CN105236961A - High temperature stable monoclinic phase-free tetragonal zirconia thermal barrier coating material and preparation method thereof - Google Patents

Abstract

The invention discloses a high temperature stable monoclinic phase-free tetragonal zirconia thermal barrier coating material (Zr0.76Ce0.16Gd0.08)O1.96 and a preparation method thereof. According to the preparation method, Ce(NO3)3.6H2O, Gd(NO3)3.6H2O, and Zr(NO3)4.3H2O with a purity of 99.99% are taken as raw materials; a mixture is prepared at a Zr4+:Ce3+:Gd3+ molar ratio of 0.76:0.16:0.08; an aqueous solution with a certain concentration is prepared by taking deionized water as a solvent; appropriate amounts of citric acid and polyethylene glycol are added, and an obtained mixed solution is subjected to magnetic stirring to be clear and transparent; purified air with a pressure of 0.3MPa is taken as an atomizing medium, and is delivered into a corundum crucible with a temperature of 500 DEG C via atomizing; after atomizing, the temperature is increased to 1200 DEG C for 6h of calcining so as to obtain the pure tetragonal zirconia raw material. High temperature phase stability of the high temperature stable monoclinic phase-free tetragonal zirconia thermal barrier coating material is excellent, no monoclinic phase tetragonal zirconia is generated after 80h of calcining at 1500 DEG C, tetragonal phase content is 48mol%, the preparation method is high in phase purity and low in temperature, and the preparation method is simple.

Description

A kind of high-temperature stable and without the tetragonal zircite heat barrier coat material and preparation method thereof of monoclinic phase

Technical field

The present invention relates to a kind of high-temperature stable and without the tetragonal zircite heat barrier coat material and preparation method thereof of monoclinic phase, belong to thermal barrier coating field.

Background technology

Thermal barrier coating (ThermalBarrierCoatings, be called for short TBCs) typically refer to the ceramic coating [N.P.Padtureetal. being deposited on refractory metal surface, there is good effect of heat insulation, Science, 296,280 – 284 (2002)].Use thermal barrier coating that body material can be made from high temperature oxidation and corrosion, and the working temperature of matrix surface, the efficiency of combustion of raising oil plant can be reduced, and greatly can extend the life-span of gas turbine engine, have a wide range of applications in fields such as aerospace, boats and ships, the energy.In order to meet the growth requirement of novel aero gas turbine engine, require that the surface temperature of thermal barrier coating of future generation reaches more than 1500 DEG C [J.H.Perepezko, Science, 326,1068 – 1069 (2009); C.G.Levietal., MRSBull., 37 [10] 932 – 941 (2012)].

The heat barrier coat material of current classics is ~ 7wt% (or ~ 4mol%) yttrium oxide (Y ₂o ₃) partially stabilized zirconium white (ZrO ₂) material (be called for short 7YSZ) [N.P.Padtureetal., Science, 296,280 – 284 (2002)].Compared with entirely stable cubic zirconia, 7YSZ has higher fracture toughness property, and the thermal cycle life of its coating is longer [C.Merceretal., Proc.R.Soc.A, 463,1393 – 1408 (2007)].But, 7YSZ easily occurs to Tetragonal by metastable tetragonal zirconia phase (being called for short t ') (to be called for short and t) (to be called for short transformation c) with Emission in Cubic more than 1200 DEG C, when temperature be reduced to ~ 1000 DEG C near time, t phase occurs to monoclinic phase, and (there is the volumetric expansion [E.H.Kisietal. of 3 ~ 5Vol% in the transformation be called for short m), KeyEng.Mater., 153 – 154, 1 – 36 (1998)], the stress that this volume effect produces easily causes coating cracking, peel off [D.R.Clarkeetal., Annu.Rev.Mater.Res., 33, 383 – 417 (2003)].Therefore, 7YSZ coating can only use below 1200 DEG C, other rare earth oxides REO _1.5(RE=Nd, Gd, Yb) doping or REO _1.5-YbO _1.5t '-the ZrO of (RE=Y, Nd, Gd) codoped ₂also similar with 7YSZ [K.Jiangetal., J.Am.Ceram.Soc., 97,990 – 995 (2014)].

According to the literature, CeO ₂t '-the ZrO of doping ₂stablize mutually in 1400 DEG C of-1600 DEG C of intervals, and there is hyperelastic feature [A.Laietal., Science, 341,1505 – 1508 (2013)].On the other hand, 8mol% gadolinium sesquioxide (GdO _1.5) stable t '-ZrO ₂thermal conductivity lower than 7YSZ ~ 20% [M.N.Rahamanetal., ActaMater., 54,1615 – 1621 (2006)], this means by add CeO ₂gdO can be improved _1.5stable t '-ZrO ₂high-temperature-phase stability, if realize this object, be not hard to predict, this coating all will obviously be better than traditional 7YSZ coating in use temperature and thermal cycle life two.

