Research On NiZn Power Ferrite Material With High Strength And Resisitance To Thermal Shock

The application of N iZn power ferrite is becoming more and more extensive in the field of electronic technology.In view of the development miniaturization,integration and chip of electronic devices,as well as the promotion of lead-free solder technology,this paper aims to gain a kind of power N iZn ferrite material which has both electromagnetic and thermal shock resistance properties.Through the basic formula adjustment,process improvement,multiple compound doping and other means,the paper finally get the kind of N iZn power ferrite material which has the properties of high saturation magnetic induction Bs,high initial permeability μi,low loss,high strength and excellent thermal shock resistance.Firstly,the effects of ZnO content and C uO content on the properties of N iZn ferrite were studied in order to obtain N iZn ferrite materials with both electromagnetic properties,mechanical strength and thermal shock resistance.After analyzing the properties of the materials,a kind of N iZn ferrite base formula with good microstructure,excellent electromagnetic performance and relatively high mechanical strength was determined.Secondly,Bi₂O₃-SnO₂,Bi₂O₃-MgO,Bi₂O₃-Al₂O₃,Bi₂O₃-SnO₂-CaO₃-SiO₂,Bi₂O₃-Sn O₂-MgO-SiO₂ composite doping’s effects on the electromagnetic properties were studied on the basis formula.Studies have shown that the appropriate amount of SnO₂ doping can promote grain growth,reduce porosity,to ensure good electromagnetic performance,while improving the mechanical strength and thermal shock resistance.0.3wt% Bi₂O₃ + 0.1wt% MgO doping can promote grain growth,while ensuring the magnetic loss is low,while improving the electromagnetic properties and thermal s hock resistance.Doped with 0.3 wt% Bi₂O₃ + 0.2wt% Al₂O₃,the sample density was improved,the magnetic loss was obviously reduced,the strength was increased to 150 MPa,and the sample integrity rate is up to 95%.Bi₂O₃-SnO₂-MgO-SiO₂ composite doping improved the mechanical strength to 180 MPa,showing excellent thermal shock resistance.Doped with 0.05wt% CaCO₃ + 0.15wt% SiO₂,the saturation magnetic induction intensity reached 420 mT,the initial permeability was close to 650,the relative magnetic loss factor was less than 100 × 10-6,and showed excellent thermal shock resistance.Thirdly,a large number of experiments and analysis were studied in the mechanical strength of materials and thermal shock performance.According to the theoretical basis of mechanical strength and thermal shock,the factors influencing its performance were analyzed.The influence on the mechanical strength and thermal shock resistance of the material was explained from the microscopic mechanism of gra in size,compactness,porosity,grain boundary thickness and quantity.