Korea Institute of Machinery & Materials

Hai-Doo Kim

Young-Wook Kim

In-Hyuck Song

Shin-Han Kim

Kyu Hwan Lee

Dong-Soo Park

Jae-Woong Ko

Do-Kyung Kim

Jung-Yeul Yun

Hyung-Sik Chung

Chul Bum Park

Sang Ro Lee

Yoo-Dong Hahn

Yongsoo Jeong

Doyon Chang

Chul-B Park

Jaimoo Yoo

Disclosed herein are a highly porous ceramic having a high porosity of not less than 60% and a pore density of not less than 10pores/cmfabricated from expandable microspheres and a preceramic polymer, and a method for fabricating highly porous ceramic. The method for fabricating highly porous ceramic from expandable microspheres and a preceramic polymer comprises the steps of: homogeneously mixing a preceramic polymer powder and expandable hollow microspheres, if necessary, a ceramic powder, and molding the mixture to form a molded body; heating the molded body to expand it; curing the expanded molded body; and pyrolyzing the cured molded body. Since the highly porous ceramic has a higher porosity and pore density than conventional porous ceramics, it can be suitably used for various high temperature structure materials, kiln furniture, bulletproof materials, shock-absorbing materials, insulating materials, refractory materials, lightweight structure materials, etc.

Highly porous ceramics fabricated from preceramic polymer and expandable microspheres, and method for fabricating the same

Microporous ceramic materials used in structural materials, high-temperature filters, electrode materials or preform materials for infiltration by homogeneously mixing and molding a ceramic precursor powder polymer. The powder is saturated by introducing fluid to a pressure vessel. The fluid is super saturated by adjusting pressure in the vessel. Micropores are formed in the molded bodies by evolving the fluid from the molded bodies by heating and hardening the molded bodies. The hardened molded bodies are heated to pyrolysis. Pore characteristics (e.g., pore size and pore size distribution) suitable to target materials are controlled by adjusting pressure at a non-critical state without requiring additional processes or devices.

Microporous ceramic materials and the producing method of the same

A porous molybdenum disilicide-based material prepared by preheating a preform consisting of size-controlled molybdenum (Mo) powder and content-controlled silicon (Si) powder and igniting the preform to initiate self-propagating high temperature synthesis, and a method for preparing the same, are disclosed. The method comprises the steps of a) mixing molybdenum (Mo) powder and silicon (Si) powder in the stoichiometric ratio of 1:2; b) molding the mixed powder into a preform; c) preheating the preform under inert atmosphere; and d) igniting the top end of the preheated perform. The porous molybdenum disilicide-based material can control its pore size by appropriately controlling the size of molybdenum (Mo) powder, the content of silicon (Si) powder and preheating condition. Therefore, since the pore size gradient of the porous material is possible to form, the porous material can be used for filters with improved dirt-holding capacity.

Porous molybdenum disilicide-based material prepared by self-propagating high temperature synthesis process, and method for preparing the same

Disclosed are composition and a method for making a high volume reinforced Al composite by use of a dipping process. Through the method comprising mixing 20-50 wt % of exothermic reaction-causing Ti and C or Ti and B powders, 20-60 wt % of exothermic reaction-controlling diluent powders, and 5-30 wt % of infiltration-aiding Al or Al alloy powders, then preparing mixture powders; preforming the mixture powders into a predetermined shape; fitting the preformed body in a reaction container, followed by dipping in an Al melt of 700-1,100&deg; C.; and separating the synthesized composite from the reaction container after removal from the Al melt, a high volume reinforced Al composite can be prepared from the mixture powders through such exothermic synthesis in a metal melt that reinforced particles are uniformly distributed while restraining the generation of pores. As such, the exothermic reaction-controlling diluent powders are selected from the group consisting of TiC, TiB , SiC, WC or mixtures thereof.

Method for making high volume reinforced aluminum composite by use of dipping process

Disclosed is an Ni-plated layer of biaxial texture, which is formed by electroplating. In the Ni-plated layer,peaks measured on a &thgr;-rocking curve have a FWHM of 7&deg; or less in terms of the misorientation on the c-axis; and peaks measured on &phgr;-scan have a FWHM of 21&deg; or less in terms of the misorientation on the plane formed by the a-axis and the b-axis. Also, a process of electroplating a Ni layer are disclosed. The process comprises forming a Ni-plated layer of biaxial texture under a magnetic field by electroplating and subjecting the Ni-plated layer to thermal treatment to develop the biaxial texture. This electroplating process is expected to give a significant contribution to the development of the electroplating technology and to replace the vacuum deposition used for the preparation of thin film magnetic materials or thin film piezoelectric materials.

Electroplating process for preparing a Ni layer of biaxial texture

An electrical discharge machinable MgO-Partially Stabilized Zirconia (PSZ) and titanium di-boride (TiB.sub.2) ceramic composite body of good mechanical properties and the method of making it are disclosed. The ceramic composite comprising less than 40% by weight of TiB.sub.2 balanced by 10 mole % of MgO-Partially Stabilized Zirconia is fully densified by pressureless sintering at 1850.degree. C.-1900.degree. C. and exhibits the fracture toughness (K.sub.IC) value of 8-11 MPa.multidot.m.sup.1/2 measured according to the indentation crack length method and Evans-Charles' method provided in Journal of the American Ceramic Society volume 59 �7-8!, 371-372 (1976) after annealing at 1320.degree.-1400.degree. C.

Electrical discharge machinable MG-PSZ/TIB2 ceramic composite

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Kyungsangnam-do, South Korea

Hai-Doo Kim