氟和碳酸根复合替代磷灰石的制备及性能研究
发布时间：2018-09-14 15:53
【摘要】：羟基磷灰石(简称HA)具有良好的生物活性和生物相容性,作为骨植入材料广泛应用医学领域。然而由于人体自然骨中的羟基磷灰石是非化学计量的,其中碳酸根(CO_3~(2-))是含量最多的替代离子。由于复合替代在优化磷灰石结构和性能方面能够取长补短,因此在单一替代的基础上,不少学者将目光放在了复合替代的研究上。碳酸根和氟离子替代对磷灰石的结构和性能均有不同程度的影响,因此可以通过控制碳酸根和氟离子的替代调控磷灰石的综合性能。本文通过化学沉淀法制备碳氟共替代羟基磷灰石粉体(CFHA),探讨了制备工艺参数对碳酸根和氟离子共替代的影响,并对CFHA粉体和块体进行热处理研究,利用XRD、SEM、TEM、FTIR、DTA/TG等一系列表征手段研究了碳酸根和氟共替代对HA结构和性能的影响。通过化学沉淀法合成CFHA粉体,研究了反应温度和pH值、CO_3~(2-)/F-原料的初始浓度和添加顺序、碱液添加时机、原料中Na~+的共替代、n(Ca)/n(P)摩尔比等工艺参数对磷灰石中碳酸根和氟的替代、结构和形貌的影响。研究结果表明:(1)随着反应温度升高,晶粒尺寸和长径比增加;随着pH值的增大,纳米HA晶粒尺寸和长径比都随之减少,并且碱性的反应环境更有利于HA结晶和替代的发生。(2)碳酸根和氟离子共替代时,氟离子浓度对于HA形貌影响不大,而随着碳酸根浓度增加,HA晶粒尺寸和长径比相应减少,且在高F-和CO_3~(2-)浓度下,更利于碳酸根的B型替代。合成粉体中氟和碳酸根含量随初始氟、碳酸根离子浓度的增加而非线性增加,但碳酸根含量测量值高于理论值,而氟离子含量测量值远低于理论值。(3)先加碱液的方式使晶核形成速率过快出现大量晶体团聚的现象;后加碱液方式制备得到的晶体呈片状。(4)Na~+的存在促进磷灰石晶体的生长,且含Na~+体系中会发生Na~+/CO_3~(2-)共替代,更有利于碳酸根B型替代的发生。(5)原料的钙磷配比会影响CFHA的碳酸根替代和最终的物相组成。将CFHA粉体和块体在湿CO_2保护气氛下进行热处理,研究了碳氟共替代对CFHA粉体的热稳定性、CFHA的块体烧结性能、热膨胀系数和抗折强度的影响。研究结果表明:(1)湿CO_2保护气氛有利于CFHA的热稳定性;而碳氟替代对于样品的热分解影响不明显。(2)在湿CO_2保护气氛进行热处理,当处理温度为850℃时,随着初始碳含量增加,CFHA烧结试样的吸水率降低,当处理温度为950℃时,碳氟替代对于样品的烧结致密度影响不大。(3)CFHA试样的膨胀系数随着温度升高而增大,随着初始碳氟替代含量的增加而减小。(4)CFHA试样的抗折强度随着初始碳氟替代含量的增加而增大。
[Abstract]:Hydroxyapatite (HA) has good bioactivity and biocompatibility. However, hydroxyapatite in human natural bone is nonstoichiometric, in which CO_3~ (2-) is the most abundant substitute ion. Because compound substitution can complement each other in optimizing apatite structure and performance, many scholars have focused on the study of composite substitution on the basis of single substitution. The substitution of carbonate and fluorine ions has different effects on the structure and properties of apatite, so the comprehensive properties of apatite can be controlled by controlling the substitution of carbonate and fluorine ions. In this paper, the influence of preparation parameters on the co-substitution of carbonate and fluorine ions in (CFHA), powder prepared by chemical precipitation method was investigated, and the heat treatment of CFHA powder and bulk was studied. The effects of carbonate and fluorine co-substitution on the structure and properties of HA were studied by means of XRD,SEM,TEM,FTIR,DTA/TG and other characterization methods. CFHA powder was synthesized by chemical precipitation method. The initial concentration and addition order of reaction temperature and pH value were studied. The substitution of carbonate and fluorine in apatite was studied, such as the initial concentration and addition order, the addition time of alkali solution, the molar ratio of co-substitution of Na~ to n (Ca) / n (P) in the raw material, and so on. The influence of structure and morphology. The results show that: (1) with the increase of reaction temperature, the grain size and aspect ratio increase, and with the increase of pH value, the grain size and aspect ratio of nanometer HA decrease. And the alkaline reaction environment is more favorable to the crystallization and substitution of HA. (2) the concentration of fluorine ion has little effect on the morphology of HA, but with the increase of carbonate concentration, the grain size and the ratio of length to diameter of HA decrease correspondingly, (2) when the carbonate and fluorine ions are co-substituted, the concentration of fluorine ion has little effect on the morphology of HA. At high concentration of F-and CO_3~ (2 -), type B substitution of carbonates is more favorable. The content of fluorine and carbonate in the synthesized powder increases linearly with the increase of the initial fluoride and the concentration of carbonate ion, but the measured value of the content of carbonate is higher than the theoretical value. However, the measured value of fluorine ion content is far lower than the theoretical value. (3) the nucleation rate of crystal is too fast by adding alkali solution, and then the crystal prepared by adding alkali solution is flake. (4) the existence of Na~ promotes the growth of apatite crystal. The co-substitution of Na~ / CO3- ~ (2-) in the system containing Na~ is more favorable to the occurrence of substitution of B type of carbonate. (5) the ratio of calcium to phosphorus of raw material will influence the substitution of carbonates and the final phase composition of CFHA. The effects of carbon-fluorine co-substitution on the bulk sintering properties, thermal expansion coefficient and flexural strength of CFHA powders were studied. The results show that: (1) the wet CO_2 protective atmosphere is favorable to the thermal stability of CFHA, while the substitution of fluorocarbon has no obvious effect on the thermal decomposition of the samples. (2) when the temperature is 850 鈩，
