GLASSES FOR MICROANALYSIS : NEW NBS (U.S.A.) STANDARD REFERENCE MATERIALS

HAL Id: jpa-00223851

https://hal.archives-ouvertes.fr/jpa-00223851

Submitted on 1 Jan 1984

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

GLASSES FOR MICROANALYSIS : NEW NBS (U.S.A.) STANDARD REFERENCE MATERIALS

R. Marinenko, D. Blackburn

To cite this version:

R. Marinenko, D. Blackburn. GLASSES FOR MICROANALYSIS : NEW NBS (U.S.A.) STAN-

DARD REFERENCE MATERIALS. Journal de Physique Colloques, 1984, 45 (C2), pp.C2-769-C2-

774. �10.1051/jphyscol:19842177�. �jpa-00223851�

GLASSES FOR M I C R O A N A L Y S I S : NEW NBS ( u , s , A , ) STANDARD REFERENCE M A T E R I A L S

R.B. Marinenko and D.H. Blackburn

Center for AnaZytical Chemistry and Center for Materials Science, National Bureau of Standards, Washington, D.C. 20234, U.S.A.

~ 6 s u m k - Un lpt d e quinze verres est en train d ' e t ~ e

certifie' par le NBS, en qualitg dgQtalons calibres (SRMgs) pour la microanalyse.

Abstract - A group of fifteen glasses are being certified by NBS as new SRM's for microanalysis.

A new group of Standard Reference Materials (SRM's) for microanalysis is being certified by the National Bureau of Standards (NBS), U. S. A. The fifteen glasses in the group will be issued as five separate SRM's of three glasses each. Each SRM will consist of a base glass composed of two or three oxides only and two additional glasses composed of the base glass plus seven to eleven other oxides in concentrations of two weight percent or less. The compositions of the glasses are shown in Tables I through V. Only the concentration of the major constituents in these glasses are being certified. The quantitative determination of the minor elements by the electron probe microanalyzer (EPMA) and any other technique used will be reported as information values only in the certificate. For comparison purposes in these tables, the nominal values, or the weighed quantity added to the melt, are in parentheses.

This is the second group of glasses to be certified by NBS as SRM's for microanalysis. The first was a pair of glasses, K-411 and K-412, issued together as SRM 270, Mineral Glasses for Microanalysis (1). They were prepared from the oxides and carbonates of magnesium, aluminum, silicon, calcium, and iron.

Glasses help to fill a gap in the standards needed for calibration and performance verification of microalytical techniques such as the EPMA and secondary ion mass spectrometry (SIMS). Often pure element standards are not available or are not satisfactory for particular types of analyses. Some oxides, stoichiometric compounds, and minerals are useful standards, but they are not always available in a form appropriate for microanalyses. Glasses can be prepared from many different oxides, thus making possible a wide range of often unique standards. In addition, they can be made homogeneous on the micrometer scale even when large numbers of elements are present.

These new glasses were prepared by melting the oxides, carbonates, and phosphates in electrically heated furnaces with an air atmosphere. Platinum crucibles were used to pre are the melts to prevent contamination. The melts were stirre$ for two hours with platinum-rhodium propeller-type stirrers to assure homogeneity.

Melting, stirring, and pouring temperatures ranged from 1 1 0 0 - 1 5 0 0 ~ ~ ,

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19842177

JOURNAL DE PHYSIQUE

and annealing temperatures ranged from 425-62S°C depending on the glass composition.

The oxide combinations represented in these SRM's -- lead-silicon, lead-germanium, barium-silicon-zinc, aluminum-boron-lithium, and phosphorus-magnesium-aluminum -- are not available in previously prepared standards. This uniqueness, as well as the additional oxides added as dopants, sometimes presented difficulties in the certification process. Most of the major constituents were analyzed by wet chemical procedures by J. Bodkin and associates at the Mineral Constitution Laboratories at The Pennsylvania State University, University Park, Pennsylvania. Triplicate analyses were done for each element. The aluminum in glass,es K-490, K-546, K-497, and K-1013 was not analyzed by wet chemical techniques because of the difficulty in analyzing this element in the presence of the additional oxides, many of which interfere with the determination of aluminum.

The macro- and microhomogeneity of the glasses were determined with the electron microprobe for all major constituents except boron.

The microhomogeniety procedure has been described in detail (2).

The specimen is moved in 1-pm steps under a 1-pm diameter electron beam for a distance of about 6 0 pm. At each point, counts are accumulated for 10 s before moving to the next point. A periodic integrator trace such as the one illustrated in figure 1 can provide an immediate visual estimate of the amount of inhomogeneity. This trace can be evaluated by statistical methods as well. By repeating the 10-s counting periods at each point, an experimental error can be determined for the counting procedure, and this error can be separated from the point-to-point variation. These traces were made from each of the fifteen glasses. None showed any statistically significant inhomogeneities.

For the macrohomogeneity tests, five specimens were randomly selected from the final lot of about 100 specimens. They were mounted and polished together in the same specimen mount. Each specimen was sampled at 6 points. Replicate readings were taken at each point for 10-s counting periods and each specimen was sampled twice. An experimental error, a between-specimens error, and a within-specimen error were determined. In Table VI these errors are listed for two homogeneity tests on glass K-497. Details of the calculations of these errors have been described (3). The results of the homogeneity tests on all the glasses are similar to these.

Most errors were less that one percent relative, and very few exceeded one percent. Such errors are sufficiently low to conclude that the glasses are homogeneous.

