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Toshiba • PM for Electronics and Energy The Toshiba Corp. ranks among the giants in the world of microelectronics with sales in its financial year ending March 31. 1989, having risen to a staggering Yen 3,800 billion (USS28,794 million) and exports accounting for about one third of this amount. Whilst much of the company's growth can be accounted for by the brisk demand for electronic devices, notably semiconductors· Toshiba is the world's fifth largest semiconductor producer - them are a number of other important industrial sectors which make up the corporate picture. These include: information processing and control systems; electronics and communications; electron and cathode ray tub"es; energy systems; industrial equipment; consumer products; and finally the materials and components group which includes the company's metal division and new material division. It is Ihe laller which produces a range of PM products mainly for use in consumer products such as audio and video products, refrigerators, freezers, air conditioners, lighting, etc., but also for computers, printers and other business machines. It has long been Toshiba's philosophy to improve its products from the ground up and hence the company places considerable emphasis on the research and de\'elopment of new materials and components which will serve as the building blocks of promising new products. Over 6.0% of sales - Yen 230.4 FIG. 1 Sintered tungsten-based heavy alloy components in proauction at Toshiba FIG. 3 PM structural parts used in refrigerators and air conditioners MPR June 1990 billion (USS1,745 million) was'ploughed back into R&D in 1988, but of course much of this went into the development of information technology and semiconductor-related areas. The materials area is not, however, beiog ignored and considerable effort is being put into advancing the properties and performance of existing materials such as PM special alloys and sintemd magnets, and to develop new structural engineering ceramics based on silicon nitride which arc now finding applications for diesel engines and ceramic roller bearings for gas turbine engines and semiconductor manufacturing equipment.' HereToshiba is ableto call upon its many years of experience with other types of powder products which have been in production for several decades notably: sintered electrical contacts, tungsten and molybdenum lighting clements, self lubricating bearings, sintered magnets and structural PM parts, and cemented carbide tools, all of which have been produced on one site at the company's metal works in Yokohoma since 1971, and which was visited five years ago by MPR. On this occasion, MPR held discussions on PM production with engineers from the Yokohama plant at Toshiba's headquarters in Tokyo. PM PRODUCTS Toshiba first started producing sintered products at the beginning ofthis century when FIG. 2 Selection of Ag-IV and Gil-IV contacts and components l'Jli. 4 :ielectlOn a} structural 1',\1 parts produced for Toshiba's range of business machines it hecame the first company in Japan to produce tungsten filalJlcnts hy refinin" tungsten ore to powder and reducing consolidated tungsten powder bar 10 wire using a series of swaging and drawing processes. Today, the modern Yokohama facility is capable of producing tungsten wire down to 10 micron diameter, and additional products based on tungsten have been developed for heavy metals, anodes for X-ray tubes. electrodes for discharge lamps, etc. (Fig.1) Products made from sintered molybdenum are also manufactured including wire, plate and sheet, discs, furnace clements and boats, elc. In the 1930s the company developed copper-tungsten electrical contacts (1931) followed a short time later by sintemd silver- tungsten contacts, and these continue to be produced along with other Ag-W and Cu-W alloys for electrospark machining and electrodes for resistance welding at a current rate of 2 tonnes/month. (Fig.2) Self lubricating bronze bearings were introduced in 1938 followed by structural PM parts in the late 1950s - both finding applications in the company's expanding range of household appliances such as fans, washing machines, refrigeralors, air conditioners, and mechanical office equipment. Despite the fact that many of the PM parts for office equipment were made redundant through the introduction of microelectronics, and that many of the gears and bearings used in modern business machines are now made from plastics, in-house PM part production at Toshiba has continued 10 grow over the years. Figs.3 and 4 show a selection of the current range of PM parts in production for business machines and refrigerator compressors. Only a few PM parts are currently produced for automotive applications, but the company is planning to expand its activities in transmission parts whem it sees good growth opportunities. PM self lubricating bearings made from Fe-S, Fe-Pb, Fe-Cu-C, and Cu-Sn-Pb-Zn-C powders also remain an important product group with large scale production for the company's range of audio and video products, domestic appliances, business machines, etc. with several million bearings produced each year at Yokohama. However, it is in Ihe areas of business machines, such as copiers, personal compulers and computer printers, where Toshiba has experienced the highest growth in recent years with resultant growth for new PM structural parts, sintered iron soft magnets and rare earth magnets. The company's range of Tosrex rare earth cobalt (R z Co I7 ) magnets (Fig.5) with their high residual induction and maximum energy product have, for example, found applications in stepping molors, loudspeakers, headphones, coreless motors, voice coil motors, optical pick-up heads, to name a few. whilst soft magnets are being used in increasing quantities in the print head of computer printers, voice coil motors in floppy disk drives, etc. Rare earth magnet production is of the order of 6 tonnes/month. Engineering ceramics arc also playing an increasingly important role in the product mix with the development of aluminium titanate 459
