JP5613891B2 - Stress luminescent material and method for producing the same - Google Patents

Description

  The present invention relates to a stress-stimulated luminescent material that emits light by converting mechanical energy into light energy, and a method for producing the same.

  Measuring the magnitude of the stress generated in each part of an object is important in many technical fields, including the field of machine or structure design. The technical fields in which stress measurement has been performed so far include uses such as a pressure sensitive sheet, a light emitting ball, an optical fiber sensor, or a vibration sensor.

  Stress measurement has the potential to be applied in various technical fields. For example, a plant or equipment manufacturer can be applied to safety inspection by monitoring plant piping. Stress distribution or strain measurement can be used in a very wide range of fields, from large structures such as buildings or towers to nano-level structures.

  Various methods for measuring the stress distribution have been developed so far, and a method of measuring stress by attaching a strain gauge to an object to be measured is common. However, in this method, in order to measure the stress distribution, strain gauges need to be attached to a large number of measurement points, and the work time is long. Moreover, it is impossible to measure the stress distribution in a fine region, and only the strain value at each measurement point can be measured.

  Infrared stress imaging methods have also been developed that measure the stress distribution by detecting infrared rays emitted from an object. In this method, since it is necessary to apply periodic stresses dedicated to analysis to the measurement object and to apply a stress synchronization signal to the infrared camera, it is not possible to measure stress in real time under actual use conditions.

  In addition to these, a method called a photoelastic method has been developed in which a model close to the substance of a measurement object is made of a transparent resin that can be easily measured optically, and stress distribution is measured by applying a weight to the model. This method involves working time and cost for producing a model, and because of the difference in material between the substance and the model, it is not possible to measure real-time stress measurement under the actual usage conditions of the measurement object.

  On the other hand, a method of measuring stress using a stress luminescent material (mechanoluminescence material) that emits light by converting mechanical energy into light energy when mechanical external force is applied has been developed. Examples of the stress luminescent substance include a europium complex disclosed in Patent Document 1, a composite semiconductor crystal having a coexistence structure of a wurtzite structure and a zincblende structure disclosed in Patent Document 2, and disclosed in Patent Document 3 Known composite metal oxides containing strontium and aluminum, and barium composite oxides disclosed in Patent Document 4 are known.

  Non-Patent Document 1 discloses that manganese (Mn) is added to zinc sulfide (ZnS) to function as a stress luminescent substance.

Japanese Patent Laid-Open No. 10-130639 JP 2004-43656 A JP 2004-059746 A JP 2006-124725 A

K. MEYER, D. OBRIKAT, M. ROSSBERG, Kristall und Teknik, 5, 1, P5-49 (1970).

  A stress-stimulated luminescent substance can measure stress applied to an object to be measured in real time based on a simple principle that it emits light when stressed, and has a very wide application range. However, the stress-stimulated luminescent materials known so far cannot be said to have sufficient light emission luminance, and have poor practicality.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a stress-stimulated luminescent material that has higher emission intensity than that of a conventional stress-stimulated luminescent material and is inexpensive, and a method for producing the stress-stimulated luminescent material.

  The present inventor has focused on ZnS: Mn (a material obtained by adding Mn to ZnS and calcined), which has a piezoelectric property and has a high stress luminescence intensity. In order to improve the luminescence intensity, ZnS: The optimum value of Mn concentration to be added to was investigated. Further, in addition to Mn, gallium (Ga) is further added to ZnS so as to have a specific concentration, and the emission intensity can be improved by firing in a reducing atmosphere, thereby completing the present invention. It came to.

Specifically, the present invention
It is obtained by firing ZnS containing Mn in a concentration range of 0.5 mol% to 2.0 mol% and Ga in a concentration range of 0.01 mol% to 0.3 mol% at a temperature of 1000 ° C to 1250 ° C in a reducing atmosphere. The present invention relates to a stress luminescent material.

