The ALCAN Spectrochemical Standard and ARMI

In January of 1992, Analytical Reference Materials International (ARMI) and ALCAN International Limited, Arvida Research and Development

Center of Canada (ALCAN), entered into a strategic alliance for the marketing, sales, and future development of aluminum spectrochemical Certified

Reference Materials (CRMs) worldwide.  As a result, all CRMs produced by ALCAN are available through ARMI in Golden, Colorado, USA.

The inventory consists of over 500 aluminum spectrochemical CRMs.  In addition to the traditional spectrochemical disk for Optical Emission, all

CRMs are also available in chips for classical chemistry and wet instrumental techniques, and thin disks for EDXRF/WDXRF.

ALCAN spectrochemical standards are not derived from production material.  They are produced from a direct-chill continuous casting process

resulting in bar stock of 75mm in diameter.  Each billet is scalped and thereafter cut into 25mm thick slices of 57mm in finished diameter.  Although

this method of manufacture is expensive, the continuous-cast disk has resulted in excellent homogeneity leading to reliable results for the analysis of

both the simple and the most complex aluminum alloys for over 50 years.

For homogeneity testing, 12 samples are selected from each billet cast and are each sparked 7 times on the spectrometer following a pseudo-random

technique.  The results obtained are statistically evaluated by an analysis of variance to determine the uniformity of composition within and among the

samples tested.  Once the series is determined to be homogenous, chips are prepared for wet chemical analysis.  Every element to be certified is then

analyzed using the most widely recognized methods.  Each sample is analyzed at least in duplicate by two technicians using two different analytical

techniques that include ICP, AA, X-Ray fluorescence, colorimetric, fluorimetric, and titrimetric methods.  The individual values reported are

statistically evaluated, and the mean values are compared to the results obtained by Optical Emission Spectrometry.  Finally, the check samples are

circulated among other ALCAN laboratories for verification.  These laboratories perform their own chemical analysis and report their results to the

Arvida Research Center.  Worldwide comparison analysis involving top specialists in the field ensures high confidence in the values obtained.

ALCAN produces three basic categories of CRMs.  Alpha characters located at the end of a part number indicate the alloy series or heat.

Standard Alloy part numbers have a 2 alpha characters suffix such as “-AC” and are alloys in which some 23+ elements including

traces are certified.

Ultra Hi-Purity Alloys have a 3 alpha characters suffix such as “-CAD” and are alloys produced from ultra hi-purity ingredients

without any trace elements present.

Special Alloys are prefixed by an unusual designation such as “1S” and are located in a separate section in the ALCAN portion of

the catalog.  These alloys include some binaries and special experimental compositions.