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Hydroxyapatite(HAP,Ca10(PO4)6(OH)2in one of the quite important bone implant materials.The hydroxyapatite crystals were synthesized under hydrothermal condition.The specimen was verified to be HAP crystal by the X-ray powder diffractometry(XRD).Then the specimen was distinguished single crystal from polycrystal by the use of the transmission electron microscope(TEM).The diffraction pattern of the specimen is neatly affanged diffraction spots,that verified the crystals were single crystals.The interplanar distance d calculated from diffraction spot is coincided with that of HAP‘s JCPD card.Moreover,crystal face angles calculated from crystal face index are coincided with the values by measuring on the pattern.The HAP crystals are needle-like in shape with about 3μm in diameter and 180μm in length.Most of the crystals are whiskers.Their length/diameter ratio ranges from 40 to 100.The average ratio is about 60. 相似文献
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通过在实验室控制海水温度模拟不同海域和季节海水环境。采用恒位移应力腐蚀实验和慢应变速率拉伸实验(SSRT)考察温度对Ti80钛合金应力腐蚀敏感性的影响规律,结合电化学阻抗谱、Mott-Schottky曲线以及三维视频显微镜和扫描电镜(SEM)分析温度对钛合金的影响机制。结果表明:在常压,5~35℃范围内,随着温度的降低,钛合金样品的应力腐蚀开裂敏感性指数逐渐增大,临界强度因子K1SCC值逐渐减小,应力腐蚀倾向增加。低温海水环境下样品断口局部甚至出现河流花样特征和撕裂岭准解理特征。这是因为低温海水环境中钛合金样品裂纹尖端钝化膜电阻较小、缺陷较多、位错容易堆积从而导致钝化膜局部应力集中,膜致应力增大,与外加应力协同作用下,裂纹成核和扩展加快,导致钝化膜难以修复,应力腐蚀速率加快。 相似文献
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In the paper, the effect of heat-treatment on thestrength and toughness of AlN-SiC whisker composites with Y_2O_3+SiO_2 additives have been studied. When the sample contining 10wt%Y_2O_3+SiO_2(Y_2O_3/SiO_2=1/0. 66) was treated at 1330℃ in air for 140hours,the flexural strength of composites was raised from 481 MPa to784 MPa the toughness was also enhanced slightly. The phase composi-tion microstructure and grain boundary phase structure have been char-acterized by combining XDR, SEM, TEM/EDXA and HREM tech-niques. reinforcenent and toughening mechanism of the composites re-sults from the crystallization of glass phase in the grain boundary atthe high temperature oxidizing atmosphere to form the crossing struc-ture of 2H°sialon fibrous phase and SiC whisker 相似文献
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SiC晶须,晶板增韧AlN陶瓷的研究 总被引:3,自引:0,他引:3
本文利用现代测试技术对SiCw,SiCp增韧AlN材料的力学性能,显微结构进行研究,并分析探讨了材料的增韧机理,结果表明;SiCw可有效改善材料的断裂韧性和断裂强度,其增韧机理主要为裂纹偏转和晶须拔出效应,SiCp加入的断裂韧性起到良好的促进作用,但对材料的断裂强度则有不良的作用,其增韧机理主要为裂纹偏转和分枝效应。 相似文献
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利用粉煤灰烧制玻化砖 总被引:4,自引:0,他引:4
主要介绍了利用火力发电厂排出的工业废渣——粉煤灰和粘土矿物烧制玻化砖的工艺过程,并分析了粉煤灰对烧制玻化砖工艺性能和烧成性能的影响。 相似文献
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本文研究了Al2O3、Y2O3、La2O3、Y2O3+SiO2几种类型的添加剂对AIN陶瓷力学性能和高温抗氧化性能的影响。结果表明:Y2O3+SiO2为一种较好的AIN陶瓷添加剂,材料在烧结过程中由于2H^5Sialon及8H-Sialon等纤维状的Sialon相形成,对材料起到一种自补强作用,SiO2的存在使用AIN陶瓷在氧化工程中形成Mullite保护层,故使AIN陶瓷肯有良好的力学性能及高温 相似文献
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通过料浆发泡和注浆成形技术制备出轻质化日用陶瓷制品,并研究了发泡剂添加量、减水剂种类、料浆pH值对料浆流动性、坯体成形和烧成性能的影响。结果表明:随着发泡剂添加量的增多,坯体脱模难度增大,且陶瓷生坯强度、烧成强度和体积密度均会有所下降。适当控制发泡剂的添加量,通过料浆微孔发泡技术可制备出符合要求的轻质日用陶瓷,其适宜的条件是水玻璃添加量为2%、料浆pH值为9、水料比为0.55。当外加发泡剂添加量为0.8‰时,所得试样的显气孔率可提高一倍以上、体积密度可下降25%以上,但其抗折强度仍可达28MPa以上。该技术将为日用陶瓷行业的节能减排提供一种有效的技术途径。 相似文献