钛合金基磷酸钙涂层的制备及机理研究

使用电结晶法在钛合金表面沉积磷酸钙薄膜 ,使复合材料具有更好的韧性、强度和生物相容性。涂层沉积的最佳条件为Ca(NO3 ) 2 0 .1 0mol/L ,(NH4) 2 HPO40 .0 6mol/L ,电压 2 .5V ,电极间距离 2 5cm ,pH值 4 .4 ,温度 2 5℃ ,沉积时间 5h。强调了pH值是特别重要的因素 ,并分析了沉积的电化学反应机理     

流化床喷雾制备磷酸二氢钙成粒条件的实验研究

在底部直径为200 mm的锥形流化床中,研究了喷雾造粒制备粒状磷酸二氢钙的成粒条件,实验考察了喷淋密度、床层温度及流化气速等因素对成粒过程的影响,分析了磷酸二氢钙颗粒层式生长与团聚生长的机理,并给出了两种生长成粒的操作条件。     

Synthesis,spray granulation and plasma spray coating of lanthanum phosphate nanorods for thermal insulation coatings

Nanorods of lanthanum phosphate obtained by a wet chemical precipitation route were granulated to obtain sizes in the range of 10–15 µm by spray drying from aqueous slurry of 35 wt% solid loading and 2 wt% of PVA binder. The powders thus obtained displayed enhanced flowability and were plasma sprayed on to stainless steel substrates resulting in the formation of adherent coatings of 150–180 µm thickness. These coatings were characterized using electron microscopy, X-ray diffraction analysis and Raman spectroscopy. X-ray analysis indicated phase instability of LaPO₄ during plasma spraying resulting in the formation of oxy and polyphosphates of lanthanum (La₂P₄O₁₃ and La₃PO₇). However, post deposition heat treatment of coated samples at 1100 °C for 2 h resulted in the reversible formation of stoichiometric lanthanum orthophosphate (LaPO₄). Raman spectral analysis was used to confirm the phase structure of the coatings deposited at various plasma input powers. The coatings obtained were found to effectively lower the thermal conductivity of the substrates from ~24 W/mK to less than 19 W/mK (~10%) even at 200 °C.     

Uptake of fluoride ion by amorphous calcium phosphate

Fluor-bearing apatites were obtained by suspending amorphous calcium phosphate in NaF solutions, The amounts of absorbed F increased with lowering of pH in the fluoride solutions and elevation of temperature. The apatite formation may be interpreted in terms of a certain dissolution-crystallisation mechanism.     

多孔双相钙磷钛合金微弧氧化膜层的制备及生物相容性

为克服钛合金生物膜层单一相的缺陷,以Ti6A14V合金为基体,用微弧氧化法制得具有双相钙磷复合陶瓷膜层(BCP)的钛合金器件.通过控制工作液成分制得由不同比例的β-磷酸三钙(β-TCP)和羟基磷灰石(HA)组成的多孔性复合膜层.研究了电源占空比对BCP膜孔隙率和孔径大小的影响.采用能谱仪和X射线衍射仪分析了BCP膜层的...     

快速固化型磷酸钙骨水泥的研究

用模拟体液(simulated body fluid,SBF)作为固化液,对磷酸四钙(TTCP)+一水磷酸二氢钙(MCPM)+β-磷酸三钙(β -TCP)系骨水泥理化性质进行研究.结果表明,随液固比增大,抗压强度先增加后降低,当液固比为0.445时,抗压强度达到最大值15.23 MPa;骨水泥固化较快,液固比为0.594时,t_f为12 min;随着浸泡时间的增加抗压强度逐渐减小;X射线(XRD)和扫描电镜(SEM)分析结果显示,随液固比改变,固化反应结晶物均有羟基磷灰石(HA)相出现;浸泡后的骨水泥没有新物相产生.     

酸热法脱氟磷酸钙的生产

阐述了酸热法脱氟饲料磷酸钙生产工艺流程短、焙烧温度低、生产成本低等优点，提出应该重视酸热法脱氟磷酸钙的生产。     

Computational simulation of cold spray process assisted by electrostatic force

The integrated model of compressible thermofluid, splat formation and coating formation for the cold spray process has been established. In-flight behavior of nano-micro particles and the interaction between the shock wave and the particles in a supersonic jet flow impinging onto the substrate and further effect of electrostatic force on the particle acceleration are clarified in detail by carrying out a real-time computational simulation. The optimal particle diameters for an impinging particle velocity exceeding critical velocity exist. Particles with the diameter of submicron interact with shock wave and particles are decelerated prior to the impact. However, the particles can be accelerated considerably by utilizing electrostatic forces even in the presence of unavoidable shock waves. Finally, based on the integrated model, the coating thickness in an electrostatic assisted cold spray process is evaluated.     

