CN103760055A - Method for measuring silver content in silver slurry - Google Patents

Abstract

A method for measuring silver content in a silver slurry comprises: burning a silver slurry sample in a muffle furnace with a temperature of 550 DEG C to remove organic matters, filtering for two times to remove other inorganic matters, so as to singly precipitating silver in a form of silver nitrate, utilizing excessive chloride ions and silver ions to fully generate silver chloride white precipitation, according to the mass conservation law, measuring the mass of generated silver chloride through a weight method, and calculating out the percentage of the silver content in the silver slurry, and performing a blank experiment on the filter paper, so as to guarantee the accuracy of the measurement. The method provided by the invention has the characteristics of being accurate in weighing and low in measuring cost.

Description

The method of testing of silver content in a kind of silver paste

Technical field

The present invention relates to a kind of method of testing of silver content, particularly the method for testing of silver content in a kind of silver paste.

Background technology

Silver paste is as a kind of novel conductive material at present, and complicated components, seldom has the document publication of silver content method of testing, the general main titrimetry of silver-colored detection, X-fluorescent spectrometry for high-load.

There is very large drawback in the test of carrying out high content silver in silver paste by above two kinds of methods.The one X-fluorescent spectrometry test belongs to instrumental analysis scope, mainly carry out inorganic powder or alloy and admittedly plant the classical method of testing that method titrimetry is traditional high content silver, but silver paste is different from conventional inorganic silver salt, silver paste is mainly complicated component, it is a kind of potpourri that collects gas chromatography and multiple inorganics, disturb too greatly, cause carrying out accurate titrimetry.The second body sample detection, requires sample non-volatility and non-corrosiveness, and silver medal material is as the potpourri of organism and inorganics, and viscosity is large, and sample preparation cake is difficult for, and is mainly the organic gas that constantly volatilizees, and corrosion instrument, so can not test.

Summary of the invention

In order to overcome the shortcoming of above-mentioned prior art, the object of the present invention is to provide the method for testing of silver content in a kind of silver paste, can utilize the precipitation method and gravimetric method to test silver content in silver paste, have the advantages that test is accurate, testing cost is low.

In order to achieve the above object, the technical scheme that the present invention takes is: the method for testing of silver content in a kind of silver paste, and its step is as follows:

Step 1: take 2-5g(and be accurate to 0.0001g) silver paste sample, be put in the porcelain crucible of crossing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, by the gross mass of sample and crucible after the electronic balance weighing calcination of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁, according to following formula, calculate the residual rate w of burning of silver paste sample:

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 1-4g(m _burnbe accurate to 0.0001g) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, is placed on low-temperature furnace and slowly heats more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, take off beaker and make solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 15-20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record the weight m before filter paper use at a slow speed ₂with the weight m of filter paper before dry at a slow speed in filter paper blank assay ₃, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record matter and the dried weight m of filter paper at a slow speed ₅, the dried weight m of filter paper at a slow speed in paper blank assay ₄, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, draws the numerical value of silver content, and computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample;

W---is the residual rate of the burning of silver paste sample;

M _burn---for 550 ℃, silver paste sample burns the sample weighting amount after residual, unit: gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, unit: gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, unit: gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, unit: gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, unit: gram;

K---for filter paper at a slow speed dry after vector correction factor.

