News of the Week chemical community. For example, it calls for raising over the next five years a total of $1.1 billion by increasing the maximum fine the Occupational Safety & Health Administration can impose. The fine would rise from $1000 to $5000 for nonserious violations, and from $10,000 to $50,000 for serious violations. The pact would raise an additional $500 million by taxing substances such as carbon tetrachloride, methyl chloroform, and several chlorofluorocarbons, which are suspected of being ozone depletors but are not yet regulated under international agreements. On the benefit side, the budget agreement would extend the research a n d experimentation tax credit for one year through Dec. 31, 1991. And it would exclude chemical feedstocks from the 2 cent-pergal tax on refined petroleum products. Janice Long
Du Pont chief revamps management's structure In his most dramatic action since becoming Du Pont's chairman and chief executive officer in April, Edgar S. Woolard Jr. is abolishing the company's venerable executive committee in an effort to free managers of excessive bureaucracy. In its place, he is establishing a new office of the chairman. He is abolishing the departmental distinctions within operating divisions, formed Du Pont Chemicals out of the former departments of petrochemicals and of chemicals and pigments, and made several changes in titles. Nicholas Pappas, 60, executive vice president of corporate plans a n d t e c h n o l o g y , a n d James F. Kearns, 61, executive vice president of fibers—both members of the almost 90-year-old executive committee to be abolished Nov. 1—will retire by the end of the year. The new office of the chairman will consist of Woolard; Elwood P. Blanchard Jr., vice chairman; Constantine S. Nicandros, executive vice president of Du Pont, and president and CEO of Conoco; Jerald A. Blumberg, senior 6
October 8, 1990 C&EN
vice president of human resources and corporate plans; and John J. Quindlen, senior vice president of finance. Du Pont's executive committee differed from the like-named board committees at other firms. It consisted of company insiders who, in effect, had final approval over company strategy and operations. But the new office of the chairman "is not another name for the executive committee it replaces/' says a company spokesman. Although the new office of the chairman retains strategic decision-making, it relinquishes operations authority to line executives. Du Pont is also dropping the department distinctions within its businesses in an effort to break the parochial mold the department designations implied. Moreover, business managers and research executives who formerly bore the title of director will in most cases instead receive a vice president's title—a bow to industry practice. Also retiring by the end of the year is Robert M. Aiken, group vice president of petrochemicals, and W. Robert Clay, vice president of imaging systems. John A. Krol, group vice president of agricultural products, will succeed Kearns as senior vice president of fibers. James E. Newall, chairman and CEO of Du Pont Canada, will assume responsibility for agricultural products. Marc Reisch
Ceramics toughened simply, at low cost A team of British researchers has invented a simple, inexpensive way to toughen ceramics so that they resist cracking. The new process counters the intrinsic brittleness of ceramics and thus promises to help them fulfill their potential as structural materials. The new process is noteworthy because it creates a very tough, laminated material by layering a strong component—silicon carbide (SiC)— with a thinner, weaker layer of graphite. Cracks tend to get deflected along the weak SiC/graphite interface, making the composite less prone to catastrophic failure. Details
of the process were published last week in Nature [347, 455 (1990)]. Scientists have made other crackresistant composites by, for example, infiltrating ceramic fibers with a gaseous ceramic precursor or by encasing ceramic fibers in a ceramic or polymer matrix. But ceramic /ceramic composites have been difficult and expensive to fabricate, while polymer/ceramic composites cannot withstand high temperatures. The new SiC /graphite composite does not have these disadvantages. It is made from inexpensive ceramic powders, and the process is fast, says ceramist William J. Clegg of ICI Adv a n c e d M a t e r i a l s in R u n c o r n , Cheshire. He and his coworkers prepared the composite by coating thin, doughlike sheets of a SiC /polymer paste with graphite. The coated sheets were stacked, pressed, heated to pyrolyze the polymer, and then sintered at about 2000 °C. The resulting laminate requires 100 times as much work to break as uncoated SiC sheets. Any cracks that form find it easier to grow along the weak interface than through the SiC layers, Clegg explains. Such crack formation, however, does weaken the material, he says. According to Robert W. Cahn of the University of Cambridge, the ICI team "has improved upon nature in two ways: Their material is tougher than hardwood, and it can certainly be safely heated to red heat." Wood, he notes, is nature's favorite composite. Clegg foresees using such composites in traditional aerospace applications, such as forming the leading edge of wings. Use of ceramics in these areas has been limited by their high price, he says. Other possible applications include automobiles, armor, and cutting tools. The ICI process is not restricted to making sheets. For example, Clegg and his coworkers have extruded zirconia fibers from a plastic mix and pressed them together into a ropelike structure. After sintering, the material was found to be 10 times more resistant to cracking than a similar size solid rod of zirconia. The interface between the (uncoated) fibers in this material serves to deflect incipient cracks. Ron Dagani
