by Stephen W. Freiman and George D. Quinn

NIST’s Steve Freiman and George Quinn start this feature with the premise that property test standards are not barriers to trade when it comes to new materials’ entry to the market. Using the example of test methods created by ASTM technical committees, they show how standardization works to positively influence trade and regulations.

Introduction

Let us begin with a bold statement. Based upon numerous conversations with individuals in industry and elsewhere, it is our conclusion that, “For new materials, property test standards are not a barrier to trade.” Experience suggests that neither the existence nor the lack of property test standards enable one country to influence sales of new materials or impede trade in some way. Indeed, standards sometimes lag behind the introduction of new materials to the marketplace.

What then, is the importance of property test standards? The road for a new material from the research laboratory to commercial application may be smoothed by standards. As a new, improved material is introduced to the marketplace as an alternative to familiar materials, data generated by standard test methods can facilitate the acceptance of the new material. More radical changes occur when innovative materials and products are introduced for which there are neither precedents nor standards. The path from the research laboratory to the commercial sector is often strewn with pitfalls of inconsistent data that cause confusion, inefficiency, and added costs. Recognition of the data inconsistency problem usually occurs when an innovative material has matured to the point that multiple sources or users are involved. They may have collected data using different methods or variations of a method. With recognition of the problem comes a commitment to standardization, but the standardization process can be time consuming, frustrating, and may even delay commercialization.

The ability to make common measurements on the same materials at various places on the globe is critical to world commerce due to the increasing globalization of markets. We must have consensus based standards and specifications to facilitate trade. Both users and suppliers of materials around the world need the assurance that the property of the material obtained in one country was obtained in the same way as in another. For new materials in emerging markets such standards are particularly important. In this article, we will attempt to provide specific examples of standards really making a difference for the entry of new materials into the marketplace.

Advanced Ceramics As an Example

We intend to use “advanced ceramics” as one broad class of materials from which examples of standards relating to market development will be extracted. Standards are important for other materials as well, but the examples that we will show are wide-ranging enough in character that they make a case for themselves.

It is important at the outset to define what we mean by advanced ceramics, because the first thing that people think of when the word is mentioned is traditional ceramics such as bathroom fixtures, dinnerware, or tiles. Ceramics are much more than that. Ceramics, as a class of materials, are extensive (in some respects, any inorganic non-metal), and they are present in many different applications including automotive components, biomedical devices, cell phones, and ball bearings. Advanced ceramics are used in these myriad applications because of their unique structural, electronic, magnetic, and optical properties.

Standards Lead to Cost Savings

Obviously, one of the problems with ceramics is that they are brittle. So whenever we use them, whether in structural applications such as engine components or elsewhere, it is important for the designer to be able to predict the safe, reliable operation of a component over a long period of time. So for anyone developing a new ceramic material, being able to accurately measure its strength is an important consideration.

The easiest way to test the strength of a ceramic is to bend it in what is called a flexure test. Ceramic specimens will usually remain elastic up to specimen fracture. The rectangular prismatic specimen is cut from ceramic plates or components. This type of test is the bread-and-butter method of the ceramics industry and is much simpler than traditional tensile strength tests with dog-bone shaped specimens. The latter are costly to machine in hard ceramics (greater than $100 per specimen), require a lot of material, and require meticulous alignment during the strength test.

Before the development of harmonized measurement procedures, everything about the flexure test could change from one laboratory to the next. So material suppliers would test their products in different ways, giving rise to the reporting of different properties, because they were, in fact, using different kinds of tests. In addition, one of the significant costs in testing ceramics is associated with machining a specimen. Grinding must be done with diamond abrasive grit wheels. Because of their hardness and susceptibility to damage, machining costs for ceramics are significant. Prior to the development of standard test methods, preparation of a typical specimen costs in the range of $20 to $33 in today’s dollars.

With the development in 1990 of ASTM C 1161, Test Method for Flexural Strength of Advanced Ceramics at Ambient Temperature, developed by ASTM Committee C28 on Advanced Ceramics, the cost of those tests dropped to $10. Why? Because now standard fixturing can be employed, and machine shops know that they are always going to make exactly the same specimen for everybody. This allowed the test costs to drop precipitously, resulting in savings on the order of $800,000 to $1.5M a year for the ceramic industry.

Savings benefits accrued in other ways. Flexural strength testing was often performed for quality control purposes. A producer or user repeatedly tested sample sets of specimens from new batches during the material or product development phase. Prior to standardization, it was recognized that the myriad methods then in use were not optimized and were faulty. Nevertheless, it was rationalized that the data was good enough for comparative purposes. While this attitude was probably adequate for testing within a single laboratory, the limitations were quickly felt when data was exchanged between multiple producers and users. Data discrepancies led to confusion and even distrust. Furthermore, rudimentary quality control or materials development data often did not meet the more stringent requirements for design or materials specifications. This often led to costly, duplicative testing. The adoption of a simple, technically rigorous standard method solved the problem. Now almost everyone tests flexural strength of advanced ceramics to ASTM C 1161. Data collected for quality control purposes is immediately acceptable for the most stringent design applications and the costs of redundant testing have been eliminated. The intangible costs of doubt and distrust between producer and user have also been significantly reduced.

