1、DRAFT FOR DEVELOPMENT Advanced technical ceramics lest methods for ceramic powders Determination of calcium, magnesium, o 4 4 o o o iron and aluminium in silicon nitride by using flame atomic absorption spectroscopy (FAAS) or inductively coupled plasma atomic emission spectroscopy (ICP-AES) ICs 81.0
2、60.30 DD ENV 14226:2002 Iron 5 x to 250 x (w/w); Magnesium 5 x to 200 x (w/w); Aluminium 5 x to 1000 x (wh). 4 Principle The test sample is decomposed using either acid pressure digestion, or acid pressure microwave digestion. The resulting solution is diluted to a defined volume and nebulization in
3、to a flame for FAAS, or into a plasma, for ICP-AES (see clause i). For each element, comparison is made of the recorded absorbance or emitted intensity for a determined analytical peak with those of a range of solutions of known concentrations. 5 Sampling Bulk sampling is not within the scope of thi
4、s European Prestandard and the method starts with a laboratory sized sample. 3 ENV 14226:2002 (E) 6 Reagents and materials 6.1 General All reagents, and substances, shall be of at least analytical grade. Distilled or de-ionised water, conforming to IS0 3696, shall be used throughout the whole proced
5、ure. 6.2 Reagents for preparation 6.2.1 Hydrofluoric acid HF p20 about 1,16 g ml- 6.2.2 Nitric acid “03 p20 about 1,4 g ml-I 6.3.Reagents for calibration 6.3.1 All reagents shall be of ultra high purity. 6.3.2 Silicon, commercial solution with very low and known impurity levels, concentration 1 O gl
6、-I 6.3.3 Calcium, commercial solution or solution obtained by the dissolution of a pure chemical product, concentration O, i g1-l. 6.3.4 Magnesium, commercial solution or solution obtained by the dissolution of a pure chemical product, concentration O, 1 gl-. 6.3.5 Iron, commercial solution or solut
7、ion obtained by the dissolution of a pure chemical product, concentration O, i g1-l. 6.3.6 Aluminium, commercial solution or solution obtained by the dissolution of a pure chemical product, concentration O, 1 gl-. 7 Apparatus 7.1 Spectrometer used for FAAS and ICP-AES analysis should comply with the
8、 requirements laid down in ECSCK 9. The ICP-AES shall be equipped with a nebulization system and torch resistant to hydrofluoric acid. 7.2 Drying oven, capable of being controlled at (1 10 f 10) OC. 7.3 Desiccator containing effective desiccant. 7.4 Balance, to read to 0,l mg. 7.5 Sample jar or bag,
9、 with a seal. 4 ENV 14226:2002 (E) 7.6 50 ml volumetric flasks, resistant to hydrofluoric acid (e.g. polypropylene, PTFE). 7.7 Vessels, resistant to hydrofluoric acid, of at least 30 ml capacity, and suitable for operation at (170 f 15) “C for 15 h, for use with (7.8). 7.8 Acid pressure digestion ap
10、paratus. 7.9 Vessels, resistant to hydrofluoric acid, for use with (7.10). 7.1 O Microwave digestion system. 8 Sample preparation Dry approximately log of the sample at (1 10 f 10) OC, in the drying oven (7.2) for at least 1 h. Remove and cool it to room temperature in a desiccator (7.3). When cool
11、store the sample in a jar or bag that is airtight (7.5). 9 Procedure 9.1 General 9.1.1 Dissolve the test sample by acid pressure digestion (9.2) or by acid pressure microwave digestion (9.3) 9.1.2 Run a blank in parallel with the chosen procedure, using identical reagents, conditions, and dilutions
12、throughout. 9.2 Acid pressure digestion Weigh (0,100 f 0,000 5) g of test sample (8) into the PTFE-lined vessel (7.6). Carefully add 3 ml of HF (6.2.1) and 1 ml of “03 (6.2.2). Install the cap and close the pressure vessel according to the manufacturers instructions. Place the pressure vessel into t
13、he heating block and digest for 15 h at (170 f 15) “C. Allow to cool. After cooling, open the pressure vessel according to the manufacturers instructions. Check that the test portion has been completely digested. If not, repeat the digestion. 5 ENV 14226:2002 (E) Transfer the dissolved sample to a 5
14、0 ml volumetric flask (7.6) and rinse the pressure vessel, and lid with distilled or de-ionised water. Make up to the mark with distilled or de-ionised water and mix well. 9.3 Acid pressure microwave digestion Examples of procedures: 9.3.1 Weigh 0,lg f 0,000 5 g of test sample (8) into the vessel (7
15、.9). Add 5ml of HF (6.2.1) and 1 ml of “03 (6.2.2) and seal according to the manufacturers instructions. Put the capped vessel into the microwave. Apply the following stages: - Stage 1 : Power level 60% for 2 min; Stage 2: Power level 30% for 15 min; Stage 3: Power level 0% for 5 min; Stage 4: Power
16、 level 20% for 20 min. - - - Allow the vessel to cool in the microwave for about 20 min. Repeat the heating cycle once more. Inspect to see if the test sample has completely digested. When cool, open the vessel according to the manufacturers instructions. Transfer the dissolved sample into a 50 ml p
17、olypropylene volumetric flask (7.6), and rinse the pressure vessel, and lid with distilled or de-ionised water. Mix, and make up to the mark with distilled or de-ionised water. 9.3.2 Weigh 0,l g f 0,000 5 g of test sample (8) into the pressure vessel (7.7) Add, carefully, 10 ml of HF (6.2.1) and 2 m
