« iepriekšējāTurpināt »
He was educated at Shinshu University public. A portion of the revenue from practices is that they are beginning to and joined the faculty upon receiving the product is used to improve its per- do more applied research than they his doctorate.
formance through further R&D. In the were doing in the past. This change is The financial support for this group eyes of the Japanese, the United States beginning to impact the number of is divided into two-thirds from the does the inverse procedure by identify- graduate students and faculty memMinistry of Education and the remainder ing a product, doing a lot of R&D so a bers in the universities because the from industry. In addition, Endo has sophisticated product can be made, then industrial pay is greater, the hours are indirect support through collaboration trying to find ways of making it cheaper shorter, and the working conditions with over 50 different companies. This so the product can be marketed. In and equipment are better. means that data are collected from terms of the development of C/Cs, Endo processing runs from a company that is believes Japan will know as much about Program Status having production problems but does how to make this material as the United not have the "know how" to solve the States does by 1995. Then Japan will go One of the major areas of research problem. These data are sent to Endo, ahead of the United States technolog in Endo's group is the detection and who evaluates the data on a scientific ically by 1997 or 1998. Part of the incen- identification of defects in fibers. He basis to understand how the process tive for making this advance is because
tive for making this advance is because believes that by accurately knowing the functions. With this knowledge, he of the MITI C/C initiative that was concentration and type of defects, it is advises the company's management what started in the late 1980s and will end by possible to calculate the reduction of changes have to be made to the process 1998. Endo also believes there will be the thermal mechanical properties from to increase production or to improve a shortage in Japan of technical persons
a shortage in Japan of technical persons the theoretical values for a perfect crystal the product. In return for this service, in the future. This view was substanti
in the future. This view was substanti- of graphite. Conversely, if the influEndo receives further support for the ated by a Reuter's article on 19 January ence of different types of defects is group and can use the data to further 1991 stating that a recent survey indi- known, then it should be possible to his research efforts. A key to the suc- cated that by the year 2005 there will modify the processing procedures to cess of this approach is that large quan- be a shortage in Japan of 510,000 scien- eliminate them, thereby improving the tities of data are very carefully col- tists and engineers because young people properties of the fibers. Endo is worklected to be statistically significant. are not entering the field due to low ing with Prof. Mildred Dresselhouse of Furthermore, the type of data selected salaries, poor working conditions, and the Massachusetts Institute of Techis one that will give the best insight into long hours. As a current example of nology (MIT) in this area of research. how the process operates. This system long hours, Endo works 6 days a week Numerous techniques are being used of problem solving is advantageous to from 0730 until 2000. This is not unusual in this laboratory to identify the defects both parties because the company for any number of professors that I've in fibers such as TEM, at magnificadoesn't have to keep someone on its questioned. The problem of getting and tions up to 1 million, laser Raman staff full time just in case a problem keeping trained persons is being com- spectroscopy, magneto resistivity and arises and the professor gains useful pounded by a change in the work ethic other electrical characteristics, and information with which to continue his by industry. Previously, when a person thermal mechanical properties. All of studies. In addition, the problems get was hired by an organization, it was a this information is being fed into a solved faster because of the professor's lifetime commitment by the employee computer-aided system that evaluates expertise. As an example, Endo men- and the company. Until even 5 years the data in terms of the type and orientioned that Mitsubishi Heavy Indus- ago, a technical person could not make tation of the defects or in effect protries uses his services in this manner more than one move to another com- vides an absolute image analysis of the even though it has 150 researchers in pany without getting a black mark. Endo defect distribution in the fiber being its laboratories. In the course of describ- says the hiring and firing practices of examined. This approach has been used ing the different modes of corporate big corporations have changed. Now by Nippon Steel for its pitch fiber operations, Endo made the point, as the corporations are hiring 50% more where the specific modulus and strength others have, that the philosophy of graduates than they will need in the values exceed those of PAN fibers. A developing a product is entirely differ- next 3 years. This allows the corpora- major portion of the defects in the ent in Japan than in the United States. tions to screen the group, pick the best pitch fibers has been eliminated, which In Japan, a market is identified for a ones, and fire the lower 50%. This results in large increases of the mechannew product, a process is developed for procedure certainly puts a lot of pres- ical properties. These changes are sufproducing an acceptable but unsophis- sure on the beginning engineer or sci- ficiently large so that they compensate ticated product, and it is sold to the entist. Another aspect of industrial for the higher density of the pitch fiber compared to the PAN fiber and that and applicability as a substitute for on this whole assessment trip. These results in the larger specific properties. activated carbon.
