Background technology
Fusible alloy is that a kind of temperature of fusion scope is little, to the solder of thermotonus sensitivity, and requires to have mechanical property and welding property preferably.Be widely used in the connecting material of Electronic Packaging; Thermal Cutoffs in the device such as fire-fighting, electrical equipment, fire alarm is the low melting point alloy type material that a class has development potentiality.
Thermal Cutoffs is a kind ofly in temperature, to surpass the rated function temperature (temperature that the Thermal Cutoffs conduction state is changed; refer to the rated function temperature definition of GB GB9816-20093.10) time; the thermal sensing element of the protected circuit of energy quick acting switching-off, wherein the rated function temperature of Thermal Cutoffs depends primarily on the fusing point of fusible alloy.
Its chemical composition of fusible alloy that Thermal Cutoffs is used is mainly to take tin as basis, adds some low melting point compositions: as bismuth, indium, antimony, lead, zinc etc., be configured to the alloy of various fusing points by suitable composition proportion.But, along with issuing of the unleaded instructions such as Rohs, Pb etc. are non-, and the environmental protection composition is sternly banned use of, therefore need a series of unleaded fusible alloys of exploitation to replace lead-containing alloy, the Sn-37Pb eutectic alloy that the fusing point especially be widely used is 183 ℃.And the special construction of Thermal Cutoffs and its fact in weak acid environment for a long time, require this class fusible alloy that mechanical property, corrosion resistance and antioxidant property are preferably arranged.
The lead-free brazing be widely studied has Sn-3.0Ag-0.5Cu, and its fusing point is 217 ℃; The fusing point of Sn-9Zn is 199 ℃, and anticorrosive poor with antioxidant property, and particularly, after the burn into oxidation occurring, its poor effect that fuses, even the situation that can't effectively fuse because of oxidation can occur; The Sn-57Bi fusing point is 139 ℃, and plasticity is poor, easily fracture.Above alloy is because the difference of its fusing point all can't replace the Sn-37Pb eutectic alloy to be used as fusible alloy, and the Thermal Cutoffs achieved possesses the accurate fusing point of 183 ° ± 3 ℃, has good erosion resistance, oxidation-resistance and plasticity simultaneously.
Summary of the invention
Can't reach the defect of 183 ° ± 3 ℃ for existing unleaded fusible alloy taking into account corrosion resistance and fusing point, the present invention proposes a kind of unleaded fusible alloy, and use it to become a kind of Thermal Cutoffs, make its fusing point accurately, there is good erosion resistance and oxidation-resistance; Its technical scheme is as follows:
A kind of fusible alloy, its component and corresponding mass percent comprise:
Ag:1.0-3.8;
Cu:0.3-1.0;
Bi:0.0-3.0;
In:16-22;
Sb:0.0-2.0;
Surplus is Sn; Wherein the purity of this alloy is not less than 99.99%.
As a class preferred version of this alloy, its component and mass percent are:
Ag:2.0-3.0;
Cu:0.4-0.6;
Bi:1.3-1.5;
In:18-20;
Sb:0.3-0.7;
Surplus is Sn.
A kind of Thermal Cutoffs, it forms in a kind of fusible alloy, and its component of this fusible alloy and corresponding mass percent comprise:
Ag:1.0-3.8;
Cu:0.3-1.0;
Bi:1.0-3.0;
In:16-22;
Sb:0.1-2.0;
Surplus is Sn; Wherein the purity of this alloy is not less than 99.99%.
As the preferred version of this safety fuse, its component and mass percent are:
Ag:2.0-3.0;
Cu:0.4-0.6;
Bi:1.3-1.5;
In:18-20;
Sb:0.3-0.7;
Surplus is Sn.
The beneficial effect of this programme has:
This scheme has realized the standard performance of traditional leaded Thermal Cutoffs on the one hand, comprises possessing 183 ° ± the accurate fusing point of 3 ℃, and simultaneously, the Thermal Cutoffs than containing zinc, have good anticorrosive, antioxidant property.
Except Thermal Cutoffs, this programme can also apply to the scolder field in fact, can directly as soldering tin material, use, and has substituted leaded scheme; Have and stablize accurate fusing point, environmental protection, anticorrosive, oxidation resistant over-all properties.
