Authors: Kyung Sik Oh, Soo Ryong Kim
Abstract: Effect of the starting compostion was studied in bone cement containg coarse b-tricalcium phosphate (b-TCP) granules which was very dense and round. With respect to the mixing ratio between b-tricalcium phosphate and monocalcium monophophate (T:M), the properties such as setting time, density and compressive strength were measured. The properties of bone cement prepared from normal powdery b-TCP was strongly dependent on the initial mixing ratio (T:M). Though the compressive strength as well as density was maximum at T:M = 6:4, small departure of compostions from T:M=6:4 resulted in drastic decrease of compresive strength. On the contrary, in the specimens from granular b-TCP, compressive strength was much less deependent on the initial mixing ratio. Range of optimum compressive strength covered from T:M=6:4 to 8:2. Therefore,
granular groups provided more degree of freedom to control other properties such as setting time while maintaing its compressive strength.
141
Authors: J.W. Paek, Beom Seob Kim, Deug Joong Kim
Abstract: Ceramic foams containing MoSi2 were prepared by a self-blowing process of poly-silsesquioxane with MoSi2 as filler. Ceramic foams prepared by polymer pyrolysis were composed of MoSi2 and silicon oxycarbide glass matrix. Densities, pore sizes and mechanical properties of ceramic foams were depended on the filler content and heating rate for curing of polymer. Depending on the foaming condition, ceramic foams with a density of 1.2∼0.4 and a compressive strength of 3∼30 MPa were obtained.
129
Authors: Joo Eon Park, Mitsugu Todo
Abstract: Novel reinforcements such as beam, film, and porous frame were developed to improve the mechanical properties of poly(L-lactide) (PLLA) scaffolds. A solid-liquid phase separation method was used to fabricate porous structures such as core portions and porous frame of reinforced scaffolds. The beam and film reinforcements were also fabricated from PLLA pellets by applying the thermal-press technique. In the standard scaffold, the localized deformation was characterized as buckling of the pore structures. On the contrary, the primary microstructural deformation mechanism in the beam and the film reinforced scaffolds was characterized as buckling deformation and interfacial failure of the matrix and the reinforcement respectively. It is also seen that the inner porous structure could maintain the initial structure without local buckling of the pore structure. The compressive mechanical properties of the reinforced scaffolds were dramatically improved by about 2 ~ 5 times compared to the standard scaffold.
303
Authors: Jun Li, Wen Jie Yuan, Cheng Ji Deng, Hong Xi Zhu
Abstract: Effect of different sintering additives on reaction-bonded Si3N4/SiC composite ceramics under pressureless was investigated. Si3N4/SiC composite ceramics were sintered at the temperature 1550 °C under nitrogen atmosphere with different sintering additives Y2O3, Y2O3:Al2O3=1:1, Y2O3:Mg2AlO4 :Mg3(Si4O10)(OH)2: SiO2=5:2:1:1, and ZrO2 by using SiC with different particle sizes, and Si as raw materials. The phases, microstructure and mechanical property were characterized by XRD, SEM, and compressive strength test. The results demonstrated that when the particle gradation consisted of silicon carbide of 74 μm (5 wt.%), 44 μm (10 wt.%) and 0.5 μm(30 wt.%) and silicon powder of 74 μm (42 wt.%), the more dense samples with the bulk density of 2.43 g/cm3 and the higher compressive strength of 324 MPa could be obtained when Y2O3 was used as sintering additives.
2349
Authors: Tao Jiao, Li Chao Hu, Jian Ping Zhou, Jian Fu
Abstract: With low content in CaO, blast furnace slag is a unique local engineering material with characteristic of multi-hole structure and high strength. Based on requirement of highway base material, strength performance test and feasibility analysis is conducted in this paper. With different proportion of cement content, through comparison of test data between cement stabilized slag and traditional cement stabilized material, traditional gravel aggregate could be substituted completely by Pangang blast furnace slag in application of highway base.
1297
