NBS

PUBLICATIONS

NBS SPECIAL PUBLICATION 260"74

U.S. DEPARTMENT OF COMMERCE/National Bureau of Standards

Standard Reference Materials:

PREPARATION AND CHARACTERIZATION

OF K-411 AND K-412 MINERAL GLASSES

FOR MICROANALYSIS: SRM 470
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act of Congress on March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is per- formed by the National Measurement Laboratory, the National Engineering Laboratory, and

the Institute for Computer Sciences and Technology. THE NATIONAL MEASUREMENT LABORATORY provides the national system of

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standards, and data on the properties of materials needed by industry, commerce, educational

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2 Some divisions within the center are located at Boulder, CO 80303.
1J«M»T Standard Reference Materials: JUL 7 1982 not £lc^~ bee.

PREPARATION AND CHARACTERIZATION

OF K-411 AND K-412 MINERAL GLASSES

FOR MICROANALYSIS: SRM 470

fvtb$> %^UOlX (LuA~G Cain en^

R. B. Marinenko

National Measurement Laboratory

National Bureau of Standards Washington, DC 20234

HO. ^O-I^f

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director Issued April 1982
Library of Congress Catalog Card Number: 82-60051

1

National Bureau of Standards Special Publication 260-74

Nat. Bur. Stand. (U.S.), Spec. Publ. 260-74, 25 pages (Apr. 1982) CODEN: XNBSAV

U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 1982
PREFACE

Standard Reference Materials (SRM's) as defined by the

National Bureau of Standards are wel 1 - character i zed materials

produced in quantity and certified for one or more physical

or chemical properties. They are used to assure the accuracy

and compatibility of measurements throughout the Nation.

SRM's are widely used as primary standards in many diverse

fields in science, industry, and technology, both within the

United States and throughout the world. They are also used

extensively in the fields of environmental and clinical analysis. In many applications, traceability of quality control

and measurement processes to the national measurement system

are carried out through the mechanism and use of SRM's. For many of the Nation's scientists and technologists it is therefore of more than passing interest to know the details

of the measurements made at NBS in arriving at the certified

values of the SRM's produced. An NBS series of papers, of

which this publication is a member, called the NBS Special

Publication - 260 Series , is reserved for this purpose.

This 260 Series is dedicated to the dissemination of

information on different phases of the preparation, measurement, certification and use of NBS-SRM's. In general, much

more detail will be found in these papers than is generally

allowed, or desirable, in scientific journal articles. This

enables the user to assess the validity and accuracy of the

measurement processes employed, to judge the statistical

analysis, and to learn details of techniques and methods

utilized for work entailing the greatest care and accuracy.

These papers also should provide sufficient additional information not found on the certificate so that new applications

in diverse fields not foreseen at the time the SRM was originally issued will be sought and found.

Inquiries concerning the technical content of this paper

should be directed to the author. Other questions concerned

with the availability, delivery, price, and so forth will

receive prompt attention from:

Office of Standard Reference Materials

National Bureau of Standards

Washington, D.C. 20234

George A. Uriano, Chief

Office of Standard Reference Materials

i i i
OTHER NBS PUBLICATIONS IN THIS SERIES

Catalog of NBS Standard Reference Materials (1981-83 edition), R. W. Seward, ed., NBS

Spec. Publ. 260 (November 1981). Michaelis, R. E., and Wyman, L. L. Standard

Reference Materials: Preparation of White Cast

Iron Spectrochemical Standards. NBS Misc. Publ. 260-1 (June 1964). CO M 74- 1 1 06 1 * * Michaelis, R. E., Wyman, L. L., and Flitsch, R., Standard Reference Materials: Preparation of NBS Copper-Base Spectrochemical Standards. NBS Misc. Publ. 260-2 (October 1964). COM74-

11063**

Michaelis, R. E., Yakowitz, H., and Moore, G. A., Standard Reference Materials: Metallographic

Characterization of an NBS Spectrometric LowAlloy Steel Standard. NBS Misc. Publ. 260-3 (October 1964). COM74- 1 1060** Hague, J. L. Mears, T. W., and Michaelis, R. E., Standard Reference Materials: Sources of

Information, NBS Misc. Publ. 260-4 (February

1965). COM74-11059

Alvarez, R., and Flitsch R., Standard Reference

Materials: Accuracy of Solution X-Ray Spectrometric Analysis of Copper-Base Alloys. NBS

Misc. Publ. 260-5 (March 1965). PB168068**

Shultz, J. I., Standard Reference Materials: Methods for the Chemical Analysis of White

Cast Iron Standards, NBS Misc. Publ. 260-6

(July 1975). COM74-1 1068**

Bell, R. K., Standard Reference Materials: Methods for the Chemical Analysis of NBS

Copper-Base Spectrochemical Standards. NBS

Misc. Publ. 260-7 (October 1965). COM74-

1 1067** Richmond, M.S., Standard Reference Materials: Analysis of Uranium Concentrates at the

National Bureau of Standards. NBS Misc. Publ. 260-8 (December 1965). COM74- 1 1066** Anspach, S. C, Cavallo, L. M. Garfinkel, S. B. Hutchinson, J. M. R., and Smith, C. N., Standard Reference Materials: Half Lives of Materials Used in the Preparation of Standard Reference Materials of Nineteen Radioactive Nuclides

Issued by the National Bureau of Standards NBS Misc. Publ. 260-9 (November 1965). COM74-1 1065**

Yakowitz, H., Vieth, D. L, Heinrich, K. F. J., and

Michaelis, R. E., Standard Reference Materials: Homogeneity Characterization on NBS Spectrometric Standards II: Cartridge Brass and LowAlloy Steel, NBS Misc. Publ. 260-10 (December

1965). COM74-1 1064** Napolitano, A., and Hawkins, E. G., Standard Reference Materials: Viscosity of Standard

Lead-Silica Glass, NBS Misc. Publ. 260-11 (November 1966). NBS Misc. Publ. 260-11** Yakowitz, H., Vieth, D. L., and Michaelis, R. E., Standard Reference Materials: Homogeneity

Characterization of NBS Spectrometric Standards HI: White Cast Iron and Stainless Steel Powder Compact, NBS Misc. Publ. 260-12

(September 1966). NBS Misc. Publ. 260-12** Spijkerman, J. L., Snediker, D. K., Ruegg, F. C,

and DeVoe, J. R., Standard Reference Materials: Mossbauer Spectroscopy Standard for the Chemical Shift of Iron Compounds, NBS Misc. Publ. 260-13 (July 1967). NBS Misc. Publ.

260-13**

Menis, O., and Sterling, J. T., Standard Reference

Materials: Determination of Oxygen in Ferrous

Materials - SRM 1090, 1091, and 1092, NBS

Misc: Publ. 260-14 (September 1966). NBS Misc.

Publ. 260-14**

Passaglia, E., and Shouse, P. J. Standard Refer- ence Materials: Recommended Method of Use

of Standard Light-Sensitive Paper for Calibrat- ing Carbon Arcs Used in Testing Textiles for Colorfastness to Light, NBS Misc. Publ. 260-15 (June 1967). (Replaced by NBS Spec. Publ.

260-41.) Yakowitz, H., Michaelis, R. E., and Vieth, D. L., Standard Reference Materials: Homogeneity

Characterization of NBS Spectrometric Standards IV: Preparation and Microprobe Characterization of W-20% MO Alloy Fabricated by Powder Metallurgical Methods, NBS Spec.