18、l of “03 (6.2.2), and seal the vessel according to the manufacturers instructions. Place the capped vessel into the microwave. Apply the following stages: 6 ENV 14226:2002 (E) - Stage 1: Temperature 50C for 2 min; Stage 2: Temperature 150C for 6 min; Stage 3: Temperature 260C for 18 min; Stage 4: Te
19、mperature 0C for 10 min. - - - Cool and open the vessel according to the manufacturers instructions. Inspect the solution. If the sample has not completely dissolved repeat stages 1 to 4 again. Transfer the solution into a 50 ml volumetric flask (7.6), washing the pressure vessel and lid with distil
20、led or de-ionised water. Mix and make up to the mark with distilled or de-ionised water. 10 Calibration solutions A calibration graph is obtained using calibration solutions prepared to span the range of concentrations of elements to be determined in the test solution. The calibration solutions are
21、prepared using the same acids that were used to digest the test sample to ensure accurate matrix matching. The following procedure is given as an example: Prepare the calibration solutions by adding the volumes of solutions indicated in Table 1 to a series of 50 ml volumetric flasks (7.6). When addi
22、tions are complete, mix and make the volume of each flask up to the mark with distilled water or de-ionised water. 7 ENV 14226:2002 (E) HF (6.2. i), ml Table 1 - Preparation of calibration solutions 3,OO I 3,OO I 3,OO I 3,OO I 3,OO Fe (6.3.5), ml Concentration, i (WIV) O 0,025 0,05 0,15 0,30 O 0,05
23、0,lO 0,30 0,60 Al (6.3.6) Concentration, i (WIV) Using ether FAAS or ICP-AES, make measurements of the calibration solutions for each of the elements and prepare a calibration curve of absorbance or intensity against concentration for each O 0,lO 0,25 0,50 1 ,o0 O 0,20 0,50 1 ,o0 2,oo element. 11 FA
24、AS-Analysis 11.1 General Fit the correct burner and light the flame in accordance with the manufacturers instructions for igniting and extinguishing the nitrous oxide/acetylene flame to avoid explosion. If necessary, wear tinted safety glasses whenever the flame is burning. Set the wavelength for th
25、e element to be analysed. NOTE The wavelengths in Table 2 can be used for the analysis. According to analytical procedure and element concentration, other wavelengths may be used. After preheating the burner for 10 min, adjust the fuel and the burner to obtain maximum absorbance while aspirating the
26、 highest calibration solution. Aspirate water and the calibration solutions to establish that the absorbance reading is not drifting and set the initial reading for SO to zero absorbance. Aspirate water and ascending calibration solutions to obtain data to construct a calibration graph. Aspirate wat
27、er and then the blank solution to obtain an absorbance a value. Aspirate water and then test sample to obtain an absorbance value. Calculate the concentration of element in the test sample (clause 12). 8 ENV 14226:2002 (E) Element Ca Mg 11.2 Inductively coupled plasma spectrometer FAAS ICP-AES 422,7
28、 393,366 285,2 279,553 Follow the manufacturers instructions for igniting the plasma. If necessary, wear anti UV safety glasses whenever the plasma is on. See note in 1 1.1. NOTE Interferences can be encountered and should be corrected according to manufacturers instructions. Aspirate water and the
29、calibration solutions to establish that the emission intensity reading is not drifting and set the initial reading for SO to zero. Aspirate water and ascending calibration solutions to obtain data to construct a calibration graph. Aspirate water and then the blank solution to obtain an intensity val
30、ue. Aspirate water and then the test sample solution to obtain an intensity value. Calculate the concentration of element in the test sample (clause 12). Table 2 - Possible analytical lines in nm I 259,940 I 248,3 I Fe I I 396,152 I 309,3 I Al I 12 Calculation X 50 (1 Op6 w I v of sample solution -
31、1 Op6 w I v blank) Sample weight lop6 w/ w of element = 9 ENV 14226:2002 (E) 13 Test report The test report shall contain at least the following information: name of testing establishment; place and date of test, report identification, signatory; reference to this European Prestandard, including inf
32、ormation on the method used (FAAS or ICP-AES); details of the equipment used, if needed; any information on the decomposition of the sample; calibration procedure; material type, manufacturing code, batch number; relevant test parameters; results of individual analyses; mean result and standard devi
33、ation for each element; reproducibility and repeatability of the method; comments about the test and test results. 10 ENV 14226:2002 (E) Bibliography ECSC/CI 9 Chemical analysis of ferrous materials - Operational guidelines for the application of flame atomic absorption spectroscopy in standard meth
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