Low Silver Nickel Brazing Material for Corrosion Resistance
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Solution Overview
Problem
Silver-based brazing materials are costly and have disadvantages such as residue and oxide layer formation, while traditional bronze brazing leaves aesthetically displeasing residues, necessitating a low silver, low nickel brazing material with improved strength and corrosion resistance.
Innovation Solution
A brazing material composed of silver, copper, and zinc with a low nickel content, available in various forms including homogenous cast, flux cored, powder, and paste, offering improved braze joint strength and corrosion resistance, and compatibility with different heating methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silver-based filler metals are used for brazing, then braze joint strength and corrosion resistance are improved, but material cost increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters of the filler metal by reducing silver content from traditional high levels (e.g., 60-80%) to lower levels (e.g., 20-40%), and adjusting nickel content to optimize performance. This parameter modification allows achieving adequate joint strength and corrosion resistance at lower material cost.
Solution Approach 2:
The patent creates a composite filler metal composition combining multiple elements (silver, copper, zinc, nickel, and optional trace elements) where each component contributes specific properties. The synergistic interaction of these elements compensates for reduced silver content while maintaining or improving overall brazing performance.
2Quantity of substance
If traditional bronze brazing is used, then material cost is reduced, but residue and oxide layer formation worsen
Solution Approach 1:
The patent modifies the chemical composition by incorporating specific elements and ratios (particularly nickel and zinc in controlled amounts) that alter the oxidation behavior and residue characteristics during brazing, reducing harmful byproducts while maintaining cost-effectiveness.
Solution Approach 2:
The patent develops a cost-effective filler metal composition that can be used in conventional brazing processes without requiring expensive protective atmospheres or complex flux systems, making the process simpler and more economical while reducing residue formation.
3Reliability
If high silver content brazing material is used, then corrosion resistance is improved, but manufacturing cost increases
Solution Approach 1:
The patent adjusts the chemical composition parameters to reduce silver content while adding or optimizing other elements (nickel, zinc, copper) that contribute to corrosion resistance. This rebalancing of compositional parameters maintains protective properties at lower cost.
Solution Approach 2:
The patent develops a multi-element composite filler metal where nickel and zinc work synergistically to provide corrosion resistance that compensates for reduced silver content, creating a cost-effective alternative with maintained reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The material provides strong, corrosion-resistant joints with lower costs compared to silver-based fillers, is easy to fabricate, and suitable for various applications, including those requiring flux or controlled atmospheres, while minimizing hazardous materials like cadmium.
Implementation Method 1
brazing is a joining process whereby a filler metal is heated to a melting temperature which is lower than the melting temperature of the base metal
Implementation Method 2
The molten filler metal interacts with the base metal and then cools to form a strong, sealed joint
Implementation Method 3
Brazing with silver-based filler metals has commonly been used as an alternative to bronze brazing because silver brazing does not suffer from the disadvantages that prior forms of bronze brazing have, such as, for example, the left-behind residue and oxide layer formation on the base metal
Data Source
AI summary
A homogenous brazing material essentially consisting of relatively low amounts of silver and nickel together with copper, zinc, and other constituents is provided. The brazing material has a working temperature exceeding 630° F. and is preferably between about 1250° F. and 1500° F. The brazing material preferably has about 30 percent by weight of silver, about 36 percent by weight of copper, about 32 percent by weight of zinc, and about 2 percent by weight of nickel. The addition of nickel in the above-specified amount improves resistance against interface corrosion in aqueous solutions, aids in the strength of the alloy, and provides improved wettability on ferrous and non-ferrous substrates. The brazing material may also include a flux, such as a core or a coating.