Publ. 260-16 (January 1969). COM74-1 1062** Catanzaro, E. J., Champion, C. E., Garner, E. L., Marinenko, G., Sappenfield, K. M., and Shields, W. R. Standard Reference Materials: Boric

Acid; Isotopic and Assay Standard Reference

Materials, NBS Spec. Publ. 260-17 (February

1970). Out of Print

TV
Geller, S. B., Mantek, P. A., and Cleveland, N.

G., Standard Reference Materials: Calibration of NBS Secondary Standard Magnetic Tape (Computer Amplitude Reference) Using the Reference Tape Amplitude Measurement

"Process A, "NBS Spec. Publ. 260-18 (November

1969). (See NBS Spec. Publ. 260-29.) Paule, R. C, and Mandel, J., Standard Reference

Materials: Analysis of Interlaboratory Measurements on the Vapor Pressure of Gold (Certifica- tion of Standard Reference Material 745). NBS

Spec. Publ. 260-19 (January 1970). PB190071**

Paule, R. C, and Mandel, J., Standard Reference

Materials: Analysis of Interlaboratory Measure- ments on the Vapor Pressures of Cadmium and

Silver, NBS Spec. Publ. 260-21 (January 1971). COM74-1 1359** Yakowitz, H., Fiori, C. E., and Michaelis, R. E., Standard Reference Materials: Homogeneity

Characterization of Fe-3 Si Alloy, NBS Spec.

Publ. 260-22 (February 1971). COM74- 1 1 357**

Napolitano, A., and Hawkins, E. G,, Standard

Reference Materials: Viscosity of a Standard

Borosilicate Glass, NBS Spec. Publ. 260-23 (December 1970). COM7 1-00 1 57**

Sappenfield, K. M., Marineko, G., and Hague, J. L., Standard Reference Materials: Comparison

of Redox Standards, NBS Spec. Publ. 260-24 (January 1972). COM72-50058**

Hicho, G. E., Yakowitz, H., Rasberry, S. D., and

Michaelis, R. E., Standard Reference Materials: A Standard Reference Material Containing

Nominally Four Percent Austenite, NBS Spec.

Publ. 260-25 (February 1971). COM74- 1 1 356** Martin, J. F., Standard Reference Materials:

National Bureau of Standards-US Steel Corportion Joint Program for Determining Oxygen and Nitrogen in Steel, NBS Spec. Publ. 260-26

(February 1971). 85 cents* PB 81 176620

Garner, E. L., Machlan, L. A., and Shields, W. R., Standard Reference Materials: Uranium

Isotopic Standard Reference Materials, NBS

Spec. Publ. 260-27 (April 1971). COM74-

1 1358**

Heinrich, K. F. J., Myklebust, R. L., Rasberry, S. D., and Michaelis, R. E., Standard Reference Materials: Preparation and Evaluation of SRM's 481 and 482 Gold-Silver and GoldCopper Alloys for Microanalysis, NBS Spec.

Publ. 260-28 (August 1971). COM7 1-50365**

Geller, S. B., Standard Reference Materials: Cali- bration of NBS Secondary Standard Magnetic Tape (Computer Amplitude Reference) Using

the Reference Tape Amplitude Measurement

"Process A-Model 2," NBS Spec. Publ. 260-29 (June 1971). COM71-50282

Gorozhanina, R. S., Freedman, A. Y., and

Shaievitch, A. B. (translated by M. C. Selby), Standard Reference Materials: Standard

Samples Issued in the USSR (A Translation from the Russian). NBS Spec. Publ. 260-30 (June

1971). COM71-50283**

Hust, J. G., and Sparks, L. L., Standard Reference

Materials: Thermal Conductivity of Electrolytic Iron SRM 734 from 4 to 300 K, NBS Spec. Publ. 260-31 (November 1971). COM7 1-50563** Mavrodineanu, R., and Lazar, J. W., Standard

Reference Materials: Standard Quartz Cuvettes,

for High Accuracy Spectrophotometry, NBS

Spec. Publ. 260-32 (December 1973). 55 cents* SN003-003-01213-1 Wagner, H. L., Standard Reference Materials: Comparison of Original and Supplemental

SRM 705, Narrow Molecular Weight Distri- bution Polystyrene, NBS Spec. Publ. 260-33 (May 1972). COM72-50526**

Sparks, L. L., and Hust, J. G., Standard Reference

Materials: Thermoelectric Voltage, NBS Spec.

Publ. 260-34, (April 1972). COM72-5037 1 ** Sparks, L. L., and Hust, J. G., Standard Refer- ence Materials: Thermal Conductivity of

Austenitic Stainless Steel, SRM 735 from 5 to 280 K, NBS Spec. Publ. 260-35 (April 1972.) 35 cents* COM72-50368**

Cali, J. P., Mandel, J., Moore, L. J., and Young, D.

S., Standard Reference Materials: A Referee Method for the Determination of Calcium in Serum, NBS SRM 915, NBS Spec. Publ. 260-36 (May 1972). COM72-50527**

Shultz, J. 1. Bell., R. K. Rains, T. C, and Menis,

O., Standard Reference Materials: Methods of Analysis of NBS Clay Standards, NBS Spec.

Publ. 260-37 (June 1972). COM72-50692**

Richmond, J. C, and Hsia, J. J., Standard Refer- ence Materials: Preparation and Calibration of Standards of Spectral Specular Reflectance, NBS Spec. Publ. 260-38 (May 1972). COM72-

50528**

Clark, A. F., Denson, V.A., Hust, J. G., and

Powell, R. L., Standard Reference Materials The Eddy Current Decay Method for Resistivity Characterization of High-Purity Metals, NBS

Spec. Publ. 260-39 (May 1972). COM72-50529**

V
McAdie, H. G., Garn, P.D., and Menis, O., Standard Reference Materials: Selection of Thermal

Analysis Temperature Standards Through a Cooperative Study (SRM 758, 759, 760), NBS

Spec. Publ. 260-40 (August 1972.) COM72-

50776** Wood, L. A., and Shouse, P. J., Standard

Reference Materials: Use of Standard LightSensitive Paper for Calibrating Carbon Arcs Used in Testing Textiles for Colorfastness to Light, NBS Spec. Publ. 260-41 (August 1972) COM72-50775**

Wagner, H. L. and Verdier, P. H., eds.. Standard

Reference Materials: The Characterization of Linear Polyethylene, SRM 1475, NBS Spec. Publ. 260-42 (September 1972). COM72-

50944**

Yakowitz, H., Ruff, A. W., and Michaelis, R. E., Standard Reference Materials: Preparation and Homogeneity Characterization of an Austenitic Iron-Chromium-Nickel Alloy, NBS Spec. Publ. 260-43 (November 1972). COM73-50760**

Schooley, J. F., Soulen, R. J., Jr., and Evans, G. A.,

Jr., Standard Reference Materials: Preparation and Use of Superconductive Fixed Point

Devices, SRM 767, NBS Spec. Publ. 260-44 (December 1972). COM73-50037**

Greifer, B., Maienthal, E. J. Rains, T. C, and

Rasberry, S. D., Standard Reference Materials: Powdered Lead-Based Paint, SRM 1579, NBS

Spec. Publ. 260-45 (March 1973). COM73-

50226**

Hust, J. G., and Giarratano, P. J., Standard Refer- ence Materials: Thermal Conductivity and

Electrical Resistivity Standard Reference Materials: Austenitic Stainless Steel, SRM's 735 and

798, from 4 to 1200 k, NBS Spec. Publ. 260-46 (March 1975). SN003-003-0 1278-5 Hust, J. G., Standard Reference Materials: Electrical Resistivity of Electrolytic Iron, SRM 797, and Austenitic Stainless Steel, SRM 798, from 5 to 280 K, NBS Spec. Publ. 260-47 (February

