CN104291773B - The preparation method of the anti-intense radiation block materials that a kind of low density ultrahigh-temperature is stable - Google Patents

Abstract

The present invention relates to the preparation method of the stable anti-intense radiation block materials of a kind of low density ultrahigh-temperature.Concrete steps are: be dissolved in by agar in the deionized water of more than 70 DEG C, again the opalizer powder body material of surface hydrophilic is put into this solution to be uniformly mixed, after add silica hydrogel, then pour mould into and treat that cooling after-pouring is shaping, and then carry out lyophilize.Namely obtain after 450 DEG C of thermal treatments removing agar that density is low reaches 0.18Kg/m ³high temperature resistant low thermal conductivity block xerogel.In addition, utilize this method can also solve the problem of powder body material dispersing property difference in body material, prepare fiber composite block materials.

Description

The preparation method of the anti-intense radiation block materials that a kind of low density ultrahigh-temperature is stable

Technical field

The present invention relates to the preparation method of the anti-intense radiation block materials of a kind of low density superhigh temperature resistant.

Background technology

The development of aerospace, catalytic field proposes requirements at the higher level to high-temperature hot protection.Current thermally protective materials has matrix material, thermal insulation inorganic material and the coated materials such as carbon back, resin, ceramic base.Wherein, organic lagging material and carbon-based material all have ablation characteristics, belong to loss-type thermal protection.Stupalith has high heat resistance, but its density is comparatively large, and solid thermal conductance is difficult to reduce, and preparation process needs thousands of degree high temperature, and technique is comparatively loaded down with trivial details.Aerogel material is owing to having unique three-dimensional nanoparticles skeleton and mesoporous (2-50nm) is main microporous structure, solid state heat can be effectively suppressed to conduct and gaseous exchange heat transfer, therefore aerogel has excellent low temperature heat-insulating flame-retardant performance, but along with temperature raises, radiation thermal conduction sharply increases, and aerogel heat-proof performance significantly reduces.In addition, the preparation of high temperature resistant aerogel needs through the strict ethanol supercritical drying process controlled, and complicated process of preparation, the processing condition of High Temperature High Pressure have certain risk, and energy consumption is large.

The materials such as Rutile Type titanium oxide and potassium titanate crystal whisker all have good infrared barrier characteristic, can be used for the radiant heat conductance under reduction high temperature.But these materials itself have larger density, solid thermal conduction is comparatively large, does not reach the requirement of lower thermal conductivity; In the research of forefathers, by Rutile Type titanium dioxide powder and aerogel compound, reduce hyperthermia radiation thermal conductivity to reach, keep the heat conducting object of low gas-solid simultaneously, obtain certain progress.But titanium dioxide powder is very easily sedimentation in aerogel recombination process, causes compound uneven, condition is difficult to control, and utilizes the materials such as aerogel not reach energy-conservation object as composite substrate.So the method preparation probing into cheap and simple has low density and has that high-temperature stability is good simultaneously, high temperature resistance thermal radiation, low thermal conductivity material there is its necessity.

Summary of the invention

The object of the present invention is to provide the preparation method of the anti-intense radiation block materials of a kind of Low-density high temperature resistant.

The preparation method of the anti-intense radiation block materials that the low density ultrahigh-temperature that the present invention proposes is stable, is characterized in that concrete steps are as follows:

(1) agar powder being put into 70-80 DEG C of hot water with the ratio of 2.5-3.5wt% mixes to evenly;

(2) putting into the prepared solution of step (1) by through the titanium dioxide of hydrophilic treatment, potassium titanate crystal whisker powder body material, stirring 40min to mixing;

(3) silica hydrogel pH value is adjusted to neutrality, adds in the prepared mixed solution of step (2), stirring 20min to mixing;

(4) mixed solution that step (3) obtains is poured in pre-prepd mould, agar solidification after cooling, build shaping;

(5) cooled colloidal materials is put into refrigerator and cooled and is frozen 10h, then puts into freeze drying equipment, vacuumizes dry 30h, obtain anti-intense radiation block materials under about-40 DEG C of conditions.

