升温速度对多孔生物陶瓷特性的影响

Effect of temperature-rising speed on characteristics of porous bioceramics

目的：观察升温速度对多孔生物陶瓷孔结构、显气孔率与容重、水渗透率、收缩率以及压缩强度的影响。方法：实验于2005-09/2007-09在武汉理工大学生物中心和重庆邮电大学生物实验中心完成。①在保温时间为2h,烧成温度为850℃条件下,有机泡沫微球与骨料质量配比为0.25时,粘结剂的添加量为20%,升温速度分别为30,60,90,120,150和200℃/h条件下,采用有机泡沫微球作为成孔剂的热压铸多孔陶瓷的制备方法制得不同样品。②用电子扫描显微镜观察孔道和表面形貌;根据GB/T1964～1967-1996和GB/T1969～1970-1996测量显气孔率、容重;用自制水渗透率测定仪测定水渗透率;用体积法测定收缩率;用ASTM材料强度测试机测定压缩强度。结果：①升温速度变化对孔径〉100μm大孔的影响明显,对孔径〈50μm小孔的影响不明显,对晶体的长大影响也明显。②随着升温速度从30℃/h提高到150℃/h,显气孔率从72%增加到82%,容重从0.89×10^3kg/m^3下降0.52×103kg/m3,水渗透率从12×10^-3cm^2增加到25×10^-3cm^2,收缩率27%从减少到23%,抗压强度从17.3MPa降低到1.59MPa。结论：升温速度对孔结构、显气孔率与容重、水渗透率、收缩率以及抗压强度有着重要的影响,为了保证成品有较好的孔结构、较高的显气孔率的同时具有一定的机械强度,升温速度选择在120℃/h左右较佳。

AIM： To observe the influence of temperature-rising speed on pore structure, apparent porosity, volume weight, percolation rate of water, contracted ratio and compression strength of porous bioceramics. METHODS： From September 2005 to September 2007, the experiment was carried out in the Biomedical Materials and Engineering Center of Wuhan University of Technology and the Biological Experimental Center of Chongqing University of Post ＆ Telecommunication.①The temperature-keeping time was 120 minutes, the sintering temperature was 850 ℃, the molar ratio of organic-foam microsphere and aggregate ceramics powder was 0.25, the composition of agglutinant was 20%, the speed of temperature rise was 30, 60, 90, 120, 150 and 200 ℃/h, respectively. Accordingly, different samples of hot pressure casting porous ceramics were made, taking organic-foam microsphere as pore-forming agent.②The interconnection of pore path and pore surface were observed by scanning electron microscope; the apparent porosity and volume weight were measured according to GB/T1964-1967-1996 and GB/T1969-1970-1996; the percolation rate of water was tested by the self-developed instrument; the contracted ratio was tested by volumetric method; the compression strength was tested by ASTM strength4esting instrument. RESULTS： ①The temperature-ring speed had a conspicuous influence on big pore （its aperture 〉 100 μ m） and crystal growth, but had an unconspicuous influence on small pore （its aperture 〈 50μ m）.②When the speed of temperature rise was accelerated from 30 ℃/h to 150 ℃/h, the apparent porosity increased from 72% to 82%, volume weight descended from 0.89×10^3 kg/m^3 to 0.52×10^3 kg/m^3, the percolation rate of water raised from 12 × 10^3 cm^2 to 25× 10^3 cm^2, contracted ratio reduced from 27% to 23%, and compression strength reduced from 17.3 MPa to 1.59 MPa. CONCLUSION： The speed of temperature rise has an important influence on pore structure, apparent porosity, volume weight, the percolation rate of water, contracted ratio and the compression strength. The speed of temperature rise is better set around 120 ℃/h to guarantee that products have better pore structure, high apparent porosity and compression strength as well.