CN100507074C

CN100507074C - Compounded conducting mix and silver coating FeO powder and preparation method thereof

Info

Publication number: CN100507074C
Application number: CNB2007100266931A
Authority: CN
Inventors: 张海燕; 曹晓国
Original assignee: Guangdong University of Technology
Current assignee: Guangdong University of Technology
Priority date: 2007-02-02
Filing date: 2007-02-02
Publication date: 2009-07-01
Anticipated expiration: 2027-02-02
Also published as: CN101012553A

Abstract

The invention discloses a composite conductive fill-silver-plating Fe3O4 powder and making method, which comprises the following steps: adding Fe3O4 powder into silver ammino solution; adding alcohol; heating the composite solution to reacting temperature; dispersing through ultrasound; adding reducer to do chemical plating; filtering the obtained powder; washing; drying or drying naturally; adopting Fe3O4 powder as basic core with a layer of plated silver.

Description

A kind of complex conductive fillers--silver plated F e 3O 4Powder and preparation method thereof

Technical field

The present invention relates to a kind of complex conductive fillers--silver plated F e ₃O ₄Powder and preparation method thereof, prepared silver plated F e ₃O ₄Powder can be applicable to the electromagnetic shielding composite material field.

Background technology

Along with the widespread use of the developing rapidly of electronic industry especially computer and mobile phone, electronics and electrical equipment, the electromagnetic interference (EMI) problem is more serious, has become a kind of new pollution, is subjected to the extensive concern of countries in the world.For solving the electromagnetic interference (EMI) problem, electromagnetic shielding material is developed rapidly.According to Schelkunoff electromagnetic shielding theory as can be known, electromagnetic shielding material is decided by electrical conductivity and the magnetic conductivity of material to electromagnetic reflection loss and absorption loss, only having good electric conductivity could realize well to electromagnetic reflection loss, and want better electromagnetic wave absorption, then material need have very high magnetic conductivity, yet still can not directly find this have simultaneously good conductance and the ideal material of magnetic conductivity in the material of reality.

Fe ₃O ₄Powder is because preparation technology is simple, cheap, absorbing property is good, is that the people sets about research the earliest, also be the most ripe one of the absorbing material of excellent magnetic that has, but it is anti-oxidant and acid-proof alkaline is poor, and its application is restricted.To Fe ₃O ₄The powder surface coats one deck silver, both can improve conduction and the chemical stability of powder, keeps again Fe ₃O ₄The absorbing property of powder, this complex conductive fillers can utilize the silver-colored reflection electromagnetic wave of high conductivity, and part is then had the kernel Fe of excellent magnetic through the electromagnetic wave of silver layer ₃O ₄Powder absorbs.

Summary of the invention

First purpose of the present invention provides a kind of to have the Fe of high magnetic permeability ₃O ₄Powder is the NEW TYPE OF COMPOSITE conductive filler-silver plated F e of metallic silver layer with good electric conductivity of kernel, its outer wrapping ₃O ₄Powder.

Second purpose of the present invention provides a kind of silver plated F e for preparing ₃O ₄The method of powder.

Technical scheme of the present invention is:

A, under the condition that constantly stirs with Fe ₃O ₄Powder adds in the silver ammino solution, adds a certain amount of ethanol again, and mixed liquor is heated to reaction temperature, with ultrasonic cleaner it is disperseed simultaneously.

B, reducing agent is added in the above-mentioned mixed solution, behind the reaction certain hour, with the Fe after silver-plated ₃O ₄Powder filters, washing, oven dry or air dry.

Above-mentioned silver ammino solution is the fresh solution by following requirement configuration: the certain density AgNO of preparation in a container ₃Solution stirs lower slow dropping ammonia, and the lucky dissolve complete of precipitation that extremely generates earlier is clear solution.AgNO ₃The concentration range of solution is 0.01～0.2mol/L, AgNO ₃Consumption and the Fe that joins in the silver ammino solution ₃O ₄The relationship between quality of powder is: m _AgNO3/ m _Fe304=9～22/10.

The volume relationship of above-mentioned ethanol consumption and used silver ammino solution is: V _Ethanol/ V _{Silver ammino solution}=0.2～1.0.

The scope of above-mentioned temperature of reaction is 30～90 ℃.

Above-mentioned reductive agent is a kind of in glucose, formaldehyde, Seignette salt or the dimethylin borine.

The scope in above-mentioned reaction times is 5～60min.

The silver plated F e of above-mentioned preparation method's preparation ₃O ₄Powder, its core is Fe ₃O ₄Powder is at Fe ₃O ₄The outer surface parcel layer of metal silver of powder.

The invention has the beneficial effects as follows and combine silver and Fe ₃O ₄Advantage, by at Fe ₃O ₄The powder coated with silver on surface is prepared electromagnetic shielding composite material, and the existence of material because the conductive silver metal inside is magnetic increases shielding electromagnetic wave effect greatly.

Embodiment

By specific examples the present invention is further described.

