CN104828790A - A static loading synthetic method for Ag2X compounds - Google Patents

Abstract

A static loading synthetic method for Ag2X compounds is disclosed for the first time. Ag and an X elementary substance are adopted as raw materials and static load is applied to prepare the Ag2X compounds, wherein the X is Se or Te. The particle sizes of Ag2Se and Ag2Te particles prepared by the method reach the nanometer level. The method is short in preparation time, particularly simple in process, low in equipment requirement, energy-saving, environmental friendly and suitable for large-scale production, completely breaks limitations of chemical methods on solutions and limitations of physical methods on high-temperature conditions, and lays good foundations for large-scale preparation and large-scale application of the Ag2Se and the Ag2Te.

Description

Ag 2the static load synthetic method of X compound

Technical field

The invention belongs to technical field of material, be specifically related to a kind of Ag ₂the static load synthetic method of X compound.

Background technology

At material science, Transition-metal dichalcogenide has special photoelectric property because of it and chemical property causes investigator's interest widely, thus has driven the development of Transition-metal dichalcogenide technology of preparing.

In numerous Transition-metal dichalcogenide, compd A g ₂se, Ag ₂te is one of material being subject to people's extensive concern always.Semi-conductor Ag ₂se, Ag ₂the narrow bandgap semiconductor material of Te material Jun Shi I-VI race, Ag ₂there is reversible transformation (rhombic system-body-centered cubic crystallographic system) at 406K in Se, Ag ₂the reversible transformation temperature of Te is then 421K (oblique system-centroid cubic crystal system), and before and after phase transformation, the electrical property of compound is undergone mutation, and mainly comes from the noticeable change of energy band structure.Because first-order phase transition completes instantaneously, this makes compd A g ₂se, Ag ₂te may be used for the photonic crystal manufacturing hot changeable stopband.

Research shows, the compd A g of nonstoichiometry ratio _{2+ δ}se, Ag _{2+ δ}te shows giant magnetoresistance effect, by modifying ingredients, can change giant magnetoresistance effect and show significant temperature, to such an extent as to it also can be observed in room temperature.Giant magnetoresistance effect has purposes widely, is widely used in the fields such as magnetic sensing, magnetometer, electronic compass, position and angular transducer, vehicle detection, GPS navigation, instrument, magnetic storage (magnetic card, hard disk).

The compd A g of high-temperature-phase ₂se, Ag ₂te is fast-ionic conductor, for Ag ₂se compound, during higher than 406K, Se atomic building body-centered cubic structure, Ag ⁺can in the space of Se atom framework free migration; For Ag ₂te compound, during higher than 421K, Te atomic building face-centred cubic structure, Ag ⁺can in the space of Te atom framework free migration.Fast-ionic conductor, also known as solid electrolyte, is just being widely used in the fields such as energy industry, electronic industry, electromechanical integration as a kind of special and excellent electro-conductive material.

Compd A g ₂se, Ag ₂te occupies critical role equally at heat-electric energy conversion art, because it is excellent thermoelectric material.β-Ag ₂se has low lattice thermal conductivity (≈ 5mWcm ^-1k ^-1), high specific conductivity (≈ 2000Scm ^-1), relatively high Seebeck coefficient (≈-150 μ VK ^-1).The people such as Ferhat and Nagao report that its ZT when 300K, up to 0.96, can match in excellence or beauty with Bi (Sb) Te (Se) alloy commercial at present.Same, α-Ag ₂have very little density of states(DOS) at the bottom of Te compound conduction band, cause it to have high electronic mobility, in conjunction with the lattice thermal conductivity that its intrinsic is low, therefore it has very superior thermoelectricity capability.The medium people of Pei Yan uses PbTe to adulterate, and makes it at 500-600K scope ZT > 1.The Ag of people's synthesis such as G.Jeffrey Snyder ₂se _0.5te _0.5alloy when 420K ZT up to 1.4.

At present, compd A g ₂se, Ag ₂the synthetic method of Te mainly concentrates on hydrothermal method, solvent-thermal method etc., and these prepare Ag in the solution ₂se, Ag ₂the method of Te, often needs complicated reaction process and strict reaction conditions.More regrettably, the chemical reagent using some poisonous is needed, time consumption and energy consumption, contaminate environment.And adopt the preparation of conventional long high-temperature melting method, high-temperature solid phase reaction method, then harsh to equipment requirements, consume energy simultaneously, easily cause the disappearance of Se or Te, be difficult to accurate control composition.Therefore, seek a kind of normal temperature and pressure, Simple energy-saving, environmental protection, can the Ag of accurately control composition and microstructure ₂se, Ag ₂te technology of preparing seems extremely urgent.

