A Study On The Synthesis Of ZrSiO₄ Powder And The Preparation Of ZrSiO₄ Coating

Zirconium silicate,ZrSiO₄,is the island structure of silicate minerals.It has the properties of high melting point,low heat conductivity,low expansion coefficient,excellent chemical and phase stability.It is widely used in refractory,pigment and ceramic industries.Sintered zirconium silicate has excellent thermal shock resistance,so it is an important candidate material for high temperature structural ceramics,it has been applied to protecting the surface of metal materials in the corrosive environment.In this thesis,synthesis of zirconium silicate by new chemical routes and preparation of zirconium silicate coating on titanium have been studied.One studied route of zirconium silicate synthesis is sol-gel method. By choosing a suitable mineralizer,zirconium silicate precusor was synthesized.High purity zirconium silicate was obtained by firing the precusor at 800℃which is much lower than the ordinary synthesis temperature(1400℃). Another studied synthesis route is microemulsion method.ZrSiO₄ precursor was synthesized by reaction in a W/O microemulsion made by water/TX-10/cyclohexane.The precusor was then heat treated at high temperature to obtain zirconium silicate.The use of microemulsion can control the particle size and the distribution of the final powder.The microemulsion route also has relative low firing temperature.ZrSiO₄ coatings on titanium substrates were obtained by Plasma-spray method.The coating thickness is about 0.5mm.Laser treatment of the sprayed coating can reduce the surface porosity of the coating.ZrSiO₄ coatings on pure titanium was also obtained by electrophoris deposition(EPD) method in acetone and ethanol solution.The best volume ratio of acetone and ethanol is 1:3 under the deposition voltage of 30V/cm and in 4 minutes deposition time.After heat-treatment,the coating had an excellent corrosion in acid.