Environment-Friendly and Low Toxicity Polishing Solution Preparation and Performance Testing for Medical Titanium Alloy Materials

For further reducing the environmental hazard of waste polishing solution and surface toxicity of medical titanium alloy materials, an environment-friendly and low toxicity polishing solution was proposed. The simulated Hanks's solution was chosen as the basic liquid considering of the compatibility with the body environment. The silicon dioxide abrasive with particle diameter of 3.5 μm was added for the grinding mediums. Then, the citric acid (H₃Cit) was used as the complexing agent and the glycerol was used as dispersant. After this, the chemical mechanical polishing experiments were carried out with titanium alloy materials, and the material removal rate (MRR) and surface roughness Ra were obtained for evaluating its performance. Moreover, the surface elemental composition of the samples after polishing was detected using scanning electron microscope and energy-dispersive spectrometer (EDS). The findings showed that the highest MRR of 0.66 μm/min and the lowest surface roughness of 0.043 μm were achieved. However, the toxic residues on the titanium alloy surface are dramatically decreased, which meets the need for its application in the field of medicine. The analysis results indicate that complexation reaction occurred between the aluminum ions and citrate ions, which makes the toxic residues less on the surface of titanium alloy. In addition, citric acid is biodegradable and does not pollute the environment. This paper provides a new environment-friendly and low toxicity polishing solution to reduce the toxic residues on the surface of medical titanium alloy materials.