CN103964691A - Fluorescent glass ceramic material and preparation method thereof - Google Patents

Abstract

The invention provides a fluorescent glass ceramic material. The chemical formula of the fluorescent glass ceramic material is (Ca0.99Eu0.01)3Si2O7; the fluorescent glass ceramic material is prepared from raw materials and a rare earth additive; the raw materials include SiO2 and CaCO3; the total raw materials include 80-90wt% of SiO2 and the balance of CaCO3; the rare earth additive is high-purity EuO3; the fluorescent glass ceramic material is formed into a core-shell structure, wherein the core is formed by Ca2SO4, while the shell is formed by Eu<2+>; the fluorescent glass ceramic material is prepared by use of the high-enthalpy hydrogen plasma quick melting technology. The fluorescent glass ceramic material has the advantages that 1, the enthalpy of the hydrogen plasmas is increased so as to guarantee melting of materials, namely keeping body crystallization of a solid phase in high-temperature solid-liquid coexistence; 2, the rare earth ions Eu are promoted to be reduced into low chemical valence by use of high reducibility of the hydrogen plasmas, and therefore, f to d broadband electron transition characteristic emission of the rare earth ions Eu<2+> can be realized and visible light with typical characteristics can be emitted.

Description

A kind of fluorescent glass stupalith and preparation method thereof

Technical field

The present invention relates to fluorescent glass stupalith and preparation method thereof.

Technical background

Optical functional glass or title photonic glass are class important materials in the fields such as information generation, demonstration, transmission, storage, detection, passive biography light by the past develops into active illuminating (as laser glass), and Application Areas relates to the key areas such as solid-state illumination packaged glass, photonic glass.These glass generally will mix rare earth ion, have and the essentially identical class line spectrum of free ion luminescence feature, and rare earth ion need to revert at a low price to realize broad-band illumination, and the ceramic of glass can strengthen crystal field impact, strengthens luminous efficiency.In the preparation of existing glass-ceramic, synthetic, processing technology, conventionally adopt method and the rare-earth sol-gel process of melt cooling-subsequent heat treatment crystallization.Consider from development manufacturing industry Key Common Technologies angle, adopt the glass melting of the melt cooling method of Simens technology, in 150 years since 1860, never reformed.Glass industry is big power consumer, and thawing, the clarifying treatment of raw material need to consume the long period, and industrial thawing furnace power consumption accounts for approximately 70% of glass production energy consumption; Found the lower concentration CO that process produces ₂, NO _xand SO _xbe not easy collection and treatment, contaminate environment.In addition, the advantages such as plasma technique is high with its temperature, ion kinetic energy is large, chemical property is active obtain a wide range of applications, wherein, plasma spraying coating technology has developed into the large-scale industrial application stage, relates to the broad fields such as the thermal boundary, wear-and corrosion-resistant, photochemical catalysis, biology of metal, pottery, matrix material.

Utilize plasma fast thawing technology to manufacture the work of glass, start recently studies have reported that, such as, the work of the Watanabe of the Tokyo Institute of Technology aspect thermal plasma fast thawing glass, they have studied quick thawing, the vitrifying rule of the material particles spraying in flight course, think and there is the remarkable advantages such as composition is even, the thawing time sharply shortens, energy-conservation, but flight particles fuse is insufficient, enthalpy is large not, vitrifying does not allow manageable problem to need to solve; Domestic also have a report that utilizes the particle flight course of plasma technology to manufacture specially glass, such as, TiA1 ₆v ₄on matrix, prepare AP40 glass ceramic coating.The control of the plasma fast thawing behavior of material particles in flight course is key issue, if material particles appearance partial melting is recurrent phenomenon.