In the present invention, the required powdered material that must prepare is carried out hydrophilic pre-treatment by step (2), increase powder surface hydroxy radical content, thus improve powder property compatible with water and promote that in preparation process, particle is cross-linked, thus when at high temperature using, removing organism back skeleton is kept.

In the present invention, the silica hydrogel with nano particle is mixed with agar-opalizer system, the silicon oxide particle obtained serves further by the effect that opalizer particle is crosslinked, improves homogeneity and the formability of material simultaneously, obtains the porous blocks of nanometer-submicron particles compound.

Beneficial effect of the present invention is:

1) utilize agar to dissolve in the hot water and keep better viscosity, the feature of cooling after coagulation, can be dispersed in powder body material in agar gel.

2) in mixed solution, add silica hydrogel cheap and easy to get, energy high degree improves crosslinked plasticity and the stability of block materials.

3) for the powder body material of the comparatively large easily sedimentation of particle, the mode of mixed solution fast cooling being solidified agar can be adopted to fix macrobead powder, keep dispersing uniformity.

4) select titanium dioxide, potassium titanate crystal whisker prepares material as block, it has good high-temperature stability and intercepts infrared emissivity, can be applied to high-temperature hot safeguard system.

5) mixed solution is injected fibrefelt, the even compound of powder body material and fibrefelt can be realized.

6) material preparation adopts water as solvent, with low cost, and compared with organic solvent, ensure that the security of preparation process.Starting material required for preparation, as agar, silica hydrogel etc., with low cost, safety and environmental protection; The materials such as titanium oxide, metatitanic acid whisker are industrial mass production gained, without the need to through special process process.

Accompanying drawing explanation

Fig. 1 is embodiment 1 sample drawing.

Fig. 2 is embodiment 2 sample photo and SEM figure thereof.Wherein: (a) is sample photo, (b) is SEM figure.

Fig. 3 is embodiment 3 sample photo and SEM figure thereof.Wherein: (a) is sample photo, (b) is SEM figure.

Fig. 4 is embodiment 4 sample photo and SEM figure thereof.Wherein: (a) is sample photo, (b) is SEM figure.

Fig. 5 is embodiment 5 spectrogram.

Fig. 6 is embodiment 6 sample drawing.

Fig. 7 is embodiment 7 sample drawing.

Fig. 8 is embodiment 8 sample drawing.

Embodiment

The invention will be further described by the following examples, but these embodiments must not be used for explaining limiting the scope of the invention.

embodiment 1: by agar with 3% ratio put into 70 DEG C of hot water and mix to evenly.The Rutile Type titanium oxide powder powder material of the 250nm particle diameter through hydrophilic treatment being put into above-mentioned gained solution, stirring 40min to mixing.Above mixed solution is poured in pre-prepd mould, agar solidification after cooling, build shaping.Cooled material is put into refrigerator and cooled and is frozen 10h, after put into freeze drying equipment, under-40 DEG C of conditions, vacuumize dry 30h, then the sample of agar obtained above and titanium oxide compound is removed agar through 450 DEG C of thermal treatments, obtaining density is 0.16Kg/m ³rutile titanium oxide xerogel block.Fig. 1 is the sample photo obtained.Dried sample maintains general shape, but has certain contraction compared with before drying, surface irregularity.

embodiment 2:the present embodiment adds the silica hydrogel of a certain amount of pH=7 as different from Example 1 in the mixed solution of agar and titanium dioxide powder.Obtaining shaping complete density is 0.18Kg/m ³, porosity reaches the titania-silica porous blocks of 90%.Fig. 2 is sample photo (a) and SEM figure (b) thereof that obtain.Sample formation is good, basic ungauged regions compared with before drying, surfacing, and pore distribution is even, concentrates as 20nm and 32 μm of two-stage hole, visible silica sol add the formability significantly improving this block materials.

embodiment 3: block embodiment 2 obtained carries out 1200 DEG C of thermal treatment 1h, plasticity remains intact, linear shrinkage is photo (a) and SEM figure (b) thereof that 3%. Fig. 3 are 1200 DEG C of rear samples of process, and visible sample maintains primary morphology, has good high-temperature stability.

