CN1535933A

CN1535933A - Preparation method of alumyte base beta-sialon

Info

Publication number: CN1535933A
Application number: CNA031261361A
Authority: CN
Inventors: 钟香崇; 张海军; 叶方保; 刘战杰
Original assignee: Zhengzhou University
Current assignee: Zhengzhou University
Priority date: 2003-04-28
Filing date: 2003-04-28
Publication date: 2004-10-13
Anticipated expiration: 2023-04-28
Also published as: CN1242956C

Abstract

The present invention provides a method for preparing beta-Sialon powder. The method uses bauxite as raw material, adds metal silicon pwoder, aluminium powder and crystal seed, and adopts nitriding reduction process to prepare bauxite base beta-Sialon. The method is simple, its condition is easily controlled, and the obtained product is higher in purity, the beta-Sialon content is above 80%. Said powder material can be extensively used in the fields of metallurgical industry, mechanical industry and ceramic industry, etc.

Description

The preparation method of based on bauxite beta-Sialon

Affiliated field:

The present invention relates to a kind of preparation method of ceramic powder, be specifically related to a kind of preparation method by the synthetic beta-Sialon of alumine reduction nitridation.

Background technology:

Sialon (Sai Long) is Si ₃N ₄With Al ₂O ₃Sosoloid, take the lead in proposing in 1972 by people such as K.H.Jack.Si ₃N ₄β-Si is arranged ₃N ₄And α-Si ₃N ₄Two kinds of variant are called beta-Sialon, α-Sialon with their isostructural sosoloid.The Sialon material has better comprehensive performance, is subjected in recent years paying close attention to widely.As: with single-phase oxide material (Al ₂O ₃Deng) compare, they have much superior heat-shock resistance, and mechanical behavior under high temperature is suitable, simultaneously multiple smelting slag is had resistance to fouling preferably; With single-phase non-oxidized substance (as Si ₃N ₄, SiC etc.) compare, they have much higher oxidation-resistance again.These characteristics make the Sialon material be more suitable for using under high temperature, corrosive atmospheres such as metallurgy, chemical industry, also can utilize simultaneously his characteristics such as high strength, high rigidity and use as cutter or bearing.In decades, also very many about the research of Sialon material every aspect, yet its practical application still be restricted, this be because: the synthetic Sialon of (1) direct reaction method will synthesize Si earlier ₃N ₄With the AlN powder, and then with SiO ₂, Si ₃N ₄, Al ₂O ₃, AlN is raw material, after mixing by a certain percentage according to the Si-Al-O-N phasor, at high temperature synthetic after solid state reaction, often follow the existence of many impurity phases in the technology relative complex of this method, the synthetic Sialon powder, and the sintering temperature (about 1700 ℃) that general requirement is higher, and this method is with high costs, the Si of for example Japanese UBE company ₃N ₄Price surpasses 1000RMB/Kg, and the price of domestic AlN powder also will surpass 600RMB/Kg; (2) adopt metal Si, Al and oxide compound thereof as the synthetic Sialon powder of starting raw material reaction sintering, this technology cost is also higher.(3) adopting clay etc. be the synthetic Sialon powder of material carbon thermal reduction nitrogenize, this technology exists in the synthetic product that impurity is mutually more, impurity level greatly, be difficult to problem such as control.

A kind of preparation method of Sialon powder is provided in the Chinese patent application case of publication number for CN1168872A.He utilizes self-propagating high-temperature technology, this complex process equipment, requirement condition height, and cost is higher, is difficult to realize scale operation.

Provide a kind of Sialon preparation method in the Chinese patent application case of publication number for CN1270153A in conjunction with the SiC powder.He utilizes river sand to be raw material, and synthetic product exists a large amount of SiC in mutually, and low melting point in the synthetic materials simultaneously is as K ₂O (2.9%), Na ₂O (3.5%) content height is not suitable for being applied in the hot industry field.

The method of the synthetic Sialon ceramic powder of a kind of low cost is provided in the Chinese patent application case of publication number for CN1349956A.The raw material that he adopts is metallurgical slag or flyash, and the synthetic product is α-Sialon.

The method of the grand composite diphase material of a kind of synthetic match is provided in the Chinese patent application case of publication number for CN1363535A.The raw material that he adopts is flyash and coal gangue, and the synthetic product also has a large amount of X-Sialon and SiC except that beta-Sialon.

Publication number is in the Chinese patent application case of CN85107936A and CN1142478A, and what provide then all is to utilize the direct reaction method to synthesize alpha-beta-Sialon matrix material.

China has abundant alumine raw material resources.But because raw materials quality is stable inadequately, composition is even inadequately, kind is single, not only can't satisfy the demand of special refractories, selling price on the world market is also far below countries such as Guyana, Brazil (be about 70-80 dollar/ton as bauxite clinker price China, and Guyana, Brazilian price being about 155-165 dollar/ton).If with its (alumine) is raw material, add suitable reductive agent, through suitable technology, be translated into Sialon, to satisfy the demand of domestic and international pyrotic smelting key position, not only can reduce production costs significantly, reduce the consumption costs of hot industry with refractory materials; But also can improve the added value of alumina greatly, and be reasonable development China alumine resource, improve foreign exchange earning, good condition is provided.And the present invention is just aiming at the technological gap of international and domestic this research field, with the development of the beta-Sialon material of realizing low cost, high-performance, high added value.