聚合物磷酸钙分散剂述评

如何在冷却水中控制磷酸钙垢已变得更为重要.在过去的三十年间人们已经开发了许许多多能控制和分散磷酸钙垢的均聚物、二元和三元共聚物;研究了聚合物磷酸钙分散剂的结构/性能关系;并探讨了悬浮物及金属离子对它们用于磷系配方时的影响.简略回顾了聚合物磷酸钙分散剂的开发过程,报道了磷酸钙分散剂目前的性能与水平,并探讨了它的发展趋势.     

盐酸浸取磷矿生产磷酸氢钙的工艺研究

采用盐酸对贵州织金新华胶磷矿石进行酸溶解,研究了氨水加入方式和pH值等因素对磷酸氢钙产品质量的影响。通过实验得到的最佳工艺条件为:反应终点pH≥5.0,温度50℃,时间60min,烘干温度80℃。在此条件下得到的磷酸氢钙产品达到GB/T 22549-2008《饲料级磷酸氢钙》中Ⅰ型产品的技术指标要求。     

医用双相磷酸钙陶瓷的制备工艺研究

医用双相磷酸钙（BCP）陶瓷是β-磷酸三钙（β-TCP）和羟基磷灰石（HA）的复合体,其成分与骨矿物组成类似。它具有良好的生物相容性,在生物医学领域具有非常广阔的应用前景。且在生理环境下能发生不同程度的降解,被组织吸收。通过化学沉淀法制备纳米羟基磷灰石,然后通过可溶性钙盐和磷酸盐反应工艺制得β-磷酸三钙,最后将二者进行机械复合而制得双相磷酸钙,将所得样品用X射线衍射仪（XRD）进行了表征。结果显示：所得的双相磷酸钙中掺杂有β-焦磷酸钙,但是它的结晶较好,并且可以改善双相磷酸钙陶瓷的力学性能。     

矿粉脱氟法生产饲料级磷酸氢钙工艺探讨

利用磷精矿粉脱氟法生产饲料级磷酸氢钙,介绍其脱氟原理、生产工艺流程,按脱氟净化生产净化磷酸,萃取过滤生产粗磷酸,石灰乳中和过滤生产饲钙,分别说明其工艺控制指标,并与两段中和法对比,说明该方法生产饲钙的特点是P2O5回收率高,磷矿、硫酸、石灰乳消耗低。     

多级喷雾碳化法制备纳米碳酸钙工艺研究

研究了多级喷雾碳化制备纳米碳酸钙的工艺,并详细讨论了雾化、碳化条件及添加剂量等对纳米碳酸钙粒径的影响,碳化后的沉淀物真空干燥,其原始粒径约为30nm。经表面改性处理,可得到粒径在30－40nm范围的活性纳米碳酸钙粉体材料。     

微波辅助烷基磷酸酯改性重质碳酸钙的研究

在微波加热条件下,研究十八烷基磷酸酯改性重质碳酸钙的工艺条件。结果表明,改性最佳工艺条件为：改性剂用量2.5%,微波功率为中档,改性时间为10 min。在此条件下,所得产品活化度94.5%,吸油值由0.365 2 mL/g变为0.204 5 mL/g,粘度由204 mPa.s变为132 mPa.s,沉降体积由1.51 mL/g变为0.95 mL/g,白度由85.3%变为95.4%,碳酸钙性能明显提高。与常规水浴加热相比,微波辅助改性时间大大减小,产品性能更优。     

配矿对过磷酸钙生产的影响

介绍了过磷酸钙生产中配矿的作用及计算方法 ,说明配矿可使企业合理利用磷矿、稳定工艺指标和提高经济效益。     

Enhancing mechanical and biological properties of biphasic calcium phosphate ceramics by adding calcium oxide

