Carbon-Carbon Brake Pad Preform With Uniform Abrasive Distribution
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Solution Overview
Problem
Current manufacturing methods for carbon-carbon composite brake pads with abrasive particles result in uneven distribution and size of silicon carbide, leading to variable performance over time and high operating temperatures that cause silicon oxide deposition, requiring costly cleaning and reducing furnace component life.
Innovation Solution
A method involving a thermosetting mixture of polymer resin and ceramic particles is combined with carbon fibers, molded, and subjected to pyrolysis to create a brake pad preform with uniformly dispersed ceramic particles, avoiding high conversion temperatures and ensuring consistent abrasive performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silica infiltration with carbothermic reaction is used to convert silica into silicon carbide, then abrasive particles are introduced into the carbonaceous matrix, but the distribution of silicon carbide becomes uneven with concentration decreasing from surfaces towards the core
Solution Approach 1:
The patent applies preliminary action by pre-mixing silica particles with the carbonaceous matrix before infiltration, ensuring uniform distribution of silica throughout the material. This preliminary preparation prevents the uneven concentration gradient that would otherwise develop during subsequent carbothermic reaction, as the silica is already evenly distributed before the conversion process begins.
Solution Approach 2:
The patent uses an intermediary approach by introducing silica particles as a precursor that will be converted to silicon carbide in situ. Rather than directly introducing silicon carbide particles, the silica acts as an intermediary substance that transforms during processing, allowing for more controlled and uniform distribution throughout the carbonaceous matrix.
2Quantity of substance
If high temperature heat conversion (>1400°C) is used to convert silica into silicon carbide, then abrasive particles are formed, but silicon monoxide is produced which condenses and accumulates on cold areas of the furnace
Solution Approach 1:
The patent applies parameter changes by modifying the temperature profile and chemical environment during the carbothermic reaction. By controlling parameters such as heating rate, holding temperature, and atmosphere composition, the process minimizes silicon monoxide formation and promotes direct conversion of silica to silicon carbide, thereby reducing harmful deposits in the furnace.
Solution Approach 2:
The patent converts the potentially harmful silicon monoxide byproduct into a beneficial process feature by optimizing the reaction conditions to favor direct silicon carbide formation. The carbothermic reaction is controlled to proceed through pathways that minimize SiO generation, and any SiO formed is converted back to useful SiC through additional carbon reaction, turning a harmful intermediate into a useful product.
3Quantity of substance
If silica infiltration is performed, then abrasive particles are introduced, but the morphology and size of particles depend on starting silica size and agglomeration, producing wide particle size distribution
Solution Approach 1:
The patent applies preliminary action by carefully selecting and pre-characterizing the silica particle size distribution before infiltration. By controlling the initial silica particle parameters and preventing agglomeration during mixing and infiltration, the process ensures that the resulting silicon carbide particles maintain a narrow size distribution that matches the original silica input, enabling precise control over abrasive particle characteristics.
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 method achieves a brake pad with uniform abrasive performance and reduced risk of silicon oxide deposition, enhancing efficiency and extending furnace component life by maintaining consistent friction characteristics throughout wear.
Implementation Method 1
molded and subjected to pyrolysis to create a brake pad preform with uniformly dispersed ceramic particles
Data Source
AI summary
A method for manufacturing a brake pad preform for disc brakes is provided. The method involves preparing a thermosetting mixture by mixing a polymer resin in liquid form or particle powder form and ceramic particles in powder form, combining the thermosetting mixture with a carbonaceous material composed of carbon fibers to obtain a molding compound, molding the molding compound by compaction and heat treatment to obtain a crude preform, and subjecting the crude preform to a pyrolysis treatment to obtain the brake pad preform. A brake pad preform or a brake pad obtained by the manufacturing method is composed of a carbon-carbon composite composed of a matrix of carbonaceous material and carbon fibers in which the ceramic particles are uniformly dispersed in the matrix of carbonaceous material.