investigations are directed toward the No values of modulus or strength were
different aspects of the solid state of given because of the company's confi- • Studying the mechanisms of inter- carbonaceous materials. The informadentiality agreement. The next stage of calation processes in carbon fibers tion that is obtained is used to optimize this research program is to apply these to enhance their electrical proper- the fiber's properties for particular same techniques to identify defects on ties and thermal stability.
applications. Therefore, a wealth of the surfaces of fibers. Again, the objec
information exists here. It is expected tive is to relate the types and distribu- • Determining if real time or in-situ that these research efforts will contions of defects to the bonding charac- measurements of the electrical tinue for many years to come. As far as teristics of the fiber with its surround- properties of fibers can be used as a collaboration with U.S. organizations ing carbon/graphite matrices. In addi- means of controlling the processing is concerned, Endo has for years been a tion, the defect distributions will be conditions to obtain the desired co-investigator with Prof. Mildred compared to the processing conditions microstructure and physical prop
Dresselhouse of MIT. He would like to and this should eventually permit the erties. Right now the industry is continue and broaden the number of selection of the proper processing evaluating fibers by characterizing these interactions. conditions to eliminate adverse defects. fibers that are being taken from It is strongly recommended that every
Other areas of Endo's research efforts batches at different stages of the effort be made to continue and extend include:
process. The types of undesirable communications with Prof. Endo. If
defects are believed to be caused by possible, more collaborative investiga• Optimizing the orientation of the such items as chemical impurities, tions should be initiated.
mesophase-based pitch fiber to variations in viscosity during the
Kita-ku, Nagoya 462, Japan
energy storage batteries and the field
of biotechnology. The dimensions Background • Defining the phenomena and con- of these fibers are approximately
ditions for the transformation of 1 micron in diameter and 10 microns Dr. Kikuo Nakano was my host for the amorphous carbon to the long.
this visit. He is the chief of the High graphitic phase. It is Endo's opinion
Temperature and Ceramic Material that if the radius of curvature of the The laboratory facilities are very Division. The research here is primarily microstructure is less than 150 to extensive and unique, especially for directed toward ceramics as matrices 200 Å, no graphiticstructure will be the characterization of fibers. The excep- in composites where the fibers are made formed.
tion is that no mechanical tests are of both ceramic and carbon materials.
conducted here. But this is not a prob- Some of the research areas include: • Reducing the cost of pitch fibers by lem because of collaborative programs
using the less expensive isotropic with the producers of fibers who provide • Superplastic deformation of ceramic pitch as the precursor. Finding and Endo with all the data that he needs. systems where 100% deformation eliminating the defects in these fibers
may take only 50 seconds at 1,400°C to improve their mechanical prop- Assessment
and 29,000 psi. The systems being erties and applicability to a larger
investigated include silicon nitrides number of engineering uses.
The research program, under the and carbides and zirconium oxide.
