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ASSESSMENT OF CARBON-CARBON COMPOSITE RESEARCH IN THE FAR EAST

Dr. Robert A. Meyer conducted this study for the Office of Naval
Research between December 1990 and March 1991. His trip to the Far

East included visits to six universities and seven research institutes in
Japan, Taiwan, China, Korea, Australia, and India. He also attended a
meeting of the China Association of Science and Technology in Beijing.
This report summarizes Dr. Meyer's observations and assessments from

his visits to these organizations and attendance at the meeting.

by Robert A. Meyer

INTRODUCTION

the processing and fabricating proce- composition ofthe C/Con its behavior.

dures in a step-by-step developmental Such information is derived from more The potential for utilizing carbon- manner from small laboratory size research activity so that further direccarbon composite (C/C) materials is samples to very large and full-scale tions for research and development large because of carbon's unique phys- hardware. In other situations, previous (R&D) and alternative processes can ical properties. For example, one form manufacturing experience is used to be defined for obtaining the desired of carbon is graphite, which has high modify an existing process by making properties in a more economical manner. specific strength and stiffness values at small incremental changes over an Unfortunately, the financial support temperatures in excess of 2,000 °C, zero extended period. With either approach, for C/C research efforts in the United or negative thermal expansion values the large pieces of hardware are very States has been steadily declining for between £200 °C, and low outgassing costly because of the materials they the past 8 or more years. This means characteristics. Thus, C/Cs, which contain and the months of time it takes the enhancement of C/Cproperties has contain large portions of graphite, are to fabricate them. Obviously, failure to and does occur in a limited way by an excellent material for space appli- properly make one of these pieces or to gradually changing current processing cations. Another advantage of using have it “destruct” during its operation conditions using one of the two glas is the ability to change the material's is unacceptable. Some of these failures approaches already described. Another physical properties by altering the type have been attributed, in part, to a lack impact of using these approaches is and distribution of yarns and to vary of knowledge. Either the material's true that of not having available sufficient the microstructure of the matrix that physical properties were not used for research information to improve the exists within and between these yarns. defining the design criteria or the most possibilities that unique, original, and This ability to fabricate composites with important parameters for the control significantly large advances can be made. different types of characteristics ena- of the process were not identified to This also means the technology that is bles the designer to select and obtain insure the desired physical properties currently being used is derived from the proper type of material that will and high degree of reproducibility research data that were probably withstand specific adverse environments. from piece to piece. Furthermore, the obtained 5 or more years ago.

The United States has been very need for improved processing control If this situation continues to exist, successful in translating engineering is becoming more critical because the the lack of research information will requirements and process "know-how” C/Cs are now required to function under eventually limit the ability of the United into C/Cs with good operating charac- more severe operating conditions. As States to develop improved C/Cs, not teristics. But this success is costly. In these requirements become more only for our use but in competition some cases, the improvements are extreme, it is necessary to have a better with foreign countries. The questions accomplished by means of scaling up understanding of the influence of the that naturally arise are: What should be done? and is the United States ahead, readily made of the research efforts as be included that are concerned with equal, or behind other countries in its well as the types of organizations that oxidation resistance efforts as they are research capabilities and knowledge for are sponsoring the research either within applied to C/Cs. developing advanced C/Cs in a timely or between countries. manner? This assessment study and The process used for selecting the REPORTING FORMAT interpretive report is being undertaken organizations consisted of reviewing for the purpose of providing informa- the literature and then seeking the advice A specific format is used for pretion to be used in answering these of senior research persons who have senting the information that is obtained questions and to assist in formulating had interactions with the researchers from each organization to provide as future program plans for research efforts from each of the organizations that uniform and complete information as in this field.

were being be considered. The other possible so that comparisons can be

factors that were important include the made between them. The format is OBJECTIVE

organization's overall research reputa- divided into three sections: Background,

tion, the staff, past and present publi- Program Status, and Assessment. The The overall objective of this survey cations, activities in professional meet- Background section is to acquaint the is to evaluate the current status and to ings, and the expectation that these reader with the past and current thrusts estimate the future directions of foreign trends will continue in the future. of the organization and who the priresearch efforts that are being conducted The type of information that was mary research leaders are in the orgain the area pertaining to carbon-carbon sought from each organization had three nization. It is hoped this information composite materials and related tech- purposes. The first was to determine will enable the reader to understand nologies. Based on this evaluation, a the significant directions and unique some of the reasons for the existence of general assessment will then be pre- research results. This information was the various types of research programs pared concerning the expected impact used to evaluate the research capabili- that are being conducted at each site. that these foreign activities could have ties of the organization and to inform The Program Status section conon the research and development capa- the reader of the types of research being tains information about the current bilities of the United States for produc- conducted so that more in-depth com- activities of each organization. In paring advanced C/Cs in the long term. munications could be conducted if so ticular, unique results or experimental

desired. The second objective was to approaches will be cited as well as a APPROACH

understand what the organization's synthesis of the relevant discussions.

