SU894497A1 - Method of measuring flaw concentration in solid body - Google Patents

Description

(54) METHOD OF MEASURING THE CONCENTRATION OF DEFECTS IN A SOLID BODY

I

This invention relates to fluorescent flaw detection.

There is a known method for intending to concentrate defects over the depth of a body solid, based on measuring the optical density parallel to the surface of layers of a solid 1.

The disadvantages of this method are the need to create the optical smoothness of the lateral surfaces of the TBepiROro body, the inability to measure the distribution of the concentration of defects in opaque solids, the resolution of the depth is small, which determines the accuracy of the mechanical movement of the solid during measurements and the width of the slit used for optical density measurement of the spectrophotometer.

The closest to the present invention is a method for measuring the concentration of defects in a solid, which consists in excitation of luminescence and its registration.

The crystalline quartz is irradiated with ultraviolet radiation in the range of 150-380 by It, and the luminescence intensity of the sample surface is measured in the range of 480-510 Nm. The depth of the disturbed surface layer in this method is determined by comparing the luminescence intensity of the sample under investigation with the luminescence intensity of reference articles 2.,

The disadvantage of this method lies in the limited functionality. The method allows to determine

10 to divide only the average depth of the disturbed surface layer, requires the use of an ultraviolet radiation source with a given radiation spectrum and the registration of radiation in

15 a certain range of the spectrum, applicable only for the study of defects in transparent solids.

The purpose of the invention is to expand the functional capabilities of the south.

29

This goal is achieved by the fact that in the method of measuring the concentration of defects in a solid, which consists in the excitation of luxification and its registration, a solid body is attached

25 form the disk, immerse it in a solvent and excite luminescence by rotating the disk in a solvent at a constant angular velocity with a Reynolds number of 100-5000, the intensity dependence is measured

thirty

luminescence from the time of dissolution of the disk in the solution and from its calibration graph determine the distribution of the concentration of defects by depth.

The Reynolds number is calculated by the formula.

), 1) where 4J is the angular .speed, rad / s; g - disk radius, cm; O - kinematic viscosity,

.

The solvent should be a liquid in which, when dissolved, the defects in the solid body under study lead to the appearance of luminescence, the intensity of which depends on the concentrations of the defects. For many solids with defects, luminescence occurs when dissolved in water. In the case of alkali halide crystals, the F centers are responsible for the luminescence of the defects. Luminescence When a solid with defects is dissolved, it also appears when dissolved in many non-aqueous solvents, for example, when alkali and alkaline earth metals fluorides are dissolved in concentrated acids. To increase the intensity of the luminescence and, hence, the sensitivity of the process, impurities of phosphors can be added to the solvent.

The intensity of the luminescence occurring at each instant of disc disclosure is determined by the concentration of defects in the disc layer dissolving at that moment, the gradual uniform dissolution of the disc uniformly over the entire surface is ensured by a uniform. -1500.

The thickness of the dissolved part of the deck is calculated by the formula

d 0,) (CH-Co) t / p (2) where d is the thickness of the dissolved part

disk, cm;

D is the diffusion coefficient of the substance of a solid s solution, cMVc; 3 Р - density, g / cm; С „is the concentration of the valuable. solution of solidity,

C0 is the initial concentration of a substance in a fluid body in solution,

t is the time of dissolution, s. Formula (2) is applicable when the following dissolution conditions are met, ensuring a laminar dissolution regime: the Reynolds number for a rotating disk must be less than the critical one at which turbulent fluid begins and a larger square root of Grasgof number for a rotating disk; the dimensions of the cell in which dissolution takes place and the radius of the rotating disk must be much larger than the thickness of the hydrodynamic boundary layer

tf 3,6- / vi / ur. (3) where СГ is the thickness of the hydrodynamic layer, and the surface irregularities of the disk must be less than the thickness of the boundary layer.

FIG. 1 shows a plot of the intensity of CL over the time of dissolution of KCff single crystals; in fig. 2 - calibration graph of the intensity of CL on the concentration of defects, respectively, for additively stained SCF; in fig. 3 - the obtained distribution of the concentration of defects in the CSS.

Example. A KSe single crystal with a radius of 4 mm, additively colored in sodium vapor is taken, dissolved in 3D ml of distilled water at a rotation speed of 50 rad / s, the luminescence generated during the dissolution process is measured and the time luminescence intensity is obtained ( fig, 1). Using the formula (1) and the error log (Fig. 2), the depth distribution of the defect concentration is determined (Fig. 3). The calibration graph is obtained by measuring the luminescence that occurs during the dissolution of a single crystal COB with a known defect concentration distribution (F-center). The concentration of defects is determined by measuring the optical density in parallel surface layers unevenly over the depth of a colored KC0 crystal at a wavelength of 563 km. The depth distribution of the concentration of defects for the studied samples is determined both by measuring the luminescence intensity that occurs during the dissolution time and by measuring the optical density. The concentration of defects (P centers) near the surface (at a depth of 0.5 mm) of CS crystals as measured by the luminescence of 5.7 flO cm. As the depth increases, the concentration of defects (F centers) decreases monotonically, reaches 2.5 mm at a depth of 2.5 mm. 4, 2 Yu.

Measurement of optical density gives the same distribution of defects in the xer crystal. The agreement of the results of luminescent measurements and measurements by optical absorption confirms the applicability of the luminescence method. A) A calibration graph is obtained by measuring the intensity of the luminescence that occurs during dissolution in 30 ml of concentrated sulfuric acid irradiated on a PXM-20 unit of disks of lithium fluoride single crystals with a radius of 5 mm from the known, op

Claims (1)

Claim A method of measuring the concentration of defects in a solid, which consists in exciting luminescence and registering it, characterized in that, in order to expand the functionality, the solid is shaped into a disk, immersed in a solvent and excite luminescence by rotating the disk in a solvent with a constant angular velocity the value of the Reynolds number 1005000, measure the dependence of the luminescence intensity on the time of dissolution of the disk in the solution and determine the distribution, concentration d Effects by depth.