This study reports the effect of sodium fluoride on the dissolution kinetics of pure metallic titanium in a citric acid solution. The effects of sodium fluoride concentration, citric acid concentration, temperature, stirring speed, and disc surface area were examined. The dissolution rate of titanium increases strongly with increasing citric acid and sodium fluoride concentrations. Fluoride ions react with hydrogen ions to form hydrofluoric acid, which removes the passive layer of titanium dioxide. An increase in the concentration of NaF and acid causes the formation of a brown layer on the surface of titanium. X-ray diffraction and SEM-EDX analyses showed that the layer composition is mostly of titanium fluoride (TiF) and titanium fluoride oxide (TiOF). A mixed kinetic model with an activation energy of 26.4 kJ/mol can be used to explain the reaction kinetics.

中文翻译：

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转盘法氟化钠对柠檬酸溶液中金属钛溶解动力学的影响


本研究报告了氟化钠对柠檬酸溶液中纯金属钛溶解动力学的影响。研究了氟化钠浓度、柠檬酸浓度、温度、搅拌速度和圆盘表面积的影响。钛的溶解速率随着柠檬酸和氟化钠浓度的增加而急剧增加。氟离子与氢离子反应形成氢氟酸，去除二氧化钛的钝化层。 NaF和酸浓度的增加导致钛表面形成棕色层。 X射线衍射和SEM-EDX分析表明该层的成分主要是氟化钛(TiF)和氟化钛氧化物(TiOF)。活化能为 26.4 kJ/mol 的混合动力学模型可用于解释反应动力学。