Summary of the invention

The object of this invention is to provide a kind of high-temperature stable and without the tetragonal zircite heat barrier coat material and preparation method thereof of monoclinic phase.Without monoclinic phase after this material calcines 80 hours at 1500 DEG C, tetragonal zircite phase content is 48mol%, and this material utilizes Sol-spray pyrolysis and obtains.

According to an aspect of the present invention, provide a kind of high-temperature stable and the preparation method of tetragonal zircite heat barrier coat material without monoclinic phase, it is characterized in that comprising the following steps:

(1) in molar ratio

Ce (NO ₃) ₃6H ₂o: Gd (NO ₃) ₃6H ₂o: Zr (NO ₃) ₄3H ₂o=0.16: 0.08: 0.76 batching, is mixed with transparent aqueous solution;

(2) additional appropriate additive citric acid and polyoxyethylene glycol, magnetic agitation is to the colloidal sol of clear;

(3) with the pure air of certain pressure for atomizing medium, colloidal sol is atomised to corundum crucible;

(4) again temperature is risen to certain temperature after atomization to heat-treat and obtain desired raw material;

(5) raw material is positioned over high-temperature calcination in corundum crucible.

Comprise according to a kind of high-temperature stable of the present invention and without the tetragonal zircite heat barrier coat material preparation method of monoclinic phase:

1), molar ratio ingredient is pressed

Ce(NO ₃) ₃·6H ₂O∶Gd(NO ₃) ₃·6H ₂O∶Zr(NO ₃) ₄·3H ₂O＝0.16∶0.08∶0.76。

2), colloidal sol preparation

2.1) take deionized water as solvent, preparing metal total ion concentration is the aqueous solution of 0.1 mol/L;

2.2) additional additive citric acid, its addition is 80 grams per liters, additional additives polyethylene glycol, and its molecular weight is 20000, and addition is 50 grams per liters;

2.3) magnetic agitation is to clear.

3), raw material preparation

3.1) employing purity is the air of 99.99% is atomizing medium, and its pressure is 0.3MPa;

3.2) corundum crucible temperature is 500 DEG C;

3.3) thermal treatment temp is 1200 DEG C.

According to an aspect of the present invention, provide a kind of high-temperature stable and the preparation method of tetragonal zircite heat barrier coat material without monoclinic phase, it is characterized in that comprising the following steps:

(1) in molar ratio

Ce (NO ₃) ₃6H ₂o: Gd (NO ₃) ₃6H ₂o: Zr (NO ₃) ₄3H ₂o=0.16: 0.08: 0.76 batching, is mixed with transparent aqueous solution;

(2) additional appropriate additive citric acid and polyoxyethylene glycol, magnetic agitation is to the colloidal sol of clear;

(3) with the pure air of certain pressure for atomizing medium, colloidal sol is atomised to corundum crucible;

(4) again temperature is risen to certain temperature after atomization to heat-treat and obtain desired raw material;

(5) raw material is positioned over high-temperature calcination in corundum crucible.

According to another aspect of the present invention, the tetragonal zircite heat barrier coat material prepared by above-mentioned preparation method is provided.

This tetragonal zircite heat barrier coat material and preparation method thereof has following effect:

(1) 1500 DEG C of calcining is after 80 hours, and tetragonal zircite phase content is 48mol%, without monoclinic phase

(2) preparation temperature is low, phase purity is high;

(3) cost is low, efficiency is high;

(4) process stabilizing, is applicable to batch production.

Accompanying drawing explanation

Fig. 1 a and Fig. 1 b is material (Zr of the present invention _0.76ce _0.16gd _0.08) O _1.96and through the powder diffraction pattern of 1500 DEG C of calcinings after 6-80 hour.

Fig. 2 is material (Zr of the present invention _0.76ce _0.16gd _0.08) O _1.96through 1500 DEG C calcining 6-80 hour after phase content figure.

Embodiment

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

embodiment

With the Ce (NO that purity is 99.99% ₃) ₃6H ₂o, Gd (NO ₃) ₃6H ₂o, Zr (NO ₃) ₄3H ₂o is raw material, in molar ratio Ce (NO ₃) ₃6H ₂o: Gd (NO ₃) ₃6H ₂o: Zr (NO ₃) ₄3H ₂weigh at O=0.16: 0.08: 0.76, and preparing metal ion total energy concentration is the aqueous solution of 0.1mol/L, and add additive citric acid, polyoxyethylene glycol, its addition is respectively 50 grams per liters, and magnetic agitation obtains the colloidal sol of clear for 0.5 hour.

Adopt that purity is 99.99%, pressure be the air of 0.3MPa is atomizing medium, colloidal sol being atomised to temperature is remove moisture fast in the corundum crucible of 500 DEG C, obtains presoma.

