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Raising a glass to stookey
News[ Sliding Doors PBSC h a s a d d e d a sliding d o o r t r a n s f e r h a t c h to is r a n g e o f high-tech cleanroom compon e n t s . W i t h a u n i q u e interlocking door system and counter-balanced, toughened glass d o o r leaves, t h e t r a n s f e r h a t c h h a s easy c l e a n surfaces w i t h n o visible, o r dust-gathering fixings. A v e n t i n g facility which draws contamination away from the hatch ensures t h e h a t c h itself r e m a i n s clean, and doesn't allow product
escapes to adjoining rooms. R o o m p r e s s u r e is m a i n t a i n e d via t h e t w i n d o o r airlock syst e m a n d t h e s y s t e m - cons t r u c t e d f r o m p h e n o l i c resin o r 304 g r a d e stainless steel is fully fire resistant. Vertically sliding d o o r s allow a streaml i n e d , h i n g e - f r e e s y s t e m if s p a c e is l i m i t e d a n d c o n v e y o r s y s t e m s c a n b e fitted to a l l o w manual or automated transfer of products.
Raising a Glass to Stookey In my column in Vol. 2/4, I commented on the Russian term metaUovedenk as meaning 'looking at metals'. An Israeli materials scientist of Byelomssian origin, Eugene Rahkin, kindly wrote in to correct me. "M~id, if it existed, would have that meaning, but with an 'e' instead of an T, the word means 'knowing about metals thoroughly', from an old Russian verb, vedat', which means to know thoroughly (as in the German word 'Kunde'). l~dat' is extinct in Russian, but not in Rabkin's Bydorussian. My error reveals the perils of amateur etymology.
Microwave-assisted lab kilns
A captious critic might complain that I devote too much attention to words, rather than to the reality they denote. So here are a few words about one bit of reality.
EATechnology has launched a n e w g e n e r a t i o n of laboratoryscale kilns that solve the problem of balancing inputs f r o m r a d i a n t e l e c t r i c elem e n t s a n d m i c r o w a v e energy. T h e n e w kilns c a n p r o d u c e uniform heating of the body w i t h o u t " h o t spots", so react i o n s c a n t a k e p l a c e at l o w e r t e m p e r a t u r e s a n d m o r e rapidly t h a n in r a d i a n t - o n l y o r
When I was a youngish professor of materials science at Sussex University, I became fascinated by the then-novel field of glass-ceramics, useful ceramics made by devitrifying (i.e., crystallizing) glasses of complex compositions, and taught undergraduates about this theme. The undisputed father of this category of materials (folloWing an unsuccessful attempt by R~aumur in France 200 years ago) is the chemist S. Donald Stookey, now 85 years old and retired from his lifelong employment with the Coming Glass Company in upper New York State. He began working there in 1940 and at first studied ruby glass. Such a glass contains gold in solution and, if it contains a suitable sensitiser, will become deeply coloured if exposed to ultraviolet light;, the exact colour depends on the size of the gold nanocrystals which are formed, and that depends on the nucleation efficiency of the chemical system. He then had the idea of using the gold nanocrystals to act as heterogeneous nucleating sites for other inorganic phases; one such glass could be treated to become locally white and opaque, and was useful for light fittings.
m i c r o w a v e - o n l y o v e n s . For example, ceramic compon e n t s c a n b e fired w i t h highe r quality, c o n s i s t e n t results, m o r e t h a n t h r e e t i m e s faster t h a n in radiant-only kilns. In t h e s e n e w kilns, m i c r o w a v e i n p u t is typically 10-20% of the thermal input producing t e m p e r a t u r e s u p to 1750°C. F u r t h e r details c a n b e f o u n d at w w w . e a t e c h n o l o g y , c o m .
Then, in 1948, Stookey had another brainwave, when his research director asked him to think about ways of making literally millions of tiny holes or slits in a glass sheet. He went back to one of his heterogeneously crystallizable glasses, containing lithium silicate as well as disotved metal catalyst, exposed it to UV light through a mask, heat-treated it and found a way of etching with hydrofluoric acid that would completely remove the crystallized fraction while leaving the glassy residue almost unaffected. He had discovered photochemically machinable glass, tradenamed FOTOFORM TM O f this major product, gradually improved and varied, Stookey himself said in 1985: "It has taken almost 30 years to become a big business in its own right; it is now used in complexly shaped structures for electronic, communications, and other industries (computers, electronic displays, electronic printers, even as decorative collectibles,)" The invention also became a key event in the history of new glass technology, which went on to generate products of mass appeal, such as zero~expansion glass-ceramic kitchenware~ The passage quoted above comes from a delightful little autobiographical book by Stookey, Journey to the Center of the CrystalBall, published in 1985 by the American Ceramic Society (ACeramSoc).A second edition is due out this year. An essay about Stookey's life, datelined March 2000, can also be seen on the ACeramSoc's Bulletin website, www.cerambulletin.org, The industrial Success of FOTOFORM TM raises an intriguing general issue. The processing of this glass-ceramic has to be done entirely in-house at Coming, because the conditions of heat-treatment and etching have to be controlled with great expertise. When one looks at other recent developments in materials chemistry, especially the bttrgeoning field of self-assembled materials which looks likely to have microdectronic applications, one is driven to wonder whether semi-finished materials (like hot-roiled steel sheet) will increasingly give way to fully finished components prepared entirely on the premises of the material producer. The industrial implications could be very considerable.
