CN101597165A - A kind of hydrothermal synthesis method of sodium niobate powder - Google Patents

Abstract

The invention discloses a kind of hydrothermal synthesis method of sodium niobate powder.With mol ratio is that 0.05～10 Niobium Pentxoxide and sodium hydroxide are put in the autoclave, and the filling ratio according to 50～90% adds deionized water in autoclave, regulate concentration sodium hydroxide to 0.1～15mol/L; After the autoclave sealing, put into pit furnace or baking oven, rise to 120～240 degrees centigrade with the heat-up rate of 1～5 degree centigrade of per minute, be incubated 4～72 hours, then furnace cooling; Taking-up was also opened autoclave, and products therefrom is poured beaker into, uses deionized water filtration washing repeatedly, becomes neutrality until washings, and the powder of gained is put into baking oven, 40～100 degrees centigrade of bakings 6～24 hours.The inventive method is simple, energy-saving and emission-reduction, and cost is lower, is fit to produce in batches; The sodium niobate powder of preparation, purity height, good fluidity, narrow diameter distribution, the particle agglomeration degree is light, crystal development is complete.

Description

A kind of hydrothermal synthesis method of sodium niobate powder

Technical field

The present invention relates to a kind of hydrothermal synthesis method of sodium niobate powder, belong to inorganic chemical synthesis technical field.

Background technology

Sodium columbate (NaNbO ₃) be a kind of good leadless piezoelectric ceramics.Sodium columbate belongs to antiferroelectric ceramics.Be mainly used in two aspects: the one, utilize antiferroelectric-two ferroelectric hysteresis loops during ferroelectric phase transition, make energy storage container, piezoelectricity regulatory element; The 2nd, utilize the volume effect of antiferroelectric-ferroelectric phase transition, as transverter.The common methods of preparation sodium niobate powder has sol-gel method, solid sintering technology.These preparation methods need the high-temperature heat treatment in later stage, cause the reunion between the powder particulate and the volatilization of grain growth and sodium.With the additive method ratio, the powder of Hydrothermal Preparation has purity height, good fluidity, narrow diameter distribution, the particle agglomeration degree is light, crystal development is complete, technology is simple relatively and sintering activity advantages of higher [Lanfredi S, Dessemond L, MartinsA C Rodrigues.Dense ceramics of NaNbO ₃Produced from powders preparedby a new chemical route.Journal of the European Ceramic Society, 2000,20 (7): 983-990.].Simultaneously, the Hydrothermal Preparation powder is once to finish in liquid phase, does not need subsequent crystallization heat treatment, thereby has avoided hard aggregation, the crystal grain of powder to grow up voluntarily and sneak into shortcomings such as impurity easily.

Summary of the invention

Purpose of the present invention just provides the hydrothermal synthesis method of a kind of purity height, good fluidity, narrow diameter distribution, the particle agglomeration degree is light, crystal development is complete sodium niobate powder.

Concrete steps are:

(1) with Niobium Pentxoxide (Nb ₂O ₅) and sodium hydroxide (NaOH) weighing after put in the autoclave, the mol ratio of Niobium Pentxoxide and sodium hydroxide is 0.05～10, filling ratio according to 50～90% adds the deionized water of respective volume in the autoclave, regulate the amount of raw material, making concentration sodium hydroxide is 0.1～15mol/L, slowly stirs with glass stick and makes dissolution of sodium hydroxide;

(2) after the autoclave sealing, put into pit furnace or baking oven, rise to 120～240 degrees centigrade, be incubated 4～72 hours, then furnace cooling with the heat-up rate of 1～5 degree centigrade of per minute;

(3) take out and open autoclave, step (2) products therefrom is poured into beaker, use deionized water filtration washing repeatedly, become neutrality until washings, the powder of gained was put into baking oven, 40～100 degrees centigrade of bakings 6～24 hours.

(4) use X-ray diffractometer to detect thing phase, the crystalline structure of step (3) gained powder;

(5) use scanning electronic microscope to detect the pattern and the size of step (3) gained powder.

The invention has the beneficial effects as follows: adopt the low-temperature hydrothermal method to synthesize the well-developed high-purity sodium niobate powder of crystal formation, in the hot water environment of elevated pressures, dissolving has taken place in water-fast at normal temperatures and pressures Niobium Pentxoxide, and chemical reaction can take place and generate novel substance, crystallization and crystal growth can take place in these novel substances.Effective simplification of the present invention sodium columbate preparation process and lowered its production cost, energy consumption and environmental pollution have been reduced, obtained the high-purity preferably powder of crystal formation, for the energy storage of sodium columbate pottery and the raising of transducing performance provide the necessary technology support.

