Spark Plug Electrode Alloy Composition for Oxidation Resistance
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Solution Overview
Problem
High-temperature operating conditions in internal combustion engines lead to degradation of spark plug electrodes made from Ni-based nickel-chromium-iron alloys, resulting in reduced resistance to oxidation, sulfidation, and increased risk of fracture and deformation, which can cause engine performance issues and failure.
Innovation Solution
A solution-strengthened Ni-based nickel-chromium-iron alloy with specific additions of zirconium and boron, along with other elements, is used to enhance the electrodes' resistance to high-temperature oxidation, sulfidation, and mechanical stress, improving tensile, creep rupture, and fatigue strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher operating temperatures are used to achieve improved engine efficiency, then engine efficiency is improved, but resistance to high temperature oxidation and sulfidation decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the Ni-based alloy by adding specific amounts of zirconium (0.005-0.5 wt%) and boron (0.001-0.1 wt%), along with controlling chromium (14.5-25 wt%), iron (7-22 wt%), and other elements. These parameter changes in the alloy composition improve resistance to high temperature oxidation and sulfidation, enabling the electrode to maintain reliability at higher operating temperatures for improved engine efficiency.
2Productivity
If higher operating temperatures are used to achieve improved engine efficiency, then engine efficiency is improved, but tensile, creep rupture and fatigue strength decrease significantly
Solution Approach 1:
The patent creates a composite alloy system by combining Ni-based nickel-chromium-iron alloy with specific additions of zirconium and boron. This composite material structure, with zirconium providing solution strengthening and boron enhancing grain boundary strength, maintains tensile, creep rupture and fatigue strength at higher operating temperatures, thereby supporting improved engine efficiency without sacrificing mechanical strength.
3Reliability
If zirconium and boron are added to improve high temperature properties, then resistance to oxidation, sulfidation and mechanical stress is improved, but alloy composition complexity increases
Solution Approach 1:
The patent manages alloy composition complexity by precisely controlling the parameter ranges of zirconium (0.005-0.5 wt%) and boron (0.001-0.1 wt%) additions within the Ni-based nickel-chromium-iron alloy system. These controlled parameter changes provide the necessary improvement in resistance to oxidation, sulfidation and mechanical stress while maintaining manageable compositional complexity through defined concentration ranges rather than uncontrolled additions.
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 alloy provides improved resistance to corrosive wear and thermo-mechanical stresses, reducing the likelihood of electrode failure and maintaining engine performance under extreme conditions.
Implementation Method 1
a solution-strengthened Ni-based nickel-chromium-iron alloy which includes, by weight: 14.5-25% chromium; 7-22% iron; 0.2-0.5% manganese; 0.2-0.5% silicon; 0.1-2.5% aluminum; 0.05-0.15% titanium; 0.01-0.1% total of calcium and magnesium; 0.005-0.5% zirconium; 0.001-0.01% boron
Data Source
AI summary
An electrode for an ignition device is made from a Ni-based nickel-chromium-iron alloy which has improved resistance to high temperature oxidation, sulfidation, corrosive wear, deformation and fracture includes, by weight of the alloy: 14.5-25% chromium; 7-22% iron; 0.2-0.5% manganese; 0.2-0.5% silicon; 0.1-2.5% aluminum; 0.05-0.15% titanium; 0.01-0.1% total of calcium and magnesium; 0.005-0.5% zirconium; 0.001-0.01% boron, and the balance substantially Ni. It may also include at least one rare earth element selected from the group consisting of: yttrium, hafnium, lanthanum, cerium and neodymium in amounts ranging from 0.01-0.15% by weight, and incidental impurities, including cobalt, niobium, molybdenum, copper, carbon, lead, phosphorus or sulfur. These total of these impurities will typically be controlled to limits of 0.1% cobalt, 0.05% niobium, 0.05% molybdenum, 0.01% copper, 0.01% carbon, 0.005% lead, 0.005% phosphorus and 0.005% sulfur. The ignition device may be a spark plug which includes a ceramic insulator, a conductive shell, a center electrode disposed in the ceramic insulator having a terminal end and a sparking end with a center electrode sparking surface, and a ground electrode operatively attached to said shell having a ground electrode sparking surface, the center electrode sparking surface and the ground electrode sparking surface defining a spark gap therebetween. At least one of the center electrode or the ground electrode includes the solution-strengthened Ni-based nickel-chromium-iron alloy. The Ni-based nickel-chromium-iron alloy electrodes of the invention may also include a core with thermal conductivity greater than that of the Ni-based nickel-chromium-iron alloy, such as copper or silver or their alloys.