1974). COM74-50176** Mangum, B. W., and Wise, J. A., Standard Refer- ence Materials: Description and Use of Precision Thermometers for the Clinical Laboratory,

SRM 933 and SRM 934, NBS Spec. Publ. 260-48 (May 1974). 60 cents* SN003-003-0 1 278-5 Carpenter, B. S., and Reimer, G. M., Standard

Reference Materials Calibrated Glass Standards for Fission Track Use, NBS Spec. Publ. 260-49 (November 1974). COM74-51185

Hust, J. G., and Giarratano, P. J., Standard Refer- ence Materials: Thermal Conductivity and Electrical Resistivity Standard Reference Materials:

Electrolytic Iron, SRM's 734 and 797 from 4 to 1000 K, NBS Spec. Publ. 260-50 (June 1975). $1.00* SN003-003-0 1425-7 Mavrodineanu, R., and Baldwin, J. R., Standard

Reference Materials: Glass Filters Asa Standard Reference Material for Spectrophotometry;

Selection; Preparation; Certification; Use-SRM

930, NBS Spec. Publ. 260-51 (November 1975). $1.90* SN003-003-01481-8

Hust, J. G., and Giarratano, P. J., Standard Refer- ence Materials: Thermal Conductivity and Electrical Resistivity Standard Reference Materials 730 and 799, from 4 to 3000 K, NBS Spec. Publ. 260-52 (September 1975). $1.05* SN003-003-

01464-8 Durst, R. A., Standard Reference Materials: Standardization of pH Measurements, NBS

Spec. Publ. 260-53 (December 1975, Revised). $1.05 SN003-003-01551-2

Burke, R. W., and Mavrodineanu, R. Standard

Reference Materials: Certification and Use of Acidic Potassium Dichromate Solutions as an

Ultraviolet Absorbance Standard, NBS Spec.

Publ. 260-54 (August 1977). $3.00* SN003-003-

01828-7

Ditmars, D. A., Cezairliyan, A., lshihara, S., and

Douglas, T. B., Standard Reference Materials: Enthalpy and Heat Capacity; Molybdenum

SRM 781, from 273 to 2800 K, NBS Spec. Publ. 260-55 (September 1977). $2.20* SN003-003-

01836-8

Powell, R. L., Sparks, L. L., and Hust, J. G., Standard Reference Materials: Standard

Thermocouple Materials, Pt.67: SRM 1967, NBS

Spec. Publ. 260-56 (February 1978). $2.20* SN003-003-0 18864

Cali, J. P. and Plebanski, T., Guide to United

States Reference Materials, NBS Spec. Publ. 260-57 (February 1978). $2.20* PB 277173

Barnes, J. D., and Martin, G. M., Standard Refer- ence Materials: Polyester Film for Oxygen Gas

Transmission Measurements SRM 1470, NBS

Spec. Publ. 260-58 (June 1979) $2.00* SN003-

003-02077 Chang, T., and Kahn, A. H., Standard Reference Materials: Electron Paramagnetic Resonance

Intensity Standard; SRM 2601, NBS Spec.

Publ. 260-59 (August 1978) $2.30* SN003-

003-01975-5
Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel, J., and Moody, J. R., Standard Refer- ence Materials: A Reference Method for the Determination of Sodium in Serum, NBS Spec.

Publ. 260-60 (August 1978). $3.00* SN003-003

01978-0

Verdier, P. H., and Wagner. H. L, Standard Refer- ence Materials: The Characterization of Linear Polyethylene (SRM 1482, 1483, 1484), NBS

Spec. Publ. 260-61 (December 1978). $1.70* SN003-003-02006-I

Soulen, R. J., and Dove, R. B., Standard Reference

Materials: Temperature Reference Standard

for Use Below 0.5 K (SRM 768). NBS Spec.

Publ. 260-62 (April 1979). $2.30* SN003-003-

02047-8 Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel, J., Machlan, L. A., and Gramlich, J. W., Standard Reference Materials: A Reference Method for the Determination of Potassium in Serum. NBS Spec. Publ. 260-63 (May 1979). $3.75* SN003-003-02068

Velapoldi, R. A., and Mielenz, K. D., Standard

Reference Materials: A Fluorescence Standard

Reference Material Quinine Sulfate Dihydrate (SRM 936), NBS Spec. Publ. 260-64 (January

1980). $4.25* SN003-003-02 148-2 Marinenko, R. B., Heinrich, K. F. J., and Ruegg,

F. C, Standard Reference Materials: Micro- Homogeneity Studies of NBS Standard Reference

Materials. NBS Research Materials, and Other Related Samples. NBS Spec. Publ. 260-65

(September 1979). $3.50* SN003-003-02 1 14-

1

Venable, W. H., Jr., and Eckerle, K. L., Standard

Reference Materials: Didymium Glass Filters for Calibrating the Wavelength Scale of Spectro- photometers (SRM 2009, 2010, 2013). NBS Spec.

Publ. 260-66 (October 1979). $3.50* SN003-003-

02127-0

Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel,

J., Murphy, T. J., and Gramlich, J. W., Standard

Reference Materials: A Reference Method for the Determination of Chloride in Serum, NBS Spec.

Publ. 260-67 (November 1979). $3.75* SN003-

003-02136-9 Mavrodineanu, R. and Baldwin, J.R., Standard

Reference Materials: Metal-On-Quartz Filters as a Standard Reference Material for Spectrophoto- metry-SRM 2031, NBS Spec. Publ. 260-68

(April 1980). $4.25* SN003-003-02 167-9

Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel, J., Machlan, L. A., Garner, E. L., and

Rains, T. C, Standard Reference Materials: A

Reference Method for the Determination of Lithium in Serum, NBS Spec. Publ. 260-69 (July)

1980). $4.25* SN003-003-02214-4 Marinenko, R. B., Biancaniello, F., Boyer, P. A., Ruff, A. W., DeRobertis, L., Standard Reference

Materials: Preparation and Characterization of an Iron-Chromium-Nickel Alloy for Microanalysis, NBS Spec. Publ. 260-70 (May 1981). $2.50* Seward, R. W., and Mavrodineanu, R., Standard

Reference Materials: Summary of the Clinical Laboratory Standards Issued by the National Bureau of Standards, NBS Spec. Publ. 260-71

(in press). Reeder, D.J., Coxon, B., Enagonio, D., Christensen,

R. G., Schaffer, R., Howell, B. F., Paule, R. C,

Mandel, J., Standard Reference Materials: SRM

900, Antiepilepsy Drug Level Assay Standard, NBS Spec. Publ. 260-72 (June 1981). $4.25*

Interrante, C. G., and Hicho, G. E., Standard Refer- ence Materials: A Standard Reference Material Containing Nominally Fifteen Percent Austenite (SRM 486), NBS Spec. Publ. 260-73 (in press). Marinenko, R. B., Standard Reference Materials: Preparation and Characterization of K-411 and

K.-412 Mineral Glasses for Microanalysis: SRM

470. NBS Spec. Publ. 260-74 (in press).

* Send order with remittance to Superintendent

of Documents, US. Government Printing Office, Washington, DC 20402. Remittance from

foreign countries should include an additional one-fourth of the purchase price for postage.

