CN102677174B

CN102677174B - Preparation method of Y4Si3O12 crystal whiskers

Info

Publication number: CN102677174B
Application number: CN201210140071.2A
Authority: CN
Inventors: 黄剑锋; 杨柳青; 曹丽云; 王雅琴
Original assignee: Shaanxi University of Science and Technology
Current assignee: Suqian Yichuang Intelligent Technology Co.,Ltd.
Priority date: 2012-05-08
Filing date: 2012-05-08
Publication date: 2015-04-22
Anticipated expiration: 2032-05-08
Also published as: CN102677174A

Abstract

The invention relates to a preparation method of Y4Si3O12 crystal whiskers, which comprises the steps of: dissolving Y (NO)3.6H2O and Na2SiO3.9H2O in anhydrous ethanol to obtain solution A; adding ethylenediaminetetraacetic acid (EDTA) and high-density polyethylene (HDPE) into the solution A and magnetically agitating for ultrasonic reaction to obtain solution B; and placing the solution B in a hydrothermal reaction kettle lined with polytetrafluoroethylene for constant-temperature reaction, conducting centrifugal separation, successively washing with distilled water and anhydrous ethanol and finally drying to obtain Y4Si3O12 crystal whiskers. The preparation method of the Y4Si3O12 crystal whiskers has the advantages that the process is simple to control, the cost is lower, the preparation temperature is low, the later-stage crystallization is not required and the possible defects that the crystal grains grow up, are coarsened or curled and the like in the later-stage heat treatment process are avoided to some extent. The appearance control can be realized and the Y4Si3O12 crystal whiskers with high purity and even grain size can be prepared.

Description

A kind of Y 4si 3o 12the preparation method of whisker

Technical field

The present invention relates to a kind of Y of morphology controllable ₄si ₃o ₁₂preparation method, be specifically related to a kind of Y ₄si ₃o ₁₂the preparation method of whisker.

Background technology

The physical and chemical performance of the constructional feature that yttrium silicate material possesses self and a series of excellence, as characteristics such as low elastic modulus, low high-temperature oxygen rate of permeation, low linear expansion coefficient, low vaporization at high temperature rate, resistances to chemical attack, become a kind of high performance structures material, be widely used in aerospace field.There are three kinds of crystal phase structures in yttrium silicate, is Y respectively ₂siO ₅, Y ₂si ₂o ₇and Y ₄si ₃o ₁₂.

At present, although about Y ₄si ₃o ₁₂bibliographical information considerably less, yet there is not been reported for its lattice parameter, but because its fusing point is up to 1950 DEG C, has extremely low high-temperature oxygen rate of permeation, simultaneously Y ₄si ₃o ₁₂thermal expansivity (4.31 × 10 ^-6K ^-1) and the internally coated thermal expansivity (4.5 × 10 of SiC ^-6k ^-1) closely [Sun ZQ, Zhou YC, Wang JY, et al. γ-Y ₂si ₂o ₇, amachinable silicate ceramic:mechanical properties and machinability.TheAmerican Ceramic Society, 2007,90 (8): 2535-2541.], and Y ₄si ₃o ₁₂and there is good physical chemistry consistency [Ogura Y, Kondo M, Morimoto T.Oxygenpermeability of Y between SiC ₂siO ₅.Materials Transactions [J], 2001,42 (6): 1124-1130.], being thus considered to SiC is one of optimal top layer material in internally coated composite coating structure, has a wide range of applications in high-temp antioxidizing material.