The present invention also provides:
An addition step of adding manganese in a concentration range of 0.5 mol% to 2.0 mol% and gallium in a concentration range of 0.01 mol% to 0.3 mol% with respect to zinc sulfide;
A firing step of firing manganese sulfide and gallium sulfide in a reducing atmosphere at a temperature of 1000 ° C. to 1250 ° C.,
The present invention relates to a method for producing a stress-stimulated luminescent material.

  Only by adjusting the concentration of Mn added to ZnS, the emission intensity cannot be sufficiently improved as compared with the conventional stress luminescent material. However, the present inventors have found for the first time that the emission intensity can be improved by further adding Ga in a concentration range of 0.01 mol% to 0.3 mol%.

  The inventors have also found for the first time that the emission intensity can be sufficiently improved only when the firing temperature is within a specific range. The firing temperature is more preferably 1150 ° C. or higher and 1250 ° C. or lower. Moreover, it is preferable that baking time shall be 1 hour or more.

  The addition concentration of Mn with respect to ZnS is more preferably 0.8 mol% or more and 1.5 mol% or less. Further, the Ga addition concentration with respect to ZnS is more preferably 0.03 mol% or more and 0.22 mol% or less.

  In the present invention, “baking in a reducing atmosphere” means, for example, (1) baking in an inert gas atmosphere such as nitrogen gas or argon gas or in a hydrogen gas atmosphere; (2) This applies to: putting a sample in an inner crucible and putting carbon (for example, granular, granular or powdered activated carbon) in an outer crucible and firing it in a double crucible state.

  According to the present invention, it is possible to obtain a stress-stimulated luminescent material that has higher emission intensity than a conventional stress-stimulated luminescent material and that is inexpensive.

It is a graph which shows the measurement result of the stress luminescence intensity of eight types of disk-shaped molded objects from which Mn addition density | concentration differs. It is a graph which shows the measurement result of the stress luminescence intensity of seven types of disk-shaped molded objects from which Ga addition density | concentration differs. It is a graph which shows the relationship between a calcination temperature and luminescence intensity about two types of stress luminescent substances. ZnS: Mn ₁ Ga _0.1 the disk-like molded body produced by using a photograph of the light emitting state when the stress light-emitting intensity measured. FIG. 5 is a photograph of the light emission state when a compression load of 600 N is applied in the vertical direction to the same disk-shaped molded body as in FIG. 4. _ZnS: Mn _{0.92 Cu 0.05} to disk-shaped molded body produced using a photograph of the light emitting state when the longitudinal direction times the compressive load of 600N.

  Embodiments of the present invention will be described with reference to the drawings as appropriate. The present invention is not limited to the following description.

<1. Optimum concentration of Mn added to ZnS>
5N ZnS (zinc sulfide) and 3N Mn (NO ₃ ) ₂ .6H ₂ O (manganese nitrate hexahydrate) in a molar ratio of ZnS: Mn = 100: x (x = 0.25, 0.5, 0.8, 1.0, 1.5) 2.0) and weighed into an alumina mortar, added with ethanol and wet mixed. After about 20 g of the mixture was placed in the crucible, the crucible containing the mixture was placed in a larger crucible. In the outer crucible, about 10 g of granular activated carbon was put, and it was covered to make a double crucible. In this state, firing was performed in an electric furnace at 1100 ° C. for 2 hours.

  Further, 5N ZnS (zinc sulfide) and 2N MnS (manganese sulfide) were weighed so as to have a composition of ZnS: Mn = 100: x (x = 4.0, 10.0) in molar ratio, and the same operation as above was performed. .

  The obtained eight kinds of stress-luminescent substance powders were pulverized using an alumina mortar so that the average particle size was 44 μm or less. Thereafter, the powder was dispersed in an epoxy resin (Epok812) and solidified at 60 ° C. for 12 hours to obtain a disk-shaped molded body having a diameter of 20 mm and a thickness of 3 mm.