future research goals will be based on The technical depth of the discussions The major thrust in gathering infor- its interests and the types of persons with the individual investigators will mation for this report was directed that are expected to be there. The third depend on the availability of the investowards those areas of research that objective was to evaluate the degree of tigators' time as well as the number of are considered to have the greatest collaboration each organization would activities that are to be discussed in the potential impact for improving the be willing to undertake with organiza- allotted time for each site visit. performance of C/Cs. This means first tions in the United States. The term The third part is the Assessment priority was given to the areas of fibers, “collaboration” is purposefully not section. In it the research capabilities their architecture in woven forms, specifically defined so a variety of def- of each organization will be discussed processing and densification methods, initions are possible, such as just an in terms of its current and possible the influence of matrix microstructure exchange of research thoughts, or a future contributions to the field of to physical properties, bonding phe- foreign country's support of its stu- C/Cs and related technology. The posnomena, and characterization meth- dents/professors at U.S. universities, sible impact of these capabilities on the ods. Other interesting areas of research or perhaps complementary research that Department of Defense's (DOD) C/C activity were also included when it was could be undertaken on an interna- and technology research programs will possible. tional basis.

also be included as well as the possiThis survey is organized into two Some information is also included bilities and advantages of using the major categories: (1) the country where in this report about important areas of visited organizations' strong points to the research organization is located technology that are of secondary inter- augment the DOD's own technical capaand (2) whether each organization is est relative to the objectives of this bilities through international cooperadirectly supported by a university, the study but that were discussed during tion programs. government, or industry. This cate- the course of the investigators' presengorization permits comparisons to be tations. For example, comments will

MUSASHI INSTITUTE OF Program Status

are being conducted using annealing TECHNOLOGY

temperatures between 700 and 1,000 °C.

A current area of research interest The current data indicate that the Carbon Research Laboratory

is the electrical properties of pure car- changes to the electrical characterisDept. of Physics

bonaceous systems. The samples are tics of the samples are due to the scat1-28-1 Tamazutsumi

rather unique in that they are derived tering of electrons by interstitial carSetagaya-ku, Tokyo 192, Japan by the pyrolysis of scotch tape where bon atoms that have been displaced Tel: (03) 703-3111

the heating rate is 400 °C per hour to a from their normal positions in the crysDate: 6 Dec 1990

maximum temperature of 1,000 °C. This tal structure by the reactor neutrons.

method produces a very thin film of Apparently, the electrical resistance and Background

pure carbon upon which four very thin magnetic resistance measurement tech

electrical leads are fastened to it by a niques are sufficiently sensitive to detect The host for this site visit was Prof. gold film derived from a suspension of 20% changes in values with only a Yoshihiro Hishiyama, who is in charge gold particles in a solvent that is evap- small amount of reactor exposure on of the Carbon Research Laboratory in orated, at room temperature, after it is the order of 1 million neutrons per the Physics Department at this insti- applied at the junction of the wire and square centimeter. tute. Hishiyama has been here for more the sample.

The laboratory capabilities at this than 26 years and is a senior staff member. Another area of research is the institute are very adequate to support The institute was started as an engineer- characterization of the crystalline struc- the carbon research that is being coning school about 40 years ago when the ture by advanced scanning electron ducted. Most of the high precision and Japanese Government expanded its microscopy (SEM) methods where low sophisticated electrical characterization educational program beyond the voltages of 1 kV are used with a new equipment is in Hishiyama's laboranational university system that had been method of electron detection using a tory. This includes two pieces of magin existence before World War II. The lens field emission electron gun that netic resistance equipment that operinstitute is privately funded and has has a resolution capability down to 3 nm ate between 1.2 and 300 K in a field of more than 4,000 students, of which 200 rather than the current value of 10 nm 1 T (11 kG/cm2). This magnetic field are graduate students.

that is attained at 10 kV with today's strength can be increased by more than Hishiyama's primary area of research technology. The use of the lower voltage sixfold using superconducting magnets. is in the solid state physics of carbon has the added advantage that the incident In addition to the measuring equipand, in particular, the electrical char- electrons do not penetrate as much ment, there is a capability to heat treat acteristics of carbon as determined by into the sample and therefore provide samples to more than 2,900 °C in a its structure from <1.2 Kto >2,600 K. a more accurate representation of the graphitization furnace that is now in His group consists of an associate pro- sample's topography. Between the better the process of being reactivated. To fessor, four graduate students, and six resolution power and the fidelity of better understand the physics of these part-time undergraduate students. depicting the surfaces, there is a great carbonaceous materials, some samples Hishiyama is considered to be Japan's deal more information available about are prepared and measured with the best researcher in the field of magneto- the microstructure and its changes with intent of having the highest degree of resistance and in the definition of the processing conditions. This type of perfection of the graphite crystal struccrystalline structure of carbonaceous information is most valuable in ture within them. Consequently, these systems through the use of electron furthering the understanding about the samples can be as small as 2x3x0.5 mm microscopic techniques. He also uses microfracturing behavior of these because the grain size is small even other electrical characterization tech- crystallites.

