CN1153751C - Process for preparing functional superfine powder of multi-element composite metal oxide ceramics - Google Patents

Abstract

The invention relates to a preparation method of multi-component composite metal oxide functional ceramic micropowder. The process is to mix the original reaction materials such as metal oxides, hydroxides or salts with an aqueous solution of an organic dispersant through mechanical grinding to make a slurry, and then burn it after drying to cause a solid-state reaction to form the required composite metal. oxide, and then pulverized and ground to obtain the fine powder of composite metal oxide functional ceramics. This method has simplified process, convenient operation, high efficiency, low cost, and can be produced in large quantities. The obtained powder has high purity, small particle size, basically spherical shape, and high reactivity of the powder.

Description

A kind of method for preparing functional superfine powder of multi-element composite metal oxide ceramics

Technical field

The present invention relates to the preparation method of functional superfine powder of multi-element composite metal oxide ceramics.

Background technology

The polynary metal oxide function ceramics has excellent characteristic, and it has wide application at aspects such as piezoelectricity, conduction, magnetic, optics and sensor, Solid Oxide Fuel Cell and gas separation membrane materials.And the key of preparation high-performance polynary metal oxide function ceramics is the fine powder that preparation is highly active, granularity arrives submicron order at tens nanometer.

The traditional method of preparation functional ceramic powder is conventional solid reaction process.For example, (skill newspaper hall is published out city different formula commercial firm to " ceramic process " that the Japan mountain pass is tall and willow Tian Boming compiles, 1984) book is introduced, from metal oxide or metal carbonate, nitrate etc., through ground and mixed, briquetting, through the long calcination of high temperature, make it to take place solid state reaction, form material requested thing phase, and then mechanical disintegration forms powder then.High, time-consuming length that this method not only consumes energy, and in order to obtain single thing phase, also need promptly to carry out the solid state reaction of repeated multiple times through repeatedly grinding and high temperature sintering.Because the at high temperature long-time repeatedly calcination of material, may partially sinter the formation agglomerate between the powder, need again mechanical disintegration to obtain powder, the diameter of particle of Xing Chenging is big and uncontrollable like this, and the particle diameter shape that obtains differs, the poor activity of powder, and in milled processed, also inevitably sneak into container and abrasive impurity, thereby influence its functional property, so the powder of this method preparation does not often conform with continuous thereafter requirement of using.

For above-mentioned reasons, people have been developed a series of wet chemical preparation methods.Such as good that think S. Ruide (Janes S.Reed) work " Principle of Pottery Technology " (Principle of Ceramics Processing, U.S. John Wiley ﹠amp; Sons company, nineteen ninety-five publishes) described in chemical coprecipitation.Chemical coprecipitation at first is the mixing solutions of preparation metal-salt, add certain coprecipitator (normally alkali metal hydroxide, ammoniacal liquor or oxalic acid etc.) again, each metallic element is precipitated out simultaneously with the form of oxyhydroxide or oxalate, and drying, calcination obtain the composite oxides powder again.This method requires to find to all effective coprecipitator of all elements, otherwise the component non-uniform phenomenon can occur.When the preparation multicomponent composite oxide, the occasion that particularly needs strict control of material to form, this coprecipitator generally is difficult to find.The concentration of pH value, temperature and reagent during strict in addition control reaction etc., the solution-operated amount is big, the dry difficulty of filtration washing, process is numerous and diverse, power consumption is taken a lot of work etc., generally is unsuitable for producing in enormous quantities.

In recent years, some new wet chemical preparation methods receive publicity, and they relate to organic application.As chemical communication (Chem.Lett.) magazine the 665th page of report a kind of " the citric acid compound legal system is equipped with the perovskite composite oxide ceramics powder " in 1987, U.S.'s pottery can have been reported a kind of " metal-EDTA inner complex method prepares partially stabilized tetragonal zircite (PTZ) ceramic " by will (J.Am.Ceram.Soc.) 75 volume (nineteen ninety-five) 65-69 pages or leaves.These methods are all based on the principle of metal precursor chemical fixation, precursor costs an arm and a leg and organism consumption very big (its mole dosage often is several times as much as metal), this has improved preparation cost and has polluted easily, simultaneously because the existence of large amount of organic, in the afterglow process of back, tend to form carbonate, some carbonate chemistry combination is very stable (as alkaline earth metal carbonate) also, must could decompose by high temperature.For this reason, obtain required composite oxides thing phase, also must improve calcination temperature, thereby cause powder active poor.

Summary of the invention

The object of the present invention is to provide the method for active high, the functional superfine powder of multi-element composite metal oxide ceramics that granularity is little of a kind of preparation simple, with low cost.

Solution of the present invention is as follows: based on existing solid reaction process, its key is to add organic dispersing agent in the mixing process of primitive reaction material, that is: metal oxide, oxyhydroxide or salt are carried out mechanical mill with the aqueous solution of organic dispersing agent and mix, make slurry, carry out calcination after the drying again and make the generation solid state reaction, form required complex metal oxides, obtain micro mist after crushed; Described organic dispersing agent is organic polymer polyelectrolyte polymethyl acrylic acid, polyacrylic acid and its esters, or linear polymer polyvinyl alcohol, the polyoxyethylene glycol of non-ionic type, and dispersant dosage is 0.1～4% of an initial material weight.

