Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/9723
標題: 電解沉積ZrO2/HA生醫陶瓷薄膜於Ti-6Al-4V合金上之研究
The Study of Electrolytic Deposition ZrO2/HA Bioceramic Coatings on Ti-6Al-4V Alloy
作者: 林素苹
關鍵字: Hydroxyapatite;氫氧基磷灰石;ZrO2;electrolytically deposited;osteoblasts culture;composite coating;attachment;氧化鋯;電解沉積;細胞培養;複合鍍層;貼附
出版社: 材料工程學研究所
摘要: 
氫氧基磷灰石不但具生物親合性,甚至有可與骨組織產生化學鍵結的特性,當它植入與骨組織接觸後能在短期內促進骨組織的生長,所以它有引導骨生之能力,是一種生物活性材料。但由於受限於氫氧基磷灰石強度並不理想,而無法符合長期使用之要求,因此將之與氧化鋯(ZrO2)陶瓷薄膜結合被覆於金屬植入材上,一方面解決疲勞強度的問題並改善金屬生物親合性不佳及固定的問題(即增強植入材與組織間的鍵結);另一方面也可解決金屬材料釋放離子的問題。
本研究選擇以生醫用Ti-6Al-4V(ASTM F-136)合金為基材,利用電解沉積方式將氧化鋯(ZrO2)陶瓷薄膜沉積於基材上,藉由控制不同的電化學參數製程(改變濃度、沉積電位與時間),尋找出最佳沉積條件後再進一步由Ca/P比值為1.67之Ca(NO3)2 ∙4H2O及NH4H2PO4的混合溶液沉積氫氧基磷灰石的陶瓷薄膜於ZrO2鍍層上,結果發現氫氧基磷灰石能填進氧化鋯陶瓷薄膜層,而在Ti-6Al-4V基材表面形成ZrO2/HA之介面層,再經由後續的燒結使其薄膜層與基材形成更穩定之鍵結。選擇適當的鍍膜條件後,將製備後的ZrO2、HA及ZrO2/HA鍍層藉由XRD、SEM/EDS、膜厚測定儀、恆定電位儀(動態極化測試)、刮痕試驗機、微硬度試驗機及浸泡試驗進一步來探討這三種鍍層之特性,並作細胞培養測試來觀察細胞在鍍層上之生長及附著情形。
由於氧化鋯陶瓷薄膜具有優異的機械性質,在耐腐蝕性及抗磨耗性方面亦都有優異的表現,最重要的一點是它與基材的附著性非常好且又有高強度的韌性。所以,本實驗的目的是希望在基材上先披覆一層氧化鋯陶瓷薄膜來提高它的抗腐蝕及耐磨耗性,並藉著在其上面披覆另一層氫氧基磷灰石陶瓷薄膜來增加它的生物活性,引導骨細胞的生長,並且能與骨組織直接產生化學鍵結。
配合ZrO(NO3)2溶液、Ca(NO3)2 ∙4H2O及NH4H2PO4之混合溶液的陰極極化曲線可知,在C6、V3、td3的條件下沉積氧化鋯後再以T d1、V3、td4之條件沉積氫氧基磷灰石可得一較佳的複合鍍層。且經由循環極化的實驗結果也顯示,具ZrO2/HA複合鍍層比基材及單層HA鍍層具有抗蝕的效果,這是因為薄膜緻密性較佳的結果所造成。
由刮痕試驗及超音波震盪測試結果知,具有ZrO2/HA複合鍍層之試片有極佳的附著力,其附著力可達34N,比單層HA鍍層之附著力還好。配合SEM/EDS可將刮痕分成二個階段:第一階段為單純彈性壓應變之摩擦,對薄膜沒有任何影響;第二階段為鍍膜被壓破,而此時在薄膜上只出現裂紋,ZrO2/HA鍍層幾乎還是完整附著在基材上,到了較末段處HA鍍層才逐漸被刮起。
在浸泡試驗的結果知,將具有HA及ZrO2/HA複合鍍層之試片浸泡於模擬的人體體液中時,鍍層不但不會有附著性不佳而剝落的現象出現反而有再析出的能力。此結果可配合XRD的分析知,在28.13、29.18、45.5、56.2及66.28(其晶格面為(102)、(210)、(203)、(500)及(143))等角度的地方並會有這些新的HA peak出現。同時,由SEM觀察其表面型態亦可發現,具有HA及ZrO2/HA複合鍍層之試片表面會自發性析出片狀的磷灰石結構而變的更緻密。
在細胞培養測試部份:以骨母細胞體外培養方式來探應用在骨科領域之不同陶瓷鍍層及Ti Alloy基材對骨母細胞的初期生物反應(附著力、型態變化及生長指數)。由實驗結果知,骨母細胞可在1~2天內附著在基材及所有鍍層表面,其中以具有HA及ZrO2/HA複合鍍層之試片,細胞更能完全貼附而穩定持續生長。在附著型態及生長狀況方面,以PS(Poly-Styrene)作為對照組並進行比較,可發現ZrO2/HA複合鍍層最佳,HA鍍層其次,而在基材及ZrO2鍍層上雖然細胞亦有貼附,但其生長狀況較前面兩著差。故由以上結果知,先沉積ZrO2再沉積HA所形成的複合鍍層並不會影響細胞的貼附與生長,且細胞的生長情況良好,而由此也得到證明,氫氧基磷灰石具有引導骨細胞貼附、生長的能力。

Hydroxyapatite(HA)has been used for bone substitution, middle
ear reconstruction, orthopedic and dental application, because of its favorable bioactivity, superior compatibility with these tissues and very tight bond with living bone. However, the principle limitation of this material is its low mechanical strength and brittleness which restrict the clinical orthopaedic and dental applications for long - term used. In this study, electrolytic ZrO2/HA composite coating was conducted to increase the hardness and bonding strength of HA on implant alloy.