** May be ordered from: National Technical Information Services (NTIS), Springfield,

Virginia 22151.

vii
TABLE OF CONTENTS

PAGE Preface iii

1. Introduction 1 2. Preparation 2 3. Chemical Composition 2 4. Homogeneity 4

5. Conclusions 14

6. References 14

LIST OF TABLES

TABLE NO. PAGE

1. Wet chemical procedures used in the analysis of glasses K-411 and K-412 3

2. Wet chemical analyses of SRM 470, mineral glasses for microanalysis 4

3. Mineral standards used for quantitative EPMA of mineral glasses K-411 and K-412 .... 5 4. Electron probe microanalyses of NBS SRM 470, mineral glasses for microanalysis 6

5. Comparison of statistical data from homogeneity tests (weight percent) 9

6. Homogeneity evaluation of five specimens of glass K-411 11

7. Homogeneity evaluation of five specimens of glass K-412 12

8. Comparison of uncertainty intervals for glass K-411 in weight percent of oxide 13

9. Comparison of uncertainty intervals for glass K-412 in weight percent of oxide 13

LIST OF FIGURES FIGURE NO. PAGE

la. Periodic integrator homogeneity traces of iron and calcium simultaneously

recorded from NBS SRM 470, Mineral Glass K-411 7 lb. Periodic integrator homogeneity traces of iron and calcium simultaneously

recorded from NBS SRM 470, Mineral Glass K-412 8 National Bureau of Standards Certificate of Analysis, Standard Reference Material 470, Mineral Glasses for Microanalysis 15

viii
PREPARATION AND CHARACTERIZATION OF K-411 AND K-412 MINERAL GLASSES FOR MICROANALYSIS: SRM 470

R. B. Marinenko

Center for Analytical Chemistry

National Bureau of Standards Washington, DC 20234

The two mineral glasses in SRM 470, K-411 and K-412, were quantitatively analyzed for major constituents. The results of wet chemical analyses from two independent laboratories

were in excellent agreement; therefore, these results were used for certification. Quanti- tative electron probe microanalysis also agrees favorably with the certified compositions.

Specimens were evaluated for micro- and macrohomogenei ty with the electron microprobe by using random sampling and periodic integrator homogeneity trace techniques. Statistical analyses as well as the homogeneity traces showed no obvious composition fluctuations

either within each specimen or among different specimens. These glasses are therefore excellent standards for microanalytical techniques. They are primarily composed of silicon, iron, magnesium, calcium, and aluminum oxides, none of which is present in less than 9 weight percent nor more than 55 weight percent.

Key words: chemical analysis; digital periodic integrator; electron probe microanalysis; glass standards; homogeneity testing; microhomogeneity; mineral glasses; Standard Reference Material.

1 . Introduction

The Mineral Glasses K-411 and K-412 are the first vitreous materials to be certified as microanalytical standards. At least six other Standard Reference Materials (SRM's) are available for microanalysis [1-6], but these are all binary or tertiary metal alloys. Glasses provide a large number of possibilities for new standard materials. Numerous oxide glass-forming systems offer wide flexibility in selecting matrices in which the elements of analytical interest can be incorporated. Since the resulting glasses are essentially structureless, they can be made homogeneous with a large number of elements present. The glasses are composed of four and five different oxides, respectively, in concentrations of

no less than nine percent by weight for any one oxide. The results of the quantitative analyses and homogeneity evaluation will be described.

1
2. Preparation

The glasses K-411 and K-412 were developed by D. H. Blackburn and prepared by D. A. Kauffman at NBS. The carbonate and oxides were melted in platinum crucibles and stirred for homogeneity with propeller-type, platinum-10 percent rhodium alloy stirrers. Melting was done in an air atmosphere

with electrically heated furnaces. Temperatures for the melting and stirring procedure were in the range of 1450 to 1500 °C. The stirring time was 3 hours. The compounds used in the preparation

were high purity crushed quartz, and reagent grade ferric oxide, magnesium oxide, calcium carbonate,

and anhydrous aluminum oxide. The glasses were cast into rectangular blocks with approximate

dimensions of 9 x 5 x 2 cm. These blocks were annealed at 625 °C. For SRM distribution, at least 100 specimens were cut from each glass block. Each specimen

is approximately 2 x 2 x 20 mm. A precision wafering saw was used with a 0.07 x 15.2 cm (0.028 x 6") 100-grit diamond wheel and a petroleum-based coolant. An acetone-soluble adhesive was used to mount

the glass block and slices onto the cutting plate. Several 2 mm slices were cut from the glass

block. These slices were in turn cut at 2 mm intervals. The glass slices were removed from the cutting plate and rinsed with acetone several times to remove all traces of adhesive.

3. Chemical Composition

The certified compositions of the glasses K-411 and K-412 are based on classical wet chemical analyses from two independent laboratories. Although the glasses were also analyzed with the electron microprobe (EPMA), the wet chemistry values were selected for certification because they showed consistency between the two analyses and because greater accuracy is usually associated with wet

chemical analyses of this type than with EPMA. The accuracy expected from the former is generally

better than 1 percent while a conservative estimate of the accuracy associated with the latter is

2 percent. The EPMA results are discussed here for comparative purposes only. The wet chemical analyses were performed by E. Jarosewich and J. Norberg of the Smithsonian

Institution, Washington, D. C. (Lab A) and by J. C. DeVine and N. H. Suhr of the Pennsylvania State University, University Park, Pa. (Lab B). The procedures used are briefly described in Table 1. For

a single analysis of each oxide in a glass a 1-gram sample was used. Pieces were broken off the glass bar for this purpose. The results of the analyses from the two independent laboratories and the certified values are in Table 2. There is excellent agreement between the two laboratories.

Lab A did duplicate analyses. Lab B was given only enough sample for a single analysis of each oxide in each glass. The certified values for each oxide are the averages of the two independent

results. A 2-sigma (standard deviation) of ±0.20 weight percent was assigned to each of the certified compositions. This is a pooled value taken from all of the oxides and estimated from the ranges between the two laboratories. Trace or minor amounts of some elements were found in the glasses. These probably originated

in the starting materials. Lab A detected the presence of manganese. This was later verified by Lab B which detected MnO by atomic absorption in concentrations of 0.13 weight percent in K-411 and 0.09 weight percent in K-412. A trace of aluminum was also found by Lab B. Less than 0.1 percent aluminum was detected spectrographically but Lab B was unable to chemically observe this

small amount.

2
Table 1. Wet chemical procedures used in the analysis of glasses K-411 and K-412

Lab A Gravimetric. Sample fused with sodium carbonate followed by a double dehydration in hydrochloric acid. The hydrated silica is ignited, weighed, and volatilized with hydro- fluoric acid. The residue is ignited and weighed. Loss in weight represents silica (SiOg). - Gravimetric. Aluminum is precipitated from an aliquot of R^CL solution with 8-hydroxy- quinoline and weighed as the precipitate.

Fe ( total )- Volumetric titration. Ferric iron is reduced in a silver reductor and titrated with a and Fe 9 CL standard solution of potassium dichromate. Fe 9 0o is calculated by subtracting FeO from

c 6 total Fe.

L 6

FeO - Volumetric titration. Following dissolution in sulfuric and hydrochloric acids in a non- oxidizing atmosphere, ferrous iron is titrated with a standard solution of potassium

dichromate.

CaO — Gravimetric. Precipitation in an ammoniacal solution with ammonium oxalate. Precipitate

is dissolved in dilute hydrochloric acid and reprecipitated with the oxalate. The precipitate is ignited and weighed as the oxide. MgO - Gravimetric. Double precipitation in an ammoniacal solution with dibasic ammonium phosphate. The residue is ignited at 1100 °C and weighed as Wq^fl-j.

Lab B

Si

0

2 - Same as Lab A.

