CN1233057C

CN1233057C - Method for preparing strontium lanthanum manganate self-supporting tube of solid oxide fuel cell by utiling slip-casting process

Info

Publication number: CN1233057C
Application number: CNB031096212A
Authority: CN
Inventors: 谢朝晖; 朱庆山; 柳华; 李连萱; 李凤霞
Original assignee: Institute of Process Engineering of CAS
Current assignee: Institute of Process Engineering of CAS
Priority date: 2003-04-09
Filing date: 2003-04-09
Publication date: 2005-12-21
Anticipated expiration: 2023-04-09
Also published as: CN1536696A

Abstract

The present invention belongs to a technology for preparing a self-supporting tube of a cathode of a solid oxide fuel cell (SOFC) by a slurry casting method, which comprises the steps of making a model, mixing slurry, mixing materials by ball milling, casting slurry, releasing a mold, sintering, etc. The slurry is prepared from lanthanum strontium manganate (LSM), water, dispersing agent and plasticizing agent according to a certain proportion, wherein LSM accounts for 20 to 35 wt%, and water accounts for 65 to 80 wt%; the dispersing agent is prepared from Arabic gum powder and carboxymethyl cellulose, each of which accounts for 0.2 to 0.4 wt% of the amount of dry LSM powder, and the slurry with good suspension performance is formed after ball milling, mixing and dispersion. After the slurry is cast into a plaster mold for 3 to 15 minutes, a tubular blank with uniform thickness can be formed; after the blank is made to stand in the plaster mold for 3 to 15 hours, the mold is released; then, the blank is made to stand for 10 to 20 hours; the blank is pre-burnt at the temperature of 1000DEG C to 1200DEG C; finally, the blank is sintered into the self-supporting tube at the temperature of 1300DEG C to 1400DEG C. The present invention has simple technology, good mold release performance of a wet blank, a thin wall of the self-supporting tube, uniform thickness, a low shrinkage ratio, proper porosity, uniform distribution of pore spaces and high intensity, and is suitable for laboratories or small batch production.

Description

Slip casting method prepares Solid Oxide Fuel Cell lanthanum strontium manganate self-supporting tube side method

Technical field the invention belongs to the preparation technology of cathode of solid oxide fuel cell stay pipe.

The background technology fuel cell is little owing to polluting, the high Blast Furnace Top Gas Recovery Turbine Unit (TRT) that is counted as a new generation of energy transformation ratio.Wherein Solid Oxide Fuel Cell is strong with its fuel tolerance, efficient is high, purposes is wide and gain great popularity.Traditional tubular solid-oxide fuel battery adopts the stable zirconia of yttrium to make electrolyte, and nickel-doped zirconia cermet is done anode, and lanthanum strontium manganate is made negative electrode.Tubular solid-oxide fuel battery need adopt cathode material or anode material to make the self-supporting pipe, so that make electrolytic thin-membrane on this basis.Electrolyte is realized filming (as 10 μ m), just can make fuel cell under the prerequisite of higher open circuit voltage of maintenance and power density, and working temperature is reduced to about 800 ℃ by 900～1000 ℃.

Slip casting method is made light wall pipe and is method commonly used in the ceramic process, and is this simple for process, do not need complex apparatus, more is applicable to laboratory and small lot batch manufacture.But adopt grouting process to make earthenware, the slip that need suspension, has good stability, and also the wet base of making will have certain plasticity and intensity.Lanthanum strontium manganate is a kind of lean material of more difficult suspended dispersed, adopts relatively difficulty of slip casting method moulding.The present invention has proposed the technological package scheme at aspects such as plaster mold processing, slip modulation.By the lanthanum strontium manganate light wall pipe of this fabrication techniques, wet base release property is good, the goods wall thin and thickness is even, shrinkage is low, porosity is suitable and even aperture distribution, intensity height.Preparation for follow-up electrolytic thin-membrane and anode film provides good matrix.Summary of the invention the present invention relates to a kind of preparation method of cathode of solid oxide fuel cell stay pipe, and the invention key is to regulate slip composition and proportioning, selects suitable dispersant and plasticizer for use, and plaster mold is carried out suitable processing.The added solid material of the process of sizing mixing is a lanthanum strontium manganate, and employed dispersant and plasticizer are carboxymethyl cellulose and arabia gum rubber powder.---the process of slip casting---demoulding---sintering that technical process comprises the material of sizing mixing.Concrete processing step is as follows: the material of sizing mixing is lanthanum strontium manganate, carboxymethyl cellulose, arabia gum rubber powder and water to be put into the nylon jar mix, and obtains slip behind ball milling on the ball mill.Because the lanthanum strontium manganate powder is difficult for suspending, bring difficulty to injection forming, so the selection of dispersant and proportioning just become key issue.The present invention adopts carboxymethyl cellulose and gum arabic powder as dispersant and simultaneously as plasticizer.Lanthanum strontium manganate accounts for slip total weight 20～35% in the compound, and water accounts for slip total weight 65～80%, and carboxymethyl cellulose and arabia gum rubber powder consumption are respectively 0.2～0.4% of lanthanum strontium manganate siccative weight.After the mixing of materials, left standstill earlier 0～5 hour, ball milling is 30～180 minutes then, is used further to slip casting.Slip casting is that slip is poured in the cylindrical cavity of plaster mold, after 3～15 minutes, pours out remaining slurry.Base substrate leaves standstill the demoulding after 3～15 hours in plaster mold.Before the calcining, base substrate was displayed 10～20 hours.Base substrate after will displaying again slowly was warming up under 1000～1200 ℃ of temperature pre-burning 1～6 hour, was warming up to 1300～1400 ℃ of scope sintering again 1～15 hour.

