He was educated at Shinshu University and joined the faculty upon receiving his doctorate. The financial support for this group is divided into two-thirds from the Ministry of Education and the remainder from industry. In addition, Endo has indirect support through collaboration with over 50 different companies. This means that data are collected from processing runs from a company that is having production problems but does not have the "know how" to solve the problem. These data are sent to Endo, who evaluates the data on a scientific basis to understand how the process functions. With this knowledge, he advises the company's management what changes have to be made to the process to increase production or to improve the product. In return for this service, Endo receives further support for the group and can use the data to further his research efforts. A key to the success of this approach is that large quantities of data are very carefully collected to be statistically significant. Furthermore, the type of data selected is one that will give the best insight into how the process operates. This system of problem solving is advantageous to both parties because the company doesn't have to keep someone on its staff full time just in case a problem arises and the professor gains useful information with which to continue his studies. In addition, the problems get solved faster because of the professor's expertise. As an example, Endo mentioned that Mitsubishi Heavy Industries uses his services in this manner even though it has 150 researchers in its laboratories. In the course of describing the different modes of corporate operations, Endo made the point, as others have, that the philosophy of developing a product is entirely different in Japan than in the United States. In Japan, a market is identified for a new product, a process is developed for producing an acceptable but unsophisticated product, and it is sold to the public. A portion of the revenue from practices is that they are beginning to more than one move to another com- One of the major areas of research in Endo's group is the detection and identification of defects in fibers. He believes that by accurately knowing the concentration and type of defects, it is possible to calculate the reduction of the thermal mechanical properties from the theoretical values for a perfect crystal of graphite. Conversely, if the influence of different types of defects is known, then it should be possible to modify the processing procedures to eliminate them, thereby improving the properties of the fibers. Endo is working with Prof. Mildred Dresselhouse of the Massachusetts Institute of Technology (MIT) in this area of research. Numerous techniques are being used in this laboratory to identify the defects in fibers such as TEM, at magnifications up to 1 million, laser Raman spectroscopy, magneto resistivity and other electrical characteristics, and thermal mechanical properties. All of this information is being fed into a computer-aided system that evaluates the data in terms of the type and orientation of the defects or in effect provides an absolute image analysis of the defect distribution in the fiber being examined. This approach has been used by Nippon Steel for its pitch fiber where the specific modulus and strength values exceed those of PAN fibers. A major portion of the defects in the pitch fibers has been eliminated, which results in large increases of the mechanical properties. These changes are sufficiently large so that they compensate for the higher density of the pitch fiber compared to the PAN fiber and that results in the larger specific properties. No values of modulus or strength were given because of the company's confidentiality agreement. The next stage of this research program is to apply these same techniques to identify defects on the surfaces of fibers. Again, the objective is to relate the types and distributions of defects to the bonding characteristics of the fiber with its surrounding carbon/graphite matrices. In addition, the defect distributions will be compared to the processing conditions and this should eventually permit the selection of the proper processing conditions to eliminate adverse defects. Other areas of Endo's research efforts include: • Optimizing the orientation of the mesophase-based pitch fiber to improve its transverse strength and toughness characteristics. The microstructure is being altered by adjusting the flow characteristics of the pitch as it is extruded through the orifice by changing the pitch's viscosity and how it is stirred as it enters the orifice. Defining the phenomena and conditions for the transformation of the amorphous carbon to the graphitic phase. It is Endo's opinion that if the radius of curvature of the microstructure is less than 150 to 200 Å, no graphitic structure will be formed. and applicability as a substitute for activated carbon. Studying the mechanisms of intercalation processes in carbon fibers to enhance their electrical properties and thermal stability. on this whole assessment trip. These investigations are directed toward the different aspects of the solid state of carbonaceous materials. The information that is obtained is used to optimize the fiber's properties for particular applications. Therefore, a wealth of information exists here. It is expected that these research efforts will continue for many years to come. As far as collaboration with U.S. organizations is concerned, Endo has for years been a co-investigator with Prof. Mildred Dresselhouse of MIT. He would like to continue and broaden the number of these interactions. Determining if real time or in-situ measurements of the electrical properties of fibers can be used as a means of controlling the processing conditions to obtain the desired microstructure and physical properties. Right now the industry is evaluating fibers by characterizing fibers that are being taken from batches at different stages of the process. The types of undesirable defects are believed to be caused by such items as chemical impurities, variations in viscosity during the spinning of the fibers, and the types GIRI NAGOYA of disclinations that are formed by the various processing conditions. It is strongly recommended that every effort be made to continue and extend communications with Prof. Endo. If possible, more collaborative investigations should be initiated. 