In the fluorescent glass exploration work that adopts melt cooling method to carry out, select the CaO-SiO of Eu ion activation ₂glass system.At CaO-SiO ₂in system, the Ca that divalent europium is activated ₂siO ₄transmitting green light particle fluor, Ca ₃si ₂o ₇launch orange red light, royal purple optical excitation mixed phase can produce white light.Conventionally, luminescent glass ceramic need to be from homogeneous amorphous glass crystallization, Surface Crystallization pattern is in the majority, body crystallization need to be by adding nucleating agent induction crystallization to realize, but additional nucleator absorbs incident photon energy possibly, by absorbing, reflection, self lattice resonance, the phase boundary energy mechanism such as scatter and disappear, effective luminescence center transition radiation is not affected, cause the reduction of luminous efficiency.Therefore need to find the luminescent glass ceramic processing technology of preparing that does not need external Nucleating Agent and there is body crystallization.There is very much feature, by CaO-SiO ₂binary phase diagram is known, when temperature continues to raise, and single-phase Ca ₂siO ₄will there is molten brilliant reaction and generate Silicon-rich liquid phase L+ crystalline phase Ca ₂siO ₄.Can infer thus, be (Ca according to metering ratio _2.99eu _0.01) ₃si ₂o ₇powder raw material under protection of reducing atmosphere, be melted to this solid-liquid two-phase region quenching and get off, will directly obtain containing Ca ₂siO ₄: Eu ²⁺the luminescent glass ceramic of crystalline phase, is distributed with ceramic light-emitting particles in glass.This process, adopts the method for traditional melt cooling-subsequent heat treatment crystallization to be difficult to realize, and need to find new technique means.

Plasma fast thawing pottery During Vitrification in vitro according to being interaction between the particle-plasma of particle mission phase, therefore can be condensed go out the differentiation physical model of a single grain matter, describe the physical and chemical changes that feed particles, plasma area, flight, cooling stages stand; Although developed some fast thawing on-line monitorings, the understanding of article on plasma fast thawing unit details is still limited to " black box " research mode more, and rare earth ion can meticulously be indicated procedural information sensitively as light probe.About plasma heat content problem, in order to improve plasma heat enthalpy value, conventionally can be at carrier gas (Ar or N ₂) in sneak into a small amount of hydrogen (H of appropriate volume ratio ₂) or other fuel (such as propane), object is originally mainly insufficient in order to prevent particles fuse.When adding after a small amount of rare earth ion, these reducing gass can impel be reduced into rare earth ion at a low price simultaneously, and the glass being processed into can be under light stimulus, and transmitting has the visible ray of characteristic feature.Found the valence state problem of glass intermediate ion about plasma, Muscovite Bessmertnyi etc. observe appraising at the current rate in Cr, Ti, Fe oxide compound plasma, find that wherein part is reduced.When plasma fast thawing glass, the valence state problem of rare earth ion, does not see and has been report so far.

Summary of the invention

The object of the invention is for above-mentioned existing problems and technical Analysis, a kind of fluorescent glass stupalith and preparation method thereof is provided, this preparation method can improve plasma heat content, guarantees the thawing of material, or keeps the solid phase in the solid-liquid of high temperature to realize body crystalline substance; Hydrogen is reduced into rare earth ion Eu at a low price, to realize rare earth ion Eu ²⁺f → d wideband electronic transition characteristic emission.

Technical scheme of the present invention:

A kind of fluorescent glass stupalith, chemical formula is (Ca _0.99eu _0.01) ₃si ₂o ₇, being formed by initial material and rare earth additive, initial material is by SiO ₂and CaCO ₃composition, SiO in initial material total amount ₂mass percent be 80-90%, CaCO ₃for surplus; Rare earth additive is the Eu of purity 99.5-99.99% ₂o ₃, Eu ₂o ₃the interpolation quality 1-5% that is initial material; Described fluorescent glass stupalith is " core-shell " structure, and its center is Ca ₂siO ₄, shell is Eu ²⁺, nuclear diameter is 200 nanometer-5 micron, shell diameter is 10 microns.

A preparation method for described fluorescent glass stupalith, utilizes high enthalpy hydrogen plasma fast thawing technology preparation, and step is as follows:

1) preparation of complex sol particle

By SiO ₂, CaCO ₃and Eu (NO ₃) ₃according to the stoichiometric ratio preparation of fluorescent glass stupalith composition, obtain complex sol powder, then send in spraying equipment, obtain the xerogel discrete particles of high-specific surface area through spraying;

2) plasma fast thawing-thermal treatment

Above-mentioned gel particle, under reducing gas protection, is utilized to the plasma fast thawing technology of high hydrogen enthalpy, the composition that makes glass evenly and rare earth ion fully reduced, melt so far solid-liquid two-phase region, after quenching, obtain containing Ca ₂siO ₄: Eu ²⁺the glass-ceramic light-emitting particles fluorescent material of crystalline phase, processing condition are: temperature of fusion is 560-2860 DEG C, powder sending quantity is 80-140g/min, reducing gas is the gas mixture of argon gas and hydrogen, in gas mixture, the mass percent of hydrogen is 5-10%, reducing gas utilizes 80kw high energy plasma gun to add, and flame passes Flow Velocity is less than 1000m/s, and the flight velocity of melting powder is 180-260m/s;

