多孔Al-Si12合金的制备与性能研究

采用真空—压力烧结—溶解工艺制备出了孔隙率44%～76%、平均孔径30～110μm的多孔Al-Si12合金,对多孔Al-Si12合金的制备、孔结构、抗弯强度及渗透性能进行了研究。结果表明,真空环境下的压力烧结可明显提高多孔Al-Si12合金的抗弯强度,最佳的制备工艺为压制压力500MPa、烧结温度565℃、烧结时间2h以及烧结压力150～200MPa;多孔Al-Si12合金的相对渗透系数随其孔隙率和平均孔径的提高而增大;多孔Al-Si12合金的抗弯强度高于相近孔结构的多孔铝,渗透性能优于相近孔结构的多孔不锈钢及多孔铝。     

多孔镍载体材料的制备

试验在常规粉末冶金方法基础上通过添加造孔剂的办法制备出高孔率(70%以上)、小孔径(最大冒泡孔径＜5 μ m)、高透过量,通孔率(通孔率可达97%以上)的多孔镍载体材料.主要进行了粉末粒度及形貌的分析选择研究,造孔剂的添加量与多孔镍载体性能关系的研究、烧结工艺对材料性能影响的研究.主要从孔率、最大冒泡孔径、透气系数、通孔率等方面着手,研究了造孔剂加入量及烧结工艺对该性能的影响,同时对不同条件下样品的性能进行了测试.     

高温除尘用堇青石陶瓷支撑体的制备研究

以廉价的工业级堇青石粉体为原料,分别采用粒径为5,10,15,20μm的聚苯乙烯微球为造孔剂,通过挤压成型和高温固相反应法制备了堇青石支撑体。探究了不同造孔剂粒径及不同烧结温度对支撑体基本性能的影响,并用XRD和SEM技术对样品的物相组成和断面形貌进行了表征。研究结果表明,造孔径粒径越大材料内部孔径分布越宽、支撑体开孔率及空气渗透速率越高而抗压强度及耐酸腐蚀性越小;过高的烧结温度会促进烧结液相的产生,降低材料孔隙率及空气渗透速率,当烧结温度为1 300℃,添加粒径为10μm的造孔剂时可制备出开孔率为54.12%,抗压强度为8.25 MPa,空气渗透速率为7.62 m~3/(h·Pa·m~2),耐酸腐蚀率为99.59%的堇青石陶瓷支撑体。     

粉煤灰基多孔陶瓷膜的制备研究

用工业废弃物粉煤灰为主要原料,采用模压成型和挤压成型工艺,在较低温度下烧制成了多孔陶瓷过滤膜.研究了造孔剂、烧成温度等对多孔陶瓷样品的孔隙率、孔结构以及物相和强度等的影响.研究表明,反应烧结是主要的烧结过程机制,烧成样品以莫来石相和方石英相为主要物相.在优化的条件下,即造孔剂添加量为20%、烧成温度1250℃时,样品的孔隙率为51.2%,中位孔径为3.72μm,N2气体通量高达1.4×104 m3·m-2·h-1·bar-1,其弯折强度达64MPa,可以满足作为高温气-固分离过滤介质的要求.     

骨组织工程用多孔HA生物材料的制备

用PVB、NH4HCO3和(NH4)2CO3粒子作造孔剂,制备了骨组织工程用多孔HA生物材料.讨论了烧结工艺和造孔剂含量等对材料结构的影响.研究表明,较佳的烧结工艺为1200℃烧结4h,烧结后样品主要是HA相.造孔剂PVB、(NH4)2CO3、NH4HCO3含量分别为10vol%、15vol%和20vol%时,多孔HA陶瓷拥有大于100μm和5～50 μm的贯通孔,具有较好的孔连通性与孔结构,有利于细胞和组织的生长以及营养输送;其最大孔隙率为50.3%,抗压强度为6.33MPa.     