Through the lanthanum strontium manganate pipe that said process makes, thickness is applicable to the Solid Oxide Fuel Cell of self supporting structure in 1.0～2.0mm scope.

The appended Fig. 1 of description of drawings is the gypsum mold profile that is used to manufacture the lanthanum strontium manganate pipe, it be an axis of centres to the cylinder that has column type cavity (1), the bottom of central cavity (2) are sealed, and the top of cavity is open grouting port (3).The correct processing of plaster mold is a key that guarantees smooth demoulding.Need to seal at plaster mold upper surface (4), in order to avoid moisture content is from this plane evaporation with sealing compound (as silicone resin).Make plaster mold have same water evaporation rate up and down like this, guarantee that plaster mold inside has uniform hole and water absorptivity everywhere.Another measure of taking for plaster mold is exactly on the top (5) in the scope of plaster mold end face 10mm of central cavity (1), to adopt fluid-tight film (as the adhesive sticker adhesive tape) to paste along the cavity wall.Can guarantee that so made base pipe upper port is smoothly neat, and be easy to the demoulding.

Plaster mold is an integral body, and its axial slices is " recessed " font.Central cavity is for the usefulness of self-supporting pipe moulding.The sidewall of central cavity is vertical, and the self-supporting pipe of moulding is a straight bobbin like this, but not bullet.Before slip casting, can coat a little release agent (as silicone oil) equably at the wall of cavity, so that the demoulding.In the bottom of central cavity, can before slip casting, spread with one deck hard plastic sheet, can avoid slip to adhere to like this, thereby make all open self-supporting pipe in two ends in the deposition of bottom.When needs self-supporting Guan Yiduan is open, when the other end seals, then needn't spread this plastic sheet.

Embodiment (embodiment one) is got plaster mold ready.In the lanthanum strontium manganate powder of 100 parts of weight ratios, add 0.34 part carboxymethyl cellulose and 0.32 part gum arabic powder respectively, add 220 parts water again, display 30 minutes after, on ball mill the mill 1 hour.Slip injects plaster mold and pours out the residue slurry after 4 minutes, pours out the lanthanum strontium manganate base substrate after 10 hours, obtains the base pipe of the about 2mm of thickness, external diameter 20mm, high 150mm.The base pipe is put into stove then and is heated air drying 15 hours, and heating rate is 5 ℃/min, and 1300 ℃ of insulations 5 hours, slowly cooling then when being cooled to room temperature, was taken out finished product.The face shaping rule, no cracking phenomena.Through scanning electron microscopic observation, sintered particles evenly, porous nickel, no microfissure, adopt drainage to record porosity about 30%.

(embodiment two) get plaster mold ready, in the lanthanum strontium manganate powder of 100 parts of weight ratios, add 0.4 part carboxymethyl cellulose and 0.28 part gum arabic powder respectively, add 250 parts water again, display 30 minutes after, on ball mill the mill 2 hours.Slip injects plaster mold and pours out the residue slurry after 7 minutes, pours out the lanthanum strontium manganate base substrate after 8 hours, obtains the base pipe of the about 2mm of thickness, external diameter 25mm, high 100mm.The base pipe is put into stove then and is heated air drying 12 hours, and heating rate is 3 ℃/min, 1000 ℃ of insulations 2 hours, is warming up to 1300 ℃ and be incubated 4 hours then.Slowly cooling then is cooled to room temperature and takes out finished product.The face shaping rule, no cracking phenomena.Through scanning electron microscopic observation, sintered particles evenly, porous nickel, no microfissure, adopt drainage to record voidage about 35%.

Claims

1. a slip casting method prepares the technology of Solid Oxide Fuel Cell lanthanum strontium manganate self-supporting pipe, comprise the slip preparation-slip casting-demoulding-sintering process, it is characterized in that: so-called slip preparation, be that the lanthanum strontium manganate powder that will account for slip total weight 20～35% mixes with the water that accounts for slip total weight 65～80%, add gum arabic powder and the carboxymethyl cellulose that accounts for lanthanum strontium manganate grain weight amount 0.2～0.4% more respectively, this mixture is after displaying 0～5 hour, ball milling 30～180 minutes is made the good slip of suspension; So-called slip casting is that the slip that will prepare injects in the column type cavity of plaster mold, constantly replenishes slip to remain full of state, pours out the residue slip after 3～15 minutes; The so-called demoulding is that base substrate leaves standstill the demoulding after 3～15 hours in plaster mold, base substrate is displayed in air 10～20 hours again; So-called sintering is that the base substrate after displaying slowly was warming up under 1000～1200 ℃ of temperature pre-burning 1～6 hour, and then continued elevated temperature to 1300～1400 ℃ sintering temperature 1～15 hour, slowly cools to room temperature and obtains finished product.

2. the described preparation Solid Oxide Fuel Cell of claim 1 lanthanum strontium manganate self-supporting plumber plants, wherein used plaster mold, it is the cylinder that central authorities have the column type cavity, the bottom surface of cavity is sealed, the top of cavity is open grouting port, the plaster mold top annular is sealed with silicone resin on the plane, sticks a circle adhesive sticker adhesive tape along the cavity wall in the column type cavity in plaster mold top plan 10mm altitude range.