Description of drawings

Fig. 1 is the XRD figure spectrum of the embodiment of the invention 1 sodium niobate powder.

Fig. 2 is the SEM photo of the embodiment of the invention 2 sodium niobate powders.

Fig. 3 is the SEM photo of the embodiment of the invention 3 sodium niobate powders.

Embodiment

Embodiment 1:

With Niobium Pentxoxide (Nb ₂O ₅) and sodium hydroxide (NaOH) weighing after put in the autoclave, the mol ratio of Niobium Pentxoxide and sodium hydroxide is 0.2, filling ratio according to 75% adds the deionized water of respective volume in the autoclave, regulate the amount of raw material, making concentration sodium hydroxide is 6mol/L, slowly stirs with glass stick and makes dissolution of sodium hydroxide; After the autoclave sealing, put into pit furnace or baking oven, rise to 160 degrees centigrade with the heat-up rate of 3 degrees centigrade of per minutes, be incubated 16 hours, then furnace cooling; Taking-up was also opened autoclave, and reactant is poured into beaker, uses deionized water filtration washing repeatedly, becomes neutrality until washings, and the powder of gained is put into baking oven, in 50 degrees centigrade of bakings 8 hours.Fig. 1 has provided the XRD figure spectrum of gained sodium niobate powder.

Embodiment 2:

With Niobium Pentxoxide (Nb ₂O ₅) and sodium hydroxide (NaOH) weighing after put in the autoclave, the mol ratio of Niobium Pentxoxide and sodium hydroxide is 0.1, filling ratio according to 70% adds the deionized water of respective volume in the autoclave, regulate the amount of raw material, making concentration sodium hydroxide is 6mol/L, slowly stirs with glass stick and makes dissolution of sodium hydroxide; After the autoclave sealing, put into pit furnace or baking oven, rise to 180 degrees centigrade with the heat-up rate of 2 degrees centigrade of per minutes, be incubated 20 hours, then furnace cooling; Taking-up was also opened autoclave, and reactant is poured into beaker, uses deionized water filtration washing repeatedly, becomes neutrality until washings, and the powder of gained is put into baking oven, in 80 degrees centigrade of bakings 6 hours.Fig. 2 has provided the SEM photo of gained sodium niobate powder.

Embodiment 3:

With Niobium Pentxoxide (Nb ₂O ₅) and sodium hydroxide (NaOH) weighing after put in the autoclave, the mol ratio of Niobium Pentxoxide and sodium hydroxide is 0.5, filling ratio according to 75% adds the deionized water of respective volume in the autoclave, regulate the amount of raw material, making concentration sodium hydroxide is 4mol/L, slowly stirs with glass stick and makes dissolution of sodium hydroxide; After the autoclave sealing, put into pit furnace or baking oven, rise to 200 degrees centigrade with the heat-up rate of 1 degree centigrade of per minute, be incubated 12 hours, then furnace cooling; Taking-up was also opened autoclave, and reactant is poured into beaker, uses deionized water filtration washing repeatedly, becomes neutrality until washings, and the powder of gained is put into baking oven, in 40 degrees centigrade of bakings 10 hours.Fig. 3 has provided the SEM photo of gained sodium niobate powder.

Claims (1)

1. the hydrothermal synthesis method of a sodium niobate powder is characterized in that concrete steps are:

(1) will put in the autoclave after Niobium Pentxoxide and the sodium hydroxide weighing, the mol ratio of Niobium Pentxoxide and sodium hydroxide is 0.05～10, filling ratio according to 50～90% adds the deionized water of respective volume in the autoclave, regulate the amount of raw material, making concentration sodium hydroxide is 0.1～15mol/L, slowly stirs with glass stick and makes dissolution of sodium hydroxide;

(2) after the autoclave sealing, put into pit furnace or baking oven, rise to 120～240 degrees centigrade, be incubated 4～72 hours, then furnace cooling with the heat-up rate of 1～5 degree centigrade of per minute;

(3) take out and open autoclave, step (2) products therefrom is poured into beaker, use deionized water filtration washing repeatedly, become neutrality until washings, the powder of gained was put into baking oven, 40～100 degrees centigrade of bakings 6～24 hours.

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