Standards Speed Acceptance by Regulatory Agencies

With aging populations, many of us are going to need replacements for various physical parts. Biomaterials are a rapidly growing market segment, and artificial hips are one of the most prevalent uses of such materials. At present, most of the balls of such hip replacements are made of metal. But if one wants to replace hips in younger individuals, and leave them in for longer periods of time, then we must look for materials that are more inert, harder, and which have better biocompatibility.

That’s where the ceramic material comes in. However, the use of any new materials for such applications must have the approval of the Food and Drug Administration. The FDA would like to see consensus standards and specifications in place to enable them to more rapidly certify new materials. Although the FDA has the authority to write regulatory standards, they now rely on consensus standards developed in both national and international venues. Standards for biomaterials have been developed through ASTM. Committee C28 wrote the material test standards for the material properties, namely flexural strength, elastic modulus, hardness, and fracture toughness. Then ASTM Committee F04 on Medical and Surgical Materials and Devices used these standards as building blocks in three new implant material specification standards. This is one example of the benefits of two ASTM committees collaborating with two federal agencies (the National Institute of Standards and Technology (NIST) and FDA) in the construction of a grand standards infrastructure to meet the emerging market needs for new advanced materials.

Standards Facilitate Purchasing

One especially relevant example of the importance of new materials to modern technology, and an area where standards can be influential, is the cellular telephone and wireless communication in general. Without going into detail, we can state unequivocally that wireless communication would not exist today were it not for the unique electrical properties of key ceramic components. The development of these new materials for the wireless industry provides a good illustration of how a lack of standards can directly affect commerce in new materials. The following examples are particularly interesting because they are paraphrased from comments made by one of the leading manufacturers of wireless materials in this country:

• One problem with a lack of standards is that one company can promote its material over another, when in fact the only difference between the two materials is the fact that their properties are measured in two different ways. One sees apparent conflict; the buyer is not quite sure which is the right property of the material.
• Another important issue is the potential confusion in interpreting data. If one isn’t sure how the particular property was measured, then there is clearly a problem in understanding what that property is.
• Thirdly, two vendors may supply a different product even though the material was ordered to the same specification.

All of the above conditions lead to the overall problem that customer may have to qualify each of its vendor’s particular products. Property test standards lead to a harmonized set of materials data, thereby relieving most of the above mentioned problems.

When Are Standards Needed in the Development Process?

We want to touch on the issue of timing in the development of standards relative to the application of new materials. When a new material is developed, and if there is only one company manufacturing it for a particular application, specifications can result from a private agreement between the manufacturer and the end user. At this stage it is relatively easy to have this kind of communication. As the material matures, however, more manufacturers of ostensibly the same material appear, and there are more end-users that find the material attractive. At this point some kind of standard becomes important, because it defines the way that the critical properties of the material should be measured.

The development of ceramic ball bearings is an example of such timing. Because they can operate in inert environments without the need for lubrication, ceramic bearings are becoming more and more prevalent in applications such as high-speed machine tools, turbo pump motors, food processing equipment, and even dental drills. Initially, however, before the markets for such bearings developed, only a relatively few materials (essentially different varieties of silicon nitride) were available. Individual manufacturers agreed with individual users on the properties that are needed. As the market matured and users groomed second sources, these informal arrangements were no longer sufficient. A new formal standard specification for these advanced ceramic materials has been developed within ASTM’s Committee F34 on Rolling Element Bearings. Just as in the case of the ceramic surgical implant specifications, the process has been aided by the existence of a battery of generic ceramic property test method standards, e.g., flexural strength, hardness, elastic modulus, and fracture toughness created by ASTM Committee C28.

In contrast to the bearing case, radical new materials and applications may develop for which there are no property test standards. New materials often require new methods. A variety of expedient test methods often arise. No one wants to spend a lot of time and effort on refining test procedures when the material, product, or the market is unproven. Gradually it becomes apparent that the multiple methods are creating conflicting data, confusion, and doubt. The recognition that standardization is needed usually occurs when a material or product has reached the point that multiple vendors or users wish to compare data. It seems obvious that a consensus standardized method is needed, but, by then, large internal company databases may have been compiled, or very specific test procedures or specifications been locked in. There may be a genuine reluctance to have the databases or procedures rendered obsolete. At this point the interested parties may come together in consortia or in formal standards development organizations such as ASTM and begin the process of forging a consensus standard. Once standardization is accomplished, the impediments of data incompatibility, data distrust, and duplicative testing are usually eliminated and commercialization proceeds more smoothly.

