Ru-Ni Spark Plug Electrode Composition for Oxidation Resistance
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Solution Overview
Problem
Conventional spark plugs with Ru discharge members suffer from rapid oxidation and volatilization at high temperatures, leading to premature wear and reduced service life.
Innovation Solution
A spark plug design incorporating a discharge member with Ru as a main component and 0.5% to 30% by mass of Ni or Co, which is produced through powder metallurgy and sintering, enhances the wear resistance and oxidation resistance of the discharge member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discharge member made of Ru alone or Ru alloy is used, then the spark plug can achieve good ignition performance, but the discharge member is easily worn due to oxidation and volatilization at high temperature
Solution Approach 1:
The patent uses a composite material consisting of Ru particles dispersed in an Ni or Co matrix. This composite structure combines the excellent ignition performance of Ru with the high-temperature oxidation resistance and mechanical strength of Ni or Co, thereby resolving the contradiction between ignition performance and service life.
Solution Approach 2:
The patent optimizes the content of Ni or Co to be within 5-30 mass%, which changes the material parameters to achieve the best balance between oxidation resistance, mechanical properties, and ignition performance. This parameter optimization prevents excessive wear while maintaining reliable ignition.
2Reliability
If pure Ru is used for the discharge member, then the ignition performance is excellent, but the oxidation and volatilization at high temperature causes rapid wear
Solution Approach 1:
Ni or Co acts as an intermediary matrix material that protects Ru particles from direct exposure to oxidizing environments. The Ni or Co matrix has high oxidation resistance and serves as a barrier, preventing Ru from undergoing rapid oxidation and volatilization while still allowing effective ignition performance.
Solution Approach 2:
The Ni or Co matrix creates a protective environment around Ru particles, effectively isolating them from the oxidizing atmosphere in the combustion chamber. This protective environment reduces the harmful effects of oxidation and volatilization on Ru.
3Duration of action of moving object
If noble metals are used to improve wear resistance, then the service life is extended, but the cost increases significantly
Solution Approach 1:
The patent replaces expensive noble metals with a more cost-effective Ru-Ni or Ru-Co composite system. While Ru is also a precious metal, the composite structure allows for reduced Ru content (Ru particles dispersed in Ni or Co matrix) while maintaining wear resistance, thereby reducing material cost compared to pure noble metal discharge members.
Solution Approach 2:
The composite structure allows combining Ru with cheaper Ni or Co materials to achieve wear resistance comparable to or better than pure noble metals, but at lower material cost. The Ni or Co matrix provides structural support and wear resistance, reducing the amount of expensive Ru needed.
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 proposed design significantly prolongs the service life of the spark plug by reducing wear and oxidation of the discharge member, offering improved durability and cost-effectiveness compared to pure Ru or noble metal alternatives.
Implementation Method 1
Since Ru is remarkably oxidized and volatilized at high temperature, the discharge member in the conventional art is easily worn
Implementation Method 2
A spark plug design incorporating a discharge member with Ru as a main component and 0.5% to 30% by mass of Ni or Co, which is produced through powder metallurgy and sintering
Data Source
AI summary
A spark plug which is reduced in consumption of a discharge member, thereby having a longer service life. This spark plug is provided with: a first electrode that comprises a discharge member; and a second electrode that faces the discharge member, with a spark gap lying therebetween. The discharge member is mainly composed of Ru, while containing 0.5% by mass to 30% by mass of Ni or Co.