This paper provides a historical review of the development and the present status of HIP technology, as well as a look at future directions. Thanks to the unique effect of the simultaneous application of isostatic pressure and temperature, a variety of value-added matreials and machinery parts have been developed for commercial use over the past twenty years. As the appli-cation fields have expanded, the HIP apparatus has also been improved to reduce operational costs. Its success in this area has made Japan one of the leading countries in the world. It is expected that the present basic research on HIP processing in various areas will lead to new developments in HIP technology in the near future.
Magnetic head requires high density ferrite. Among various methods, hot isostatic pressing or HIP is most suitable one for the densification of ferrite, especially Mn-Zn ferrite. Like many other ceramics, in most cases, presintered ferrite block is HIP'ed without capsule. Crucial issues for ferrite are heating/cooling speed and atmosphere control. Atmosphere at HIP is controlled by ferrite powder, in which presintered ferrite block is embeded. Otherwise, Oxygen containing Argon gas is used as pressure/heat medium instead of pure Argon.
This paper provides an overview of the method of hot isostatic pressure treatment of lead-zirconate-titanate (PZT) and lead-lanthanum-zirconate-titanate (PLZT) ceramics. Densified PZT ceramics are useful for miniaturized electronic components. PLZT ceramics sintered by HIP exhibit a high transmittance spectrum without serious growth of crystal grains. These microscopically uniform PLZT ceramics are a response to demands for good machinability, and will be the best candidate for optical micro-shutters for electrophotographic printers, in which switching time in micro-seconds is required.
A variety of new material processing techniques have been developed by combining Self-prop-agating High-temperature Synthesis (SHS) with HIP technology. SHS/HIP nitriding makes it possible to produce unique complex powders, such as Si3N4-SiC and NbN1-xCx, or nitrided Ti and Nb components. SHS/HIP sintering can be used to fabricate new composites such as functionally gradient materials. SHS/HIP casting completes the sysnthesis and simultaneously forms the NiAl intermetallic. Accompanied by chemical heats of 2000 K or more, these processes can be completed within instants. This paper reviews recent developments in the SHS/HIP process and the resulting materials.
A sintering and infiltration technique to manufacture functionally gradient materials has been developed. This technique consists of two steps and is suitable for manufacturing a tungsten (W) /copper (Cu) gradient material. The first step is to make a sintered tungsten with the gradient pore distribution. The second step is to infiltrate a molten copper into the pores. In this technique, capsule-free HIP (Hot Isostatic Pressing) treatment is effectively used for fully densifying the surface tungsten layer and for eliminating only closed pores in the other layers. Capsule HIP treatment is effective to fully infiltrate a molten copper into open pores of the sintered tungsten. The tungsten/copper gradient material has an excellent ability to reduce thermal stress and has good thermal conductivity from the tungsten layer to the copper. It is because of continuous microstructure change from one layer to another. The results of heating tests using electron beam irradiation equipment successfully showed that the tungsten/copper gradient materials can endure a stationary heat flux of up to 15 MW/m2, which is necessary for divertor plate as a plasma facing component in the ITER (International Thermonuclear Experimental Reactor).
Applications of diffusion bonding for various metal composite products using Hot Isostatic Pressing (HIP) technology are introduced. Metal composite products with complex shapes by HIP have improved wear and corrosion resistance and have succeeded in saving manufacturing cost.
The applications of high pressure technology to oxide superconductors are reviewed. These applications can be classified into three categories: controlling the superconducting properties, investigating superconducting mechanisms, and producing new superconducting materials. Examples of each category are discussed. High pressure is considered to be useful means for the investigation of oxide semiconductors.
Recently, the demand for drills for printed circuit boards (PCB-drills) has increased with the growth of the electronics industry. WC-Co alloys with relatively fine grain size have been put to industrial use, but the drills are now required to have more and more excellent wear and breaking resistance, as PCB has come to have a higher density. For that reason, micro-grained cemented carbide has become to be of great importance. In such circumstances, new micro-grained grades (MD10, MD20 and MD30) specially designed for PCB-drills have been developed, and the mass production of PCB-drill blanks having a stable high quality and reliability has been available through the use of a continuous Sinter-HIP equipment.
As the applications of HIP have expanded, demands for its new abilities have also increased. And, to meet those demands, various equipment has been developed in the past twenty years. Today, the maximum temperature reaches 3000°C, the pressure ranges from 300 Pa to 980 MPa, and the pressure medium gas can be nitrogen, argon, or argon with oxygen depending on the materials treated. Moreover, various HIP systems have been developed to improve productivity or to reduce process costs, such as pre-heating-systems, or rapid cooling HIP systems, the “Sinter+HIP” system. This paper describes these trends in HIP equipment and systems.
This article reviews a new quantum mechanical conception of high pressure and some applications in solids, as one of recent developments in marionics. A new force operator in quantum mechanics, which is proposed by the author, is obtained from differentiating of momentum expectation of a quantum particle by time. When this quantum operator is worked to the wavefunctions, the force expectation values, which is called "marion force" after the marionics, can be obtained. The average pressure from this marion force is considered as the new concept of presseure due to the electron momenta in solids. This pressure is in good agreement with the virial pressure which is obtained thermodynamically from average energy of free electron solids. Marionics, which is also new idea of a industrial quantum mechanics or a quantum materials dynamics (QMD), is briefly introduced.
The first study of shock very high pressure in Japan started at Defense Academy of Japan in the latter half of 1950. About 1970, there was a movement to establish National Very High Pressure Laboratory, which ended unsuccessful. Science and Technology Agency, however, performed research and development on shock very high presuure as a project in 1972-75 and 1977-79. The project was the start to introduce a remarkable progress in shock experiment technology in Japan.
In the course of law suits for its possible infringement on GE's patents, another inspection was taken at Komatsu's Hiratsuka plant in March 1967 and proved this time that theyapparatus in question were capable of producing diamond. GE's cause was rejected in 1975 by the Tokyo District court; the 15 years of litigation came to an end when the High Court, after five more years of examination, rejected GE's appeal in 1980 and the latter decided not to appeal to the Supreme Court.
Recent development of the diamond-anvil-cell technology has made it possible to generate ultrahigh pressures exceeding 100GPa with the use of the beveled diamond anvils. Since the sample size for such studies decreases to about 50μm, it requires special devices and techniques for the sample preparation like a microdrilling machine.