# Presentation: 280423

## Materials Science Perspective on Substance Restriction Legislation 

**Materials Science Perspective on Substance Restriction Legislation **

**Timothy McGrady**
**Chairman, ASTM International Committee F40 on Declarable Substances in Materials**
**Principal Scientist, IMR Test Labs**

## Materials Science

**Materials Science is the study of the characteristics, behavior and properties of all types of materials **
**Includes: chemical composition, mechanical properties, metallography, corrosion and environmental effects, failure analysis, weld inspection**
**Materials testing may be conducted on raw materials, processed materials, materials in use or materials within finished goods **

## Materials Science

**Mature science – for example, ASTM International has been developing standards for testing and specifying materials for over 100 years**
**ASTM has approximately 140 committees; each committee has jurisdiction over certain types of materials or specific uses of materials**
**For example, Committee E01 focuses on test methods for metals and ores; Committee B09 focuses on powdered metallurgy**
**ASTM Committees are made up of producers, inspectors and users of materials**

## Materials Science versus Environmental Testing

**Some common methodology, but otherwise very different analytical sectors**
**Environmental test methods designed for analysis of air, soil, water and sludge**
**Material test methods designed for specific types of materials; for example, there are separate methods for analysis of aluminum, steel, copper, and nickel alloys; there are further differences in methods within base metal groups (analysis of stainless steel different than analysis of carbon steel)**

## Materials Science versus Environmental Testing

**In the United States, soil, air and water samples are sent to environmental laboratories who are accredited to perform EPA tests.**
**Metals, plastics, composites and other materials are sent to independent materials analysis laboratories who are accredited to perform various physical, chemical and structural tests.  Test methods used are typically ASTM standards**
**Materials laboratories typically do not analyze environmental samples; likewise, environmental laboratories typically do not analyze materials**

## Materials Science versus Environmental Testing

**Inappropriate to apply test methods for analysis of soil, air and water to analysis of metals, plastics and composites; the reverse is also true**
**Having materials analyzed by EPA methods is analogous to sending a suit to the hairdresser to have it cleaned: the results will be unsatisfactory.**
**Unfortunately, it has not been clear whether RoHS requires environmental or materials testing**
**Since products are made of materials, RoHS requires materials testing!**
**Easy to test: send known samples to both types of labs (“blind” round-robin tests)**

## Risk Assessment

**Risk Assessment**

**What is the risk of hazardous substances being present in a particular material?**
**How do we know whether hazardous substances are present?**
**Two ways to know: 1) empirical knowledge and 2) knowledge based on logic and scientific principles**
**Empirical Knowledge = *****a posteriori***** knowledge; based on measurement**
**Logic/Scientific Principles = *****a priori***** knowledge; based on deduction and knowledge**

## Hexavalent Chromium measurements = big problem in metal industries

**EU says Cr6+ must be measured in weight percent within chromate conversion coating.**
**Industry standard is mass/area, units = μg/cm****2**
**Cannot measure total mass of coating; it is too thin and is part of substrate**
**Chromate conversion coating thicknesses are 10 – 1000 nanometers!**
**Cannot “mechanically disjoint” such a coating from metal – think about a machine screw**
**Industry must have proper guidance!**

## Slide 9

## Homogeneous material

**European Commission did not give legal definition of “homogeneous material”**
**Industry needs definition**
**Some will grind up complex assemblies prior to testing – poor analytical technique**
**Some will test only each material if possible**
**Testing materials instead of semi-finished and finished products would save industry confusion and high cost**

## Pb in Solder not exempt

**Pb in Solder not exempt**

## EU RoHS: Why grinding parts is poor analytical technique

**Consider chip capacitor on previous slide**
**PbO is exempt in ceramic portion of chip capacitor**
**Pb in solder is not exempt**
**If you grind up chip, you mix exempt and non-exempt Pb**
**Test yields total Pb**
**Based on result, does product conform?**
**Cannot say product conforms or is non-conforming**

## RoHS Materials Declarations

**RoHS Materials Declarations**

**RoHS Material Declarations are lists of substances compiled from laws and customer requirements**
**Often give substance name and maximum concentrations allowed**
**Do not give test methods**
**Do not advise on which substances to test in which case**
**May become legal documents meant to solely to transfer liability to suppliers**
**Many different Materials Declaration documents**

## Materials Declarations

**Can suppliers fill out documents without proper test methods in place?**
**Documents are legal instruments – must be able to provide good information**
**Supply chain is getting poor results from laboratories (EPA methods)**
**XRF so far only good for screening (gross deviations from RoHS limits)**
**ASTM: information should be gathered on materials, not parts or finished goods **

## Supply Chain Model - Analysis

**Raw Materials**

**Manufactured Materials**

**Parts/Components**

**Sub-assemblies**

**Finished Products**

**Easiest to test, routinely tested**

**Fewest number of items to test**

**Greatest number of items to test: number in billions**

**As complexity increases, number of items to test and testing difficulty increases, as does cost**

**Greatest number of companies**

**Fewest number of companies**

## How Standards Are Used

**Buyer**

**Seller**

-  **Contract             (Purchase Order)**

**Material Standard**

**Material specifications (standards) are quite often referenced in purchase orders.**
**This greatly simplifies ordering, particularly where requirements are complex.**
**Both parties (buyer and seller) have access to the standard.**

## How Standards Are Used

**Buyer**

**Seller**

-  **Contract             (Purchase Order)**

**Material Standard**

**A standard test method is used to check whether the technical requirements of the material specification have been, or will be, met.  Both parties have access to the standard test method.**

**Test Method**

## Standards and Conformity Assessment Model

**Buyer**

**Seller**

-  **Contract             (Purchase Order)**

**Material Standard**

**Test Method**

**Certified Reference Material**

**SI Units**

## Standards and Conformity Assessment Model

**The model as described allows check and balance between parties**
**The model allows purchase orders to be assessed as legal contracts**
**Requirements are clear**
**Assessment of conformance is possible**
**Proof of nonconformance can lead to remedy**
**Supporting conformance data is legally defensible, if test is done correctly.**

## Thank You!

***Thank You!***