Above-mentioned glass-ceramic luminescent material is heated to rapidly to 1300 DEG C through the hydrogen flame of too high enthalpy hydrogen plasma fast thawing ejection, air cooling 3h again, then the glass-ceramic luminescent material powder of burning till and ammonium chloride and carbon dust are fully mixed to get to mixture, wherein ammonium chloride quality is 3% of glass-ceramic luminescent material powder quality, carbon dust quality is the 3-10% of glass-ceramic luminescent material powder quality, mixture is heated to 1300 DEG C of insulation 6h, argon-hydrogen gas mixture that the mass percent that passes into hydrogen is 5%, so that EU ³⁺fully also fast transition is EU ²⁺, be then heated 1550 DEG C, after insulation is when 0.5h, is cooled to room temperature, obtain green-emitting phosphor Ca ₂siO ₄: Eu ²⁺glass-ceramic light-emitting particles obtains red-emitting phosphors Ca after insulation is when 1h, is cooled to room temperature ₃si ₂o ₇: Eu ²⁺glass-ceramic light-emitting particles;

3) machine-shaping

According to the shape of required fluorescent glass, above-mentioned glass-ceramic light-emitting particles is sprayed into and in different moulds, carries out air cooling so that chunk glass moulding, can make required fluorescent glass after cutting polishing processing.

Advantage of the present invention is: 1) improve hydrogen plasma heat content, guarantee the thawing of material, keep the solid phase in the solid-liquid of high temperature to realize body crystalline substance; 2) utilize the high reductibility of hydrogen plasma, promote rare earth ion Eu to be reduced at a low price, to realize rare earth ion Eu ²⁺f → d wideband electronic transition characteristic emission, transmitting has the visible ray of characteristic feature.

Brief description of the drawings

Fig. 1 is fluorescent glass stupalith " core-shell " structural representation, in figure: 1. polycrystal core, 2. noncrystal shell.

Fig. 2 is this fluorescent glass stupalith preparation method's Technology Roadmap.

Fig. 3 is the Eu doping CaO-SiO standby by melt cooling legal system ₂the scanning electron microscope image of system luminescent glass ceramic sample (1550 DEG C-0.5 hour), wherein (a) figure shows: a large amount of mean diameters that distributing in substrate of glass are the spheroidal particle of 30 microns of left and right, and (b) figure shows: around spheroidal particle, occurred that a large amount of mean sizess is the platy shaped particle of hundreds of nanometer.

Embodiment

Below in conjunction with accompanying drawing, the manufacturing process of mixed crystal phosphor glass pottery of the present invention is described in detail.

Embodiment:

A kind of fluorescent glass stupalith, chemical formula is (Ca _0.99eu _0.01) ₃si ₂o ₇, being formed by initial material and rare earth additive, initial material is by SiO ₂and CaCO ₃composition, SiO in initial material total amount ₂mass percent be 85%, CaCO ₃for surplus; Rare earth additive is the Eu of purity 99.5% ₂o ₃, Eu ₂o ₃interpolation quality be initial material 3%; Described fluorescent glass stupalith is " core-shell " structure, and as shown in Figure 1, its center 1 is Ca ₂siO ₄, shell 2 is Eu ²⁺, nuclear diameter is 5 microns, shell diameter is 10 microns.

The preparation method of described fluorescent glass stupalith, utilizes high enthalpy hydrogen plasma fast thawing technology preparation, and step is as follows:

1) preparation of complex sol particle

By SiO ₂, CaCO ₃and Eu (NO ₃) ₃according to the stoichiometric ratio preparation of fluorescent glass stupalith composition, obtain complex sol powder, then send in spraying equipment, obtain the xerogel discrete particles of high-specific surface area through spraying;