We need not describe here how material property test standards are created, but we make two generalizations. Experience suggests that the sounder the technical basis of a method, the easier it is to achieve agreement. The more prestandardization groundwork addressing technical measurement challenges that has been accomplished, the faster and less contentious is the formal standardization process.

Materials Prestandardization Research

Prestandardization research may take many forms including investigating new measurement methods, clearing up gaps or inconsistencies in existing methods, preparation of reference materials, and conducting interlaboratory round robins. Prestandardization research is often conducted by leading national institutes such as the National Institute of Standards and Technology (NIST), the National Physical Laboratory, and Germany’s Federal Institute for Materials Research and Testing that have the time, resources, and the charters to investigate these matters more thoroughly than companies, universities, or other government laboratories.

In this era of the global marketplace, it is particularly important that prestandardization research be coordinated on an international level. To that end, one particularly effective forum for prestandardization research in materials has been the Versailles Project on Advanced Materials and Standards. VAMAS was formed in 1982 as one of 18 such cooperative projects, at the economic summit in Versailles, hence the name. The mission of VAMAS is to support world trade in products dependent on advanced materials technologies by providing the technical basis for harmonized measurements, testing, specifications, and standards. The project promotes collaboration among the outstanding materials laboratories throughout the world, bringing together experts in many materials fields. VAMAS is governed by a steering committee composed of the signatories of the agreement plus the European Commission. This steering committee is currently chaired by the United States through NIST. However, hundreds of researchers from many other countries participate in the work of VAMAS.

VAMAS has formal linkages to both ISO and IEC and perhaps of equal importance, the individuals who participate in VAMAS typically also participate in their national standards bodies and in international standards development. These individuals see each other frequently, work together, and ultimately develop a mutual trust, which facilitates the development of standards on an international basis.

There are now 18 technical working areas in VAMAS (Table 1) addressing many different aspects of materials.

Table 2 illustrates how, in the area of ceramics, VAMAS work has led to national, regional, and international standards. VAMAS Technical Working Area 3 on Ceramics has been particularly effective and has completed an astonishing 13 full-fledged round robins with over 12,000 experiments over the course of 15 years.(1) At a recent ASTM conference on fracture testing of ceramics, an overview paper (2) reviewed how five VAMAS round robins with over 35 laboratories and 4,500 experiments had contributed to the formation of the new fracture toughness standard C 1421, Standard Test Methods for Determination of Fracture Toughness of Advanced Ceramics at Ambient Temperatures, in Committee C28. This new ASTM material test standard is used by the materials specification standards crafted by Committees F04 and F34 on Rolling Element Bearings. Furthermore, the ASTM standard is very similar to and compatible with comparable standards in Japan and Europe, and three draft International Organization for Standardization (ISO) standards under development in TC 206, Fine Ceramics. By emphasizing international cooperation and collaborative prestandardization work at an early stage, VAMAS has eliminated many of the problems of reaching an international consensus.

NIST’s Role in Standards

Leadership in measurement and standards development is an integral part of the mission of the NIST laboratories. NIST carries out this mission in a number of ways: leadership in voluntary standards organizations such as ASTM, ISO, IEC, et al., the writing of standards, development of standard reference materials, leadership and participation in interlaboratory studies through organizations such as VAMAS, and the development of the technical bases for new measurement procedures. Through participation in organizations such as VAMAS, for example, NIST can leverage its resources to facilitate and accelerate the incorporation of technically robust measurement procedures into the international standards community. We continue to communicate with various industry groups through workshops, etc. to try to ascertain their most pressing standardization needs, and to develop collaborative relationships that allow these needs to be pursued together.

Summary

We have attempted to show how property test standards can facilitate commerce in new materials. Summarizing:

1) These standards help produce reproducible, consistent data.
2) They lead to better specifications for materials. The buyer, the end-user for whom these materials are important, knowing the true properties of that material, can select the material which best suits his application.
3) Property test standards lead to harmonized performance characteristics, which in fact is what we are looking for. Further, for a new material, the existence of data generated by a standard immediately makes that material more credible and more likely to be selected for a particular application.
4) Standards can be educational tools, in that they not only instruct a user on how to properly run a test, but also can teach users on how the data may be used and interpreted.

In conclusion, the existence of standards promotes new materials, and paves the way for their introduction into the marketplace. In addition, standards aid the end-user by providing the kind of data that is needed in order to put these new materials in place in a wider variety of applications. //

References

(1) G. D. Quinn, “VAMAS After Twelve,” Bul. Amer. Ceram. Soc., Vol. 78, [7], pp. 78-83 (1999).
(2) Quinn, G. D., “The Fracture Toughness Round Robins in VAMAS: What We Have Learned,” in Fracture Resistance Testing of Monolithic and Composite Brittle Materials, ASTM STP 1409, J. A. Salem, M. G. Jenkins, and G. D. Quinn, Eds., American Society for Testing and Materials, West Conshohocken, PA. (To be published in 2002.)

Copyright 2001, ASTM