造孔剂对新型医用多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金组织性能的影响

合金多孔化是有效降低材料弹性模量的方式之一,采用添加造孔剂的元素粉末冶金法制备了新型医用多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金,通过扫描电镜、阿基米德法、X射线衍射和压缩力学性能测试的方法研究了不同造孔剂用量和粒径尺寸对合金形貌特征、孔隙率、物相组成及力学性能的影响规律。结果表明:该方法制备所得多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金为近β型钛合金;随着造孔剂用量增加,平均孔径无变化,孔隙率呈线性增长,弹性模量和抗压强度减小,其中弹性模量的变化满足线性关系;随着造孔剂粒径尺寸增加,平均孔径增大而孔隙率基本不变,抗压强度和弹性模量减小;添加20%(质量分数)粒径尺寸为125~200μm的NH4HCO3造孔剂制备多孔Ti-14Mo-2.1Ta-0.9Nb-7Zr合金,于1300℃烧结4h孔隙率达到38.9%并含有贯穿孔结构,抗压强度达到405 MPa,而弹性模量为9.19GPa,能满足医用植入材料的要求。     

粉末冶金法制备多孔金属钛免疫隔离材料

采用粉末冶金工艺制备出微米孔径且孔隙率较高的多孔钛免疫隔离材料，分析了压制压力、烧结温度等因素对多孔金属钛孔径及孔隙率的影响。试验结果表明，随着压制压力的提高，钛粉末烧结后平均孔径尺寸和孔隙率逐渐减小，孔隙分布和孔径尺寸较均一。烧结温度对多孔金属钛影响显著，随烧结温度的升高，平均孔径尺寸逐渐增大，孔隙率先略有上升后逐渐降低。     

尿素含量对Ti-10%Mg多孔材料孔隙结构和抗压性能的影响

以尿素为造孔剂,采用粉末冶金法在630℃真空条件下烧结制备Ti-10%Mg多孔材料,研究了造孔剂含量对其孔隙结构、物相成分、孔隙率及抗压性能的影响。研究表明,造孔剂含量为25%(w)时,烧结体的孔隙大小均匀,主要相为Ti和Mg,造孔剂添加量未对其物相产生明显影响;随着造孔剂含量的增加,烧结体的孔隙率随之增加,抗压强度和弹性模量随之降低;Ti-10%Mg多孔材料的抗压强度和弹性模量分别为16~183MPa和1.87~10.15 GPa,理论上可以作为人体骨骼的替代材料。     

非传统粉末冶金制备生物医用多孔钛及其性能

以生物医用球形雾化钛粉为原料,碳酸氢铵做造孔剂,采用放电等离子烧结(SPS)技术制备了生物医用多孔钛块体材料。采用XRD、SEM分别对所制备的多孔钛的物相组成、微观形貌进行分析,并研究了多孔钛的力学性能及成骨细胞在其表面的粘附生长情况。结果表明:通过调节造孔剂添加量、控制烧结工艺可制备孔隙率为50.3%～70.5%、孔径为100～300μm的多孔钛,其力学性能(抗压强度为24.40～68.96MPa、弹性模量为1.010～1.287GPa)与人体松质骨相匹配。与SD大鼠成骨细胞的联合培养结果表明,该材料的粗糙表面和多孔结构可粘附生长成骨细胞,具有良好的生物相容性。     

造孔剂法制备硅藻土基多孔陶瓷及其性能研究

以硅藻土和烧结助剂为原料、聚苯乙烯(PS)为有机造孔剂,采用热压铸工艺,在1 150℃/2 h条件下制备了孔隙率为50%～60%的硅藻土多孔陶瓷,分别研究烧结助剂含量、造孔剂粒径及含量对多孔陶瓷孔隙率、孔径和微观结构的影响,进一步研究多孔陶瓷的孔隙率、孔径与陶瓷平均吸油速率的关系。结果表明：当硅藻土粒径为25μm、烧结助剂含量为13%(质量分数,下同),造孔剂粒径为30μm且添加含量为20%时,制备的多孔陶瓷的开放孔隙率可高达60%;平均吸油速率随多孔陶瓷孔径和孔隙率增大而提高,其中孔径的影响更大,当孔径由9.3μm增大到28.8μm时,平均吸油速率由1.1 mg/s提高到3.6 mg/s。     

