本文關(guān)鍵詞： 鎂合金 鎂基復(fù)合材料 鈣磷膜層 化學(xué)轉(zhuǎn)化膜 溶膠凝膠膜層 羥基磷灰石 氟羥基磷灰石 生物可降解　出處：《吉林大學(xué)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：與臨床應(yīng)用的不銹鋼、鈦合金和鈷鉻合金等金屬植入材料相比,鎂及鎂合金作為潛在的生物醫(yī)用植入材料,具有良好的力學(xué)相容性、生物相容性和體內(nèi)可降解性。但是,鎂合金作為骨植入材料,在人體中腐蝕降解過快,導(dǎo)致植入體在骨組織尚未完全修復(fù)前就失去其機械完整性,而且腐蝕過程中產(chǎn)生的過量氫氣會導(dǎo)致植入體和骨組織之間的連接松動,這些都限制了鎂及鎂合金作為骨植入材料的臨床應(yīng)用。為了降低鎂的腐蝕降解速率,通常采用高純化、合金化、復(fù)合材料及表面改性等技術(shù)手段提高鎂的耐蝕性能。與其他技術(shù)手段相比,在鎂合金表面制備生物相容性膜層,不僅可以使植入體在植入初期減緩降解速率,保持良好的機械完整性,而且在骨修復(fù)即將完成時膜層失效使植入體較快降解,還能有效改善植入體與骨組織的界面關(guān)系,加速骨骼修復(fù)愈合。由于Ca和P是骨骼礦物質(zhì)的主要組成元素,鈣系磷酸鹽(Ca P),例如二水磷酸氫鈣(DCPD,Ca HPO_4·2H2O)、羥基磷灰石(HA,Ca10(PO_4)_6(OH)_2),都具有天然的生物活性和生物相容性。本文通過化學(xué)轉(zhuǎn)化法和溶膠凝膠旋涂法等簡單易控方法,在鎂合金及復(fù)合材料表面制備多種不同結(jié)構(gòu)與形貌的鈣磷膜層,然后通過在模擬體液(SBF)中的電化學(xué)和浸泡礦化試驗、體外細胞培養(yǎng)試驗以及體內(nèi)植入試驗等對其腐蝕降解行為、生物礦化行為及細胞相容性等進行系統(tǒng)研究。本文的主要研究工作如下:1.采用簡單易控的化學(xué)轉(zhuǎn)化法,在鎂合金表面制備具有復(fù)合膜層結(jié)構(gòu)的鈣磷化學(xué)轉(zhuǎn)化(calcium phosphate chemical conversion,CPCC)膜層。研究分析了膜層生長過程、膜層橫截面元素含量變化、log[Mg~(2+)]-p H熱力學(xué)穩(wěn)定相圖以及鎂基體電化學(xué)反應(yīng)產(chǎn)生的Mg~(2+)對CPCC膜層成膜的影響。結(jié)果表明,CPCC膜層具有三層復(fù)合結(jié)構(gòu):內(nèi)層為三水磷酸氫鎂(MHPT,Mg HPO_4?3H2O),厚度約為1.2μm;中間層由DCPD、磷鎂鈣礦(MWH,Ca9Mg(HPO_4)(PO_4)_6)和MHPT組成,厚度約為1.5μm;外層由DCPD和MWH組成,厚度約為2.5μm。研究了成膜時間對CPCC膜層的表面形貌及電化學(xué)行為的影響,成膜時間為20 min時的膜層具有最佳的耐腐蝕性能。體外浸泡試驗、細胞培養(yǎng)試驗以及體內(nèi)植入試驗結(jié)果表明,CPCC膜層具有良好的細胞粘附能力與細胞相容性,膜層涂覆鎂合金試樣的體內(nèi)外腐蝕降解速率明顯降低。2.由于CPCC膜層中的DCPD成分在堿性環(huán)境中很容易轉(zhuǎn)化為更穩(wěn)定的HA,因此,采用一種簡單的堿熱處理方法將CPCC膜層轉(zhuǎn)化為HA膜層。研究了堿熱處理時間對膜層組織形貌及電化學(xué)行為的影響,結(jié)果表明,堿熱處理1 h形成的HA膜層具有較為均勻致密的膜層結(jié)構(gòu)和明顯改善的耐蝕性能,在SBF中表現(xiàn)出較好的生物礦化能力。3.為了制備組織更加穩(wěn)定的氟摻雜HA(fluor-hydroxyapatite,FHA)膜層,在上述堿熱處理溶液中加入氟化物,探索一種新的氟熱處理方法。分析了氟熱處理溶液的p H值和處理時間對膜層形貌和電化學(xué)耐蝕性能的影響,確定最佳的氟熱處理工藝參數(shù)為p H=12,時間為2 h。經(jīng)過氟熱處理后,鎂合金表面的CPCC膜層轉(zhuǎn)化為主要由FHA、MWH和Mg F2組成的復(fù)合膜層。電化學(xué)和浸泡礦化試驗結(jié)果表明,氟化處理后的膜層具有比CPCC膜層和HA膜層更高的耐蝕性能和生物礦化能力。4.采用溶膠凝膠旋涂法在鎂合金CPCC多孔膜層表面制備了HA、FHA、FA三種溶膠凝膠膜層,膜層表面均勻致密,對鎂合金表面CPCC膜層具有良好的封孔效果。研究了溶膠凝膠膜層中的氟含量和溶膠凝膠層數(shù)對復(fù)合膜層的形貌和電化學(xué)耐蝕性能的影響,結(jié)果表明,5層的FA溶膠凝膠膜層具有最佳的封孔效果和最優(yōu)的電化學(xué)耐蝕性能。電化學(xué)和浸泡試驗結(jié)果表明,結(jié)構(gòu)穩(wěn)定無空隙的溶膠凝膠膜層顯著降低了鎂合金的腐蝕降解速率。5.采用粉末冶金法制備了不同質(zhì)量分數(shù)的微米級HA顆粒增強鎂基復(fù)合材料。電化學(xué)試驗結(jié)果表明,20%HA/Mg復(fù)合材料的腐蝕電流密度約為純鎂的五分之一,而10%HA/Mg的腐蝕電流密度約為純鎂的2倍。為了控制復(fù)合材料的腐蝕降解速度,將化學(xué)轉(zhuǎn)化方法和后續(xù)堿熱處理應(yīng)用到復(fù)合材料的表面處理上,在10%HA/Mg復(fù)合材料表面制備了CPCC膜層和HA膜層。通過與純鎂和AZ60鎂合金表面CPCC膜層沉積過程的對比,發(fā)現(xiàn)復(fù)合材料在膜層沉積過程中表面活化更快,形核率和生長速度明顯提高。電化學(xué)和浸泡試驗表明這兩種膜層,尤其是HA膜層,顯著提高了HA/Mg復(fù)合材料在SBF中的耐腐蝕性能和表面生物礦化能力。
[Abstract]:With the clinical application compared with stainless steel, titanium alloy and cobalt chromium alloy and other metal implant materials, magnesium and magnesium alloys as biomedical implant materials potential, has good mechanical compatibility, biocompatibility and biodegradability. However, magnesium alloy used as bone implant materials, corrosion and degradation in the body is too fast, resulting in the implants in bone tissue has not been fully repaired before it loses its mechanical