1 Hirate-machi Kita-ku, Nagoya 462, Japan • Continuing investigations with the vapor grown carbon fiber, especially with respect to its applications in energy storage batteries and the field of biotechnology. The dimensions Background of these fibers are approximately 1 micron in diameter and 10 microns long. The laboratory facilities are very extensive and unique, especially for the characterization of fibers. The exception is that no mechanical tests are conducted here. But this is not a problem because of collaborative programs with the producers of fibers who provide Endo with all the data that he needs. Reducing the cost of pitch fibers by using the less expensive isotropic pitch as the precursor. Finding and eliminating the defects in these fibers to improve their mechanical prop- Assessment erties and applicability to a larger number of engineering uses. Identifying and altering the defects on the surfaces of carbon fibers to enhance their adsorption properties The research program, under the direction of Prof. Endo, is one of the best if not the best in Japan. Its depth and breadth is not equaled in any of the other laboratories that I have visited Dr. Kikuo Nakano was my host for this visit. He is the chief of the High Temperature and Ceramic Material Division. The research here is primarily directed toward ceramics as matrices in composites where the fibers are made of both ceramic and carbon materials. Some of the research areas include: • Superplastic deformation of ceramic systems where 100% deformation may take only 50 seconds at 1,400 °C and 29,000 psi. The systems being investigated include silicon nitrides and carbides and zirconium oxide. The influence of grain size (<1.0 to 20 microns), aspect ratios, and chemical composition of boundaries on the sintering and hot pressing characteristics as well as the toughness and mechanical properties of silicon nitride. • Superconductivity of Bi-Pb-Sr-CaCu-O systems. This has been under investigation for the past 2 years. The major objective is to reduce the grain boundary effects in order to increase the current densities to 10,000 A/cm2. Program Status My host was Shigeo Yasuda, who is the general manager of the Manufacturing Division, Inorganic Chemistry Department. My contact was Akira Hashimoto, who is the deputy general manager, Carbon Products Sales Division of the same department. strength value is attained due to the Background manufacturers are interested in this Assessment This is a multiproduct company that is concerned with the sales and applications of electronic boards for integrated circuits (ICs), ceramic fibers, and other items with carbon products such as finegrained (<1 to 40 microns) graphites for electrical discharge machining. This phase of the business has been in existence for 20 years and usually acquires about 10% of the company's total revenue in a year. In terms of C/Cs, the company's interest started about 5 years ago. It appears that these efforts are being expended so that Ibiden can tell its potential customers that it can make C/Cs in case a sudden and large market occurs in the near future such as for the space plane or nuclear fusion reactors. The New Products Division is also interested in different types of ceramics such as silicon nitrides and carbides and zirconium oxide. This organization has a high degree The primary research involving generation of high temperature mate- 300 Aoyanagi-cho There was no significant discussion about Ibiden's research activities or the reasons for doing so either now or in the future. The initial portion of the presentation was on general information about the entire corporation. During the course of this, several samples of C/Cs were displayed but the quality was not good, as the yarn spacing was 8 to 10 mm apart and the density was about 1.7 g/cc. The pieces were cubes with a dimension of about 100 mm. To densify the material, pitch was forced into the preform at 4,300 psi and the temperature was raised to 1,000 °C. No physical properties of this material were given. From the discussion it was apparent that Ibiden was aware that Background The discussion then centered on the characterization and interpretation of the data. The samples are only examined by optical microscopy methods at magnifications between 10X and 100X. Essentially, they are looking for gross cracks between the yarns and in the matrix. No higher magnifications are being used, even though they believe the matrix microstructure has an influence on the physical properties of C/Cs. Ibiden's primary concern about physical properties of C/Cs is that the bending strength and thermal conductivity values be as high as possible. No explanation was given as to the rationale for these choices, and it is not clear from the information what the applications might be. No mention was made of thermal expansion, modulus, fatigue, or creep. The development of C/Cs is being conducted by four researchers. No government funds are being sought so their technological advances can be held by the company. No laboratory tour or description was offered. Assessment Compared to the previous site visits, this one was disappointing. Judging by what I observed, Ibiden C/C technology is not current with companies in Japan or in other places of the world. It is recommended that no further efforts be expended on this organization in the future. MITSUBISHI HEAVY Nagoya Aerospace Systems Date: 25 Jan 1991 This visit was hosted by Yasuhiro Yamaguchi, manager of the Chemical Research Section of the Engineering Research Department. In addition, there was a manager from the advanced composites development team and a senior engineer from the Structure Designing Section of the Aircraft Engineering Department. The total number of attendees at this meeting was eight. Studies concerning C/Cs have been going on since 1985. Although not specifically stated at this meeting, MHI, along with other big corporations like Mitsubishi Chemical, has a large effort to develop C/Cs for the Japanese space plane that is being partially supported by MITI. In addition, C/Cs are being designed and fabricated for rocket engines in launch vehicles. A tour of the resin matrix fabrication and processing facilities clearly indicated that all types and shapes of carbon reinforced plastic composites can be made. A type of winding equipment was installed in June 1990 that is capable of winding, with 3-inch-wide tape, a whole aircraft wing to a thickness of 112 plies (15.5 mm). There are hot presses and autoclaves that operate at 400 °C and 300 psi for processing whole aircraft wing sections as the largest autoclave is 18 feet in diameter and can take pieces 51 feet long. Apparently, these facilities are being used for the fabrication of various shapes of C/Cs. For example, I was shown a portion of a leading edge section for a wing that was similar in shape to that of the U.S. space