Embodiment 1:

In a container, prepare 210mLAgNO ₃(0.05mol/L) solution stirs lower slow dropping ammonia, is clear solution to the lucky dissolve complete of precipitation that generates earlier, under the condition that constantly stirs with 1g Fe ₃O ₄Powder adds in this solution, and other adds 70mL ethanol, mixed solution is heated to 50 ℃ again, with ultrasonic cleaner it is disperseed simultaneously.Then 2.15mL formaldehyde is added in the above-mentioned mixed solution, behind the reaction 20min, with the Fe after silver-plated ₃O ₄Powder filters, washing, 80 ℃ of oven dry in baking oven.The silver plated F e of preparation ₃O ₄The specific insulation of powder is 4.734 Ω cm.

Embodiment 2:

In a container, prepare 140mLAgNO ₃(0.05mol/L) solution stirs lower slow dropping ammonia, is clear solution to the lucky dissolve complete of precipitation that generates earlier, under the condition that constantly stirs with 1g Fe ₃O ₄Powder adds in this solution, and other adds 30mL ethanol, mixed solution is heated to 50 ℃ again, with ultrasonic cleaner it is disperseed simultaneously.Then 2.15mL formaldehyde is added in the above-mentioned mixed solution, behind the reaction 20min, with the Fe after silver-plated ₃O ₄Powder filters, washing, air dry.The silver plated F e of preparation ₃O ₄The specific insulation of powder is 10.234 Ω cm.

Embodiment 3:

In a container, prepare 210mLAgNO ₃(0.05mol/L) solution stirs lower slow dropping ammonia, is clear solution to the lucky dissolve complete of precipitation that generates earlier, under the condition that constantly stirs with 1g Fe ₃O ₄Powder adds in this solution, and other adds 70mL ethanol, mixed solution is heated to 70 ℃ again, with ultrasonic cleaner it is disperseed simultaneously.Then 3.20mL formaldehyde is added in the above-mentioned mixed solution, behind the reaction 15min, with the Fe after silver-plated ₃O ₄Powder filters, washing, 80 ℃ of oven dry in baking oven.The silver plated F e of preparation ₃O ₄The specific insulation of powder is 32.078 Ω cm.

Embodiment 4:

In a container, prepare 140mLAgNO ₃(0.075mol/L) solution stirs lower slow dropping ammonia, is clear solution to the lucky dissolve complete of precipitation that generates earlier, under the condition that constantly stirs with 1g Fe ₃O ₄Powder adds in this solution, and other adds 50mL ethanol, mixed solution is heated to 50 ℃ again, with ultrasonic cleaner it is disperseed simultaneously.Then 2.15mL formaldehyde is added in the above-mentioned mixed solution, behind the reaction 40min, with the Fe after silver-plated ₃O ₄Powder filters, washing, 90 ℃ of oven dry in baking oven.The silver plated F e of preparation ₃O ₄The specific insulation of powder is 127.5 Ω cm.

Embodiment 5:

In a container, prepare 210mLAgNO ₃(0.05mol/L) solution stirs lower slow dropping ammonia, is clear solution to the lucky dissolve complete of precipitation that generates earlier, under the condition that constantly stirs with 1g Fe ₃O ₄Powder adds in this solution, and other adds 60mL ethanol, mixed solution is heated to 50 ℃ again, with ultrasonic cleaner it is disperseed simultaneously.The solution that then 40mL is contained the 9.5g sodium potassium tartrate tetrahydrate adds in the above-mentioned mixed solution, behind the reaction 40min, with the Fe after silver-plated ₃O ₄Powder filters, washing, 80 ℃ of oven dry in baking oven.The silver plated F e of preparation ₃O ₄The specific insulation of powder is 28.364 Ω cm.

Claims

1, a kind of complex conductive fillers--silver plated F e ₃O ₄The preparation method of powder is characterized in that this method may further comprise the steps:

A, under continuous stirring condition with Fe ₃O ₄Powder adds in the silver ammino solution, AgNO ₃Consumption and the Fe that joins in the silver ammino solution ₃O ₄The relationship between quality of powder is: m _AgNO3/ m _Fe3O4=9～22/10; Adding is V with the silver ammino solution volume ratio again _Ethanol/ V _{Silver ammino solution}=0.2～1.0 ethanol is heated to temperature of reaction with mixed solution, with ultrasonic cleaner it is disperseed simultaneously;

B, reducing agent is added in the above-mentioned mixed solution, behind reaction 5～60min, with the Fe after silver-plated ₃O ₄Powder filters, washing, oven dry or air dry;

The described silver ammino solution of above-mentioned steps a is the fresh solution by following requirement configuration: compound concentration is the AgNO of 0.01～0.2mol/L in a container ₃Solution stirs lower slow dropping ammonia, and the lucky dissolve complete of precipitation that extremely generates earlier is clear solution.

2, according to the preparation method of claim 1, it is characterized in that: the scope of the described temperature of reaction of step a is 30～90 ℃.

3, according to the preparation method of claim 1, it is characterized in that: the described reductive agent of step b is a kind of in glucose, formaldehyde, Seignette salt or the dimethylin borine.

4, the silver plated F e of the described preparation method's preparation of a kind of claim 1 ₃O ₄Powder is characterized in that: its core is Fe ₃O ₄Powder is at Fe ₃O ₄The outer surface parcel layer of metal silver of powder.