with some of the largest crystals of niques such as measuring the Hall Another investigation is concerned graphite that are available. These have coefficient, resistance, and thermoelec- with the effects of heat treatment tem- been derived from a special supply of tric power to help define the structure. peratures on the electrical properties Kische metal that Hishiyama obtained

Hishiyama was a postdoctoral fel- of neutron irradiated graphite crystals. many years ago. In spite of the very low at the University of Buffalo for The sample sizes are about 2 x 4 x 20 mm small sizes, the samples are cut and over a year in the mid-1960s under the and these samples contain grain sizes shaped with dental tools so that they direction of Prof. S. Mrozowski. It was between 10 and 1,000 Å In these studies have uniform cross sections and here that Hishiyama started his studies it is assumed that the grain size distri- thicknesses as well as four tabs so that in magnetoresistivity and was the first butions are similar among all the sam- wires can be fastened to them with in Japan to conduct such research. ples that were measured. These studies which to make voltage and current measurements. Obviously, great care result, companies will acquire equipment Physics and Chemistry of Carbons, which must be taken in shaping each sample, and train their own people without is edited by Prof. Thrower of not only because of its small size but seeking the assistance of experts at the Pennsylvania State University. because of the very limited supply of universities just so no one outside the To my knowledge there is no one in the raw material. Therefore, Hishiyama company will know that this particular the United States who is now conductis the only person that prepares these capability exists in the company. An ing the type and depth of research that types of samples.

example of this scenario was cited by is being performed by Hishiyama. A centralized laboratory facility also Hishiyama. He is recognized by the Therefore, it is considered important exists at this institute that provides research community as the expert in that continued awareness be maintained special types of analytical equipment Japan in the field of magnetic resis- of his work. If possible, it is recomthat are very costly and would be diffi- tance measurements and has been in mended that some sort of cooperative cult to obtain and fully utilize, on a cost this field more than 25 years. Further- research be initiated with this group effective basis, by any single depart. more, he has presented his findings at which, according to Hishiyama, would ment. In this manner, individual inves- national and international meetings be welcomed. One suggestion of a tigators have available to them special throughout these many years. Yet, possible area might be to investigate capabilities when they are needed and Hishiyama only found out, inadvertently, the potential of using electrical meapay only for the amount of service that about a year ago that magnetic resis- surements to characterize the microis rendered. In addition, this facility is tance research capabilities have been structures of graphites and carbonstaffed with specially trained operators developed and have been used for carbon composites for the purpose of who operate the equipment, prepare product development in many of the developing their optimum properties samples, and analyze the data. These large industrial research laboratories as is being done in Russia. The U.S. persons are usually undergraduate or for the past 8 years.

contribution could be to evaluate the graduate students. Apparently, this

applicability of this fundamental informethod of operation is effective because Assessment

mation for R&D purposes. in the 8 years of its operation, this central facility laboratory has never had an Prof. Hishiyama is clearly devoted TOHO RAYON accident or lost a piece of equipment to research in the solid state physics of COMPANY, LTD. due to faulty operating methods. The carbonaceous materials. His interests whole spectrum of equipment includes and the direction of his laboratory Mishima Plant a 60-kV, 18-kWxray; numerous SEMs, programs are to understand the causes 234 Kamitogari, Nagaizumi-cho including one with the most recently of the changes to the electrical proper- Sunto-gun, Shizuoka 411, Japan available new high resolution features; ties of these materials. In the pursuit of Tel: (0559) 86-1200 infrared (IR) spectrometers; ultraviolet this goal he is also interested in devel- Fax: (0559) 86-2302 (UV) spectrometers; transmission elec- oping and perfecting laboratory tech- Date: 12 Dec 1990 tron spectrometers (TEMs); along with niques and equipment that will aid in other analytical tools and the appro- acquiring more information about the Background priate data processing capabilities. This structure of these carbonaceous mateapproach of having a central facility rials. It is expected that this general My host was Kozo Tanaka, who is for first rate equipment is a partial program will continue in the future in the director and general manager of answer by the university to the these directions at least for another the entire Mishima Plant. competition that exists between the

15 years or so until Hishiyama retires. Toho was started in 1934 as a prouniversities and the big industrial Hishiyama's research work is known ducer of acrylic fibers for textile manucorporations that have available the and respected throughout the world. facturers, and today they are still the most up-to-date facilities.

