| One of the urgent problems of magnetic induction hyperthermia is how to heat up the tumor evenly to an effective treatment temperature, but do not damage normal tissue nearby. Because of small size effect.surface effect, interface effect and macroscopical quantum tunnel effect.nano powder tends to unite in the process of preparation, which leads to affect its various performance and subsequent biomedical application. A novel thermo-seed material with high thermal efficiency, good biocompatibility and good dispersion can carry out tumor target therapy. It will be a new way for the tumor hyperthermia, and has important scientific significance and practical value.In this experiment, with the good magnetic thermal properties of Mn-Zn ferrite materials, excellent biocompatibility and chemical stability of silica. Mn-Zn ferrite/ SiO2 composite materials were made by means of chemistry coprecipitation and Sol-gel method. Some influencing factors were studied systematically, and the preparation process was optimized. The main content and results are as follows.Mn-Zn ferrite former body power was synthesized by ammonium bicarbonate coprecipitation method, which was aged by hydrothermal treatment and sintering treatment respectively. The results show that the carbonates were obtained after hydrothermal treatment, which were formed by Fe2+, Mn2+, Zn2+ and carbonated root, the Mn-Zn ferrite with a spinel structure was obtained after sintering treatment.Base on the preparation of Mn-Zn ferrite powder, the process was optimized to search for the suitable parameters. These factors were mainly discussed:chemical composition and sintering temperature. Those conclusions can be indicated by means of XRD and TEM:(1) The position of specific peak basic in XRD map remained unchanged when the ratio of manganese and zinc was changed. The crystallinity of the product got deteriorated and the grain size became smaller along with the increase of Zn2+ content. (2) With the sintering temperature rised. Mn-Zn ferrite grain obviously growed up, the crystallinity of the product got improved, solid state reaction becomed more completely, the magnetic property increased, the specific saturation magnetization (Ms) got bigger, the coercivity (Hc) and the remanent magnetization (Mr) got smaller. When prepared by the temperature at 800℃and holding time for 5 hours, the grain size of the powder was satisfied, and this material had paramagnetic.Mn-Zn ferrite power was synthesized by ammonium oxalate coprecipitation method and sintering treatment. XRD results indicated that the products were mainly Mn-Zn ferrite, also contained a few Also contain a few Fe2O3. The influence of the sintering temperature on materials was discussed. When prepared by the temperature at 800℃and holding time for 5 hours, the grain size of the powder was satisfied. Compare with the latter precipitation agent, the product choosing ammonium bicarbonate as precipitation agent had higher purity. smaller grain size, higher specific saturation magnetization, lower coercivity and better magnetic property.By choosing citric acid as surface dispersants. Mn0.4Zn0.6Fe2O4 as matrix, TEOS as silicon source. Mn-Zn ferrite/SiO2 composite materials were made sucessfully by Sol-gel method. Those conclusions can be indicated by means of XRD, TEM and VSM:Mn-Zn ferrite grain distributed evenly, SiO2 distributed around the ferrite particles, which controlled the grain's renuion and growth to a certain degree. Along with the TEOS content increased, the coating process becomed more fully, the specific saturation magnetization and the coercivity reduced, the magnetic property decreased slowly, but the composite as-prepared still had magnetic response characteristics. |
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