Summary of the invention:

The objective of the invention is with the abundant alumine of Chinese reserves is raw material, with the general formula Si of beta-Sialon _6-zAl _zO _zN _8-zIn the z value as the grand significant parameter of design match, through suitable technology, the development beta-Sialon powder that synthesis technique is simple, cost is low, performance good, added value is high makes alumine after handling transition, its value can improve 10-20 doubly.

Technical scheme of the present invention is:

With the alumine is main raw material, is complex reducing agent with metallic silicon power, aluminium powder, adopts reduction-nitridation prepared based on bauxite beta-Sialon, and its processing method is as follows:

A, the weight fraction of choosing raw material are: alumine 40-60%

Pure Silicon Metal 40-60%

Metallic aluminium 5-15%

Beta-Sialon crystal seed 0.1-5%

B, alumine, Pure Silicon Metal, metallic aluminium and beta-Sialon crystal seed are mixed, add the wedding agent of raw material total amount 1-5%, mechanical pressing or extrusion molding;

C, place nitriding furnace to carry out nitrogenize the pug of piece material after the b moulding or not moulding, under flowing nitrogen atmosphere, be warming up to 800 ℃, be incubated 1 hour, temperature rise rate is 120-300 ℃/hour; Continue to be warming up to 1100 ℃, be incubated 1 hour, temperature rise rate is 100-300 ℃/hour; Be warming up to 1300 ℃ again, be incubated 2 hours, temperature rise rate is 20-100 ℃/hour; Be warming up to 1400-1550 ℃ at last, be incubated 4-10 hour, temperature rise rate is 120-300 ℃/hour; Close nitrogen after being cooled to 100-800 ℃ then, after continuing to be cooled to room temperature, make based on bauxite beta-Sialon.

In above-mentioned preparation method, alumine is raw material or light-burned material, the Al after its igloss ₂O ₃Mass percent is 70%-90%, SiO ₂Mass percent 5%-20%; Wedding agent is one or more in dextrin, polyvinyl alcohol, xylogen, carboxymethyl cellulose, the number fat; The pressure of mechanical pressing is 10-100MPa; The pressure of extrusion molding is 1-10MPa.

Compared with prior art, the invention has the advantages that:

1, preparation technology of the present invention is simple, need not complicated processing unit and technological process, is raw material with the profuse alumine of Chinese reserves simultaneously, can reduce the manufacturing cost of Sialon widely.

2, because beta-Sialon is Si ₃N ₄Sosoloid, therefore its solid solubility can change within the specific limits, does not influence the acquisition of final beta-Sialon when material component changes slightly; Therefore this technology is lower to the requirement of raw material, is fit to suitability for industrialized production.

3, the product thing after synthetic is compared purely with the present invention, and the content of beta-Sialon is more than 80%.

Figure of description:

Accompanying drawing is the XRD analysis figure of embodiment of the invention products therefrom.

The invention will be further described below in conjunction with accompanying drawing.

Embodiment:

Embodiment

Alumine (composition such as table 1), metallic silicon power, aluminium powder with Xinmi City, Henan Province are raw material, and to add a small amount of beta-Sialon in addition be crystal seed.

The alumine chemical constitution of Xinmi City, table 1 Henan Province

Component	Al ₂O ₃	?SiO ₂	?Fe ₂O ₃	?TiO ₂	?CaO	?MgO	?K ₂O	Na ₂O	Igloss
Component	Al ₂O ₃	?SiO ₂	?Fe ₂O ₃	?TiO ₂	?CaO	?MgO	?K ₂O	Na ₂O	Igloss	wt％	79.03	?1.50	?0.26	?3.74	?0.12	?0.20	?0.01	0.03	14.70

With 48 parts in alumina, 43 parts of metallic silicon powers, 9 parts of metallic aluminium powders, be positioned in the ball grinder, dried be mixed even; Taking out mixed powder is binding agent with the dextrin, and the 70-100MPa mechanical pressing is dry under the 80-110 ℃ of temperature.

Use atmosphere sintering furnace, under nitrogen atmosphere, the stage is warming up to 1500 ℃, is incubated 5 hours.Be cooled to 700 ℃ and close nitrogen, continue to be cooled to room temperature and take out, obtain the beta-Sialon powder.

The XRD analysis figure of product as shown in drawings in the present embodiment.Through XRD analysis, the product principal crystalline phase is a beta-Sialon, and other has a small amount of Al ₂O ₃, O '-Sialon, X phase.If be approximately the content of each thing phase with the integral area of various thing phase highest peaks, the relative content of beta-Sialon can reach 80%.

Claims

1, the preparation method of based on bauxite beta-Sialon is characterized in that: with alumine, Pure Silicon Metal, metallic aluminium is main raw material, and its weight fraction is:

Alumine 40-60%

Pure Silicon Metal 40-60%

Metallic aluminium 5-15%

Beta-Sialon crystal seed 0.1-5%

2,, it is characterized in that alumine is raw material or light-burned material, the Al after its igloss according to the preparation method of the described based on bauxite beta-Sialon of claim 1 ₂O ₃Mass percent is 70%-90%, SiO ₂Mass percent 5%-20%;

3,, it is characterized in that said wedding agent is one or more in dextrin, polyvinyl alcohol, xylogen, carboxymethyl cellulose, the resin according to the preparation method of the described based on bauxite beta-Sialon of claim 1.

4, according to the preparation method of the described based on bauxite beta-Sialon of claim 1, the pressure that it is characterized in that mechanical pressing is 10-100MPa.

5, according to the preparation method of the described based on bauxite beta-Sialon of claim 1, the pressure that it is characterized in that extrusion molding is 1-10MPa.