Carbonyl iron powder/lanthanum strontium manganate composite and preparation method thereof

Abstract

The invention discloses a carbonyl iron powder / lanthanum strontium manganate composite and a preparation method thereof. The composite is formed by mixing the following components in percentage by weight: 7.25 to 98.75 percent of carbonyl iron powder and 1.25 to 22.75 percent of La1-xSrxMnO3 powder, wherein x in the La1-xSrxMnO3 powder is between 0.25 and 0.55. The method comprises the following steps of: adding lanthanum oxide, strontium carbonate and manganese carbonate into aqueous solution of hydrogen nitrate according to a stoichiometric ratio of La1-xSrxMnO3 to obtain mixed liquor, and adding citric acid into the mixed liquor at the temperature of between 60 and 95 DEG C to obtain intermediate liquor; adding ammonia water into the intermediate liquor dropwise until the pH value is between 6 and 7, stirring at the temperature of between 60 and 95 DEG C to form gel, and performing heat preservation on the gel at the temperature of between 100 and 150 DEG C to obtain gel dry powder; presintering the gel dry powder at the temperature of between 200 and 350 DEG C for 2 to 4 hours, and grinding to obtain powder; performing heat treatment on the powder at the temperature of between650 and 800 DEG C for 2 to 8 hours to obtain the La1-xSrxMnO3 powder; and mixing the carbonyl iron powder and the La1-xSrxMnO3 powder according to the required ratio to obtain the composite. The carbonyl iron powder / lanthanum strontium manganate composite can absorb electromagnetic waves uniformly and effectively within the frequency range of between 8 and 12 GHz under the condition that the thickness is less than 1 millimeter.

Description

technical field [0001] The invention relates to a composite material and a preparation method, in particular to a carbonyl iron powder / strontium lanthanum manganate composite material and a preparation method thereof. Background technique [0002] In recent years, the increasingly serious electromagnetic wave pollution has made the study of absorbing materials with broadband, strong absorption, light weight and other characteristics attract extensive attention. In the design and preparation process of absorbing materials, especially when the frequency and thickness are fixed, it is required that the absorbing materials must have a large magnetic permeability and permittivity at the same time, and a good relationship between the two must be achieved. match. Magnetic metal particles, such as nickel, cobalt, and carbonyl iron particles, have high saturation magnetization and high relative permeability in the microwave band, so they can be used as microwave absorbers in the mic...

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Problems solved by technology

However, these absorbing materials based on chemical methods and their preparation processes have shortcomings. First, the thickness of the absorbing materials in the microwave band, such as the X-band, needs to be greater than 1 mm, which is difficult to meet the requirements of practical applications. In the middle, the requirements for the characteristics of broadband, strong absorption, thin thickness, and light weight that the absorbing material should have; secondly, when the preparation process prepares absorbing materials with different components, the stoichiometric ratio is difficult to control; thirdly, the preparation of absorbing materials The equipment required for the material is complex and the production cost is high

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