Summary of the invention

Technical problem to be solved by this invention is the deficiency that exists for above-mentioned prior art and provides a kind of Ag ₂the static load synthetic method of X compound, preparation process is supper-fast, can accurate control composition, and technique is simple, low for equipment requirements, suitability for scale production.

The technical scheme that the problem that the present invention is the above-mentioned proposition of solution adopts is:

A kind of Ag ₂the static load synthetic method of X compound, is characterized in that it with Ag, X simple substance for raw material, imposes static load and prepare single-phase Ag ₂x compound, wherein, X is Se or Te.

By such scheme, the ratio of described amount of substance between simple substance Ag, X is (1.9-2): (1 ~ 1.1), Composition Control is accurate.

By such scheme, described static load is: compressing tablet, after making simple substance raw material powder mix, in mechanical force lower sheeting generation building-up reactions.

By such scheme, pressure during described compressing tablet is not less than 112.5MPa and can synthesizes and obtain single-phase Ag ₂x compound, namely static load is not less than 112.5MPa.

Ag ₂the static load synthetic method of X compound, specifically comprises the steps:

1) stoichiometrically (1.9-2): (1 ~ 1.1) weighs elemental powders Ag, X powder, and mix, be reactant, wherein X is Se or Te;

2) static load building-up reactions: to step 1) gained reactant carries out compressing tablet, namely obtains single-phase Ag ₂x compound.

By such scheme, step 2) described in tableting processes be static load and synthesize single-phase Ag ₂the process of X compound, pressure during compressing tablet is not less than 112.5MPa, belongs to mechanicals efforts process.

By such scheme, step 2) described in the compressing tablet time depending on practical situation, be generally some minutes.When the total amount of reactant is 1g, usually with 112.5MPa pressure (i.e. static load) pressurize 3-5min, pure single-phase Ag can be obtained ₂x compound.Especially, when static load (i.e. pressure) is not less than 450MPa, pure single-phase Ag can be obtained without the need to pressurize ₂x Compound Compound.

Based on foregoing, under the prerequisite not departing from basic fundamental thought of the present invention, according to ordinary technical knowledge and the means of this area, the amendment of various ways, replacement or change can also be had to its content.

Compared with prior art, the invention has the beneficial effects as follows:

The first, the present invention makes public for the first time a kind of compd A g ₂se, Ag ₂the static load synthetic method of Te, at room temperature, simply can be reacted by the method imposing the static loads such as compressing tablet raw material A g and Se simple substance, Ag and Te simple substance and generate single-phase compounds Ag ₂se or Ag ₂te;

The second, the Ag in the present invention ₂the static load synthetic method of X compound, breaches the bottleneck of room temperature without synthetic materials under solution condition, has thoroughly abandoned the solution condition of conventional chemistry and the hot conditions of Physical, can obtain target product under static load effect; Simultaneously preparation cycle shortens greatly, and preparation cycle shortens in some minutes in tens hours by the past, technique is simple, can control composition and microstructure, low for equipment requirements, energy-conserving and environment-protective, be applicable to the advantages such as large-scale production, be Ag ₂se, Ag ₂the mass-producing preparation of Te compound and large-scale application are had laid a good foundation.

Accompanying drawing explanation

Fig. 1 is embodiment 1 step 2) XRD figure of product spectrum.

Fig. 2 is embodiment 1 step 2) in dwell time 5min time, the FESEM photo of products therefrom.

Fig. 3 is embodiment 2 step 2) XRD figure of product spectrum.

Fig. 4 is embodiment 2 step 2) in pressure when being 450MPa not pressurize, the FESEM photo of products therefrom.

Fig. 5 is embodiment 2 step 2) in pressure when being 675MPa not pressurize, the FESEM photo of products therefrom.

Fig. 6 is embodiment 3 step 2) XRD figure of product spectrum.

Embodiment

For a better understanding of the present invention, illustrate content of the present invention further below in conjunction with embodiment, but content of the present invention is not only confined to the following examples.

Embodiment 1

Ag ₂the static load synthetic method of Se compound, concrete steps are as follows:

1) by Ag ₂in Se, the stoichiometric ratio 2:1 of elements A g and Se weighs Ag powder and Se powder, and in mortar, medication spoon is mixed thoroughly in advance, takes 5 parts respectively as reactant, every part of 1g;

2) reactant is loaded in the mould of diameter 20mm, afterwards mould is placed on YLG-60 electric tablet machine (Hefei Ke Jing Materials Technology Ltd.), pressure setting is that (in corresponding mould, reactant true pressure is 112.5MPa to 2MPa, note: because the sectional area of oil cylinder is different from the sectional area of mould, when power is identical, pressure is different), 5 parts of reactant pressurize 1min, 2min, 3min, 4min, 5min respectively, then pressure release.