The present invention is according to law of conservation of mass, Ag ⁺energy and Cl in excessive hydrochloric acid solution ^-according to the complete combination of the ratio of 1:1, and the white precipitate of reaction generation AgCl, according to the growing amount of AgCl white precipitate, calculate Ag ⁺amount, thereby calculate in silver paste sample hundred parts of content of silver.The present invention has adopted the combination of gravimetric method and the precipitation method in implementation process, and these two kinds of methods are all methods classical in chemical analysis.The present invention starts pretreatment process that carried out 550 ℃ of tests of burning residual rates are also a kind of sample in fact, and (silver paste itself also has 550 ℃ of test events of burning residual rates, so can carry out in the lump), because silver paste itself is a kind of silver-gray paste mixture, viscosity is extremely strong, wherein there is a large amount of organic solvents, if organism is removed in not calcination, directly with salpeter solution, dissolve, there will be and cause Ag because of the parcel of organic solvent ⁺cannot be discharged completely, thus and Cl ^-the white precipitate amount that reaction generates AgCl reduces, and causes test result less than normal.550 ℃ of high temperature sinterings that adopt are processed rear organism and are become CO ₂ease is gone, even if remaining a small amount of carbon ion can be to Ag yet ⁺produce parcel, more can not affect the accuracy of test result.550 ℃ of tests of burning residual rate are put to the sample preparation process of method as this method simultaneously, shortened testing process and time, saved the consumption of test to sample, reduced power consumption, also reduced testing cost simultaneously.On the other hand, consider that filtering medium itself absorption before use has certain moisture, and the variation that filter paper has weight and exists 120 ℃ of dry front and back, this method is carried out blank assay to filter paper, weight to filter paper before deducting filter paper weight is revised, thereby eliminate the impact on test result 120 ℃ of dry front and back weight change because of filter paper, test was tied and revised, guaranteed the accuracy of test result.

More than double-deck filter paper is all used in operation.

Embodiment

Below in conjunction with embodiment, the present invention is described in further detail.

Example one:

Step 1: take 3.1904g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 24.4223g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 26.5773g, the residual rate w of burning that calculates silver paste sample according to following formula is 67.55%;

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 2.0204g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.5987g, m ₃for 1.6066g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 4.0209g, m ₄for 1.5346g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 59.07%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.

Embodiment bis-:

Step 1: take 2.6167g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 22.9085g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 24.6261g, the residual rate w of burning that calculates silver paste sample according to following formula is 65.64%;

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 1.7159g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.6060g, m ₃for 1.6150g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 3.5481g, m ₄for 1.5494g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 57.71%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.

Embodiment tri-:

Step 1: take 3.1231g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 20.5086g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 25.6854g, the residual rate w of burning that calculates silver paste sample according to following formula is 65.82%;

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 2.0204g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.6120g, m ₃for 1.6196g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 3.8991g, m ₄for 1.5388g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 58.05%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.

Embodiment tetra-:

Step 1: take 2.8843g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 24.8004g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 26.7185g, the residual rate w of burning that calculates silver paste sample according to following formula is 66.50%.

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 1.9155g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.6030g, m ₃for 1.6064g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 3.7687g, m ₄for 1.5258g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 58.52%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.

Below will be by some data, explanation is the percentage composition effect of silver in silver paste sample with the inventive method test, shown in the following subordinate list of test result, as can be seen from the table, by the percentage composition of silver in method of testing test silver paste sample of the present invention, meet test request, test result is quick, accuracy is high.

Subordinate list: this method test case process and the result table of comparisons

Claims (5)

1. a method of testing for silver content in silver paste, is characterized in that, step is as follows:

Step 1: take 2-5g(and be accurate to 0.0001g) silver paste sample, be put in the porcelain crucible of crossing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, by the gross mass of sample and crucible after the electronic balance weighing calcination of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁, according to following formula, calculate the residual rate w of burning of silver paste sample:

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 1-4g(m _burnbe accurate to 0.0001g) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, is placed on low-temperature furnace and slowly heats more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, take off beaker and make solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 15-20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record the weight m before filter paper use at a slow speed ₂with the weight m of filter paper before dry at a slow speed in filter paper blank assay ₃, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record matter and the dried weight m of filter paper at a slow speed ₅, the dried weight m of filter paper at a slow speed in paper blank assay ₄, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, draws the numerical value of silver content, and computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample;

W---is the residual rate of the burning of silver paste sample;

M _burn---for 550 ℃, silver paste sample burns the sample weighting amount after residual, unit: gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, unit: gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, unit: gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, unit: gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, unit: gram;

K---for filter paper at a slow speed dry after vector correction factor.

2. the method for testing of silver content in a kind of silver paste according to claim 1, is characterized in that, step is as follows:

Step 1: take 3.1904g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 24.4223g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 26.5773g, the residual rate w of burning that calculates silver paste sample according to following formula is 67.55%;

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 2.0204g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.5987g, m ₃for 1.6066g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 4.0209g, m ₄for 1.5346g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 59.07%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.