In fact, he is currently a member of the major customer. However, Toho has In discussions with Hishiyama, some French and Japanese cooperative pro- enlarged its product line. In 1968 the further insight was obtained about the gram that is conducting a research study rayon base fiber development program limited amount of communication that on the development of carbonaceous was initiated; in 1971 the pilot plant can exist between universities and indus- microstructure and its influence on was started, and these fibers with high trial organizations in Japan. This seems physical properties. He is also a coauthor strength and strain properties were to be the result of fierce competition of a chapter in this same area of research available as a commercial product in within the industrial community. As a for the next addition of the series titled 1975. Now prepregs are available for organic and carbon matrix composites Japan are limited because of the fierce brakes, because of its desire to enter and for the densification and produc- competition between corporations and this field and because the Japanese feel tion of composites, including C/Cs. The the laws that exist as to how financial the United States is the leader in production rates are 4,000 tons/mo for support is to be given to the university engineering and producing C/Cs on a acrylic and rayon fibers, 170 tons/mo system. Toho appears to have very large scale. for carbon fibers, and 4,000 tons last limited interactions with the carbon year for all the fibers that were pro- community. The only organization of Program Status duced. It was also stated that Toho is which it is an active member is the New the largest producer of fibers in Japan, Carbon Forum. This forum is supported Toho's overall approach toward with a total capacity of 10,000 tons/yr. by over 30 of the largest industrial research is to develop new products or Toho weaves about 5,000 m2/mo and organizations in Japan. Its purpose is to increase the reliability and producprepregs 200,000 m2/mo of unidirec

to determine applications of carbon tion capability of existing products. tional, roving, and fabric materials. systems in all areas of technology, i.e., There are two laboratory organizations The company has about 2,000 aerospace and aeronautics, biology, in the company. The Mishima Plant employees, of which 25% percent are construction, medicine, power, etc. This consists of about 60 members, of which at this Mishima site. In this plant all is a very active and costly operation 20 have Ph.D. or master's degrees, 20 portions of the fabrication process are that conducts studies and seminars, have bachelor degrees, and the rest are performed, from manufacturing of the reports on new possible areas, pro

reports on new possible areas, pro- technicians and support people. fibers and precursors for densification, vides translations, etc. The forum is The general method that is used for to weaving of the preforms, to divided into many committees and the development of a new area, such as impregnation and final heat treatment subcommittees that meet in some form a fiber or an impregnant, is the steps.

or other on a monthly basis in a partic- “Edisonian” approach. This means very General business objectives are to ular area. There is no equivalent orga- small changes are very carefully made market the company's products world nization in the United States where to the particular process being studied wide. To do this, Toho licenses and has information is exchanged so frequently and its effects are observed in the smallest cooperative agreements with organi- and in such a broad and in-depth basis. detail. In this manner, the variations or zations in different parts of the world, Government financial support is not "causes” due to any changes to the such as NARMCO in the United States, actively sought by Toho because the process are understood as an “effect" which buys Toho's prepreg, and BASF acquisition of this type of money is on the product even though the precise in Germany, where there is a joint unpredictable and is of a short term phenomenology is not understood. venture concerning fibers and prepreg. nature of only a few years. Also, it Fundamental research directions are Toho is continually trying to expand its means a lot of the technology that was used occasionally if they have the potenworldwide market and considers obtained with corporate funds must be tial of resulting in the development of Hercules and Amoco to be its main revealed if support is received from advanced products. competitors outside of Japan and Toray the Government.

Sometimes employers support their to be the major one in Japan. Some of Cooperative programs between employees who are students at the the areas that utilize carbon fibers companies rarely occur; if they do, they universities where they perform fundainclude low inertia rollers, high speed are usually between subsidiaries within mental research studies that have a spinning pots, bicycles, prestressed the same corporation or as part of a corporate goal. More often, the corpoconcrete for buildings and bridges, consortium that has been formed to ration gives the universities money for nickel-coated fibers for electrical obtain government funds. This same the general support of students that magnetic shielding for laboratories and attitude also exists relative to coopera- are studying under a particular protesting rooms and, of course, sports- tive programs with organizations from fessor or in a department where the wear. The primary market that is now other countries. At this time, there is corporation is interested in acquiring being targeted is the aerospace and no real interest in cooperative pro- first class students. Then, the corporaaeronautical industry, especially in the grams with organizations in the United tion expects to be given a “preferenUnited States, where Boeing is consid- States in the area of carbon fibers tial” choice in obtaining the best stuered the largest user of carbon fibers. because Toho believes it has more dents. This method of operation is utiToho is actively preparing for the information in this area than anyone lized because the supply of well trained future needs of the automotive industry. else so there is nothing to exchange. Its and qualified students is less than the

Communication and interactions attitude is different with respect to demand. This system is particularly between industrial organizations in C/Cs, especially concerning aircraft effective as, generally, all the

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