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EP-4400485-B1 - CERAMIC MATERIAL OF CERAMIC ELECTRODE FOR ELECTRIC FIELD TREATMENT OF TUMORS, AND PREPARATION METHOD THEREFOR

EP4400485B1EP 4400485 B1EP4400485 B1EP 4400485B1EP-4400485-B1

Inventors

  • ZHANG, JIANYI
  • LIU, SHENGJUN
  • DUAN, Hongjie

Dates

Publication Date
20260506
Application Date
20220408

Claims (10)

  1. A method for preparing ceramic material of ceramic electrode for tumor treating fields, wherein the preparation method comprises the following steps: 1) synthesizing a[0.67Bi 0.995 Ce 0.005 FeO 3 -0.33BaTiO 3 ] - b[Sr 1-x Pb x Ti 1-y Zr y O 3 ] - c[Pb(Mg 1/3 Nb 2/3 )O 3 ] in one step by a solid phase method: synthesizing a[0.67Bi 0.995 Ce 0.005 FeO 3 -0.33BaTiO 3 ] - b[Sr 1-x Pb x Ti 1-y Zr y O 3 ] - c[Pb(Mg 1/3 Nb 2/3 )O 3 ] powder by taking Bi 2 O 3 , CeO 2 , Fe 2 O 3 , BaCO 3 , TiO 2 , SrCO 3 , Pb 3 O 4 , ZrO 2 , MgO, Nb 2 O 5 as raw materials under the temperature of 750 DEG C to 850 DEG C for 4 hours; Where 0<a<0.06, 0.05<b<0.18, a+b+c = 1; 0.6≤x≤0.8, 0<y<0.2; 2) carrying out fine grinding on the a[0.67Bi 0.995 Ce 0.005 FeO 3 -0.33BaTiO 3 ]-b[Sr 1-x Pb x Ti 1-y Zr y O 3 ]-c[Pb(Mg 1/3 Nb 2/3 )O 3 ] powder synthesized in the step 1), adding a binder for granulation after fine grinding, and carrying out compression molding to obtain a biscuit; 3) performing plastic discharge to remove organic substances in the biscuit; and 4) sintering that biscuit to obtain a ceramic material.
  2. The preparation method according to claim 1, wherein step 1) comprises: taking Bi 2 O 3 , CeO 2 , Fe 2 O 3 , BaCO 3 , TiO 2 , SrCO 3 , Pb 3 O 4 , ZrO 2 , MgO, Nb 2 O 5 as raw materials, proportioning according to the stoichiometric ratio of a[0.67Bi 0.995 Ce 0.005 FeO 3 -0.33BaTiO 3 ]-b[Sr 1-x Pb x Ti 1-y Zr y O 3 ]-c[Pb(Mg 1/3 Nb 2/3 )O 3 ] and mixing by a wet ball milling method; drying that mixed material; keeping the temperature for 4 hours at the temperature of 750-850 deg c to obtain a[0.67Bi 0.995 Ce 0.005 FeO 3 -0.33BaTiO 3 ]-b[Sr 1-x Pb x Ti 1-y Zr y O 3 ]-c[Pb(Mg 1/3 Nb 2/3 )O 3 ] powder; where 0<a<0.06, 0.05<b<0.18, a+b+c = 1; 0.6≤x≤0.8, 0<y<0.2 ∘
  3. The preparation method according to claim 1, wherein in the step 2), the qualities of the ceramic powder, the grinding ball and the deionized water are as follows: ceramic powder: grinding ball: deionized water = 1: (1.8-2): (0.6-0.8).
  4. The preparation method according to claim 1, wherein the fine grinding time is 24 to 48 hours.
  5. The preparation method according to claim 3, wherein the grinding balls are zirconia balls.
  6. The preparation method according to claim 1, wherein in step 2), the binder is PVA; the addition amount of the binder is 5-8% of the mass of the ceramic powder.
  7. The preparation method according to claim 1, wherein in the step 3), the temperature of the plastic discharge is 550 to 760 deg c, and the heat preservation time is 2 to 3 hours.
  8. The preparation method according to claim 1, wherein step 4) comprises: putting the biscuit into a crucible for close sintering, that sinter temperature is 1185-1250 deg c, the heating rate is 2 deg c/min-5 deg c/min, and the heat preservation time is 2-3 hours.
  9. Ceramic material of ceramic electrode for tumor treating fields, prepared by the preparation method according to claim 1.
  10. The ceramic material according to claim 9, wherein the ceramic material has a relative dielectric constant of greater than 20,000 and a dielectric loss of less than 0.0217 at room temperature when the frequency is in the range of 1 kHz to 1 MHz.