3. the method for testing of silver content in a kind of silver paste according to claim 1, is characterized in that, step is as follows:

Step 1: take 2.6167g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 22.9085g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 24.6261g, the residual rate w of burning that calculates silver paste sample according to following formula is 65.64%;

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 1.7159g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.6060g, m ₃for 1.6150g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 3.5481g, m ₄for 1.5494g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 57.71%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.

4. the method for testing of silver content in a kind of silver paste according to claim 1, is characterized in that, step is as follows:

Step 1: take 3.1231g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 20.5086g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 25.6854g, the residual rate w of burning that calculates silver paste sample according to following formula is 65.82%;

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 2.0204g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.6120g, m ₃for 1.6196g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 3.8991g, m ₄for 1.5388g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 58.05%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.

5. described in claim 1, europium excites the preparation method of strontium borate magnesium ultraviolet fluorescence powder, it is characterized in that, step is as follows:

Step 1: take 2.8843g silver paste sample, be put in the porcelain crucible weighing 550 ℃ of constant weights, record empty porcelain crucible weight m ₀for 24.8004g, porcelain crucible is put in and in high temperature Muffle furnace, carries out calcination processing, design temperature is 550 ℃ (± 10 ℃), calcination time is 1 hour, clamp out with crucible tongs, put into silica gel drier and be cooled to room temperature, with the electronic balance weighing of precision 0.0001g, until constant weight, record the gross mass m of sample and crucible after calcination ₁for 26.7185g, the residual rate w of burning that calculates silver paste sample according to following formula is 66.50%.

$W=\frac{m_1-m_0}{m}\×100\%$

In formula: m ₀---be empty porcelain crucible quality, unit: g;

M ₁---be the gross mass of sample and crucible after 550 ℃ of calcinations, unit: g;

M---is the sample weighting amount of silver paste sample, unit: g.

Step 2: the silver paste sample that above-mentioned steps 1 is burnt after residual takes 1.9155g(m _burn) put into beaker, add the salpeter solution of 20ml, the volume ratio of nitric acid and water is 1:1, be placed on low-temperature furnace slowly heating more than 30 minutes, until the silver paste sample burning after residual dissolves completely, then stop heating, taking off beaker makes solution naturally cooling, then with Filter paper filtering, discard filtering medium, retain filtrate;

Step 3: add 20ml concentrated hydrochloric acid in the filtrate making in above-mentioned steps 2, make the silver ion in filtrate change into silver chloride white precipitate completely, the first balance weighing of use precision 0.0001g of filter paper at a slow speed, record m ₂for 1.6030g, m ₃for 1.6064g, and then pad changes into silver chloride white precipitate on glass funnel solution to this filters, and discards filtrate, retains filtering medium;

Step 4: filtering medium, at a slow speed filter paper and blank assay filter paper that above-mentioned steps 3 is retained are placed in electrically heated drying cabinet, design temperature is 120 ℃, be 2 hours drying time, filtering medium, at a slow speed filter paper and blank assay filter paper are dried, then taking out filtering medium, at a slow speed filter paper and blank assay filter paper is placed in silica gel drier, naturally cool to room temperature, cooled filtering medium, at a slow speed filter paper and blank assay filter paper are weighed to constant weight on the electronic balance of precision 0.0001g, record m ₅for 3.7687g, m ₄for 1.5258g, the chemical formula Ag of weighing result basis ⁺+ Cl ^-=AgCl ↓ calculating, the numerical value that draws silver content is 58.52%, computing formula is:

$K=\frac{m_4}{m_3}\×100\%$

In formula: W _ag---be the percentage composition of silver in silver paste sample, %;

W---is the residual rate of the burning of silver paste sample, %;

M _burn--for 550 ℃, silver paste sample burns the sample weighting amount after residual, gram;

M ₅---be filtering medium and the dried weight of filter paper at a slow speed, gram;

M ₂---be the weight before the dry use of filter paper at a slow speed, gram;

M ₃---be the weight of filter paper before dry at a slow speed in filter paper blank assay, gram;

M ₄---be the dried weight of filter paper at a slow speed in filter paper blank assay, gram;

K---for filter paper at a slow speed dry after vector correction factor.