2) plasma fast thawing-thermal treatment

Above-mentioned gel particle, under reducing gas protection, is utilized to the plasma fast thawing technology of high hydrogen enthalpy, the composition that makes glass evenly and rare earth ion fully reduced, melt so far solid-liquid two-phase region, after quenching, obtain containing Ca ₂siO ₄: Eu ²⁺the glass-ceramic light-emitting particles fluorescent material of crystalline phase, processing condition are: temperature of fusion is 1700 DEG C, powder sending quantity is 120g/min, reducing gas is the gas mixture of argon gas and hydrogen, in gas mixture, the mass percent of hydrogen is 5%, reducing gas utilizes 80kw high energy plasma gun to add, and flame passes Flow Velocity is less than 1000m/s, and the flight velocity of melting powder is 210m/s;

Above-mentioned glass-ceramic luminescent material is heated to rapidly to 1300 DEG C through the hydrogen flame of too high enthalpy hydrogen plasma fast thawing ejection, air cooling 3h again, then the glass-ceramic luminescent material powder of burning till and ammonium chloride and carbon dust are fully mixed to get to mixture, wherein ammonium chloride quality is 3% of glass-ceramic luminescent material powder quality, carbon dust quality is 7% of glass-ceramic luminescent material powder quality, mixture is heated to 1300 DEG C of insulation 6h, argon-hydrogen gas mixture that the mass percent that passes into hydrogen is 5%, so that EU ³⁺fully also fast transition is EU ²⁺, be then heated 1550 DEG C, after insulation is when 0.5h, is cooled to room temperature, obtain green-emitting phosphor Ca ₂siO ₄: Eu ²⁺glass-ceramic light-emitting particles obtains red-emitting phosphors Ca after insulation is when 1h, is cooled to room temperature ₃si ₂o ₇: Eu ²⁺glass-ceramic light-emitting particles;

3) machine-shaping

According to the shape of required fluorescent glass, above-mentioned glass-ceramic light-emitting particles is sprayed into and in different moulds, carries out air cooling so that chunk glass moulding, can make required fluorescent glass after cutting polishing processing.

Fig. 3 is the Eu doping CaO-SiO standby by melt cooling legal system ₂the scanning electron microscope image of system luminescent glass ceramic sample (1550 DEG C-0.5 hour), wherein (a) figure shows: a large amount of mean diameters that distributing in substrate of glass are the spheroidal particle of 30 microns of left and right, and (b) figure shows: around spheroidal particle, occurred that a large amount of mean sizess is the platy shaped particle of hundreds of nanometer.

Analysis on Mechanism:

1) glass-ceramic Composition Design

According to (Ca _0.99eu _0.01) ₃si ₂o ₇metering ratio, can directly obtain Ca at solid-liquid two-phase region melt quenching ₂siO ₄: Eu ²⁺body mixed crystal glass-ceramic twinkler, in two-phase region soaking time difference, can control β-Ca wherein ₂siO ₄the size of spheroidal particle and luminosity.

2) high enthalpy hydrogen plasma flows fusing and the vitrifying mechanism to single grain matter

Control the hydrogen concentration in carrier gas; by spraying into the analysis of experiments test of composition, degree of crystallinity, pattern, rare earth ion valence state and the spectral quality of glass (particle or block) after material particles and fast thawing; according to the granular model of figure mono-, disclose the heat transfer, the mass transfer that occur between gas mixture plasma and particle, react, the physical chemistry rule such as phase transformation, melting, rapid cooling, vitrifying Crystal Evolution.

3) corresponding relation between the structure of hydrogen plasma fast thawing Optimizing Technical and fluorescent glass, rare earth ion valence state.By the performance test results of fluorescent glass sample obtaining, the relation between associated material particles characteristic, glass-ceramic structure and plasma fast thawing optimisation technique parameter.

Conventional method of analysis:

Adopt dsc (Differential Scanning Calorimetry) to measure material according to design mix in advance, obtain typical DSC melting curve, whole DSC curve peak is carried out to integration for the time, just can obtain the heat content of material, and provide the phase transformation-temperature relation of material, be used for instructing plasma H ₂the amount of allocating into and the setting of parameter.Integration type is as follows:

$\mathrm{\&Delta;H}=\&Integral;\frac{\mathrm{dH}}{\mathrm{dt}}\&CenterDot;\mathrm{dt}$

Granule-morphology in colloidal sol atomization-sintering process is developed, according to the gas of having set up---solid-gas sol theory, according to the formation physical chemical mechanism of the Single pellet model of the model analyzing of Fig. 1 " atomizing droplet forms a spheroidal particle ".

