微束等离子喷涂气体对HA涂层结晶度的影响
Effect of microplasma spraying working gas on crystallinity of HA coatings
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摘要: 采用微束等离子喷涂方法,分别选用工业纯氩气和含50%氦气的氦氩混合气体为工作气体,在Ti-6Al-4V基体上制备羟基磷灰石涂层.通过SEM和XRD对涂层形貌、相组成和结晶度进行研究.结果表明,两种工作气体均可以制备杂质相含量少且不产生TTCP(磷酸四钙)和CaO等杂质相的涂层,结晶度高于70%,对植入体在体内的稳定性有利.采用氦氩混合气体为工作气体的微束等离子弧热焓值高于氩气工作气体,前者涂层中的结晶相主要以再结晶的为主,后者结晶相以大量未熔HA内核为主.Abstract: Hydroxyapatite(HA) coatings were prepared on Ti-6Al-4V substrate by using the method of microplasma spraying.Commercially pure argon gas and helium/argon(50% in volume) mixed gas were used as working gas in the spraying processing respectively.The surface morphology, phase compositions and degree of crystallinity of the coatings were examined by scanning electron microscope(SEM) and X-ray diffraction(XRD).Results show that less impurity phases and no TTCP and CaO phases were found in the coatings.The crystallinity of coatings is higher than 70%, which is beneficial for implantation materials stability in vitro and vivo.The enthalpy of microplasma arc in which helium/argon mixed is used as working gas is higher than that in which commercially pure argon gas is used.The crystalline phases in the former coatings mainly consist of recrystallization grains while the latter coatings were mainly made up of lots of unmelted HA particles.