Lead-free solder for soft soldering

Abstract

The present invention relates to a lead-free solder for a soldering which is characterized in that the solder consists of materials with the following weight percentage: Cu from 0.1 percent to 1.0 percent, Ni from 0.1 percent to 0.2 percent, Ce from 0.01 percent to 0.10percent, Bi from 0.05percent to 2.0percent, Pr or / and Nd from 0.01percent to 0.10percent and the rest being Sn. The lead-free solder of the present invention, belonging to the environmental protecting products, has the advantages and effects of such as an anti-oxidation property, a mechanical property and corrosion resistance which can improve the performance of the solder, a uniform metallographic organization, refined grain, a good product quality, low cost and a proper reduction of the melting point.

Description

technical field

[0001] The invention relates to a lead-free solder for soldering, in particular to a lead-free solder containing copper, nickel, cerium, bismuth, praseodymium or / and neodymium and tin as the balance, belonging to the field of tin solder alloys. Background technique

[0002] The rapid development of the electronics industry has higher and higher requirements for solder performance, and the development of high-integration, high-performance electronic and electrical design has made the solder joints smaller and smaller, and the requirements for reliability are getting higher and higher. Traditional tin-lead solder, lead and its compounds are toxic substances, which bring great harm to the human living environment and safety. The European Union issued two directives. From July 1, 2006, electronic products must not contain lead, etc Lead is the first to bear the brunt of the six harmful substances in the chemical industry, so the research and application of lead-f...

Examples

Embodiment 1

[0026] Test results of Example 1: expansion rate: 77.0%, wettability: 65.6mN, melting point: 215°C, metallography (200 times magnification): uniform metallographic structure, fine grain, resistivity: 1.30μ′Ω .cm, QFP lead 45° tensile test: 24.25N, chip component solder joint shear test: 30.00N.

Embodiment 2

[0027] Test results of Example 2: expansion rate: 77.2%, wettability: 65.4mN, melting point: 217°C, metallographic (200 times magnification): uniform metallographic structure, fine grain, resistivity: 1.30μ′Ω .cm, QFP lead 45° tensile test: 24.23N, chip component solder joint shear test: 31.20N.

Embodiment 3

[0028] Test results of Example 3: expansion rate: 77.8%, wettability: 65.8mN, melting point: 218°C, metallographic (200 times magnification): uniform metallographic structure, fine grain, resistivity: 1.31μ'Ω .cm, QFP lead 45° tensile test: 24.00N, chip component solder joint shear test: 31.10N.

technical field

[0001] The invention relates to a lead-free solder for soldering, in particular to a lead-free solder containing copper, nickel, cerium, bismuth, praseodymium or / and neodymium and tin as the balance, belonging to the field of tin solder alloys. Background technique

[0002] The rapid development of the electronics industry has higher and higher requirements for solder performance, and the development of high-integration, high-performance electronic and electrical design has made the solder joints smaller and smaller, and the requirements for reliability are getting higher and higher. Traditional tin-lead solder, lead and its compounds are toxic substances, which bring great harm to the human living environment and safety. The European Union issued two directives. From July 1, 2006, electronic products must not contain lead, etc Lead is the first to bear the brunt of the six harmful substances in the chemical industry, so the research and application of lead-f...

Examples

Embodiment 1

[0026] Test results of Example 1: expansion rate: 77.0%, wettability: 65.6mN, melting point: 215°C, metallography (200 times magnification): uniform metallographic structure, fine grain, resistivity: 1.30μ′Ω .cm, QFP lead 45° tensile test: 24.25N, chip component solder joint shear test: 30.00N.

Embodiment 2

[0027] Test results of Example 2: expansion rate: 77.2%, wettability: 65.4mN, melting point: 217°C, metallographic (200 times magnification): uniform metallographic structure, fine grain, resistivity: 1.30μ′Ω .cm, QFP lead 45° tensile test: 24.23N, chip component solder joint shear test: 31.20N.

Embodiment 3

[0028] Test results of Example 3: expansion rate: 77.8%, wettability: 65.8mN, melting point: 218°C, metallographic (200 times magnification): uniform metallographic structure, fine grain, resistivity: 1.31μ'Ω .cm, QFP lead 45° tensile test: 24.00N, chip component solder joint shear test: 31.10N.