shuttle. However, the flange thicknesses in it appeared to be thinner (3 mm) and the yarn layups were straighter and more evenly spaced. Also shown was a thin C/C, SiC coated, flat panel, 1 by 2 feet, with an integrally woven rib that was also 3 mm thick. Apparently, the expertise that has been gained in fabricating resin matrix composites is being used to make excellent prototype C/Cs. The carbon effort at MHI is reported to be four to six staff and five support persons and the R&D has been going on for about 5 years. It is expected, based on other information that was obtained elsewhere, the C/C efforts will continue here for at least another 7 to 8 years. Program Status The discussion was very directed by the MHI representatives towards trying to get answers to specific questions, such as which type of architecture was better--2D, 3D, or some other architecture? Or, what were the shear properties of the U.S. space shuttle C/Cs? But the MHI group was reticent to provide any specifics about its programs or the research in connection with C/Cs. However, as the discussion went on, some information was obtained about its 2D C/Cs. They are fabricated by stacking layers of carbon/graphite cloth that has been prepregged, cured, and polymerized in the usual manner. After the preform has been carbonized to 1,000 °C, it is reimpregnated with furfuryl alcohol five to seven times and carbonized after each impregnation. At some point of the densification process, there is at least one graphitization step at 2,500 °C. The final density of the C/C is about 1.7 g/cc, which is typical for this type of material. Pitchbased fibers are used and the bending strengths of the C/Cs are around 20 to 30 kpsi. Again, these numbers are comparable to similar types of C/Cs that are produced elsewhere. Apparently, the quality of these current C/Cs is evaluated by the usual mechanical testing procedures and optical and SEM microstructural observations. However, the discussions would indicate that MHI is not yet sensitive to the importance and the influence of the matrix microstructure and the types of fiber-to-matrix bonds on the performance of C/Cs. They do find that graphitization does increase the modulus, lower the tensile and compressive strengths, and increase the by better communication and coordistrain values. nation between the other large corporations that MITI has formed into different consortia. There probably is a great deal of developmental information available here. How much research there is that is not connected to immediate problems is not clear. MHI says that collaboration is possible with organizations in the United States. Before this can be defined, communications between us need to be improved. I think this can be achieved judging from how relatively open this meeting ended after a very guarded start. MHI has been performing research studies for the past 10 years on approaches toward resisting the oxidation effects on C/Cs. They have been involved in two different methods of applying SiC coatings to C/C substrates. MHI finds that the conversion of silicon oxide to the carbide forms a better bond. But, vapor depositing silicon carbide provides better protection. In each case the layers are "200 microns thick. They are also trying the combination of conversion and vapor deposition methods to form a protective coating. Then on top of this a thin layer of a high melting point metal such as Hf, Zr, or Ir is deposited. Other types of refractory metal layers are being tried. This work is just starting and the goal is to provide protection to 2,000 °C. Thermal cycling between 22 and 1,700 °C is being included as part of the evaluation procedures of the coatings. No data were provided concerning any GIRI KYUSHU portion of the oxidation investigations. Assessment The recommendation is that MHI is an organization with which communications should be continued and perhaps some sort of a cooperative program should be established. Another advantage of establishing a link is that this organization is in the center of the big initiative that MITI is supporting with respect to C/Cs. Shuku-machi It is very evident that this corpo- The host for this site visit was Dr. Minoru Nakamizo, who is the Director General of this facility. A general review of the activities here was presented. Approximately 25 joint projects are conducted each year with industrial and other GIRI organizations but practically none with universities, due to the fact that the GIRI funds come from MITI and not from the Ministry of MITI and not from the Ministry of Education. There are approximately 70 research personnel at this site, of which 40% have Ph.D. degrees, and there are only 20 support persons, including secretaries. As has been mentioned before, the researchers must do practically all of their own equipment building, data collecting, analysis, and writing of the papers and reports. In addition, it is difficult to hire young persons because the salaries and laboratory facilities are so much better in the industrial sector. The plus side is that the researcher is allowed a lot more freedom in conducting his investigations than would be possible in industry. However, all directors of each GIRI organization have recently been informed that their staff must be cut back 5% each year for the next 5 years, which certainly limits the growth to practically zero, especially for the hiring of young people. The research in C/Cs started about 3 years ago, but work in the carbon area has been going on for more than 15 years under the direction of Dr. Yasuhiro Yamada with the support of three or more assistants. Other major areas of research include the development of new engineering materials, including porous metals and intermetallics; mineral processing; ceramics; processes for the reduction of environmental hazards; and other studies for the scale-up of processes that have been developed in the laboratory. Program Status The general theme of the research in carbon is to understand how the processing conditions influence the microstructure and how this, in turn, alters the physical properties of the materials that are being investigated. In this regard, fundamental studies on the mesophase state of the pitch have been underway for the past 6 or more years and will end in 1992. One of the most interesting results is the ability to form a matrix microstructure whose ab planes are oriented normal rather than parallel to the surface of the fiber. This means that the high strength direction of the graphitic structure of the matrix can be used to increase the transverse and shear strengths between fibers, normally the weak link. If a procedure |