低介电常数多孔氮化硅陶瓷的制备

采用凝胶注模成型工艺,以SiO2含量大于等于95%的空芯玻璃微珠作造孔剂,通过控制造孔剂的加入量和调节造孔剂的孔径成功制备出低介电常数、高强度的多孔Si3N4陶瓷。结果表明,随着造孔剂含量的增加,试样气孔率增大,弯曲强度降低,ε和tanδ都相应降低,ε最低为1.77;在造孔剂加入量为10%时,随着造孔剂的孔径尺寸变大,试样的孔径变大,弯曲强度降低,试样的ε和tanδ也相应降低。当造孔剂含量为10%、孔径尺寸为80μm时制备的多孔氮化硅陶瓷ε为2.13,弯曲强度达到38MPa,适合作为宽频带天线罩的夹层材料。     

The Effect of Porosity and Grain Size on the Phase Composition and Mechanical Properties of Zirconium-Dioxide-Based Ceramic

ZrO₂(Y) ceramic with embedded particles of a pore-forming agent—ultrahigh molecular weight polyethylene—has been studied. It has been shown that the porosity of samples after sintering changed from 2 to 42 vol % and the grain size changed from 0.5 to 1.55 μm depending on sintering regime. The strength of materials with minimum porosity was 3000 ± 200 MPa, while the strength of materials with maximum porosity was 100 ± 20 MPa, regardless of grain size. It has been shown that the tetragonal to monoclinic martensitic phase transformation related to mechanical stresses takes place in the material without any effect on the macrostrength of the material. Internal microscopic stresses decreasing with an increase in porosity and ceramic grain size are the main factor causing this transformation in a porous material.     

叔丁醇基凝胶注模工艺制备轻质、高强莫来石多孔陶瓷

以叔丁醇为成型溶剂, 莫来石粉为起始原料, 采用凝胶注模成型方法制备出轻质、高强莫来石多孔陶瓷. 莫来石多孔陶瓷中的孔隙形成于干燥过程中叔丁醇的快速挥发, 孔隙分布均匀且相互连通. 随烧结温度升高, 气孔率、开气孔率和比表面积分别由77.8%、76.0%和10.39m²/g下降到67.6%、65.5%和4.26m²/g, 而抗压强度则由3.29MPa显著提高到32.36MPa, 材料孔径大小受烧结温度影响较小, 孔径尺寸呈单峰分布, 且几乎所有的气孔都为开口气孔, 透气度与孔径尺寸具有一致的变化关系. 莫来石多孔陶瓷在高气孔率条件下仍然保持高强度的主要原因是材料中均匀的孔隙结构、孔径尺寸小且相对集中、以及因烧结颈的形成在空间上所表现出的一种颗粒搭接骨架结构.     

多孔NiTi形状记忆合金的制备及性能

采用球磨后的NiTi合金粉末为原料,添加尿素作为造孔剂,利用粉末烧结法制备多孔NiTi形状记忆合金.研究烧结温度、保温时间和预成型压力等条件对制备的多孔NiTi合金组织结构和力学性能的影响.结果表明:相对于传统的Ni粉和Ti粉近等原子比混合烧结方法,此方法制备的多孔NiTi合金的相组成更加纯净.且随烧结温度升高,多孔N...     

添加成孔剂法制备孔径、气孔率可控的多孔玻璃陶瓷

研究了采用添加成孔剂法制备具有相互贯通气孔的多孔生物玻璃陶瓷的方法及其性能.多孔玻璃陶瓷主晶相为氟磷灰石和β-硅灰石,气孔率在49％-82％间连续可控,气孔由成孔剂热解排除形成的球形宏观孔(孔径200-850μm)和玻璃粉体烧结形成的微观孔(孔径2-4μm)组成,宏观孔孔径取决于成孔剂粒径并通过孔壁上的孔洞(孔径50-300μm)相互连通.塑性成孔剂硬脂酸受压产生塑性变形,添加硬脂酸的素坯强度高、可加工,烧结产物强度较高、气孔为扁球状;刚性成孔剂聚苯乙烯受压产生弹性变形,添加聚苯乙烯的素坯疏松、不可加工,烧结产物强度较低、气孔呈圆球状.成形压力对添加塑性成孔剂的样品性能影响显著,而对添加刚性成孔剂的样品性能无显著影响.气孔率与成孔剂的含量成良好的线性关系,通过控制成孔剂粒径和加入量可达到气孔率、孔径可控的目的.孔径一定时抗压强度与总气孔率成良好的二次曲线关系.     

