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CN-121974682-A - Low-impulse ceramic PTC material and preparation process thereof

CN121974682ACN 121974682 ACN121974682 ACN 121974682ACN-121974682-A

Abstract

The invention relates to a low-impulse ceramic PTC material and a preparation process thereof, belonging to the technical field of ceramic PTC materials. According to the invention, on one hand, the pinning effect is formed by heavy donor and heavy acceptor doping, and the NTC effect is reduced, so that the surge is reduced, and on the other hand, excessive silicon oxide is introduced to adsorb impurities, so that the NTC effect is reduced, and the surge is reduced. The invention can reduce the impulse flow on the premise of not changing the starting current and has excellent application prospect.

Inventors

  • LI XINGYUN

Assignees

  • 上海欣帕电子科技有限公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (9)

  1. 1. The low-impact ceramic PTC material is characterized by comprising the following raw materials in parts by mole: 0.4 part of barium carbonate, and the balance of the barium carbonate, 0.5 Part of titanium dioxide, and the like, 0.1 Part of lead oxide and the like, 0.009-0.011 Parts of niobium pentoxide, 0.018-0.022 Parts of manganese carbonate, 0.0036-0.0044 Parts of silicon dioxide; Wherein the following relationships are required to be satisfied in the raw materials: The molar ratio of the manganese carbonate to the niobium pentoxide is (1.8-2.2): 1, and the molar ratio of the silicon dioxide to the manganese carbonate is (0.18-0.22): 1.
  2. 2. A process for preparing a low-impact ceramic PTC material according to claim 1 comprising the steps of: s1, ball milling and synthesizing for the first time: Weighing barium carbonate, titanium dioxide, lead tetraoxide, niobium pentoxide, manganese carbonate and silicon dioxide according to a formula, mixing to obtain raw materials, performing primary ball milling on the raw materials by taking zirconia balls and deionized water as media to obtain primary ball milling slurry, and synthesizing after drying to obtain synthetic powder; s2, secondary ball milling and granulating: Performing secondary ball milling on the synthesized powder, a solvent, a grinding medium and a binder to obtain secondary ball milling slurry, and performing spray granulation on the ball milling slurry to obtain granulated powder; S3, molding and sintering: dry-pressing the granulated powder to obtain a green body, and sintering in an air atmosphere to obtain a ceramic matrix; s4, aluminum spraying: and ball milling the surface of the ceramic matrix and spraying an aluminum electrode to obtain the low-impact ceramic PTC material.
  3. 3. The process for preparing a low-impact ceramic PTC material according to claim 2, wherein in the step S1, the temperature during synthesis is 1100-1250 ℃, and the heat preservation time is 1-3 h.
  4. 4. The process for preparing a low-impact ceramic PTC material according to claim 2, wherein in step S2, the binder is polyvinyl alcohol, polyvinyl butyral and hydroxymethyl cellulose in a mass ratio of 2:0.5:1, wherein the polyvinyl alcohol is an aqueous solution of polyvinyl alcohol having a concentration of 8.0 to 10.0 wt%.
  5. 5. The process for preparing a low-impact ceramic PTC material according to claim 2, wherein the binder is added in an amount of 5.0 to 8.0wt% based on the weight of the synthetic powder in step S2.
  6. 6. The process for preparing a low-impact ceramic PTC material according to claim 2, wherein in step S2, the particle size of the granulated powder is 100 to 200 mesh.
  7. 7. The process for preparing a low-impact ceramic PTC material according to claim 2, wherein in step S3, the sintering temperature is 1200 to 1300 ℃, and the heat preservation time is 0.5 to 2 hours.
  8. 8. The process for preparing a low-impact ceramic PTC material according to claim 2, wherein in step S3, the dry-press molding is performed under a pressure of 15 to 20mpa.
  9. 9. The process for preparing a low-rush current ceramic PTC material according to claim 2 wherein in step S3, the sintering process is performed in an air atmosphere in a closed environment.