Materials
Today
11
escapes to adjoining rooms. R o o m p r e s s u r e is m a i n t a i n e d via t h e t w i n d o o r airlock syst e m a n d t h e s y s t e m - cons t r u c t e d f r o m p h e n o l i c resin o r 304 g r a d e stainless steel is fully fire resistant. Vertically sliding d o o r s allow a streaml i n e d , h i n g e - f r e e s y s t e m if s p a c e is l i m i t e d a n d c o n v e y o r s y s t e m s c a n b e fitted to a l l o w manual or automated transfer of products.
Raising a Glass to Stookey In my column in Vol. 2/4, I commented on the Russian term metaUovedenk as meaning 'looking at metals'. An Israeli materials scientist of Byelomssian origin, Eugene Rahkin, kindly wrote in to correct me. "M~id, if it existed, would have that meaning, but with an 'e' instead of an T, the word means 'knowing about metals thoroughly', from an old Russian verb, vedat', which means to know thoroughly (as in the German word 'Kunde'). l~dat' is extinct in Russian, but not in Rabkin's Bydorussian. My error reveals the perils of amateur etymology.
Microwave-assisted lab kilns
A captious critic might complain that I devote too much attention to words, rather than to the reality they denote. So here are a few words about one bit of reality.
EATechnology has launched a n e w g e n e r a t i o n of laboratoryscale kilns that solve the problem of balancing inputs f r o m r a d i a n t e l e c t r i c elem e n t s a n d m i c r o w a v e energy. T h e n e w kilns c a n p r o d u c e uniform heating of the body w i t h o u t " h o t spots", so react i o n s c a n t a k e p l a c e at l o w e r t e m p e r a t u r e s a n d m o r e rapidly t h a n in r a d i a n t - o n l y o r
When I was a youngish professor of materials science at Sussex University, I became fascinated by the then-novel field of glass-ceramics, useful ceramics made by devitrifying (i.e., crystallizing) glasses of complex compositions, and taught undergraduates about this theme. The undisputed father of this category of materials (folloWing an unsuccessful attempt by R~aumur in France 200 years ago) is the chemist S. Donald Stookey, now 85 years old and retired from his lifelong employment with the Coming Glass Company in upper New York State. He began working there in 1940 and at first studied ruby glass. Such a glass contains gold in solution and, if it contains a suitable sensitiser, will become deeply coloured if exposed to ultraviolet light;, the exact colour depends on the size of the gold nanocrystals which are formed, and that depends on the nucleation efficiency of the chemical system. He then had the idea of using the gold nanocrystals to act as heterogeneous nucleating sites for other inorganic phases; one such glass could be treated to become locally white and opaque, and was useful for light fittings.
m i c r o w a v e - o n l y o v e n s . For example, ceramic compon e n t s c a n b e fired w i t h highe r quality, c o n s i s t e n t results, m o r e t h a n t h r e e t i m e s faster t h a n in radiant-only kilns. In t h e s e n e w kilns, m i c r o w a v e i n p u t is typically 10-20% of the thermal input producing t e m p e r a t u r e s u p to 1750°C. F u r t h e r details c a n b e f o u n d at w w w . e a t e c h n o l o g y , c o m .
Then, in 1948, Stookey had another brainwave, when his research director asked him to think about ways of making literally millions of tiny holes or slits in a glass sheet. He went back to one of his heterogeneously crystallizable glasses, containing lithium silicate as well as disotved metal catalyst, exposed it to UV light through a mask, heat-treated it and found a way of etching with hydrofluoric acid that would completely remove the crystallized fraction while leaving the glassy residue almost unaffected. He had discovered photochemically machinable glass, tradenamed FOTOFORM TM O f this major product, gradually improved and varied, Stookey himself said in 1985: "It has taken almost 30 years to become a big business in its own right; it is now used in complexly shaped structures for electronic, communications, and other industries (computers, electronic displays, electronic printers, even as decorative collectibles,)" The invention also became a key event in the history of new glass technology, which went on to generate products of mass appeal, such as zero~expansion glass-ceramic kitchenware~ The passage quoted above comes from a delightful little autobiographical book by Stookey, Journey to the Center of the CrystalBall, published in 1985 by the American Ceramic Society (ACeramSoc).A second edition is due out this year. An essay about Stookey's life, datelined March 2000, can also be seen on the ACeramSoc's Bulletin website, www.cerambulletin.org, The industrial Success of FOTOFORM TM raises an intriguing general issue. The processing of this glass-ceramic has to be done entirely in-house at Coming, because the conditions of heat-treatment and etching have to be controlled with great expertise. When one looks at other recent developments in materials chemistry, especially the bttrgeoning field of self-assembled materials which looks likely to have microdectronic applications, one is driven to wonder whether semi-finished materials (like hot-roiled steel sheet) will increasingly give way to fully finished components prepared entirely on the premises of the material producer. The industrial implications could be very considerable.
Materials
Today
11