Preparation Of TiO₂@Sb-SnO₂ Composite Nano-conductive Powder Ang Its Conductive Properties

The non-conductive properties of the plastic shell and polymer coating of instruments and equipment make them produce electrostatic accumulation in the process of use.The accumulation and release of static electricity have the potential danger of fire and damage to meters,electrical equipment,devices and household appliances.In this paper,the preparation and conductivity of TiO₂composite conductive powders coated with Sb doped SnO₂（TiO₂@Sb-SnO₂）were studied.（1）Titanate whiskers of different sizes were synthesized by hydrothermal method,and the rutile phase TiO₂@Sb-SnO₂composite nano-conductive powder was prepared by chemical coprecipitation combined with hydrothermal method using titanate whiskers as base.The electrical conductivity of rutile phase TiO₂@Sb-SnO₂composite nano-conductive powder and its effect on improving the electrical conductivity of polyester paint film were studied.（2）Titanate whiskers was synthesized by calcination,anatase phase TiO₂nanorods were prepared by acid treatment and calcination;Anatase phase TiO₂@Sb-SnO₂composite nano-conductive powder was prepared by chemical coprecipitation combined with calcination.The electrical conductivity of anatase phase TiO₂@Sb-SnO₂composite nano-conductive powder and its effect on improving the electrical conductivity of polyester,epoxy and phenolic paint films were studied.The research results of this paper are summarized as follows.（1）Titanate whiskers was synthesized by hydrothermal method using sodium hydroxide and metasilinic acid as raw materials.The effects of molar ratio,hydrothermal temperature and hydrothermal time on the structure and morphology of sodium titanate whisker were studied.Higher molar ratio of Na OH/H₂TiO₃and longer hydrothermal reaction time are favorable for crystal growth of titanate whisker.Under the conditions of molar ratio of Na OH/H₂TiO₃raw material 4:1,hydrothermal temperature 175℃and hydrothermal time 96 h,sodium titanate was synthesized as the base,Sn Cl₄·5H₂O and Sb Cl₃as Sn and Sb sources,and NH₃·H₂O as precipitator.Rutile TiO₂@Sb-SnO₂composite nanometer conductive materials were synthesized by chemical coprecipitation combined with hydrothermal method.XRD,SEM,HRTEM,XPS,EDS and four probe testers were used to characterize the phase structure,morphology and conductivity of the composite nanometer conductive powder.It was found that Sb doped SnO₂nanoparticles promoted the phase transition from titanate to rutile TiO₂during the hydrothermal reaction.XPS analysis shows that the oxidation states of Tin and antimony are Sn⁴⁺,Sb⁵⁺and Sb³⁺,respectively.TEM and HRTEM analysis showed that Sb-doped SnO₂nanoparticles with an average particle size of about 1.5 nm were uniformly bonded on the surface of TiO₂nanoparticles with an average particle size of about 20 nm.The minimum resistivity of TiO₂@（1%）Sb-（10%）SnO₂composite nano-conductive powder is 5.97×10³Ω·cm.With the addition of TiO₂@Sb-SnO₂composite nano-powder,the resistance of mylar film decreases.Filling TiO₂@Sb-SnO₂composite nano-powder can improve the conductivity of waterborne polyester film and give it electrostatic dissipation ability.（2）Potassium tetrtitanate（K₂Ti₄O₉）nanorods were synthesized by calcination using TiO₂and K₂CO₃as raw materials.Potassium tetrtitanate(K_0.3H_1.7Ti₄O₉)nanorods with low potassium content were synthesized by boiling and acid boiling.Anatase TiO₂nanorods were synthesized by calcining K_0.3H_1.7Ti₄O₉nanorods at 400-800℃.The effect of calcination temperature on the phase structure and morphology of TiO₂was studied.The results show that high calcination temperature is conducive to the crystallization of anatase TiO₂samples and leads to the shrinkage of TiO₂nanorods.Using Sn Cl₄·5H₂O and Sb Cl₃as Sn and Sb precursors and anatase TiO₂nanorods as base materials,TiO₂@SnO₂and TiO₂@Sb-SnO₂composite conductive powders were prepared by chemical coprecipitation combined with calcination.XRD,SEM,HRTEM,XPS,EDS and four probe testers were used to analyze the phase structure,morphology and conductivity of the composite nano conductive powder.SEM and EDS analysis showed that SnO₂and Sb-SnO₂nanoparticles with average diameter less than 2 nm were well combined on TiO₂substrate surface after calcination at 600℃.The XPS analysis shows that the oxidation states of Sn and Sb are Sn⁴⁺,Sb⁵⁺and Sb³⁺,and the proportion of Sb⁵⁺/(Sb⁵⁺+Sb³⁺)increases with the increase of Sb content（from 1wt%to 5wt%）,which gives TiO₂@Sb-SnO₂composite nano-powder higher electrical conductivity.The resistivity of TiO₂@（5%）Sb-（20%）SnO₂composite nano-powder prepared on the basis of TiO₂nanorods synthesized at 800℃was as low as 220Ω·cm.The filling of TiO₂@Sb-SnO₂composite nano-powder improves the conductivity of polyester,epoxy and phenolic paint films and endows them with good electrostatic dissipation ability.