Al 9 0o - Gravimetric. Double precipitation with ammonia. A1 ? CL by difference of total P

? 0o and

Fe

2 0

3 and Ti0

2

. Corrected for Si0

2

. Fe(total )— Vol umetric titration. Ferric iron is reduced with stannous chloride and titrated with a and FegO^ standard solution of potassium dichromate. Fe

2 0

3 is calculated by subtracting the Fe^Oo equivalent of FeO from total Fe. FeO —Volumetric titration. Following dissolution in sulfuric and hydrofluoric acids in a non-oxidizing atmosphere, ferrous iron is titrated with a standard solution of potassium

permanganate.

CaO — Same as Lab A, but the precipitate is ignited and weighed as calcium carbonate. Calcium

recovered from the magnesium precipitate.

MgO — Same as Lab A. Corrected for calcium and manganese.

3
Table 2. Wet chemical analyses of SRM 470, mineral glasses for microanalysis

Composition of Oxide in Weight Percent

Total Fe Si0

2 MgO CaO Al

2 03 FeO Fe

2 0

3 as FeO

Glass K-411 Lab A 54.25 14..60 15.61 4 .04 11 14..47 54.23 14..67 15.44 4..73 10 .93 ) Lab B 54.36 14,.69 15.41 3.^5 n,.55 14.,34 Certified Value 54.30±0. 20

a 14,,67±0.20 15.47±0. 20 14.,43±0 .20

Glass K-412

Lab A 45.36 19..32 15.33 9.32 2,.61 8 21

! 10..10 45.40 19.,33 15.24 9.20 2,.93 8 .09 J Lab B 45.32 19.,32 15.21 9.28 2,77 7_,83 9.,82 Certified Value 45.35±0. 20

a 19..33±0.20 15.25±0. 20 9.27±0.20 9.,96±0,.20

a The uncertainty of ±0.20 weight percent assigned to the certified values is the 2-sigma value. This error is a pooled value for all oxides estimated from the ranges between the two laboratories using

wet chemical techniques.

The two glasses were also analyzed with the electron microprobe by C. E. Fiori at NBS (Lab C). He used an excitation potential of 15 kV, crystal spectrometers, and mineral standards. Matrix corrections were made with COR [7]. The standards used were ENAL 10, Diopside, and Juan de Fuca Basaltic Glass. Their compositions are listed in Table 3. These are well -characterized standards

which are used by mineralogists and geologists for quantitative EPMA. The results of the electron probe analyses are listed in Table 4. The range between experiments

for each oxide is less than 2 percent relative except Al^O^ which is about 3 percent relative.

4. Homogeneity

The two glasses were tested for both micro- and macrohomogeneity . Periodic integration traces

and random sampling techniques were used. The former procedure which is used to test the transverse microhomogeneity of a specimen is described in detail in a recent NBS Special Publication 260-65 [8]. It uses a stepping motor on the sample stage to move the specimen in a straight line under the electron beam in 1 to 10 ym steps. X-ray counts are accumulated at each step for a preselected time period. The total number of x-ray

counts are recorded as an analog signal on a fast strip chart recorder; this signal remains unchanged

during the next counting period. In addition, the signal can be digitally multiplied by an appropriate

factor and a bias can be applied to subtract any number of counts from the display.

4
Table 3. Mineral standards used for quantitative EPMA of mineral glasses K-411 and K-412

Composition of Standards in Weight Percent

ENAL 10 (from Geophysical Laboratories) 9

[MgSi0

3 + 10% A12 0

3

]

Mg 21.80 Al 5.29

Si 25.18 0 47.73

Diopside (from Smithsonian Institution)

[CaMgSi

2 0

6

]

Ca 18.51 Si 25.93

Mg 11.23 0 44.33

Juan de Fuca Basaltic Glass (from Smithsonian Institution)

Si 23.75 Na 1,,94

Al 7.44 K 0,,16 Fe 9.20 Ti 1

.

,11 Mg 4.05 P 0.,0007

Ca 7.95 Mn 0..0017

0 44.,17

A synthetic glass. Composition based on stoichiometry.

'These standards were analyzed by wet chemistry; results appear in the following reference. Jarosevich, E.; Nelen, J. A.; Norberg, J. A. Electron microprobe reference samples for mineral analyses. Mineral Sciences Investigations 1976-1977. Smithsonian Contributions

to the Earth Sciences, No. 22. Fudali, R. F., ed. Washington, D.C.; 1979. 73p.

5
Table 4. Electron probe microanalyses of NBS SRM 470, mineral glasses for microanalysis

Composition of Oxide in Weight Percent

3

Exp. Si0 ? FeO MgO CaO

Glass K-411 Lab C

Avg. (range)

54.64(E10)

55.50(D) 54.54(JdF) 54.89(0.96)

14.39(JdF)

14.66(JdF) 14.39(JdF) 14.48(0.27)

15.05(D)

15.07(D) 15.25(E10) 15.12(0.20)

15.41(D)

15.51(D) 15.56(JdF)

15.49(0.15;

Glass K-412

Lab C 1

2

3 Avg. (range)

45.20(E10)

45.90(D) 45.13(JdF)

45.41(0.77)

9.88(JdF)

10.06(JdF)

9.88(JdF)

9.94(0.18)

19.57(D)

19.59(D) 19.82(E10) 19.66(0.25)

15.35(D)

15.46(D) 15.50(JdF) 15.44(0.15)

9.26(E10) 9.25(E10)

9.54(JdF)

9.34(0.29;

'The standard used for each analysis is noted in parentheses. ENAL 10 (E10); Diopside (D); and Juan

de Fuca (JdF).

Examples of homogeneity traces of iron and calcium recorded simultaneously from specimens of glasses K-411 and K-412 are in figures la and lb. Each specimen was moved in 1-ym steps under a 1-ym (approximate diameter) electron beam. Counting periods were 10 s and both elements were analyzed

-8 with Li F crystal spectrometers. The specimen current was about 5 x 10 A and the excitation potential was 20 kV. The theoretical ±3-sigma limits about the average number of counts per counting

period, N", for the trace are delineated by the double-headed arrows to the right of each trace. Deviations outside this 99.7 confidence limit indicates inhomogeneities within the specimen, assuming

that there are no serious instrumental fluctuations.

On the left side of each figure is a time-resolved trace made with a 20 x 20-ym scanning raster.

Signal variations for such a trace are due to expected statistical fluctuations, assuming that no systematic instrumental errors are present. Therefore, the variations should lie within the ±3-sigma

limits as in fact they do here. For a truly homogeneous specimen, assuming the concentration of an element is high enough to produce a signal above the background, the traces from these moving and stationary specimens should be similar as they are here.

6
FUNERAL GLASS K-411 STATIONARY 20 P M BEAM

12.90 WT.Z

1 yM BEAM 1 pM STEPS 10,500-

j -n_n

IRON Kct 11.21 WT.Z

9.77 wt.Z

12.44 wt.Z 21,000 oCO

CALCIUM K« 11.06 wt.Z 9.44 wt.Z 16,000-

Figure la. Periodic integrator homogeneity traces of iron and calcium simultaneously recorded from

NBS SRM 470, Mineral Glass K-411 (excitation potential = 20kV, specimen current = 5 x 10"8 A). In the traces on the right, the sample was advanced in 1-ym steps under a 1-ym electron beam after each

10-s counting period. To the left, the sample was not moved during repeated 10-s counting periods with a 20 x 20-ym scanning raster. The double-headed arrows to the right represent a range of ±3 /ft around the average number of counts per 10 s, N, for the entire trace.

7
MINERAL GLASS K-412 stationary 20 m m beam 1 um beam 1 um steps - 8.88 wt.2 7,500 -

IRON K« 7,74 wt.: 5,87 wt.% —

12.62 wt.70 -

5,000 ^

17,000.