direction of Prof. Endo, is one of the • Identifying and altering the defects best if not the best in Japan. Its depth • The influence of grain size (<1.0 to
on the surfaces of carbon fibers to and breadth is not equaled in any of the 20 microns), aspect ratios, and chemenhance their adsorption properties other laboratories that I have visited ical composition of boundaries on the sintering and hot pressing char- strength value is attained due to the Background acteristics as well as the toughness differential thermal effect between the and mechanical properties of sili- matrix and the carbon fibers as the My host was Shigeo Yasuda, who is con nitride. temperature is raised from 22 to
the general manager of the Manufac>300 °C. This is because the matrix turing Division, Inorganic Chemistry • Superconductivity of Bi-Pb-Sr-Ca- expansion can be between 3.3 and Department. My contact was Akira
Cu-O systems. This has been under 4.5 parts per million per °C as compared Hashimoto, who is the deputy general investigation for the past 2 years. with *-1.26 for the fiber in this manager, Carbon Products Sales DiviThe major objective is to reduce the temperature range. The oxidation sion of the same department. grain boundary effects in order to resistance characteristics of these This is a multiproduct company that increase the current densities to materials are not currently known as is concerned with the sales and applica10,000 A/cm2
this phase of the program has just begun. tions of electronic boards for integrated
In the future it is intended to study circuits (ICs), ceramic fibers, and other Program Status
these materials in a 3D yarn or fiber items with carbon products such as fine
configuration. As yet no thermal cycling grained (<1 to 40 microns) graphites The primary research involving with oxidation testing has been for electrical discharge machining. This carbon is the incorporation of carbon performed nor has there been any creep phase of the business has been in exisfibers into composites whose matrices tests. Within the next 3 years the goal is tence for 20 years and usually acquires are composed of nitrides and carbides to have these types of materials function about 10% of the company's total reveof silicon and boron carbide. Dr. Nakano satisfactorily at 1,800 °C. Mitsubishi nue in a year. In terms of C/Cs, the started this work about 5 years ago to Heavy Industries and other company's interest started about 5 years make materials that have good oxida- manufacturers are interested in this ago. It appears that these efforts are tion resistance and excellent mechani- material for use in the forthcoming being expended so that Ibiden can tell cal properties of the carbon fibers. These Japanese space plane that is being its potential customers that it can make materials will be used for the near term supported by the Government. C/Cs in case a sudden and large market or until the utilization temperature is
occurs in the near future such as for the raised to >1,600 °C. The current sam- Assessment
space plane or nuclear fusion reactors. ples are 30 to 40 vol %of unidirectional
The New Products Division is also intercarbon fibers wound and impregnated This organization has a high degree ested in different types of ceramics such in a mixture of silicon resin and silica of technical competence in the area of as silicon nitrides and carbides and powder. The next step is to hot press ceramic matrix composites that con- zirconium oxide. the preform at 1,700 °Corat 1,850°C iftain carbon fibers. This is a general boron carbide or silicon carbide powders direction of research that will probably Program Status are used. The plates that are formed result in the development of the next are 4 by 20 cm and 6 to 10 mm thick. generation of high temperature mate- There was no significant discussion Pitch-based fibers are preferable because rials to operate in an oxidizing atmo- about Ibiden's research activities or they do not react as much with the sphere. Therefore, it is recommended the reasons for doing so either now or different matrices as the PAN fibers. that communications be maintained within the future. The initial portion of the The cause for this difference has not this laboratory to keep abreast of the presentation was on general informabeen determined. These materials are progress and to determine if any of the tion about the entire corporation. evaluated at <1,700 °C for tensile, results can be utilized to improve the During the course of this, several samcompressive, and bending strengths as ceramic coating used on C/Cs to protect ples of C/Cs were displayed but the a function of the different types of them against the effects of oxidation. quality was not good, as the yarn spacmatrices and the processing conditions.
ing was 8 to 10 mm apart and the denFor example, the bending value of a IBIDEN CO., LTD.
sity was about 1.7 g/cc. The pieces were silicon carbide matrix composite can
cubes with a dimension of about 100 mm be 600 MPa ("87 kpsi) when measured 300 Aoyanagi-cho
To densify the material, pitch was forced at 1,600 °C. In some cases the fiber-to- Ogaki, Gifu 503, Japan
into the preform at 4,300 psi and the matrix bond can be too good, which Tel: 0584-89-3314
temperature was raised to 1,000 °C. No results in the sample fracturing Fax: 0584-89-8108
physical properties of this material were prematurely before the maximum Date: 24 Jan 1991
given. From the discussion it was
apparent that Ibiden was aware that Background
The carbon effort at MHI is reported the temperature at which the pressure
to be four to six staff and five support is applied is critical, although this value This visit was hosted by Yasuhiro persons and the R&D has been going was not divulged to me.