Embodiment
Embodiment mono-:
Below the embodiment of the present invention one, according to the following component of following mass percent weighing: 1.0Ag; 0.3Cu; 1.0Bi; 16In; 0.1Sb surplus is Sn.All the purity of component is that 99.99%, In and Bi have the effect that reduces alloy melting point; And the major function of Ag, Cu, Sb relates to and dwindles the temperature of fusion scope and improve wettability simultaneously; In addition, the purpose of interpolation Ag, Sb is to improve especially the antioxidant property in the large electric current of safety fuse, sour environment.
The metal that adds said components in Stainless Steel Kettle, melting, by the chill mould casting, obtain the fusible alloy ingot of as cast condition.
After obtaining the fusible alloy ingot, alloy carries out the fusing point test:
From melted as cast condition fusible alloy ingot, random intercepting 8mg carries out the fusing point test of alloy, and the heating top temperature is 230 ℃, and heating rate is 10 ℃/MIN.After to be tested completing, carry out the temperature of fusion analysis.The temperature range of learning this alloy melting is 182-186 ℃.
After having checked the fusing point performance of alloy, the wettability of beta alloy then, can prepare the fusible alloy silk after all qualified.
The fusible alloy ingot of fusing point and wettability test passes is carried out to wire-drawing shape by extrusion machine, can obtain the fusible alloy silk different size specification, good mechanical properties, that wettability is good.The fusible alloy silk obtained is encapsulated as to Thermal Cutoffs, and then the operating temperature of probe temperature safety fuse, be 183-186 ℃, 185.6 ℃ of averages
Embodiment bis-:
Below the embodiment of the present invention two, according to the following component of following mass percent weighing: 3.8Ag; 1.0Cu; 3.0Bi; 22In; 2.0Sb surplus is Sn.All the purity of component is 99.99%.
Adopt the method for high-frequency induction to be heated, the good said components of weighing, put into Stainless Steel Kettle and carry out melting, pours into a mould, and obtains the fusible alloy ingot of as cast condition.
After obtaining the fusible alloy ingot, alloy carries out the fusing point test:
From melted as cast condition fusible alloy ingot, random intercepting 8mg carries out the fusing point test of alloy, and maximum heating temperature is 230 ℃, and heating rate is 10 ℃/MIN.After to be tested completing, carry out the temperature of fusion analysis.Learn that this alloy melting temperature range is 180-184 ℃.
Check the fusing point performance of alloy, prepared the fusible alloy silk, the fusible alloy ingot of fusing point test passes has been carried out to wire-drawing shape by extrusion machine, can obtain the fusible alloy silk different size specification, good mechanical properties, that wettability is good.
The fusible alloy silk obtained is encapsulated as to Thermal Cutoffs, and then the operating temperature of probe temperature safety fuse, be 181-184 ℃, 181.7 ℃ of averages: this embodiment is stretched as alloy the form of hollow fibre, still has good mechanical property.
Embodiment tri-:
The component of the embodiment of the present invention three and mass percentage content are: Ag2.0; Cu0.5; Bi1.5; In18; Sb1.1; Surplus is Sn.
Adopt method melting in Stainless Steel Kettle of high-frequency induction, obtain the fusible alloy ingot of as cast condition.
After obtaining the fusible alloy ingot, alloy carries out the fusing point test:
From melted as cast condition fusible alloy ingot, random intercepting 8mg carries out the fusing point test of alloy, and maximum heating temperature is 230 ℃, and heating rate is 10 ℃/MIN.After to be tested completing, carry out the temperature of fusion analysis.Learn that this alloy melting temperature range is about 182-185 ℃.This alloy pig is carried out to wire-drawing shape by extrusion machine, then the fusible alloy silk obtained is encapsulated as to Thermal Cutoffs, then the operating temperature of probe temperature safety fuse, be 182-185 ℃, 182.5 ℃ of averages
The above, only for preferred embodiment of the present invention, therefore can not limit according to this scope of the invention process, the equivalence of doing according to the scope of the claims of the present invention and description changes and modifies, and all should still belong in the scope that the present invention contains.