生物活性梯度涂层中羟基磷灰石的相转变与结构稳定性

PHASE TRANSITION AND STRUCTURAL STABILITY OF HYDROXYAPATITE IN BIOACTIVE GRADIENT COATINGS

重点研究了生物活性梯度涂层中羟基磷灰石高温结构稳定性．探讨了羟基磷灰石在喷涂和热处理过程中的相变化，对比研究了不同热处理条件对羟基磷灰石晶体稳定性和羟基恢复的影响．发现经等离子喷涂后的生物活性梯度涂层中的羟基磷灰石结晶程度明显降低，并出现β－ＴＣＰ杂相．羟基磷灰石晶体中的羟基已完全分解脱落．适当条件的热处理可使喷涂涂层中的磷酸三钙转变为羟基磷灰石，晶体中的羟基可大部分恢复，其中大气热处理比真空热处理更有利于羟基的恢复．

Structural stability of hydroxyapatite at high temperature in bioactive gradient coatings was studied. Phase changes of hydroxyapatite in the processes of plasma_spray and heat treatment were explored. The influences of different heat treatment conditions on stability of crystal structure and OH - were studied. Hydroxyapatite in coating changes to noncrystallinity and β -TCP partly , and OH - in hydroxyapatite have dissolved fully after plasma_sprayed. Tricalcium phosphate can change back to hydroxyapatite in the process of heat treatment under suitable condition.OH - in hydroxyapatite crystal can be recovered in heat treatment. For the resurgence of OH -, atmospheric heat treatment is better than vacuum process.