  Stress emission intensity was measured for the eight types of disk-shaped molded bodies obtained. First, using a tensile / compression small material testing machine (load cell rated capacity 1000 N) manufactured by Imoto Seisakusho, a compression load by a small glass sphere having a diameter of 3 mm was applied to the disk-shaped molded body. Next, the light emission of stress generated when a compressive load was applied up to 600 N was introduced into the spectroscopic chamber of the Hitachi fluorescence spectrophotometer (F-3010 type) using quartz glass fiber. The stress emission intensity was measured by measuring the intensity of the photomultiplier tube (R928F) at a central wavelength of 580 nm and a bandpass of 10 nm at 0.1 second intervals.

  FIG. 1 is a graph showing measurement results of stress emission intensity of eight types of disk-shaped molded bodies. In FIG. 1, relative light emission intensity is plotted when the light emission intensity of a disk-shaped molded body formed from a stress light-emitting material obtained by adding 1 mol% of Mn is “1”. From FIG. 1, it was confirmed that the addition concentration of Mn is preferably 0.5 mol% or more and 2.0 mol% or less, and particularly preferably 0.8 mol% or more and 1.5 mol% or less.

<2. Optimum concentration of Ga added to ZnS>
5N ZnS, 3N Mn (NO ₃ ) ₂ · 6H ₂ O, and 3N Ga (NO ₃ ) ₃ · 9H ₂ O (gallium nitrate · 9 hydrate) in a molar ratio of ZnS: Mn: Ga = 100: 1 : Y (y = 0.01, 0.05, 0.1, 0.2, 0.3, 0.5, and 1.0) was weighed, put in an alumina mortar, added with ethanol, and wet mixed. Then, it baked in the electric furnace for 2 hours at 1100 degreeC in the reducing atmosphere similar to the above.

  In the same manner as described above, the obtained seven kinds of stress luminescent substance powders were formed into a disk-shaped molded body having a diameter of 20 mmφ and a thickness of 3 mm, and the stress luminescence intensity was measured. FIG. 2 is a graph showing the results.

  When the Ga addition concentration was 0.5 mol% and 1.0 mol%, a phenomenon was observed in which the emission intensity was lower than when Ga was not added. On the other hand, the emission intensity of ZnS: Mn is improved when the Ga addition concentration is 0.01 mol% or more and 0.3 mol% or less. From FIG. 2, the relative intensity is 1.5 or more when 0.03 mol% or more and 0.22 mol% or more. It was confirmed that

<3. Optimum firing temperature range>
5N ZnS, 3N Mn (NO ₃ ) ₂ · 6H ₂ O, and 3N Ga (NO ₃ ) ₃ · 9H ₂ O are weighed in a molar ratio of ZnS: Mn: Ga = 100: 1: 0.1, It put into the alumina mortar, added ethanol and wet-mixed. Further, 5N ZnS and 3N Mn (NO ₃ ) ₂ .6H ₂ O were weighed so that the molar ratio was ZnS: Mn = 100: 1, put in an alumina mortar, added with ethanol, and wet mixed. These two kinds of mixtures were each fired in an electric furnace in a reducing atmosphere similar to the above in a temperature range of 950 ° C. to 1300 ° C. for 2 hours.

  The obtained two kinds of stress-stimulated luminescent material powders were formed into a disk-shaped molded body having a diameter of 20 mm and a thickness of 3 mm in the same manner as described above. Then, in the same manner as described above, the stress luminescence intensity was measured for the obtained two types of disk-shaped molded bodies. FIG. 3 is a graph showing the results.

In the case of ZnS: Mn ₁ , it was confirmed that the firing temperature is preferably around 1100 ° C., but the change in the emission intensity due to the firing temperature was small. On the other hand, in the case of ZnS: Mn ₁ Ga _0.1 to which Ga was added, the firing temperature was preferably around 1200 ° C., and when 1300 ° C. was reached, a phenomenon was observed in which the emission intensity dropped sharply. From FIG. 3, it was confirmed that the firing temperature of ZnS: Mn ₁ Ga _0.1 is preferably 1000 ° C. or higher and 1250 ° C. or lower, and more preferably 1150 ° C. or higher and 1250 ° C. or lower.