本文编号：2243162
[Abstract]:Hydroxyapatite (HA) has good bioactivity and biocompatibility. However, hydroxyapatite in human natural bone is nonstoichiometric, in which CO_3~ (2-) is the most abundant substitute ion. Because compound substitution can complement each other in optimizing apatite structure and performance, many scholars have focused on the study of composite substitution on the basis of single substitution. The substitution of carbonate and fluorine ions has different effects on the structure and properties of apatite, so the comprehensive properties of apatite can be controlled by controlling the substitution of carbonate and fluorine ions. In this paper, the influence of preparation parameters on the co-substitution of carbonate and fluorine ions in (CFHA), powder prepared by chemical precipitation method was investigated, and the heat treatment of CFHA powder and bulk was studied. The effects of carbonate and fluorine co-substitution on the structure and properties of HA were studied by means of XRD,SEM,TEM,FTIR,DTA/TG and other characterization methods. CFHA powder was synthesized by chemical precipitation method. The initial concentration and addition order of reaction temperature and pH value were studied. The substitution of carbonate and fluorine in apatite was studied, such as the initial concentration and addition order, the addition time of alkali solution, the molar ratio of co-substitution of Na~ to n (Ca) / n (P) in the raw material, and so on. The influence of structure and morphology. The results show that: (1) with the increase of reaction temperature, the grain size and aspect ratio increase, and with the increase of pH value, the grain size and aspect ratio of nanometer HA decrease. And the alkaline reaction environment is more favorable to the crystallization and substitution of HA. (2) the concentration of fluorine ion has little effect on the morphology of HA, but with the increase of carbonate concentration, the grain size and the ratio of length to diameter of HA decrease correspondingly, (2) when the carbonate and fluorine ions are co-substituted, the concentration of fluorine ion has little effect on the morphology of HA. At high concentration of F-and CO_3~ (2 -), type B substitution of carbonates is more favorable. The content of fluorine and carbonate in the synthesized powder increases linearly with the increase of the initial fluoride and the concentration of carbonate ion, but the measured value of the content of carbonate is higher than the theoretical value. However, the measured value of fluorine ion content is far lower than the theoretical value. (3) the nucleation rate of crystal is too fast by adding alkali solution, and then the crystal prepared by adding alkali solution is flake. (4) the existence of Na~ promotes the growth of apatite crystal. The co-substitution of Na~ / CO3- ~ (2-) in the system containing Na~ is more favorable to the occurrence of substitution of B type of carbonate. (5) the ratio of calcium to phosphorus of raw material will influence the substitution of carbonates and the final phase composition of CFHA. The effects of carbon-fluorine co-substitution on the bulk sintering properties, thermal expansion coefficient and flexural strength of CFHA powders were studied. The results show that: (1) the wet CO_2 protective atmosphere is favorable to the thermal stability of CFHA, while the substitution of fluorocarbon has no obvious effect on the thermal decomposition of the samples. (2) when the temperature is 850 鈩，
本文编号：2243162
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