embodiment 4: the present embodiment adopts diameter to be the potassium titanate crystal whisker of 5-10 μm, length 10-15 μm as different from Example 2.Preparation method is identical with embodiment 2.Obtain porous potassium titanate crystal whisker block.Fig. 4 is gained sample photo (a) and SEM figure (b) thereof.The block materials good moldability obtained, surfacing, SEM figure shows that whisker and silicon oxide achieve good compound, and whisker distribution is comparatively even.

embodiment 5:be scattered in Potassium Bromide by the sample that embodiment 2 and embodiment 4 obtain with 5wt%, being pressed into thickness after grinding is evenly 0.3mm thin slice, surveys its spectral transmittance with Fourier transform infrared transmitted light spectrometer (FTIR).As shown in Figure 5, at 2.5-5 mu m waveband, the sample infrared light transmittance of titanium oxide and potassium titanate crystal whisker is very low, wherein, at 2.5 μm of places, bromizates the adding of the titanium oxide of 5wt% and potassium titanate crystal whisker sample potassium transmitance and to decline respectively 49% and 53%.According to blackbody radiation law, along with temperature raises, quantity of radiant energy sharply strengthens, and peak position hypsochromic shift moves, and 2.5 μm of places are 1000 DEG C of positions that radiated light energy is the strongest.Therefore embodiment 2 has the strong heat-radiating properties of good high temperature resistance with gained sample in embodiment 4.

embodiment 6: by agar with 3% ratio put into 70 DEG C of hot water and mix to evenly.The Rutile Type titanium oxide powder powder material of the 250nm particle diameter through hydrophilic treatment being put into above-mentioned prepared agar-agar soln, stirring 40 minutes to mixing.Poured into by above mixed solution in pre-prepd mullite fiber felt, cooling is built shaping.Cooled material is put into refrigerator and cooled and is frozen 10h, after put into freeze drying equipment, under-40 DEG C of conditions, vacuumize dry 24h, then through 450 DEG C of thermal treatments removing agar, obtaining density is 0.22Kg/m ³titanium oxide-fiber composite sample.Fig. 6 is gained fiber composite sample, and compound is even, good moldability.

embodiment 7: the present embodiment adds the silica hydrogel of a certain amount of pH=7 as different from Example 6 at the mixed solution of agar and titanium dioxide powder, build shaping after mixing again with fiber composite.Obtain rutile titania-silica-fiber composite sample.Fig. 7 is that gained sample formation is good, surfacing by the sample photo of gained fiber composite sample through 1200 DEG C of thermal treatment 1h, and compound is even, and the basic ungauged regions of heat treatment process, has good resistance to elevated temperatures.

embodiment 8:the present embodiment as different from Example 7, adopts potassium titanate crystal whisker and fiber composite to build shaping.Obtaining density is 0.25Kg/m ³potassium titanate crystal whisker-silicon oxide-fiber composite sample.Fig. 8 is that gained sample formation is good by the sample photo of gained fiber composite sample through 1200 DEG C of thermal treatment 1h, and surfacing is even, and heat treatment process ungauged regions, high temperature stability performance is good.

Claims (1)

1. a preparation method for the anti-intense radiation block materials that low density ultrahigh-temperature is stable, is characterized in that concrete steps are as follows:

(1) agar powder being put into 70-80 DEG C of hot water with the ratio of 2.5-3.5wt% mixes to evenly;

(2) by putting into the prepared solution of step (1) through the titanium dioxide of hydrophilic treatment or potassium titanate crystal whisker powder body material, 40min is stirred to mixing;

(3) silica hydrogel pH value is adjusted to neutrality, adds in the prepared mixed solution of step (2), stirring 20min to mixing;

(4) mixed solution that step (3) obtains is poured in pre-prepd mould, agar solidification after cooling, build shaping;

(5) cooled colloidal materials is put into refrigerator and cooled and is frozen 10h, then puts into freeze drying equipment, vacuumizes dry 30h, obtain anti-intense radiation block materials under-40 DEG C of conditions.