<4. Emission state of stress luminescent material>
FIG. 4 shows <3. In the optimum range of the firing temperature>, a disk-shaped molded product having a thickness of 20 mmφ and a thickness of 3 mm produced using ZnS: Mn ₁ Ga _0.1 obtained by firing in an electric furnace at 1100 ° C. for 2 hours, It is the photograph which image | photographed the light emission state at the time of stress light emission intensity measurement. As is clear from FIG. 4, the stress-stimulated luminescent material of the present invention produced strong luminescence due to 600 N compressive weight.

  FIG. 5 is a photograph of a light emission state when a compression load of 600 N is applied to the same disk-shaped molded body as in FIG. 4 in the vertical direction. The disk-shaped molded body is subjected to a compressive load of 600 N in the vertical direction using a flat die, and the upper end and the lower end where the stress is generated emit light.

On the other hand, FIG. 6 is a photograph of the light emission state at the time of measuring the stress luminescence intensity of a disk-shaped molded body produced in the same manner as described above using ZnS: Mn _0.92 Cu _0.05 as the stress luminescent substance. is there. Also at this time, the disk-shaped molded body is subjected to a compressive load of 600 N in the vertical direction using a flat die, and the upper end and the lower end where the stress is generated emit light.

When FIG. 5 and FIG. 6 are compared, the disc-shaped molded body of FIG. 5 has clearly higher light emission so that it can be clearly distinguished with the naked eye. In addition, <3. In the optimum range of the firing temperature>, a disk-shaped molded body of 20 mmφ and 3 mm thickness produced using ZnS: Mn ₁ obtained by firing in an electric furnace at 1100 ° C. for 2 hours is similarly longitudinal Compared with the case where a compressive load was applied to the disk, the disc-shaped molded body of FIG. 5 was clearly more luminescent so that it could be clearly distinguished with the naked eye.

<4. Luminous intensity with conventional ZnS: Mn>
Table 1 of Patent Document 2 discloses “0.9ZnS · 0.1MnS” as Example 4. This stress luminescent material has a Mn addition concentration of 10 mol% with respect to ZnS. As shown in FIG. 1, as a result of the study by the present inventors, it was confirmed that when the concentration of Mn added to ZnS is 10.0 mol%, even when a 600 N compressive load is applied, almost no stress emission occurs. . For this reason, ZnS containing Mn in a concentration range of 0.5 mol% to 2.0 mol% and Ga in a concentration range of 0.03 mol% to 0.22 mol% is calcined in a reducing atmosphere at a temperature of 1000 ° C to 1250 ° C. It was reasonably inferred that the stress-stimulated luminescent material of the present invention obtained by the above has higher luminescence intensity than any of the stress-stimulated luminescent materials disclosed in Table 1 of Patent Document 2.

  One of the characteristics of the stress-stimulated luminescent material of the present invention is that it can be produced from inexpensive raw materials such as zinc sulfide, manganese nitrate and gallium nitrate by a simple method of wet mixing and firing.

  The stress-stimulated luminescent material and method for producing the same of the present invention are useful in many technical fields including machinery, construction, and acoustics in which measurement of stress distribution is required.

Claims (2)

  Obtained by firing zinc sulfide containing manganese in a concentration range of 0.5 mol% to 2.0 mol% and gallium in a concentration range of 0.01 mol% to 0.3 mol% at a temperature of 1000 ° C to 1250 ° C in a reducing atmosphere. Stress luminescent material. An addition step of adding manganese in a concentration range of 0.5 mol% to 2.0 mol% and gallium in a concentration range of 0.01 mol% to 0.3 mol% with respect to zinc sulfide;
A firing step of firing manganese sulfide and gallium sulfide in a reducing atmosphere at a temperature of 1000 ° C. to 1250 ° C.,
A method for producing a stress-stimulated luminescent material.