Huang Jianfeng etc. successfully prepare gradient Y on C/C-SiC surface ₂siO ₅/ Y ₂si ₂o ₇/ Y ₄si ₃o ₁₂high-temperature oxidation resistant coating [Huang JF, Zeng XR, Li HJ, et al.SiC/yttrium silicate/glass multi-layer oxidation protective coating for carbon/carbon composites [J] .Carbon, 2004,42 (11): 2356-2359.] and gradient Y ₂siO ₅/ Y ₂si ₂o ₇/ Y ₄si ₃o ₁₂/ glass coating high-temperature oxidation resistant coating [Huang JF, Li HJ, Zeng XR.Yttrium silicate oxidation protection coating for SiC coated carbon/carbon composites [J] .Ceramics International, 2006,32 (4): 417-421.], wherein gradient Y ₂siO ₅/ Y ₂si ₂o ₇/ Y ₄si ₃o ₁₂/ glass coating can in the still air of 1600 DEG C available protecting C/C matrix material 200h, coating C/C oxidation weight loss is less than 0.65%.And have document [Wang Ya-qin, Huang Jian-feng, Cao Li-Yun et al " Preparation and phase composition optimization of yttrium silicates multi-composition coating for SiC pre-coated carbon/carbon composites " J.Compos.Mater.2011,46 (4): 409-415.] report can utilize the comprehensive advantage of complex phase iridium silicate coating layer to solve coefficient of thermal expansion mismatch between inside and outside coating and the anti-oxidant Problem of Failure of coating that causes.Again according to the thought of Whisker-Reinforced Ceramics, and Y ₄si ₃o ₁₂the physical chemistry consistency very good with SiC undercoat, Y ₄si ₃o ₁₂whisker has very large prospect for toughness reinforcing SiC internally coated high-temperature oxidation resistant coating preparation field.

Summary of the invention

The object of the invention is to adopt solvent-thermal method to realize morphology controllable, the high-purity and Y that granularity is comparatively homogeneous ₄si ₃o ₁₂the preparation method of whisker.

For achieving the above object, the technical solution used in the present invention is:

1) analytically pure Y (NO) is got ₃6H ₂o, Na ₂siO ₃9H ₂o, according to Y: Si=1:(1.2 ~ 1.8) mol ratio be dissolved in dehydrated alcohol, be mixed with Y ³⁺concentration is the solution of 0.36 ~ 0.86mol/L, regulates its pH=7 ~ 9, obtain solution A by NaOH solution;

2) in solution A, Y is pressed ³⁺: EDTA:HEPE=1:(0.4 ~ 1.5): the mol ratio of (0.05 ~ 0.09) adds analytically pure EDTA and HDPE as template, at room temperature magnetic agitation 0.5 ~ 2h, mixes, then ultrasonic reaction 1 ~ 3h, ultrasonic power is 300 ~ 500W, obtains solution B;

3) solution B is placed in teflon-lined water heating kettle, controlling packing ratio is 40 ~ 60%, then reactor is put into isothermal reactor, at 140 ~ 210 DEG C of reaction 48 ~ 72h;

4) question response system naturally cools to room temperature, centrifugation, and successively wash 3 ~ 5 times separately with distilled water and dehydrated alcohol, finally in the electric drying oven with forced convection of 50 ~ 80 DEG C, drying obtains Y ₄si ₃o ₁₂whisker.

The concentration of described step 1) NaOH solution is 3mol/L.

Y of the present invention ₄si ₃o ₁₂preparation method's technology controlling and process of whisker is simple, and cost is lower, and preparation temperature is low and do not need later stage Crystallizing treatment, avoid to a certain extent may cause in Post isothermal treatment process grain growth, alligatoring or the defect such as curling.

Can morphology control be realized, high-purity and that granularity is comparatively homogeneous Y can be prepared ₄si ₃o ₁₂whisker.

Due to Y ₄si ₃o ₁₂fusing point up to 1950 DEG C, Y ₄si ₃o ₁₂thermal expansivity (4.31 × 10 ^-6k ^-1) with the thermal expansivity (4.5 × 10 of SiC ^-6k ^-1) very close, and and have good physical chemistry consistency between SiC, the Y that the present invention prepares ₄si ₃o ₁₂whisker is one of crystal whisker toughened material of optimal external coating (EC) in internally coated composite coating structure with SiC, effectively can improve the antioxidant property of coating.In addition, Y ₄si ₃o ₁₂whisker has broad application prospects in electronic industry, areas of information technology.

Accompanying drawing explanation

Fig. 1 is the present invention prepared positive yttrium silicate (Y at hydrothermal temperature 140 DEG C ₂siO ₅) scanning electron microscope (SEM) photo of whisker.

Embodiment

Below in conjunction with drawings and Examples, the present invention is described in further detail.

