88 CERAMURGiA INTERNATIONAL, Vol. 4. n. 2. ,s78

Building on their recent Soviet patents for modifvinq solid solutions of lead zirconate-tItanate, workers at the Mo- scow Institute of Chemical Techno- loav and the State Porcelain lnst~tut~ (%JIIFI) have published a search data showing that adding 0.5 to 2.0 per cent of glasses to these ceramics yields electrically stable bodies and enables sintering ‘temperature to be reduceld by 100°C. Continuing their researches to do away with plaster moulds in ceramic shaping Soviet workers and their colleagues in satellite states are experimenting with the freezing of water-clay slips. A pa- tent was recently awarded to an East German team for this process and Russian engineers have now published their own findings about freezing cera. mics in metal moulds. The quartz was ballmilled with distilled water, and fro- zen in steel moulds for 1 tu 6 hours at -10 to -,15”C. The work is still expe~~rn~~ta~ but advan tages being claimed inclu’de the chance to rnake thick articles and of cutting moulding time.

SECOND PRESS

A second ‘Densomatic powder press has been supplied by Olin Energy Sy. stems to Magneti Marelli of Milan. The mess. which isostaticallv forms the ceramic insulator part of a’spark plug is fully automatic and capable of pro- ducing up to 54 high quality components per minute from spray dried alumina. It is an in-line, six-cavity model with a maximum isostatic pressure of 345 bar. It has a 30 ton capacity press frame and integrated tool set ,which allows powder fill and component ejection to take place without the need to remove moulds. The pressed parts take-off mechanjsm is equipped with six micro-switches to ensure that the press cannot be re started until1 the ejected components have operated their switches. Olin’s jntegrated tool set incorporates a single shot, high pressure intensifier which delivers the exact amount of hydraulic fluid to the pressure vessel. The intensifier is driven by a low pressure hydraulic cylinder via the too. ling, so that high-preasur0 fluid is con rained witb~n the tool set and compii.. cated h~gh~press~jr~ circuitry is elimi, nated.

ue to ths aKra(rge~r~errt it is nnyvssibje to open the press with any residual pressure remaining. Powder compacti0~ dwell time is adju. stable 0 to 6 seconds and decompression time is fullly adjustables

A~S~~~N~U~ HAS CORROS1 ESISTANT ~EAT~~~ ELEMENT

A silicon carbide bar heating element designed to operate in corrosive atmo- soheres at 800-3000°F has been deve- biped by the Graphite Prod. Div: of

arboru~d~m Co. Globar-tvPe CR ele~, ments will facilitate convei%on of fue(- fired furnaces to electric beal: and sirn

plify design of new industrial furnaces. CR bar elements are suited for appli- cations such as powder metal proces- sing, nonferrous melting and holding Furnaces, bright annealing and atmo- sphere heat treating. With over 20% greater density, the e’lements are three times stronger than standard silicon carbide heating elements and reportedly last three times longer.

Scientists at (BM Carp’s San Jose, Calif,, Research Lab have fabricated an experimental microcircuit chip that con- tains all the elements needed to rea write and store information in an array of closely packed magnetic bubbles, This is the first time the bubble lattice concept has been tested in a fully ape, rational device. Experiments with the concept indicate it may store up to 10 times as much information in a given area as other magnetic bubble devices.

The bubble lattice stores information in the form of magnetic bubbles, which are tiny cylinders of reverse magnetism formed in a thin layer of a magnetic material such as crystalline garnet. Mi- crocircuit patterms deposited on the surfaces of these films provide pathways along which the bubbles can be moved under control of an applied magnetic field or electric current. The new device has a capacity of 1024 information-bearing bubbles in its sto- rage area. They are arranged in a hexa- gonal array consisting of 32 rows and 32 columns. Each one represents a sin gle bit of information. The bubbles have a diameter of 5 urn. This gives a sto- rage density per in.’ of over 5 milhon bits.

A researcher at Alfred University has develooed what he calls an improved technique for shipping liquified coal by pipeline while reducing the pollutant con- tent of the carboniferous fuel. James E. Funk. associate professor of ceramic engineering, applied co~vent~o~a~ me= thods of manufacturing industrial ciays to the problem of fine grinding and mixing coal with water. His goal was tci create a relatively thick, but still pum. pable, fluid slurry. Prof. Funk reports he has deveioped a slurry that is 75% pulverized coal and 25% water. Under existing technology, standard slurry mixtures are half coal oowder ansd half water. We was able to increase the actual fuel content of the slush-like composition by fine milling coal and adding certain- chemicals to prevent settling.

&e important- develop was that his laboratory slurry burned cleanly during test with its water con- tent intact. Slurry normally has to be put through an 0nerg~c0naumin~ ~e~ateri~~ plant at its destination where coal pow

and water are separated by centrifuges. The powder is then burned as fuel and the water is allowed to evaporate.

FINING HAS ERDA NTRACT DEVELOP LASER SSES

Soecial laser glasses that could be used to develop the concept of laser fusion will be melted and tested by Corning Glass Works under a $761,731 contract from ERDA. Scientists will investigate techniques of melting and forming beryj- lium-fluoride glasses and other fluoride- containing glasses for use in high power lasers. Laser fusion is a potential process for harnessing the heat and power of ther- monuclear micr~~xp~osiofls to e~erat~ electricity in fusion reactors.

ATERlALS PROCESSlNG EXPERIMENT

NASA has selected five materials pro- cessing experiments, three of which are ceramic oriented, to be ‘packaged and flown on the Space Shuttle during one of its six orbital flight tests (OFT] to beain in 1979. occupying a relatively small space, the materials eauioment assembly (MEA1 package wili’be automated and unatten- ded. In admdition to the experiment equip ment, the package will contain its own power source and a minicom’puter to collect data. lhe OFT will provide scientists with additional technical and scientific in- formation about their experiments prior to Soacelab missions. Ceramic experi- ments and princi’paj investigators sklec- ted for the MEA project include: Solid Electrolytes Containing Dispersed Parti- cles, J. Bruce Wagner, Jr., Arizona Sta- te University; Containerless Preparation of Advanced Optical Glasses, Ralph A. Happe, Rockwell ~nter~at~onal~ and Va por Growth of Alloy-Type Semiconduc- tor Crystals, Herbert Wiedemeier, Rens- selaer Polytechnic Institute.

A low-density thermal ~~s~~at~(~r~ material based on PFA [puiverised fuel ash1 ~enos~beres has been develo ceramics centre at AERE collaboration with CEG The material is suitable for a~pi~catio~s up to lOOo”C, contains no asbestos, is non-toxic and can be moulded into a variety of rigi’d shapes. Panels can be machined, drilled and sawn using con- ventionajl methods. PFA cenospheres are formed during the combustion of pulverised fuel and are separated from the ash by flotation in settling lagoons. They are essentially hollow glass microspheres. These particles can be bonded together in a variety of ways to form linght- weight artefacts having a low thermal conductivity over a wide temperature

~~g~~at~ria~ is capable of witbs~andin~ contj~u0~a operation t~m~erat~r~s 0% 1000% with no change in volume.