Description

Cross-reference to Related Application The present application is a continuation application of PCT application No. PCT/CN2022/085815 filed on April 8, 2022, which claims the benefit of Chinese Patent Application No. 202111036962.9 filed on September 6, 2021. Technical field The invention belongs to the technical field of functional ceramic materials, and particularly relates to ceramic material of ceramic electrode for tumor treating fields(TTF) and a preparation method thereof. Background art Biomedical research has shown that if an electric field is directly applied to the human body using metal electrodes, under the action of conductive current, the charged mineral ions in the cells of the human body will migrate, resulting in changes in the concentration of ions in the cells, which is harmful to the human body (PNAS, vol.104, pp10152-10157, 2007). In addition, because high conduction current is directly related to the life safety of the human body, the metal electrodes are used to apply an electric field for medical research and treatment, and the voltage cannot be too high, and the applied voltage is limited. According to the principles of physics, pure capacitors are insulated for conducting current and conductive to AC electric field. Therefore, in the experiment of clinical application of AC voltage, if the AC voltage is applied using the insulated ceramic capacitors as electrodes, the conductive current in human body can be avoided, and the side effects of the conductive current on cells can be avoided. In addition, the electric field applied to the human body through the capacitive electrode in the general treatment is localized, and only localized regions are subjected to the electric field. And due to the insulating nature of the capacitor, no current is conducted through the body area to which the electric field is applied. Application of an electric field treatment using an insulated capacitor electrode has a higher safety relative to a metal conductor electrode, and a higher voltage can be applied. Biomedical experiments have demonstrated that the application of an alternating voltage through an insulated capacitor electrode at a specific AC frequency can effectively inhibit the growth of specific abnormal cells (PNAS, vol.104, pp10152-10157, 2007). Under specific electric field frequencies, the electric field can effectively inhibit the growth of tumor cells in the brain of animals and humans. Experiments show that the higher the applied voltage, the better the treatment effect. But the voltage applied to the treatment is limited by the locally prescribed safe voltage. In clinical treatment, the applied voltage must be lower than the locally specified safe voltage due to safety requirements. The purpose is to prevent the occurrence of safety accidents once short-circuited. Therefore, on the premise that the applied voltage is limited, as the capacitive reactance of the capacitor is inversely proportional to the dielectric constant of the capacitor material, the capacitive reactance of the electrode made of the dielectric material with high dielectric constant is smaller. The voltage drop across the electrodes will be smaller. In this way, under the premise of certain safe voltage, the voltage applied to the head of the patient is higher, the treatment effect will be better. In addition, the capacitor material with high dielectric loss will generate heat under the electric field, affecting the operation of the capacitor electrode, and has the risk of heating and scalding patients. Therefore, by adopting the material with high dielectric constant and low loss, the electric field can be more effectively applied to the specific part of human body or animal directly needing research or treatment through the capacitor electrode sheet with low capacitive reactance. Based on the above application background, it is extremely urgent to find the dielectric material with high dielectric constant and low loss and make the capacitor electrode with low capacitive impedance and low loss to block the conduction current and conduct the electric field to realize different applications. (1-x)PMN-xPT [(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3] (x<1) is a ferroelectric material with a high dielectric constant. However, for the synthesis of materials in this system, if one-step synthesis is adopted, the pyrochlore impurity phase is easily obtained and the performance is deteriorated. In order to obtain single-phase materials with perovskite structure with good performance, two-step synthesis is generally required. In the first step, MgNb2O6 is synthesized at the temperature above 1000 deg c, and then MgNb2O6 is used as a part of raw materials to be mixed with other oxide raw materials for a second synthesis at the temperature above 800 deg c, and finally PMN-PT ceramic powder with a perovskite structure is obtained. The problem is that the two-step synthesis has complicated working procedures, long working hours and high ene