CALCIUM Ka 10.90 m.%

8.88 wt.% 12,000 —

Figure lb. Periodic integrator homogeneity traces of iron and calcium simultaneously recorded from

NBS SRM 470, Mineral Glass K-412 (excitation potential = 20kV, specimen current = 5 x 10"8 A).

In the traces on the right, the sample was advanced in 1-ym steps under a 1-ym electron beam after

each 10-s counting period. To the left, the sample was not moved during repeated 10-s counting

periods with a 20 x 20-ym scanning raster. The double-headed arrows to the right represent a range

of ±34faround the average number of counts per 10 s, N, for the entire trace.

Two homogeneity traces similar to these were prepared for all major elements from one specimen

of each glass. The traces were normal to one another and covered a 50-ym distance across the speci- men in 1-ym steps. Duplicate data were taken on each point. The excitation potential was 15 kV. A

-8 specimen current of about 3x10" A was used. Counting periods were increased to 40 s in order to improve the counting statistics. This was especially necessary for aluminum and magnesium for which

the total number of counts per 40 s was only 4000 to 5000 counts. Higher currents were not used because the 1-ym electron beam appeared to disturb the surface of the glass specimens.

No obvious inhomogeneities were observed in these traces. Fluctuations fell within the ±3-sigma

limits about the average number of counts per 40 s, which indicates that these fluctuations were due

to counting statistics only. In addition, no differences were observed between the traces from the moving and the stationary specimen.

8
A statistical evaluation was done on these traces. The equations used and a complete description of the mathematics are in the U. S. NBS Special Publication 260-65 [9]. Using the duplicate

data from each point, two standard deviation components were calculated. These were o w

, the within

point component, and a a , the between points component. If significant i nhomogenei ties exist, a D D D would be noticeably larger than which primarily reflects the statistical fluctuations associated

with the inherent experimental errors. The results in Table 5, where the two components are compared,

show that no obvious micro-inhomogeneities are reflected in the component for these 50-ym traces.

In fact, in most cases is smaller than a^. Thus the measurement process seems to have a greater error associated with it than does the specimen i nhomogenei ty.

Table 5. Comparison of statistical data from homogeneity tests (weight percent)

Weight Trace No. or Homogeneity Comparison with

Oxide Percent Specimen No. Trace Random Sampling

a

W a

B aRS /a

W

2 + V

Glass K-411 SiO 54.30 0.37 0.35

0.28 0.460.37 0.35 MgO

CaO

4.67

5.47

0.24

0.21 0.15

0.16

0.01

0.11 0.28

0.32 0.20

0.17

0.24 0.24 0.15

0.16

FeO Glass K-412

SiO.

MgO

CaO

FeO

14.42

45.35

19.33

15.25

9.96

0.18

0.19

0.27 0.29

0.31 0.29

0.17 0.15

0.13

0.13

0.21

0.11

0.03

0.06 0.04

0.04

0.13 0.24

0.35

0.29

0.31 0.33 0.18

0.14 0.15

0.10

0.18

0.19

0.34

0.31

0.31 0.33

0.17 0.24

0.14 0.14

A1 2°3 9.27 0.14

0.13

0.17 0.14 0.14

0.13

A random sampling test in which two different specimens of each glass were analyzed was also performed to evaluate specimen microhomogeneity. The instrumental parameters, as in the previous

tests, were a 15 kV excitation potential and a specimen current of about 3 x 10 A. Counting

periods were 40 s. Thirty random samplings were made on each glass specimen. One standard deviation, a nc , was calculated from the thirty points. These values (expressed in weight percent) are

Kb i listed in Table 5; they agree favorably with the combined components of variance, ^ja^2 + a^ 2

, obtained from the staticical evaluation of the homogeneity traces.

9
The errors in Table 5 and in subsequent tables were converted from counts to weight percent concentration. Such a conversion is valid when there is a linear relationship between net counts (background-corrected) and concentration which passes through the origin. For all five elements

involved in these analyses such a linear relationship was validated by analyzing several well-characterized minerals containing the elements studied here at concentrations below and above thosp in Che K-411 and K-412 glasses. At least five samplings were taken from each mineral and the average was background-corrected for the plots of net counts vs. weight percent concentration. Wavelength

spectrometers were used. A 10 x 10-yni scanning raster was used and counting periods were 40 s. Analyses for silicon, calcium, magnesium, and aluminum were done at an excitation potential of 15 kV -8 8 and the two different currents of 1.6 x 10 A and 3.5 x 10" A. Iron data were also taken at

-8

20 kV and 1.6 x 10 A. All plots were linear, passing through the origin.

For macrohomogenei ty tests five specimens of each glass were randomly selected from the 100 or more samples of each glass that make up the stock for SRM 470. These tests were designed to evaluate differences between specimens as well as differences within each specimen. Counting periods were

20 s. For each element in each glass at least two independent tests on different days were run by two different operators, when possible. For each test, each specimen was randomly sampled six times

and duplicate readings were taken at each point. After all five specimens had been tested once, the five specimens were again sampled in random order giving a total of twelve random samplings on each specimen. Testing of a specimen in the first half and again in the second half of an experiment is expected to average out instrumental drifts if any occur. Also, such a sampling procedure can help

to distinguish between real specimen differences and instrument fluctuations.

For these homogeneity tests, an NBS electron microprobe was used. With three crystal spectrometers, three elements could be simultaneously tested. The excitation potential was 15 or 20 kV and

Q O the beam current was 1.6 x 10" A or 3.0 x 10" A, depending upon the day of the test. The beam current regulation mode on the instrument was used to minimize current drift during each experiment

which took about ~\h hours. A 10 x 10-ym scanning raster was used to minimize specimen contamination. Counting periods were 20 s. With data from this type of testing procedure, three different contributions to the errors can

2 2 be estimated. These are a«~ , the variance between different specimens, a

g

, the variance within

specimens on the micrometer scale, and the variance of a single measurement error. The equations

used to derive these components are described in detail in another recent NBS Special Publication

260-70 [6].

In Tables 6 and 7 the individual standard deviations, expressed in weight percent, are given for each oxide in each glass. These standard deviations are all small. There is apparently no significant experimental error, no significant variation within specimens, and no significant variation

between specimens. The standard deviation of a single measurement, ap, which combines these individual error components is 1.5 percent (relative) or less for glass K-411 (Table 6) and 1.7 percent

(relative) or less for glass K-412 (Table 7). For both glasses, the largest values of o

p are in the

iron oxide experiments which were run at a 15 kV excitation potential and at the lower beam current

-8 of 1.6 x 10" A. A slight improvement in these statistics results when a 20 kV excitation potential

is used which is a more favorable overvoltage for iron resulting in more favorable counting statistics.

At the lower voltage the total counts per 20 s were about 5000 and 6500 for K-412 and K-411, respectively. At the higher voltage they were about 10,000 and 15,000 respectively. For all other elements,

the total counts per 20 s were at least 20,000 in all experiments. The results of better counting

statistics can also be seen in experiments G and H for glass K-412 where the higher beam current of

10
3 x 10" A gave improved results not only for iron oxide but also for the oxides of silicon, magnesium

and aluminum.

Table 6. Homogeneity evaluation of five specimens of glass K-411

Standard Deviations in Weight Percent of Oxide.

Oxide Weight

Percent

h Exp.

Pot.

