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The injection molding of Cu powder by four kinds of binder systems(A, B, C, D) was investigated. The binder system(A) consisted of special-acrylate copolymer(AC), atactic polypropylene(APP), paraffin wax(Wax), and di-n-butyl phthalate(DBP); (B) consisted of ethylene-vinylacetate copolymer(EVA), polybutylmethacrylate(PBMA), Wax and DBP; (C) consisted of polyethylene(PE), special-polyvinylalcohol copolymer, Wax and stearic acid (St); (D) consisted of polystyrene(PS), PBMA, APP, Wax and DBP. The green body buried in sand was debinded during heating from room temperature to 300(B) or 320°C(A, C, D) in the air. The debinded part was sintered at 950(A), 970 and 1020°C(B, C, D) in H2 and Ar gas. The sintered part used the binder system(A) and the sintered part at 1020°C used the binder systems(B, D) had a relative density of over 95%. The density of sintered part relates to debinding process. The sintered part used the binder system(A) showed tensile strength of 28.27kgf/mm2, elongation of 48.5%.

The molding of calcium phosphate compound was tried using injection molding of ceramics powder. The composition changes and the physical properties of the sintered product in calcium phosphate compounds were discussed. Rod like test-piece(φ6×501)was produced by the injection molding with two compounds : (A) calcium secondary phosphate and several organic binders ; (B) calcium secondary phosphate, calcium carbonate and several organic bainders.After the binder extraction process, the test-pieces of Wand(B) were heated up to 1000°C-1300°C at the rate of 100°C of a hour. As the results of sintered process, it was found onthe basis of x-ray diffraction that (A) consists of calcium pyrophosphoric acidand calcium tertiary phosphate, whereas it was found on the basis of it that (B) consists of hydroxylapatite and calcium oxide.

For the injection molding of metallic powder, the binder which consists of polystylene, polybutyl-methacrylate, wax, and stearic acid was used. When the molding compound was injected in the mold, wax was separated from the other binder. To prevent the separation of wax, the addition of APP(atactic polypropyrene) was very effective. Because APP has good compatibility with other polymers, APP plays a roll to bind wax with other binder. The effect of the addition of APP varied with the ratio of APP and wax, how much molecular weight APP has, and what structure APP has. The green part was debinded by the thermal way, heating from room temperature to 320°C in the air for 49 hours. The debinded part was sintered at 1320°C under a vacuum of 10 ?? Torr for 2 hours. The sintered part has a relative density of 95-96%. A little decrease of Cr was caused by this debinded and sintered process. But after the surface protection was given, it doesn't matter to the corrosion resistance.

The injection molding of S-50C powder(19.7μm in average diameter)was carried out with the SA(special-acrylate copolymer)-APP(atactic polypropyrene)-Wax binder system.S-50C powder was mixed with the binder at 140°C.The molding composition was 54.2%S-50C powder, 19.5%SA, 10.7%APP, 11.3%Wax and 4.3%dibutyl phthalate in volume.The green body was debinded during heating from room temperature to 320°C in the air.The debinded specimen was sintered at 1100 to 1220°C under vacuum of 10-4 Torr.The main results are summmarized as follows:1)This binder system has good mixing, molding and binder removal characteristics.2)A specimen sintered at 1220°C for 90min has a relative density of 92.2% and shows average tensile strength of 23.8Kg/mm23)Sintered specimen are observed decarburization from surface under vacuum sintering.

The Alumina powder mixed the each organic binder(A, B, C) were molded rod like test pieces by a screw injection-molding machine. The binder(A) consisted of polystylene (PS), polybutylmethacrylate(PBMA), stearic acid(St) and paraffin wax(WAX); (B) consisted of PS, PBMA, St, WAX and atactic polypropylene(APP); (C) consisted of PS, PBMA, St, APP. The test pieces which were made of the binder(B), (C) cracked easily during the debinding process, but those which was made of the binder(A) didn't crack. From the above fact, one of the reasons was shown that owing to the radical thermal decomposition of the APP at the about 200°C, the rate of debinding of the binder(B), (C) were rapider than that of binder(A). So that it was clear that the causing cracks within the test pieces resulted from the rising rate of debinding at about 200°C.

The injection molding of Ti powder(30μm in average diameter)was carried out with the PBMA(polybutyl-metacrylate)-EVA(etylene-vinyl acetate copolymer)-wax binder system. Ti powder was mixed with the binder at 140°C.The molding composition was 56%Ti powder, 17%PBMA, 21%(EVA+wax) and 6%dibutyl phthalate in volume. The green was debinded during heating from room temperature to 300°C in the air. The debinded specimen was sintered at 1100 and 1300°C under a vacuum of 10-2 Torr. The main results are summarized as follows:1)This binder system has good mixing, molding and binder removal characteristics.2)A specimen sintered at 1300°C for 2hr has a relative density of 94.0% and shows strength of 1000MPa.3)Sintered specimens are all fractured brittle.