integrity, but also produce excess hydrogen corrosion process would result in a loose connection between the implant and bone tissue, which limits the clinical application of magnesium and magnesium alloys as implant materials. In order to reduce the corrosion degradation rate of magnesium, usually high purification, alloying, composite materials and surface modification techniques to improve the corrosion resistance of magnesium. Compared with other techniques, on the surface of magnesium alloy for preparing biocompatible coating, can not only make the implant in The early implantation slow degradation rate, maintain good mechanical integrity, but the film in bone repair is complete failure to implant rapid degradation, can effectively improve the interface between the implant and bone tissue, accelerate bone healing. Because Ca and P are the main elements of bone mineral, calcium phosphate (Ca P) for example, two water (DCPD, Ca HPO_4, dicalcium phosphate, hydroxyapatite (2H2O) HA, Ca10 (PO_4) _6 (OH) _2), are compatible with natural biological activity and biological. Through chemical conversion method and sol-gel spin coating method is simple and easy to control method, preparation of calcium phosphate coating of different structure and in the morphology of magnesium alloy and composite surface, and then in a simulated body fluid (SBF) immersion test and electrochemical mineralization in the in vitro and in vivo implantation test on the corrosion behavior, the behavior of biomineralization and cell Compatibility was studied. The main research work is as follows: 1. using the chemical transformation method is simple and easy to control, on the surface of magnesium alloy prepared with calcium and phosphorus chemical compound layer structure transformation (calcium phosphate chemical conversion, CPCC) coatings. Research and analysis of the film growth process, the cross-sectional variation in element content of log[Mg~ film. (2+)]-p H thermodynamically stable phase diagram and the electrochemical reaction of magnesium matrix Mg~ (2+) film on the impact of CPCC film. The results show that the CPCC film has a composite structure of three layers: the inner layer is magnesium hydrogen phosphate trihydrate (MHPT, Mg HPO_4? 3H2O), the thickness is about 1.2 m; the middle layer is composed of DCPD stanfieldite, (MWH, Ca9Mg (HPO_4) (PO_4) _6) and MHPT, the thickness is about 1.5 m; the outer layer by DCPD and MWH. The effect of thickness is about 2.5 M. of the film time on the CPCC film surface morphology and electrochemical behavior, film forming time is 20 mi N coating has the best corrosion resistance. In vitro immersion test, cell culture test and in vivo test results show that the CPCC film has the ability of cell adhesion and cell compatibility, corrosion rate in vivo degradation of film coating of magnesium alloy.2. decreased significantly due to the DCPD component in CPCC coatings in alkaline environments easily converted into more stable HA, therefore, using a simple