(kV) °E

c °Sa

p (rel ,%)

Si0

2 54..30 A 15 0. 15 0.,15 0.06 0.22(0.4)

B 15 0. 15 0..30 0.15 0.37(0.7)

MgO 14..67 A 15 0. 10 0.,05 0.05 0.12(0.8)

B 15 0. 10 0..03 0.04 0.11(0.7)

CaO 15. 47 C 15 0. 07 0..10 0.08 0.15(1 .0)

D 15 0. 07 0,,04 0.01 0.08(0.5)

FeO 14..42 A 15 0. 18 0.,07 0.03 0.20(1 .4)

B 15 0. 18 0.,12 0.0 0.22(1.5)

C 15 0. 14 0.,10 0.04 0.18(1 .2)

D 15 0. 14 0,,07 0.0 0.16(1.1)

E 20 0. 12 0,.02 0.04 0.13(0.9)

F 20 0. 11 0,,04 0.0 0.12(0.8)

aThe standard deviations are defined as 'follows:

<?£ = the error of a single measurement

Og = the variation within specimens on a micrometer scale

a

s

= the variation between the different specimens

Op = one standard deviation of a single measurement

combining the above errors. V2

~ 2~~ 2 a

E + aB + as

i -8 Beam current for all experiments was 1.6 x 10" A.

11
Table 7. Homogeneity evaluation of five specimens of glass K-412

Standard Deviations in

Ex Weight Percent of Oxidea Weight , Pot. a

F aR

a<- a D (rel.%) Oxide Percent Exp. (kV)

5 v

Si0 9 45.,35 A 15 0. 14 0.,26 0, 12 0,,32(0,•7)

c G 15 0. 10 0.,15 0,,10 0,,21(0,•5)

H 15 0. 10 0.,10 0,,03 0. 14(0,,3) MgO 19. 33 A 15 0. 11 0.,04 0, 02 0.,12(0,• 6)

G 15 0. 08 0.,03 0. 01 0,,09(0,• 5) CaO 15..25 C 15 0. 09 0. 04 0. 05 0.,11(0,•7)

D 15 0. 10 0.,18 0, 07 0.,22(1 4) FeO 9,.96 A 15 0. 15 0..0 0. 06 0,,16(1 • 6)

C 15 0. 15 0. 02 0, 06 0,,16(1 •6) D 15 0. 14 0.,09 0..0 0,.17(1 •7)

E 20 0. 10 0.,07 0.,0 0,,12(1 .2)

F 20 0. 10 0.,04 0.,02 0,.11(1 1)

G 15 0. 11 0.,04 0.,01 0,.12(1 .2)

H 15 0.,11 0..0 0.,02 0 .11(1 •1) A1

2 03

9.,27 C 15 0.,07 0,,04 0.,02 0,.08(0 9)

H 15 0,,05 0,,03 0..0 0,.06(0 • 7)

a Standard deviations defined the same as in Table 6. ^Beam current for experiments A, C, D, E, and F was 1.6 x 10"^ A and for experiments G and H the

-8 beam current was 3 x 10" A.

The uncertainties in the average measurement, P\ for three possible experiments that a user of SRM 470 might perform are summarized in Tables 8 and 9. These uncertainties are calculated for the

99 percent confidence interval for the mean concentration according to the expression P ± 3ap- where

2 2

n r n r n r and where n^ independent measurements are made at each of ng randomly chosen points in each of n<- specimens. More details on this equation can be found in the Appendix of reference [6]. The average of each type of error for each oxide in Tables 6 and 7 is used to calculate ±3ap- for the three possible experiments in Tables 8 and 9. For example, the average values of a^, a^, and o

s for Si0

2 calculated from experiments A, G, and H for glass K-412 are used to calculate the three different values of ±3ap- (experiments I, II, and III) for Si0

2 in Table 9. The three possible experiments and the results are meant to be of practical use to the electron

probe operator. In experiment I, 16 independent random readings are taken from one specimen; in experiment II, 8 independent readings are taken from one specimen; and in experiment III, 8 independent

readings are taken from each of two specimens. For all experiments each point was sampled only once. The best results for both glasses are obtained when using two specimens with eight samplings on each. Sixteen samplings on a single specimen is almost as good. But only eight samplings on one specimen

gives noticeably higher errors. The number of specimens and samplings used in each laboratory will

12
Table 8. Comparison 0"f uncertainty intervals

percent of oxide

(±3ap) for glass K—41 1 in weight

Ex.

Experiment I One Specimen

16 samplings

n s =l; n

B =16; n£ =l

Experiment II UMc o |JcL 1 lilcil 8 samplings

n c = 1 ; n D =8; n c =l

Experiment III Two Specimens

8 samplings

n-=2; n R =8; n F out»l Oxide

Weight

Percent

Pot.

(kV) ±3ap (rel. %) ±3ap (rel . %) ±3ap (rel. %)

Si0

2 54.30 15 ±0.41(0.7) ±0.46(0.9) ±0.32(0.6)

MgO 14.67 1 0 +n i7M 9

±U. 1

/

\

1

c

)

±0.19(1.3) ±0.13(0.9)

CaO 15.47 15 ±0.17(1.1) ±0.19(1.2) ±0.13(0.8)

FeO 14.42 15 ±0.15(1.1) ±0. 21 (1 .4) IU. I J ^ 1 . U J 20 ±0.11(0.8) ±0.15(1.1) ±0.10(0.7)

Table 9. Comparison of uncertainty intervals (±3aw) for glass K-412 in weight

percent of oxide

Ex.

'Experiment I One Specimen

16 samplings

n s =l; n B =16; n F =l

Experiment II One Specimen

8 samplings

n^=l ; rig=8; n^=l

Experiment III Two Specimens

8 samplings

n

s =2; n B =8; n£

=l Oxide

Weight

Percent

Pot.

(kV) ±3aF

(rel. %) ±3aF(rel. %) ±3ap (rel. %)

Si0

2 45.35 15 ±0.29(0.6) ±0.33(0.7) ±0.23(0.5)

MgO 19.33 15 ±0.10(0.5) ±0.13(0.7) ±0.09(0.5)

CaO 15.25 15 ±0.22(1 .4) ±0.25(1.6) ±0.17(1 .2) FeO 9.96 15 ±0.14(1.4) ±0.17(1 .7) ±0.12(1.2)

20 ±0.09(0.9) ±0.13(1.7) ±0.09(0.9)

A1

2 0

3 9.27 15 ±0.06(0.7) ±0.08(0.9) ±0.06(0.6)

depend upon the acceptable uncertainty interval for the specific analysis and the experimental

imprecision of the individual laboratory. The numbers in Tables 8 and 9, however, are only applicable to the NBS electron microprobe used to obtain the estimates of a<., ag, and o^. The value of Oj will be different for each operator's instrument.

13
5. Conclusions

These glasses have been shown to be excellent Standard Reference Materials for use in micro- analysis techniques such as EPMA and secondary ion mass spectrometry. Independent wet chemical analyses are in very good agreement and homogeneity tests have shown that all oxides in K-411 and K-412 are homogeneous on both the micrometer level and from specimen to specimen.

The author acknowledges the following associates for their contributions to the quantitative

analyses of glasses K-411 and K-412- - E. Jarosewich and J. Norberg of the Smithsonian Institution, Washington, D.C.; J. C. DeVine and N. H. Suhr of the Pennsylvania State University, University Park,

Pa.; and Cj. E. F.iori, presently with the National Institutes of Health, Bethesda, Md. The author

also wishes to thank D. H. Blackburn and D. A. Kauffman of the Ceramics, Glass, and Solid State Science Division, NBS, for the fabrication of the bulk glasses. Thanks also to R. L. Myklebust of the Gas and Particulate Science Division, NBS, for writing the computer program for the homogeneity

data evaluation and to I. Holl, a summer associate and student at Gettysburg College, Gettysburg,

Pa., for her patient assistance in acquiring some of the homogeneity data. Thanks also to K. Kirby of the Office of Standard Reference Materials for his assistance in preparing the certification for this SRM and to H. H. Ku of the Statistical Engineering Division, NBS, for assistance in determining

the certification values.

