silicon nitride powder, aluminum nitride powder, rareearth oxidate powder and mass percent and is not less than 98% silica flour and aluminium powder.After the composition proportioning weighing according to above-mentioned (1), in plastics pot, be dispersion medium with the dehydrated alcohol, Si ₃N ₄Ball is that ball-milling medium mixed 24 hours, after the oven dry of taking-up slurry, sieves through 55 eye mesh screens.

(3) powder is synthetic: the powder that mixes is put in the plumbago crucible, at shop, top layer layer of metal detonator Ti powder, the tungsten filament or the molybdenum filament of coiled spring-like are imbedded in the powder, and energising heating tungsten filament, the Ti powder that ignites, and cause the spontaneous of entire reaction and carry out.

(4) the blocky powder of synthetic is broken, in oxidation aluminium pot or agate jar, be dispersion medium with the dehydrated alcohol, Si ₃N ₄Ball is a ball-milling medium at ball milling 20-30 on the single-phase ball mill hour or on the high speed planetary ball mill ball milling 3-5 hour, take out the slurry oven dry after, sieve through 55 eye mesh screens.

Advantage of the present invention is:

(1) synthesis technique of powder and equipment are simple; React very rapid, reaction time is short; React spontaneous carrying out, need extra power hardly, cost is low.

(2) the content height of α in the synthetic powder-Sialon phase, the synthetic powder is metastable, has certain activity, helps sintering.

(3) at Ce, when Pr or Eu element and Y element are composite mixed, can be by regulating Ce in the starting raw material, the ratio of Pr or Eu element and Y element is regulated and control the phase composite of synthetic powder.Composite mixed and definite its ratio that the embodiment of the invention has exemplified Ce and Y was respectively 4: 1,3: 2 or 1: 1.In fact suitable equally to Pr involved in the present invention and Eu, and ratio also is not limited only to listed ratio, as long as in the X=0.3-0.6 scope, three kinds of elements and Y element can be regulated the phase composite of α-Sialon powder with this by the complete or corresponding α-Sialon of any ratio.

Description of drawings

XRD figure spectrum (a) Eu of the different α of Fig. 1-sialon component, the adulterated α of Pr and Ce-sialon component (b) (Eu, Y), (Pr, Y), (Ce, Y) adulterated α-sialon component (among the figure:, α ', O β ', Λ .Ce ₂Si ₆O ₃N ₈, B S-phase, 7 AlN-polytypoids)

The EDS collection of illustrative plates (right side) of α-Sialon crystal grain in the pattern (left side) of Fig. 2 synthetic powder and the corresponding powder, among the figure, (a) Eu α-sialon (c) Pr α-sialon (e) Ce α-sialon

Fig. 3 is from spreading synthetic (Ce, Y) XRD figure of α-Sialon powder spectrum (a) Ce0.5Y0 (b) Ce0.4Y0.1 (c) Ce0.3Y0.2 (d) Ce0.25Y0.25

Embodiment

Embodiment 1 usefulness cerium oxide is made stablizer, and being not less than 99% silicon nitride powder, aluminum nitride powder, cerium oxide powder and mass percent with mass percent, to be not less than 98% silica flour and aluminium powder be raw material.General formula R E at α-Sialon _xSi _12-(m+n)Al _M+nO _nN _16-nIn x, m, n be respectively m=2n=3x, x=0.3～0.6.The powder that proportioning is good is a dispersion medium with the dehydrated alcohol in plastics pot, Si ₃N ₄Ball is that ball-milling medium mixed 24 hours, after the oven dry of taking-up slurry, sieves through 55 eye mesh screens.The powder that mixes is put in the plumbago crucible, at shop, top layer one deck Ti powder, the tungsten filament of spring-like imbedded in the powder, and energising heating tungsten filament, the Ti powder that ignites, and cause the spontaneous of entire reaction and carry out.Then the blocky powder of synthetic being broken into pieces, is dispersion medium with the dehydrated alcohol in oxidation aluminium pot or agate jar, Si ₃N ₄Ball is a ball-milling medium at ball milling 20-30 on the single-phase ball mill hour or on the high speed planetary ball mill ball milling 3-5 hour, take out the slurry oven dry after, sieve through 55 eye mesh screens.The XRD figure spectrum of synthetic powder, microstructure and corresponding EDS collection of illustrative plates are respectively as depicted in figs. 1 and 2.

Embodiment 2 usefulness Praseodymium trioxides are made stablizer, according to the method synthetic powder of embodiment 1, and the preparation pottery.

The XRD figure spectrum of synthetic powder and microstructure are respectively as depicted in figs. 1 and 2.

Embodiment 3 usefulness europium sesquioxides are made stablizer, according to method synthetic powder, the preparation pottery of embodiment 1.

Embodiment 4 adopt a kind of and yttrium oxide in cerium oxide, Praseodymium trioxide and the europium sesquioxides according to 1: 1 ratio as one package stabilizer, according to embodiment 1 method synthetic powder, the XRD figure of synthetic powder is composed as shown in Figure 1.

Embodiment 5 adopts cerium oxide and yttrium oxide as one package stabilizer, and changes its ratio, and according to embodiment 1 method synthetic powder, the XRD figure of synthetic powder is composed as shown in Figure 3.

Claims

The stable A Erfasailong powder of a rare earth ion spread synthetic method certainly, it is characterized in that:

(1) with α-Sialon general formula R E _xSi _12-(m+n)Al _M+nO _nN _16-nIn x, m, n prepare burden for the parameter of selecting component point, m=2n=3x wherein, x=0.3～0.6, RE be Ce, Pr with Eu in any independent doping or composite mixed with different ratios with Y;

(2) powder of batch mixes after evenly places plumbago crucible, at shop, top layer layer of metal Ti detonator, tungsten filament or molybdenum filament imbedded powder, and initiation reaction is spontaneous to be carried out, and obtains blocky powder, and powder forms through disintegrating process.
2. spread synthetic method certainly by the stable A Erfasailong powder of the described a kind of rare earth ion of claim 1, it is characterized in that selecting for use mass percent to be not less than 99.0% silicon nitride powder, aluminum nitride powder, rare earth oxide and yttrium oxide and mass percent, to be not less than 98.0% aluminium powder and silica flour be raw material, in plastics pot, be dispersion medium after the weighing, with the different Si of diameter with the dehydrated alcohol ₃N ₄Ball is that the ball-milling medium ball milling takes out oven dry and sieves through 55 mesh sieve orders after 24 hours.
By the stable A Erfasailong powder of the described a kind of rare earth ion of claim 1 spread synthetic method certainly, it is characterized in that the block powder of self-propagating high-temperature after synthetic is dispersion medium with the dehydrated alcohol in aluminum oxide or agate jar, with the different Si of diameter ₃N ₄Ball is ball-milling medium at ball milling 20-30 on the single-phase ball mill hour or took out oven dry and sieve through 55 mesh sieve orders after ball milling 3-5 on the high speed planetary ball mill hour.
By the stable A Erfasailong powder of the described a kind of rare earth ion of claim 1 spread synthetic method certainly, it is characterized in that general formula R E _xSi _12-(m+n)Al _M+nO _nN _16-nIn X=0.5, any and Y's is composite mixed among Rare-Earth Ce, Pr and the Eu, the ratio of any rare earth and Y was respectively 4: 1,3: 2,1: 1 among Ce, Pr and the Eu.
By the stable A Erfasailong powder of the described a kind of rare earth ion of claim 1 spread synthetic method certainly, it is characterized in that tungsten filament or molybdenum filament coiled spring-like.