Description

Low-impulse ceramic PTC material and preparation process thereof Technical Field The invention belongs to the technical field of ceramic PTC materials, and relates to a low-impulse ceramic PTC material and a preparation process thereof. Background Ceramic PTC elements experience significant current surge (i.e., rush current, also known as maximum current) during cold start-up in automotive heater applications and the like. Specifically, the initial current may reach about 11.75A (corresponding to 0.235 times the rated current coefficient) at start-up, and after about 0.8s, the current may quickly rise to a peak value, which may reach about 49.40A (corresponding to 0.988 times the rated current coefficient). The instantaneous high current can cause multiple negative effects on the automobile circuit system, including but not limited to causing voltage fluctuation and current disturbance of a power grid, leading to premature aging of fuses and relays, generating arc ablation risks on power devices such as IGBT and the like, and accelerating component fatigue due to repeated thermal stress impact, so that the service lives of related components are shortened, and potential safety hazards are more likely to be brought. At present, a common coping idea in the industry is to directly reduce the starting current of the ceramic PTC, thereby indirectly reducing the rush current. However, the scheme has the obvious defect that the reduction of the starting current directly leads to the reduction of the initial heating power of the heater, influences the rapid heating performance and user experience of the system, and is difficult to be suitable for vehicle-mounted environments requiring rapid heating. Therefore, the prior art fails to effectively solve the core contradiction of "suppressing the rush current without sacrificing the start-up heating power". Therefore, there is a need to develop a low-rush ceramic PTC material capable of effectively suppressing a rush current, which can effectively suppress a peak rush current while maintaining the heater start-up power (i.e., without reducing the start-up current), thereby fundamentally relieving the impact thereof on the automotive electrical system. Disclosure of Invention The invention aims to provide a low-impulse ceramic PTC material and a preparation process thereof, and has the advantages that impulse is reduced only, starting current is not changed, and compared with the prior art, starting current is reduced, and a power scheme is influenced, the low-impulse ceramic PTC material has a better application prospect. The ceramic PTC material takes barium titanate as a matrix, and generates redundant electrons in crystal lattices by doping donor impurities (such as Y3+, la3+ for replacing Ba2+ or Nb 5⁺、Sb5 + for replacing Ti 4 +), so that the ceramic PTC material has n-type semiconductor characteristics at room temperature, provides more energy for donor atoms which are not ionized with the increase of temperature in a range from room temperature to Curie temperature, enables the donor atoms to be ionized further, releases new free electrons to cause the reduction of resistance (NTC effect), and is influenced by resistance change to generate a current. The invention ensures the power of the heater and reduces the impulse flow on the premise of not reducing the starting current. The aim of the invention can be achieved by the following technical scheme: the low-impact ceramic PTC material comprises the following raw materials in parts by mole: 0.4 part of barium carbonate, and the balance of the barium carbonate, 0.5 Part of titanium dioxide, and the like, 0.1 Part of lead oxide and the like, 0.009-0.011 Parts of niobium pentoxide, 0.018-0.022 Parts of manganese carbonate, 0.0036-0.0044 Parts of silicon dioxide; Wherein the following relationships are required to be satisfied in the raw materials: The molar ratio of the manganese carbonate to the niobium pentoxide is (1.8-2.2): 1, and the molar ratio of the silicon dioxide to the manganese carbonate is (0.18-0.22): 1. A preparation process of a low-impulse ceramic PTC material comprises the following steps: s1, ball milling and synthesizing for the first time: Weighing barium carbonate, titanium dioxide, lead tetraoxide, niobium pentoxide, manganese carbonate and silicon dioxide according to a formula, mixing to obtain raw materials, performing primary ball milling on the raw materials by taking zirconia balls and deionized water as media to obtain primary ball milling slurry, and synthesizing after drying to obtain synthetic powder; s2, secondary ball milling and granulating: Performing secondary ball milling on the synthesized powder, a solvent, a grinding medium and a binder to obtain secondary ball milling slurry, and performing spray granulation on the ball milling slurry to obtain granulated powder; S3, molding and sintering: dry-pressing the granulated powder to obtain a green body, and sintering in an air at