The glass sample that article on plasma fast thawing makes, further crystallization effect is investigated in thermal treatment.Carry out the heat analysis (DTA) of different scanning rates and step-length, determine glass transition temp (Tg), crystallization peak temperature (Tp), with classical Kissinger formula calculating crystallization activation energy, calculate Avrami parameter with Ozawa formula and judge crystallization mode (surface, body); On this basis, to the glass of special component, carry out meticulous thermal treatment.Valence state to rare earth ion and luminosity, with test absorb, position, shape and the intensity of excitation and emission spectra evaluates, for example, Eu ²⁺wideband spectrum, Eu ³⁺sharp line spectrum, Eu ⁰/ Eu ⁺not luminous.Based on granular model, electron energy loss spectroscopy (EELS) (EELS) the analytical chemistry constituent content of the EDX in use TEM and the spatial discrimination of scanning transmission electron microscope (STEM).

Claims (2)

1. a fluorescent glass stupalith, chemical formula is (Ca _0.99eu _0.01) ₃si ₂o ₇, it is characterized in that: be made up of initial material and rare earth additive, initial material is by SiO ₂and CaCO ₃composition, SiO in initial material total amount ₂mass percent be 80-90%, CaCO ₃for surplus; Rare earth additive is the Eu of purity 99.5-99.99% ₂o ₃, Eu ₂o ₃the interpolation quality 1-5% that is initial material; Described fluorescent glass stupalith is " core-shell " structure, and its center is Ca ₂siO ₄, shell is Eu ²⁺, nuclear diameter is 200 nanometer-5 micron, shell diameter is 10 microns.

2. a preparation method for fluorescent glass stupalith as claimed in claim 1, is characterized in that utilizing high enthalpy hydrogen plasma fast thawing technology preparation, and step is as follows:

1) preparation of complex sol particle

By SiO ₂, CaCO ₃and Eu (NO ₃) ₃according to the stoichiometric ratio preparation of fluorescent glass stupalith composition, obtain complex sol powder, then send in spraying equipment, obtain the xerogel discrete particles of high-specific surface area through spraying;

2) plasma fast thawing-thermal treatment

Above-mentioned gel particle, under reducing gas protection, is utilized to the plasma fast thawing technology of high hydrogen enthalpy, the composition that makes glass evenly and rare earth ion fully reduced, melt so far solid-liquid two-phase region, after quenching, obtain containing Ca ₂siO ₄: Eu ²⁺the glass-ceramic light-emitting particles fluorescent material of crystalline phase, processing condition are: temperature of fusion is 560-2860 DEG C, powder sending quantity is 80-140g/min, reducing gas is the gas mixture of argon gas and hydrogen, in gas mixture, the mass percent of hydrogen is 5-10%, reducing gas utilizes 80kw high energy plasma gun to add, and flame passes Flow Velocity is less than 1000m/s, and the flight velocity of melting powder is 180-260m/s;

Above-mentioned glass-ceramic luminescent material is heated to rapidly to 1300 DEG C through the hydrogen flame of too high enthalpy hydrogen plasma fast thawing ejection, air cooling 3h again, then the glass-ceramic luminescent material powder of burning till and ammonium chloride and carbon dust are fully mixed to get to mixture, wherein ammonium chloride quality is 3% of glass-ceramic luminescent material powder quality, carbon dust quality is the 3-10% of glass-ceramic luminescent material powder quality, mixture is heated to 1300 DEG C of insulation 6h, argon-hydrogen gas mixture that the mass percent that passes into hydrogen is 5%, so that EU ³⁺fully also fast transition is EU ²⁺, be then heated 1550 DEG C, after insulation is when 0.5h, is cooled to room temperature, obtain green-emitting phosphor Ca ₂siO ₄: Eu ²⁺glass-ceramic light-emitting particles obtains red-emitting phosphors Ca after insulation is when 1h, is cooled to room temperature ₃si ₂o ₇: Eu ²⁺glass-ceramic light-emitting particles;

3) machine-shaping

According to the shape of required fluorescent glass, above-mentioned glass-ceramic light-emitting particles is sprayed into and in different moulds, carries out air cooling so that chunk glass moulding, can make required fluorescent glass after cutting polishing processing.