Fabrication and characterization of highly porous mullite ceramics

Highly porous mullite ceramics were fabricated by a reaction-bonding technique from a powder mixture of Al₂O₃ and SiC, with graphite particles as the pore-forming agent. The effects of sintering temperature on porosity and strength as well as pore size and surface area were investigated. It has been shown that the strength and pore size increase but the porosity and surface area decrease with the increase in sintering temperature. Due to the formation of a fine-grained microstructure with well-developed necks, an average strength up to 106 MPa was achieved at a porosity of 32.4%. On the other hand, a relatively high surface area of 12.4 m² g⁻¹ was obtained for a 61% porous mullite ceramic, which was observed to have a good thermal-shock resistance to crack propagation.     

Mechanical and microstructural properties of cordierite-bonded porous SiC ceramics processed by infiltration technique using various pore formers

Cordierite-bonded porous SiC ceramics were prepared by air sintering of cordierite sol infiltrated porous powder compacts of SiC with graphite and polymer microbeads as pore-forming agents. The effect of sintering temperature, type of pore former and its morphology on microstructure, mechanical strength, phase composition, porosity and pore size distribution pattern of porous SiC ceramics were investigated. Depending on type and size of pore former, the average pore diameter, porosities and flexural strength of the final ceramics sintered at 1400 °C varied in the range of ~ 7.6 to 10.1 µm, 34–49 vol% and 34–15 MPa, respectively. The strength–porosity relationship was explained by the minimum solid area (MSA) model. After mechanical stress was applied to the porous SiC ceramics, microstructures of fracture surface appeared without affecting dense struts of thickness ~ 2 to 10 µm showing restriction in crack propagation through interfacial zone of SiC particles. The effect of corrosion on oxide bond phases was investigated in strong acid and basic salt medium at 90 °C. The residual mechanical strength, SEM micrographs and EDX analyses were conducted on the corroded samples and explained the corrosion mechanisms.     

Effect of particle size on microstructure and strength of porous spinel ceramics prepared by pore-forming <Emphasis Type="Italic">in situ</Emphasis> technique

The porous spinel ceramics were prepared from magnesite and bauxite by the pore-forming in situ technique. The characterization of porous spinel ceramics was determined by X-ray diffractometer (XRD), scanning electron microscopy(SEM), mercury porosimetry measurement etc and the effects of particle size on microstructure and strength were investigated. It was found that particle size affects strongly on the microstructure and strength. With decreasing particle size, the pore size distribution occurs from multi-peak mode to bi-peak mode, and lastly to mono-peak mode; the porosity decreases but strength increases. The most apposite mode is the specimens from the grinded powder with a particle size of 6·53 μm, which has a high apparent porosity (40%), a high compressive strength (75·6 MPa), a small average pore size (2·53 μm) and a homogeneous pore size distribution.     

表面多孔NiTi-羟基磷灰石/NiTi生物复合材料的制备与性能

利用放电等离子烧结技术制备了表面多孔NiTi-羟基磷灰石(HA)/NiTi生物复合材料,研究了烧结温度对复合材料宏观形貌、微观结构、表面孔隙特征、力学性能及体外生物活性的影响。结果表明:随着烧结温度从800℃提高到950℃,NiTi-HA/NiTi复合材料由复杂的Ti、Ni、Ti_2Ni、Ni_3Ti、HA混合相逐渐转变为单一的NiTi+HA相,内外层界面形成稳定的冶金结合且表面孔隙率与平均孔径呈缓慢减小趋势;同时抗压强度显著提高而弹性模量变化不明显。与传统NiTi、多孔NiTi及多孔NiTi-HA材料相比,950℃温度下制备的NiTi-HA/NiTi复合材料不仅具有良好的界面结合和表面孔隙特征(孔隙率45.6%、平均孔径393μm)、较高的抗压强度(1 301MPa)、较低的弹性模量(10.2GPa)以及优异的超弹性行为(超弹性恢复应变4%)的最佳匹配,而且还具有良好的体外生物活性。