Embodiment 1:

1) analytically pure Y (NO) is got ₃6H ₂o, Na ₂siO ₃9H ₂o, the mol ratio according to Y: Si=1:1.2 is dissolved in dehydrated alcohol, is mixed with Y ³⁺concentration is the solution of 0.36mol/L, regulates its pH=7, obtain solution A by the NaOH solution that concentration is 3mol/L;

2) in solution A, Y is pressed ³⁺: the mol ratio of EDTA:HEPE=1:0.4:0.05 adds analytically pure EDTA and HDPE as template, and at room temperature magnetic agitation 0.5h, mixes, then ultrasonic reaction 1h, and ultrasonic power is 500W, obtains solution B;

3) solution B is placed in teflon-lined water heating kettle, controlling packing ratio is 40%, then reactor is put into isothermal reactor, at 210 DEG C of reaction 48h;

4) question response system naturally cools to room temperature, centrifugation, and successively wash 3 times separately with distilled water and dehydrated alcohol, finally in the electric drying oven with forced convection of 50 DEG C, drying obtains Y ₄si ₃o ₁₂whisker.

Embodiment 2:

1) analytically pure Y (NO) is got ₃6H ₂o, Na ₂siO ₃9H ₂o, the mol ratio according to Y: Si=1:1.8 is dissolved in dehydrated alcohol, is mixed with Y ³⁺concentration is the solution of 0.86mol/L, regulates its pH=9, obtain solution A by the NaOH solution that concentration is 3mol/L;

2) in solution A, Y is pressed ³⁺: the mol ratio of EDTA:HEPE=1:1.5:0.09 adds analytically pure EDTA and HDPE as template, and at room temperature magnetic agitation 2h, mixes, then ultrasonic reaction 3h, and ultrasonic power is 300W, obtains solution B;

3) solution B is placed in teflon-lined water heating kettle, controlling packing ratio is 60%, then reactor is put into isothermal reactor, at 140 DEG C of reaction 72h;

4) question response system naturally cools to room temperature, centrifugation, and successively wash 5 times separately with distilled water and dehydrated alcohol, finally in the electric drying oven with forced convection of 80 DEG C, drying obtains Y ₄si ₃o ₁₂whisker.

Method as seen from Figure 1 by describing in embodiment 2, available Y ₄si ₃o ₁₂whisker, is characterized by diameter of whiskers and is about 10 ~ 200nm, and whisker length is about 3 ~ 5 μm.

Embodiment 3:

1) analytically pure Y (NO) is got ₃6H ₂o, Na ₂siO ₃9H ₂o, the mol ratio according to Y: Si=1:1.5 is dissolved in dehydrated alcohol, is mixed with Y ³⁺concentration is the solution of 0.61mol/L, regulates its pH=8, obtain solution A by the NaOH solution that concentration is 3mol/L;

2) in solution A, Y is pressed ³⁺: the mol ratio of EDTA:HEPE=1:0.95:0.07 adds analytically pure EDTA and HDPE as template, and at room temperature magnetic agitation 1h, mixes, then ultrasonic reaction 2h, and ultrasonic power is 400W, obtains solution B;

3) solution B is placed in teflon-lined water heating kettle, controlling packing ratio is 50%, then reactor is put into isothermal reactor, at 175 DEG C of reaction 60h;

4) question response system naturally cools to room temperature, centrifugation, and successively wash 4 times separately with distilled water and dehydrated alcohol, finally in the electric drying oven with forced convection of 65 DEG C, drying obtains Y ₄si ₃o ₁₂whisker.

Claims

1. a Y ₄si ₃o ₁₂the preparation method of whisker, is characterized in that:

1) analytically pure Y (NO) is got ₃6H ₂o, Na ₂siO ₃9H ₂o, is dissolved in dehydrated alcohol according to the mol ratio of Y:Si=1:1.8, is mixed with Y ³⁺concentration is the solution of 0.86mol/L, regulates its pH=9, obtain solution A by the NaOH solution that concentration is 3mol/L;

2) in solution A, Y is pressed ³⁺: the mol ratio of EDTA:HEPE=1:1.5:0.09 adds analytically pure EDTA and HEPE as template, and at room temperature magnetic agitation 2h, mixes, then ultrasonic reaction 3h, and ultrasonic power is 300W, obtains solution B;

4) question response system naturally cools to room temperature, centrifugation, and successively wash 5 times separately with distilled water and dehydrated alcohol, finally in the electric drying oven with forced convection of 80 DEG C, drying obtains Y ₄si ₃o ₁₂whisker;

Y ₄si ₃o ₁₂diameter of whiskers is 10 ~ 200nm, and whisker length is 3 ~ 5 μm.