To the present embodiment step 2) after product carries out material phase analysis respectively, and as shown in Figure 1, product all can obtain Ag ₂se compound, can obtain Ag with pressurize 1min under static load 112.5MPa ₂se principal phase, as pressurize 3min, can obtain purer single-phase Ag ₂se compound.

Fig. 2 is the present embodiment step 2) in, with the field emission scanning electron microscope photo of pressurize 5min products therefrom under static load 112.5MPa, as can be seen from the figure, product A g ₂the grain diameter of Se compound is 10-100nm, proves thus, and static load technology of preparing is not only super easy, also can obtain nanometer grade powder, is enough to match in excellence or beauty with chemical method solution techniques.

Embodiment 2

Ag ₂the static load synthetic method of Se compound, concrete steps are as follows:

1) by Ag ₂in Se, the stoichiometric ratio 2:1 of elements A g and Se weighs Ag powder and Se powder, and in mortar, medication spoon is mixed thoroughly in advance, takes 4 parts respectively as reactant, every part of 1g;

2) reactant is loaded in the mould of diameter 20mm, afterwards mould is placed on YLG-60 electric tablet machine (Hefei Ke Jing Materials Technology Ltd.), pressure is set as 8MPa, 9MPa, 10MPa, 12MPa (in corresponding mould, reactant true pressure is 450MPa, 506.25MPa, 562.5MPa, 675MPa) respectively, and pressure reaches pressure release immediately after set(ting)value.

To the present embodiment step 2) products therefrom carries out material phase analysis respectively, and as shown in Figure 3, product is single-phase Ag ₂se compound, when being not less than 450MPa compressing tablet with static load, not pressurize can obtain pure single-phase Ag ₂se compound.

Fig. 4, Fig. 5 are the present embodiment steps 2) in, the field emission scanning electron microscope photo of products therefrom under static load 450MPa and 675MPa, as can be seen from the figure, static load (i.e. pressure) is larger, product A g ₂the grain diameter particle growth of Se compound and be tending towards homogeneous, proving thus, by controlling the size of static load (i.e. tableting pressure), can control the distribution of sizes of product.

Embodiment 3

Ag ₂the static load synthetic method of Te compound, concrete steps are as follows:

1) by Ag ₂in Te, the stoichiometric ratio 2:1 of elements A g and Te weighs Ag powder and Te powder, and in mortar, medication spoon is mixed thoroughly in advance, takes 4 parts respectively as reactant, every part of 1g;

2) reactant is loaded in the mould of diameter 20mm, afterwards mould is placed on YLG-60 electric tablet machine (Hefei Ke Jing Materials Technology Ltd.), pressure is set as 8MPa, 10MPa, 12MPa, 14MPa (in corresponding mould, reactant true pressure is 450MPa, 562.5MPa, 675MPa, 787.5MPa) respectively, and pressure reaches pressure release immediately after set(ting)value.

To the present embodiment step 2) products therefrom carries out material phase analysis respectively, and as shown in Figure 6, product is single-phase Ag ₂te compound, when being not less than 450MPa compressing tablet with static load, not pressurize can obtain pure single-phase Ag ₂te compound.

Certainly, for technical solutions according to the invention, stoichiometrically (1.9-2): (1 ~ 1.1) weighs elemental powders Ag, X powder as reactant, wherein X is X is Se or Te, the stoichiometric ratio of both adjustment is taken the circumstances into consideration within the scope of this, also can realize technical scheme of the present invention, not enumerate embodiment at this.

The above is only the preferred embodiment of the present invention, it should be pointed out that for the person of ordinary skill of the art, and without departing from the concept of the premise of the invention, can also make some improvement and conversion, these all belong to protection scope of the present invention.

Claims (5)

1. an Ag ₂the static load synthetic method of X compound, is characterized in that it with Ag, X simple substance for raw material, imposes static load and prepare single-phase Ag ₂x compound, wherein, X is Se or Te.

2. a kind of Ag according to claim 1 ₂the static load synthetic method of X compound, is characterized in that the ratio of described amount of substance between simple substance Ag, X is for (1.9-2): (1 ~ 1.1).

3. a kind of Ag according to claim 1 ₂the static load synthetic method of X compound, is characterized in that described static load is compressing tablet.

4. a kind of Ag according to claim 1 ₂the static load synthetic method of X compound, is characterized in that described static load is not less than 112.5MPa.

5. according to the Ag one of claim 1-4 Suo Shu ₂the static load synthetic method of X compound, it comprises the steps: to it is characterized in that A

1) stoichiometrically (1.9-2): (1 ~ 1.1) weighs elemental powders Ag, X powder, and mix, be reactant, wherein X is Se or Te;

2) static load building-up reactions: to step 1) gained reactant carries out compressing tablet, namely obtains single-phase Ag ₂x compound.