6. References

[1] Yakowitz, H.; Vieth, D. L.; Heinrich, K. F. J.; Michaelis, R. E. Homogeneity characterization of NBS spectrometric standards II: cartridge brass and low-alloy steel. Nat. Bur. Stand. (U.S.) Misc. Publ . 260-10; 1965 December. 28 p. [2] Yakowitz, H.; Michaelis, R. E.; Vieth, D. L. Homogeneity characterization of NBS spectrometric

standards IV: preparation and microprobe characterization of W-20%Mo alloy fabricated by powder metallurgical methods. Advances in x-ray analysis. Vol. 12. New York, NY: Plenum Press; 1969. 418-438 and Nat. Bur. Stand. (U.S.) Spec. Publ . 260-16; 1969 January. 24 p. [3] Yakowitz, H.; Fiori, C. E.; Michaelis, R. E. Homogeneity characterization of Fe-3Si alloy. Nat. Bur. Stand. (U.S.) Spec. Publ. 260-22; 1971 February. 22 p. [4] Heinrich, K. F. J.; Myklebust, R. L.; Rasberry, S. D. Preparation and evaluation of SRM's 481 and 482 -golds i Tver and gold-copper alloys for microanalysis. Nat. Bur. Stand. (U.S.) Spec.

Publ. 260-28; 1971 August. 89 p. [5] Yakowitz, H. ; Ruff, A. W. Preparation and homogeneity characterization of an austenitic iron- chromium-nickel alloy. Nat. Bur. Stand. (U.S.) Spec. Publ. 260-43; 1972 November. 11 p. [6] Marinenko, R. B.; Biancaniel lo, 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. Publ.., 260.70; 1981 May. 25 p. [7] Herioc',' 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. [8] Marinenko, R. B.; Heinrich, K. F. J.; Ruegg, F. C. Microhomogeneity studies of NBS standard reference materials, NBS research materials, and other related samples. Nat. Bur. Stand. (U.S.)

Spec. Publ. 260-65; 1979 September. 73 p.

14.
U.S. Department of Commerce

Juanita M> Kreps

Secretary 7

National Bureau of Standards

Ernest Ambler. Director ^National ^Bttram of ^tanrfarrfs

(Eeritftcate of (Attaint*

Standard Reference Material 470

Mineral Glasses for Microanalysis

These glasses have been fabricated for use in microanalysis techniques such as electron probe microanalysis (EPMA) and secondary ion mass spectrometry (SIMS). The glasses are homogeneous and are especially useful

as standards for the analysis of minerals, glasses, and ceramics. Composition in Weight Percent

Constituent Si02 FeO MgO CaO AI2O3

Glass K-411

Certified Value 54.30 ± 0.20° 14.42 ± 0.20 14.67 ± 0.20 15.47 ± 0.20 Wet Chemistry LAB A

b LAB B

54.24(0.02) 54.3614.49(0.18) 14.34

14.64(0.08) 14.6915.53(0.18)

15.41 EPMA

LAB C

c 54.89(0.96) 14.48(0.27) 15.12(0.20) 15.49(0.15) Glass K-412

Certified Value 45.35 ±0.20 9.96 ± 0.20 19.33 ± 0.20 15.25 ± 0.20 9.27 ± 0.20 Wet Chemistry LAB A

b LAB B

45.38(0.04) 45.32

10.10(0.20) 9.8219.33(0.02) 19.3215.29(0.10)

15.21

9.26(0.12) 9.28 EPMA

LAB C° 45.41(0.77) 9.94(0.18) 19.66(0.25) 15.44(0.15) 9.34(0.29) The uncertainty of ± 0.20 wt.% assigned to the certified values is the 2-sigma value. This error is a pooled value for all oxides estimated from

the ranges between the two laboratories using wet chemical techniques.

bThe average and (range) of two analyses.

c The average and (range) of three analyses. The technical measurements were performed by C. E. Fiori and R. B. Marinenko under the direction of K.F.J.

Heinrich. The support aspects involved in the certification and issuance of this Standard Reference Material were

coordinated through the Office of Standard Reference Materials by R. Keith Kirby. Washington, D.C. 20234 George A. Uriano, Chief October 30, 1 98 1 Office of Standard Reference Materials

(Revision of Certificate (over) dated 4-26-79)

15
These glasses were prepared in the Ceramics, Glass, and Solid State Science Division of the National Bureau of Standards' Center for Materials -Science' by D. H. Blackburn and D. A. Kauffman. The two glasses were tested for microhomogeneity by both random sampling and periodic integrator traces. This work

was done at NBS by R. B. Marinenko. No evidence of inhomogeneity was observed in these glasses. An NBS 260 Series Special Publication is being prepared which will describe these microhomogeneity studies and the statistical evaluations. The wet chemical analyses were performed at the Smithsonian Institution, Washington, D.C. by G. Jarosewich and

J. Norberg, and at Pennsylvania State University, University Park, PA, by N. H. Suhr and J. C. Devine. EPMA was performed at NBS by C. Fiori using different standards where possible. For matrix corrections, the NBS

correction procedure, COR (Henoc. J., Henrich, K. F. J., and Myklebust, R. L., National Bureau of Standards Technical Note 769, 1 973) was used. While the EPMA results are in good agreement with the wet chemical analyses, they were

not included in the determination of the certified values. A trace, of_AJ:O.U<$- 1%) wasspectrographically detected in K-41 1 and a small amount of MnO (approximately 0. 1%) was observed in both glasses by atomic absorption.

£rU.S. GOVERNMENT PRINTING OFFICE: 1982-360-997/2055

.16
NBS-114A (REV. 2-8C) DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEE f (See instructions)

1. PUBLICATION OR REPORT NO. NBS SP 260-74

2. Performing Organ. Report No 3. Publ ication Date April 1982

4. TITLE AND SUBTITLE Standard Reference Materials: Preparation and Characterization of K-411 and K-412 Mineral Glasses for Microanalysis: SRM 470

5. AUTHOR(S)

R. B. Marinenko

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions; NATIONAL BUREAU OF STANDARDS DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

Same as No.

10. SUPPLEMENTARY NOTES Library of Congress Catalog Card Number: 82-600511

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or le s s factual summary of most si gnifi cant in formation . If document includes a significant bibliography or literature survey, mention it here) The two mineral glasses in SRM 470, K-411 and K-412, were quantitatively

analyzed for major constituents. The results of wet chemical analyses from two independent laboratories were in excellent agreement; therefore, these results were used for certification. Quantitative electron probe microanalysis also agrees favorably with the certified compositions. Specimens were evaluated for micro- and macrohomogeneity with the electron microprobe by using random sampling and periodic

integrator homogeneity trace techniques. Statistical analyses as well as the homogeneity traces showed no obvious composition fluctuations either within each specimen or among different specimens. These glasses are therefore excellent

standards for microanalytical techniques. They are primarily composed of silicon,

iron, magnesium, calcium, and aluminum oxides, none of which is present in less than 9 weight percent nor more than 55 weight percent.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; 'and separate key words by semicolons) chemical analysis; digital periodic integrator; electron probe microanalysis; glass standards; homogeneity testing; microhomogeneity ; mineral glasses; Standard Reference Material

13. AVAILABILITY

[X^ Unlimited For Official Distribution. Do Not Release to NTIS Pm Order From Superintendent of Documents, U.S. Go

20402.

Printing Office, Washington, D.C.

Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

25

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