Be that existing solid reaction process is reformed on the present invention is apparent, but come down to have utilized solution impregnation, surface chemistry dispersion, micromechanics chemistry effect effect even nanometer effect or the like Synthesis principle, in the mechanically mixing process of its primitive reaction material, add some organic dispersing agent, can improve mixed effect greatly like this and strengthen reactive behavior between the reactant, original solid reaction process must grind repeatedly for a long time to overcome, the shortcoming and the wet-chemical of compressing tablet and calcination prepare the shortcoming that method must be used special precursor, coprecipitate.Compared with the prior art the inventive method has following advantage:

(1) because raw material mixing process is to carry out mechanical mill to mix in containing the organic dispersing agent aqueous solution of (or claiming tensio-active agent), make feed composition be able to abundant pulverizing, dispersion and uniform mixing, the mechanochemical effect in the mixing process particularly, improved the reactive behavior of raw material greatly, form the mutually required calcination temperature of composite oxides thing thereby reduced, generally can reduce by 100 degree even hundreds of degree, and only need a calcination to get final product the production efficiency height.

(2) owing to once one-tenth phase and calcination temperature are low, thus compound oxidate ceramic powder purity height, the particle diameter little (tens nanometer or hundreds of nanometer) that make, the reactive behavior height of powder.

(3) raw material such as related metal oxide, oxyhydroxide or salt of present method and organic dispersing agent are simple and easy to, and are applicable to the preparation of multicomponent composite oxide micro mist widely.

(4) used organic dispersing agent consumption is few in present method, and is inexpensive nontoxic and be easy to remove, and makes the low and environmentally safe of preparation process cost.

(5) present method operating procedure is simple, need not specific installation, also need not can be mass-produced through the chemosynthesis operation, and facility investment and process cost are all low.

Embodiment

Detailed process of the present invention is: 1. with the primitive reaction material of the polynary metal oxide ceramic powder of required preparation in the required ratio of composite oxide material calculate, (used calculating, weighing technique are traditional method in weighing, repeat no more herein), used primitive reaction material is metal oxide, oxyhydroxide or salt etc.; 2. take by weighing 0.1～4% the organic dispersing agent consumption that accounts for the initial material gross weight, itself and an amount of water are mixed and made into slurry, the consumption of water is relevant with the consumption and the wettability thereof of primitive reaction material, the primitive reaction material can be soaked into, to be easy to wet-milling and to get final product; Described organic dispersing agent is the linear polymer of polyelectrolyte or non-ionic type, as polymethyl acrylic acid, polyacrylic acid and its esters, polyvinyl alcohol, polyoxyethylene glycol etc.; 3. the aqueous solution with above-mentioned primitive reaction material and organic dispersing agent carry out fully, homogeneous mechanical ground and mixed (as adopting various forms of ball millings), make mixture paste; 4. the said mixture slurry is carried out drying treatment; Described drying can adopt conventional heat drying, and also vacuum-pumping to be to shorten time of drying or to reduce drying temperature, and the moisture of looking time of drying in the mixture is as the criterion by evaporation fully; 5. dried material is carried out complete calcination, makes it to carry out solid state reaction by certain temperature schedule, to remove organism and to obtain required composite oxides, calcination temperature system (comprising calcination temperature and time) determines by the experimental technique of routine according to concrete reaction system---different with traditional solid reaction process is, here general as long as through a calcination, need not repeated multiple times; 6. with firing product again mechanical disintegration (as broken, levigate) form powder.

Below be several operational instances:

Embodiment 1: oxygen permeable film material La _0.6Sr _0.4Co _0.8Fe _0.2O _3-δThe preparation of ceramic.

Get 4.891g La ₂O ₃, 4.254g Sr (NO ₃) ₃, 3.351g Co ₂O ₃, 0.806g Fe ₂O ₃, the 0.532g polyacrylic acid, 14ml distilled water, ball milling is made slurry after mixing, and drying is 12 hours under 90 ℃, and being heated to 1000 ℃ of calcinations then became La in 5 hours _0.6Sr _0.4Co _0.8Fe _0.2O _3-δPottery obtains powder after the pulverizing.Powder particle size is about 200nm, and is spherical in shape substantially.

Embodiment 2: solid electrolyte Ce _0.8Sm _0.2O _1.9The preparation of ceramic.

Get 17.631g Ce (NO ₃) ₃6.37H ₂O, 1.744g Sm ₂O ₃, the 0.019g polyoxyethylene glycol, 20ml distilled water is made slurry after ball milling mixes, and drying is 8 hours under 60 ℃, and being heated to 700 ℃ of calcinations then became Ce in 2 hours _0.8Sm _0.2O _1.9Pottery obtains powder after the pulverizing.Diameter of particle is at 10～20nm, basic globulate.

Embodiment 3: middle temperature oxygen ion conductor La _0.8Sr _0.2Ga _0.8Mg _0.2O _3-δThe preparation of ceramic.

Get 3.261g La ₂O ₃, 1.064g Sr (NO ₃) ₂, 1.912g Ga ₂O ₃, 0.297g Mg (OH) ₂, the 0.065g polymethyl acrylic acid, 8.3ml distilled water is made slurry after the mixing and ball milling, and drying is 10 hours under 70 ℃, and being heated to 1400 ℃ of calcinations then became La in 6 hours _0.8Sr _0.2Ga _0.8Mg _0.2O _3-δPottery obtains powder after the pulverizing.Diameter of particle is about 100nm, basic globulate.

Claims (1)

1. A method for preparing multi-component composite metal oxide functional ceramic micropowder, comprising the process of mixing, burning and pulverizing metal oxides, hydroxides or salts, characterized in that the specific process is as follows: metal oxides, hydrogen The oxide or salt is mechanically ground and mixed with an aqueous solution of an organic dispersant to make a slurry, and then burned to cause a solid phase reaction to form the required composite metal oxide, which is pulverized to obtain a fine powder; The organic dispersant is polymer polyelectrolyte polymethacrylic acid, polyacrylic acid and its salts, or non-ionic linear polymer compound polyvinyl alcohol, polyethylene glycol, and the amount of dispersant is 0.1-4% of the weight of the original material .