Most of the oxides were quantitatively analyzed with EPMA. Whenever

possible, more than one standard was used. Wavelength dispersive

(WDS) as well as energy dispersive (EDS) techniques were used for

the analysis of the major constituents. FRAME4 (4) and COR3 (5)

were used for the data reduction of the WDS data and FRAMEC (6) was

used for the EDS data. The provisional certification values for the

major constituents in Tables I to V were in most cases determined

from an average value of the electron microprobe and the wet

chemical results. The values listed for the minor constituents were

determined by WDS. Only cerium in glass K-489 was excluded because

of a strong interference by the Bahpeak. In most cases, the EPMA

values agree quite favorably with the nominal values in parentheses.

REFERENCES

1. MARINENKO, R. B., Preparation and characterization of K-411 and K-412 Mineral Glasses for Microanalysis: SRM 470. Nat. Bur.

Stand. (U.S) Spec. Pub. 260-74, 1982 April, 16 p.

2. MARINENKO, R. B., HEINRICH, K. F. J., RUEGG, F. C., Micro- homogeneity studies of NBS Standard Reference Materials, NBS Research Materials, and other related samples. Nat. Bur.

Stand. (U.S.) Spec. Pub. 260-65, 1979 September. 84 p.

3. MARINENKO, R. B., BIANCANIELLO, F., DeROBERTIS, L., BOYER, P.

A . , RUFF, A . W., Preparation and characterization of an

iron-chromium- nickel alloy for microanalysis: SRM 479a. Nat.

Bur. Stand. (U.S.) Spec. Pub. 260-70, 1981 May. 25 p.

4. YAKOWITZ, H., MYKLEBUST, R. L., HEINRICH, K. F. J., FRAME:

An on-line correction procedure for quantitative electron probe microanalysis. Nat. Bur. Stand. (U.S.) Tech. Note 796;

1973 October. 46 p.

5. HENOC, J., HEINRICH, K. F. J., MYKLEBUST, R. L., A rigorous correction procedure for quantitative electron probe microanalysis (COR 2). Nat. Bur. Stand. (U.S.) Tech. Note 769; 1973 August. 127 p.

6. MYKLEBUST, R. L., FIORI, C. E., HEINRICH, K. F. J., FRAME C:

a compact procedure for quantitative energy-dispersive electron probe x-ray analysis. Nat. Bur. Stand. (U.S.) Tech. Note 1106; 1979 September. 105 p.

7. OFFICE of STANDARD REFERENCE MATERIALS; Rm B311, Chemistry Building; National Bureau of Standards; Washington, D. C.

20234; Telephone (301) 921-2045.

JOURNAL DE _PHYSIQUE

TABLE I T A B L E I1

Lead-Silicon Glasses Composition in Weight Percent

Element K-456 K-493 K-523

Total 99.32 98.93 99.70

Nominal values in parentheses

T A B L E I11 Barium-Silicon-Zinc Glasses Compositon in Weight Percent

Element K-458 K-489 K-963

Total 98.38 100.38 100.30

Nominal values in parentheses

Lead-Germanium Glasses Composition in Weight Percent

Element K-453 K-491 K-968

Total 99.51 99.46 100.36

Nominal values in parentheses

TABLE I V

Aluminum-Boron-Lithium Glasses Composition in Weight Percent

Element Al

B Li 0 Mg S i P Ti Cr Fe Ni Ge Zr Ba Ce Eu Ta Pb Th

U Total

Nominal values in parentheses

Composition in Weight Percent

Element K-496 K-497 K-1013

Al 7.04 6.82 6.99

MPS ^{32.76 6.72 31.44 6.62 31.66 6.13}

0 53.01 50.82 51.90

Total

Nominal values in parentheses

T A B L E V I . H O M O G E N E I T Y E V A L U A T I O N O F K-497 GLASS^

EXP. OXIDE WT. % STANDARD DEV. I N WT. % OF 0 x 1 ~ ~ ~ ' ~

S e Sb S s SP

B M g O 10.98 .05(.46) .06(.55) .04(.37) .09(.80)

a 1 5 k V excitation potential, 5 specimens of each g l a s s

b standard deviations are Se = the experimental error, Sb = the between-specimens error, S s = the within-specimen error, and Sp = s e 2 + ^{s b 2} + S s 2

c relative errors in percent are in parentheses

JOURNAL DE PHYSIQUE

G l a s s K-497

20pm beam lum beam lum s t e p s

6 . 0 9 w t . i 1 2 , 0 0 0

S t a t i o n a r y

Magnesium Ka 5 . 2 wt .%

__--

^- ---_---

,

P h o s p h o r u s Ka 3 3 . 2 w t . 8

Aluminum Ka 5 . 8 w t . %

F i g u r e 1. P e r i o d i c i n t e g r a t o r

h o m o g e n e i t y t r a c e s o f aluminum,

p h o s p h o r u s , and m a g n e s i um

s i m u l t a n e o u s l y r e c o r d e d from NBS

G l a s s K-497. I n t h e t r a c e on t h e

r i g h t , t h e s p e c i m e n was a d v a n c e d

1 pm u n d e r a 1 p m e l e c t r o n beam

a f t e r e a c h t e n - s e c o n d c o u n t i n g

p e r i o d . To t h e l e f t , t h e

s p e c i m e n was n o t moved d u r i n g

r e p e a t e d t e n - s e c o n d c o u n t i n g

p e r i o d s wi-th a 20 pm e l e c t r o n

beam. Double- h e a d e d a r r o w s t o

t h e r i g h t d e f i n e a r a n g e o f f 3 f l

a r o u n d t h e a v e r a g e number o f

c o u n t s p e r 1 0 s e c o n d s , W, f o r t h e

e n t i r e t r a c e . D e v i a t i o n s o u t s i d e

t h e l i m i t s d e f i n e d b y t h e a r r o w s

a r e u s u a l l y a t t r i b u t e d t o

i n h o m o g e n e i t i e s .