Ti-6Al-4V alloy (ASTM F-136)was selected as the substrate and electrolytically deposited with ZrO2/HA in an aqueous solution of zirconyl nitrate(ZrO(NO3)2)and in the mixed of solution Ca(NO3)2 · 4H2O and NH4H2PO4(the ration of Ca/P is 1.67), respectively. By controlling the electrochemical parameters such as concentration, potential and time, the best deposited condition for ZrO2 /HA coating on Ti-6Al-4V alloy substrate has been investigated. It was found that HA can fill into ZrO2 layers and form composite coated films of ZrO2/HA on Ti-6Al-4V alloy substrate. Coated specimes were further characterized by using XRD, SEM/EDS, porfilemetry tests, polarization tests, scratch tests, vickers hardness tests and immersion tests, respecpively. Finally, in vitro tests of osteoblasts culture were conducted to study the bio-compatibility and cell adhesion for various coatings.
Scratch tests showed that the adhesion of ZrO2/HA composite coating on Ti-6Al-4V alloy substrate can resist the load up to 34N which revealed an excellent adhesion with substrate. Combining SEM/EDS observations , the scratch test of ZrO2/HA composite coating contains 2 stages: 1. the coatings only beared elastic pressure strain(1N~34N); 2. the HA coating was crushed in advance and gradually worn away.
Through the cyclic polarization tests in Hank's solution, it was found that the corrosion potential and protection potential of the ZrO2/HA composite coating is higher, and passivation and corrosion currents are lower than HA coated or uncoated. In other words, the composite coating showed the greater corrosion resistance. The immersion tests in Hank's solution indicated that HA films can further precipitate on both HA and ZrO2/HA composite coatings, and the growth rate of the latter was much greater.
Osteoblast culture wells were seated with different implant materials, including electrodeposition ceramic coating(HA, ZrO2/HA and ZrO2)and Ti-6Al-4V alloy, with poly - styrene(PS)well as the control. The cultures were investigated with SEM and growth index in order to observe the effect of different implant materials on the osteoblasts in adherence morphology, growth and proliferation. The osteoblast showed better and faster attachment on ZrO2/HA and HA coatings than ZrO2 coating and Ti-6Al-4V alloy. From SEM observations and growth index, osteoblast cultured on ZrO2/HA composite coating and HA coating exhibited a more confluent and compact structure, and a higher proliferation rate. The bone in-growth of Hydroxyapatite(HA)was proved again .
URI: http://hdl.handle.net/11455/9723
Appears in Collections:材料科學與工程學系

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