Yamaguchi, manager of the Chemical on for about 5 years. It is expected, The discussion then centered on the Research Section of the Engineering based on other information that was characterization and interpretation of Research Department. In addition, there obtained elsewhere, the C/C efforts will the data. The samples are only exam- was a manager from the advanced continue here for at least another 7 to ined by optical microscopy methods at composites development team and a
8 years. magnifications between 10X and 100X. senior engineer from the Structure Essentially, they are looking for gross Designing Section of the Aircraft Program Status cracks between the yarns and in the Engineering Department. The total matrix. No higher magnifications are number of attendees at this meeting The discussion was very directed by being used, even though they believe was eight.
the MHI representatives towards trythe matrix microstructure has an Studies concerning C/Cs have been ing to get answers to specific questions, influence on the physical properties of going on since 1985. Although not such as which type of architecture was C/Cs. Ibiden's primary concern about specifically stated at this meeting, MHI, better--2D, 3D, or some other archiphysical properties of C/Cs is that the along with other big corporations like tecture? Or, what were the shear propbending strength and thermal conduc- Mitsubishi Chemical, has a large effort erties of the U.S. space shuttle C/Cs? tivity values be as high as possible. No to develop C/Cs for the Japanese space But the MHI group was reticent to explanation was given as to the ration- plane that is being partially supported provide any specifics about its proale for these choices, and it is not clear by MITI. In addition, C/Cs are being grams or the research in connection from the information what the applica- designed and fabricated for rocket with C/Cs. However, as the discussion tions might be. No mention was made engines in launch vehicles. A tour of went on, some information was obtained of thermal expansion, modulus, fatigue, the resin matrix fabrication and pro- about its 2D C/Cs. They are fabricated or creep.
cessing facilities clearly indicated that by stacking layers of carbon/graphite The development of C/Cs is being all types and shapes of carbon rein- cloth that has been prepregged, cured, conducted by four researchers. No forced plastic composites can be made. and polymerized in the usual manner. government funds are being sought so A type of winding equipment was After the preform has been carbonized their technological advances can be held installed in June 1990 that is capable of to 1,000 °C, it is reimpregnated with by the company. No laboratory tour or winding, with 3-inch-wide tape, a whole furfuryl alcohol five to seven times and description was offered.
aircraft wing to a thickness of 112 plies carbonized after each impregnation.
(15.5 mm). There are hot presses and At some point of the densification Assessment
autoclaves that operate at 400 °C and process, there is at least one graphitiza
300 psi for processing whole aircraft tion step at 2,500 °C. The final density Compared to the previous site visits, wing sections as the largest autoclave is of the C/C is about 1.7 g/cc, which is this one was disappointing. Judging by 18 feet in diameter and can take pieces typical for this type of material. Pitchwhat I observed, Ibiden C/C technol- 51 feet long. Apparently, these facili- based fibers are used and the bending ogy is not current with companies in ties are being used for the fabrication strengths of the C/Cs are around 20 to Japan or in other places of the world. ofvarious shapes of C/Cs. For example, 30 kpsi. Again, these numbers are
It is recommended that no further I was shown a portion of a leading edge comparable to similar types of C/Cs efforts be expended on this organiza- section for a wing that was similar in that are produced elsewhere. Appartion in the future.
shape to that of the U.S. space shuttle. ently, the quality of these current C/CS
However, the flange thicknesses in it is evaluated by the usual mechanical MITSUBISHI HEAVY
appeared to be thinner ("3 mm) and testing procedures and optical and SEM INDUSTRIES, LTD. (MHI) the yarn layups were straighter and more microstructural observations. However,
evenly spaced. Also shown was a thin the discussions would indicate that MHI Nagoya Aerospace Systems
C/C, SiC coated, slat panel, 1 by 2 feet, is not yet sensitive to the importance 10, Oye-cho
with an integrally woven rib that was and the influence of the matrix microMinate-ku, Nagoya 455, Japan also 3 mm thick. Apparently, the structure and the types of fiber-to-matrix Tel: (052) 611-2111 x5325
expertise that has been gained in fabri- bonds on the performance of C/Cs. They Fax: (052) 613-0752
cating resin matrix composites is being do find that graphitization does increase Date: 25 Jan 1991
used to make excellent prototype C/Cs. the modulus, lower the tensile and compressive strengths, and increase the by better communication and coordi- data collecting, analysis, and writing of strain values.
