Preparation And Properties Of Zr₂P₂WO₁₂ And Zr₂P₂WO₁₂/PI Composites

In recent years,the field of materials science has developed rapidly,and the thermal expansion performance of materials has become one of the most important problems in the material industry,which is very important for studying the thermal stability of materials.However,due to the existence of temperature gradient between the inside and the surface of the object,thermal expansion caused by thermal expansion and contraction will lead to micro-cracks or even fracture device.It is precisely because of the emergence of negative thermal expansion material,making the negative expansion of materials and positive expansion of the material and the preparation of near-zero expansion of materials,controllable thermal expansion material can be achieved.Usually the solid material is composed of different size particles,particle size seriously affected the structure and performance of the material,so to carry out the material particle size control and characterization research is necessary.Zr₂P₂WO₁₂?ZWP?is an excellent negative thermal expansion material which exhibits a negative thermal expansion property over a wide temperature range of room temperature to 1073 K with a thermal expansion coefficient of about-3^-5×10-6/K and has excellent chemical stability,Thermal stability and low cost of raw materials,no phase change,and therefore favored.In this paper,the negative thermal expansion material Zr₂P₂WO₁₂ was prepared by solid state reaction method,and the particle size of the negative expansion ceramic was controlled by different milling time.The effect of particle size on the properties of Zr₂P₂WO₁₂ was studied in detail.At the same time,the inexpensive polymer-based Zr₂P₂WO₁₂/PI composites were prepared on the basis of maintaining the original thermal stability and dielectric properties of polyimide by in-situ polymerization method,and the Fourier Infrared spectroscopy,microstructure,thermal expansion properties,thermal stability,compactness and electrical properties were investigated.The main research results are as follows:1.The results show that with the increase of milling time,the particles of Zr₂P₂WO₁₂ powder obtained by different milling time?2h,12 h,24h,48 h,72h,96h?are observed by scanning electron microscopy and related software.The diameter of the powder is reduced from 2700 nm of ball milling to 650 nm of ball milling for 96 h,and the particle size of the ceramic material is optimized.2.The results show that the thermal expansion coefficient of the ceramic material decreases with the increase of the milling time,and the relative density and Vickers hardness increase with the increase of the milling time of the Zr₂P₂WO₁₂ negative swelling material prepared under different milling times.The dielectric properties of the composites have been improved,and the composite dielectric properties are better at 96 h after ball milling: the lower dielectric constant and dielectric loss are 4.7 and 0.0316,respectively.3.Zr₂P₂WO₁₂/PI composites were prepared by in-situ polymerization method.The properties of the composites were tested.The results show that the thermal expansion coefficient of the composites decreases with the increase of ZWP content,and the thermal stability is improved.The dielectric constant is reduced and the relative density and Vickers hardness increase.These two materials achieve an effective compound,achieving the desired effect.