Again temperature is risen to 1200 DEG C of calcinings after atomization and obtain desired raw material in 6 hours.

Get appropriate raw material and be placed in corundum crucible, at 1500 DEG C of calcining 6-80 hour.

The model adopting Dutch PANalytical company to produce is X ' PertPRO, be furnished with the Multi-functional X ray diffractometer of the super detector of X ' Celerator carries out thing and tests mutually, and x-ray is Cu target k _{α 1}, wavelength .The powder diffraction result of raw material and 1500 DEG C of calcining °-80 °, 2 θ=20 after 6-80 hour refers to Fig. 1 a, and the powder diffraction result of °-76 °, 2 θ=71.5 refers to Fig. 1 b.

From 1200 DEG C of-6h (hour) collection of illustrative plates in Fig. 1 a and Fig. 1 b, raw material is pure tetragonal zircite;

From 1500 DEG C of-6h, 1500 DEG C of-20h, 1500 DEG C of-40h and 1500 DEG C of-80h collection of illustrative plates difference in Fig. 1 a and Fig. 1 b, without monoclinic zirconia phase after 1500 DEG C of calcining 6-80h, be by four directions (t ') and cube (c) two phase composite;

Phase content calculates and adopts conventional Miller formula [R.A.Milleretal., inAdvancesinCeramics, AmericanCeramicSociety, Columbus, OH, 1981, pp.241 – 253]:

$\frac{M_c=0.88}{M_{t^{\′}}}=0.88\frac{I_c\left(400\right)}{I_{t^{\′}}\left(004\right)+I_{t^{\′}}\left(400\right)}$

In formula, M _c, M _{t '}be respectively the molar fraction of c and t ' phase, I _cand I (400) _{t '}(004), I _{t '}(400) (400) and (004) of c and t ' phase, the X-ray diffraction intensity of (400) crystal face is respectively.

Utilize above-mentioned formula and by 1500 DEG C of-6h, 1500 DEG C of-20h, 1500 DEG C of-40h and 1500 DEG C of-80h collection of illustrative plates in Fig. 1 b, calculate four directions (t ') and cube (c) phase mole fraction as shown in Figure 2.

Compared with material of the present invention, t '-(Zr _0.92ln _0.08) O _1.96(Ln=Y, Nd, Gd, Yb and Nd-Yb, Gd-Yb, Y-Yb) even if etc. series material in relative temperature lower and the time is relatively short all have monoclinic zirconia and occur mutually, if 1450 DEG C of calcinings are after 10 hours, the monoclinic zirconia phase content of these materials is at more than 20mol% [K.Jiangetal., J.Am.Ceram.Soc., 97,990 – 995 (2014)]; Thus, advantage of the present invention is apparent.

Claims (8)

1. high-temperature stable and a preparation method for tetragonal zircite heat barrier coat material without monoclinic phase, is characterized in that comprising the following steps:

(1) in molar ratio

Ce (NO ₃) ₃6H ₂o: Gd (NO ₃) ₃6H ₂o: Zr (NO ₃) ₄3H ₂o=0.16: 0.08: 0.76 batching, is mixed with transparent aqueous solution;

(2) additional appropriate additive citric acid and polyoxyethylene glycol, magnetic agitation is to the colloidal sol of clear;

(3) with the pure air of certain pressure for atomizing medium, colloidal sol is atomised to corundum crucible;

(4) again temperature is risen to certain temperature after atomization to heat-treat and obtain desired raw material;

(5) raw material is positioned over high-temperature calcination in corundum crucible.

2. preparation method according to claim 1, is characterized in that:

Described Ce (NO ₃) ₃6H ₂o, Gd (NO ₃) ₃6H ₂o and Zr (NO ₃) ₄3H ₂the purity of O is 99.99%.

3. preparation method according to claim 1, is characterized in that:

The metal ion total concn of described transparent aqueous solution is 0.1 mol/L.

4. preparation method according to claim 1, is characterized in that in step (2):

Citric acid addition is 80 grams per liters,

Molecular weight polyethylene glycol is 20000, and addition is 50 grams per liters.

5. preparation method according to claim 1, is characterized in that:

The purity of the pure air described in step (3) is 99.99%, and pressure is 0.3MPa, and corundum crucible temperature is 500 DEG C.

6. preparation method according to claim 1, is characterized in that:

Be tetragonal zircite after 1200 DEG C of calcining 6h in described step (4).

7. preparation method according to claim 1, is characterized in that:

In described step (5), calcine without monoclinic zirconia phase after 80 hours for 1500 DEG C, content of tetragonal phase is 48mol%.

8. with tetragonal zircite heat barrier coat material prepared by the preparation method of any one in claim 1-7.