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Release: November 27, 1997


NGK INSULATORS, LTD. (President: Masaharu Shibata, Head Office: Nagoya) will start full-scale production of substrates for hard disks, made of glass ceramic, from 1998. The initial production is scheduled to be 2 million pieces per month.

Hard disks use round-shaped substrates, coated with magnetic films on which information is stored by magnetizing the substrates. Until recently, aluminum has been the main material for substrates; however, it has started giving way to glass ceramic, especially for 2.5" substrates used for lap-top type personal computers which require high shock resistance.

Glass ceramic substrates have higher Young's modulus and a smoother surface than aluminum substrates. Young's modulus indicates stiffness, and greater stiffness enables higher-speed rotation of disks. A smoother surface can make it possible to store information more densely. On the other hand, the higher cost has restricted the use of glass ceramic substrates for larger size substrates such as 3" and 3.5".

NGK has succeeded in producing glass ceramics with uniform flatness and superior smoothness with its excellent material for glass ceramics, glass forming technology, and super-precision processing technology fostered in the field of magnetic recording. NGK also has the prospect of providing large-size glass ceramic substrates of 3" and 3.5", which are competitive with super polished aluminum substrates.

The present market share of large-size substrates accounts for approximately 80%, but with the new requirement of lighter and high modulus substrates, which are capable of high-speed rotations, it is expected that the demand for glass ceramic substrates will increase.

Glass substrates, which NGK has decided to produce full-scale, are made of crystallized glass ceramic. It is mechanically strengthened by crystallizing glass. Compared with chemically strengthened glass surrounded with a compressed layer, crystallized glass ceramic can be better adapted to large-size disks.

NGK set up a pilot line for glass ceramic substrates in February, 1997, in its R&D facility located in Nagoya, and has developed technology for their mass production. Since the products made on an experimental basis have been highly appreciated by our clients, NGK decided to start their full-scale production. The production process from melting glass to crystallizing glass, will be conducted at NGK's Komaki plant, and the latter part of the process will be done at NGK Okhotsk, Ltd. (President: Soichiro Matsuzawa, Head Office: Abashiri-city, Hokkaido) . NGK is planning to enlarge the production capacity to 5 million pieces per month by 1999 and to make glass ceramic substrates one of the main products of its electronics business.

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