alkali heat treatment methods CPCC film into HA film. The alkali heat treatment time effect on morphology and electrochemical behavior of films, the results show that the alkali heat treatment 1 h formation of the HA film has more uniform and compact film structure corrosion resistance was significantly improved, showing fluorine doped HA good biological mineralization ability of.3. in order to prepare the organization more stable in SBF (fluor-hydroxyapatite, FHA) in the treatment of alkali heat film Fluoride solution, to explore a new treatment method of fluorine heat. The fluorine heat treatment solution P H value and the effect of treatment time on film morphology and electrochemical corrosion resistance, determine the parameters f the best heat treatment process for P H=12, time of 2 h. After fluoride after heat treatment, the surface of the magnesium alloy CPCC film into mainly by FHA, MWH and Mg composite film composed of F2. The electrochemical and immersion mineralization test results showed that the fluoride treated film is better than that of CPCC film and HA film corrosion resistance and biological mineralization of.4. by sol-gel spin coating method on CPCC magnesium alloy surface preparation of HA porous film FHA, FA, three kinds of sol gel coatings, uniform coating surface is compact, has good sealing effect on the surface of CPCC magnesium alloy film by sol-gel film. The fluorine content and sol gel layers on the film morphology and electrical Effect of chemical corrosion resistance, the results show that the electrochemical corrosion resistance of FA coating by sol gel layer 5 has the best sealing effect and optimal. The electrochemical and immersion test results show that the sol gel film structure stable void free significantly reduces the corrosion degradation rate of.5. magnesium alloy by powder metallurgy method of micron HA particles of different quality the fraction of reinforced magnesium matrix composites were prepared. The electrochemical test results show that the corrosion current density of 20%HA/Mg composite is about 1/5 mg, while the corrosion current density of 10%HA/Mg is about 2 times that of pure magnesium corrosion. In order to control the degradation speed of composite materials, the chemical conversion method and subsequent alkali heat treatment is applied to the surface processing of composite materials, on the surface of 10%HA/Mg composite material prepared CPCC film and HA film. With pure magnesium and CPCC magnesium alloy AZ60 surface film deposition process In contrast, the composite film deposition process of surface activation faster, the nucleation rate and growth rate was significantly improved. The electrochemical and immersion test showed that the two kinds of films, especially HA film, HA/Mg was significantly increased in SBF composite corrosion resistance and surface biological mineralization ability.

【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TG174.4

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