There is a big challenge to achieve a balance between mechanical characteristics and biological properties in biphasic calcium phosphate (BCP) ceramics. The present study investigated the effects of calcium oxide (CaO) addition on the sintering behaviors and biological performances of BCP ceramics. The characterizations of surface structure, phase composition and crystal structure demonstrated that the addition of CaO could stabilize calcium-deficient hydroxyapatite (CDHA) phase and reduce grain size in BCP ceramics, so as to better mimic chemical composition and crystal structure of the natural bony minerals. Mechanical tests indicated that the addition of CaO could increase the compressive strength, flexural strength and fracture toughness of BCP ceramics, because of the enhanced crack deflection associated with a transgranular to intergranular cracking. Due to high content of CDHA phase, small grain size and slightly alkali environment, BCP ceramics with appropriate amount of CaO addition (2%) could promote the spreading and osteogenic differentiation of BMSCs. The strong bone-like apatite formation ability predicted a good osteoinductive potential of BCP ceramics with CaO addition. In summary, these findings suggest that the addition of CaO offers a promising strategy for design and fabrication of BCP ceramics with superior mechanical and biological properties.     

Ru-doped nanostructured carbon films

Pure and Ru-doped carbon films are deposited on Si (100) substrates by electron cyclotron resonance chemical vapor deposition. The films are characterized by transmission electron microscopy, electron energy loss spectroscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. In both the pure and Ru-doped samples, diamond nanocrystallites are formed in amorphous carbon matrices. The Ru-doped film contains much smaller diamond nanocrystallites (approx. 3 nm) than the pure samples (approx. 11 nm). Lower surface roughnesses are observed in both pure and Ru-doped samples as compared to other reported nanocrystalline diamond films. The conductivity of the Ru-doped film is significantly higher than that of the pure film. The results show that Ru-doped nanocrystalline diamond films have unique structures and properties as compared to pure nanocrystalline diamond films or metal doped diamond-like carbon films, which may offer advantages for electrochemical, optical-window, field emission or tribological applications.     

Soluble phosphate salts as setting aids for premixed calcium phosphate bone cement pastes

Recently, premixed calcium phosphate cement pastes have been proposed as biomaterials for bone tissue repair and regeneration. Use of premixed pastes saves the time and removes an extra step during a medical operation. α-Tricalcium phosphate (α-TCP) based cements set to form calcium deficient hydroxyapatite which has a moderate bioresorbtion speed. α-TCP cements require a setting aid, usually a sodium or potassium phosphate salt, to speed up the setting process. Within the current research we investigated which setting aid has significant advantage, if α-TCP is used in form of non-aqueous premixed paste. This approach offers the application of simple ingredients to produce a premixed calcium phosphate cement. The following properties of cement formulations were evaluated: cohesion, phase composition, microstructure, pH value of the liquid surrounding the cement, and compressive strength.Compositions using mixture of basic and acidic potassium phosphate salts (KH₂PO₄ and K₂HPO₄) in sufficient amounts give the best overall results (adequate cohesion and pH of the surrounding liquid, hydrolysis of starting materials within 48 h, and compressive strength of 12 ± 3 MPa). Cement prepared with basic sodium phosphate salt (Na₂HPO₄) as setting aid had considerably higher compressive strength 22 ± 1 MPa, but the pH of the surrounding liquid was basic (9.0).     

酸热烧结法制备饲料级脱氟磷酸钙的研究

以四川清平磷矿为原料,用酸热烧结法制备饲料级脱氟磷酸钙,研究了磷矿脱氟的主要影响因素。实验结果表明：磷酸配比、烧结温度以及烧结时间对脱氟反应有显著影响,而磷酸浓度对脱氟反应的影响不明显。实验得出的最佳工艺条件为：磷酸配比控制在27％～30％,烧结温度1180-1230℃,烧结时间120min,磷酸w（P2O5）45％左右。在此条件下可制得质量合格的饲料级脱氟磷酸钙产品。     

木素稀硝酸氧化及其与磷酸钙作用的研究

研究了造纸黑液木素稀硝酸氧化法制备活性氧化木素的适宜条件。结果表明,当磷酸含量为4.0%,木素与稀硝酸的质量配比为1∶10,可得到腐殖酸含量达46%的氧化木素。研究了氧化木素和氨化氧化木素对3种磷酸钙的溶解性的影响,讨论并合理地解释了反应机理。