nation between the other large corpo- the papers and reports. In addition, it is MHI has been performing research rations that MITI has formed into dif- difficult to hire young persons because studies for the past 10 years on ferent consortia. There probably is a the salaries and laboratory facilities approaches toward resisting the oxida- great deal of developmental informa- are so much better in the industrial tion effects on C/Cs. They have been tion available here. How much research sector. The plus side is that the researcher involved in two different methods of there is that is not connected to imme- is allowed a lot more freedom in applying SiC coatings to C/C substrates. diate problems is not clear. MHI says conducting his investigations than would MHI finds that the conversion of sili. that collaboration is possible with be possible in industry. However, all con oxide to the carbide forms a better organizations in the United States. directors of each GIRI organization bond. But, vapor depositing silicon Before this can be defined, communi- have recently been informed that their carbide provides better protection. In cations between us need to be improved staff must be cut back 5% each year for each case the layers are 200 microns I think this can be achieved judging the next 5 years, which certainly limits thick. They are also trying the combi- from how relatively open this meeting the growth to practically zero, especially nation of conversion and vapor deposi- ended after a very guarded start. for the hiring of young people. tion methods to form a protective The recommendation is that MHI The research in C/Cs started about coating. Then on top of this a thin layer is an organization with which commu- 3 years ago, but work in the carbon area of a high melting point metal such as nications should be continued and has been going on for more than 15 years Hf, Zr, or Ir is deposited. Other types perhaps some sort of a cooperative under the direction of Dr. Yasuhiro of refractory metal layers are being tried. program should be established. Another Yamada with the support of three or This work is just starting and the goal is advantage of establishing a link is that more assistants. to provide protection to 2,000 °C. this organization is in the center of the Other major areas of research include Thermal cycling between 22 and 1,700°C big initiative that MITI is supporting the development of new engineering is being included as part of the evalua- with respect to C/Cs.
materials, including porous metals and tion procedures of the coatings. No
intermetallics; mineral processing; data were provided concerning any GIRI KYUSHU
ceramics; processes for the reduction portion of the oxidation investigations.
of environmental hazards; and other Shuku-machi
studies for the scale-up of processes Assessment Tosu-shi, Saga-ken 841, Japan
that have been developed in the Tel: 0942-82-5161
laboratory It is very evident that this corpo- Fax: 0942-83-0850 ration has and will continue, probably Date: 28 Jan 1991
Program Status for the next 8 years, to develop C/Cs for high temperature applications. My Background
The general theme of the research limited observations of the types of
in carbon is to understand how the C/Cs that are being fabricated indicate The host for this site visit was Dr. processing conditions influence the that the quality is very good and com- Minoru Nakamizo, who is the Director microstructure and how this, in turn, parable to that which is produced in General of this facility. A general review alters the physical properties of the the United States. This situation does of the activities here was presented. materials that are being investigated. point out that Japan is doing exactly Approximately 25 joint projects are In this regard, fundamental studies on what they say they are going to do. conducted each year with industrial and the mesophase state of the pitch have Namely, Japan will become as knowl- other GIRI organizations but practi- been underway for the past 6 or more edgeable as the United States by 1994 cally none with universities, due to the years and will end in 1992. One of the or 1995 concerning their capabilities fact that the GIRI funds come from most interesting results is the ability to for processing and fabricating C/Cs. MITI and not from the Ministry of form a matrix microstructure whose aThen, Japan expects to surpass the Education. There are approximately b planes are oriented normal rather United States by 1997 or 1998 in the 70 research personnel at this site, of than parallel to the surface of the fiber. technological capabilities for produc- which 40% have Ph.D. degrees, and This means that the high strength direcing advanced C/Cs! The information there are only 20 support persons, includ- tion of the graphitic structure of the that will allow Japan to gain this posi- ing secretaries. As has been mentioned matrix can be used to increase the transtion will come primarily from its own before, the researchers must do practi- verse and shear strengths between fibers, research and development efforts and cally all of their own equipment building, normally the weak link. If a procedure