Continuous Siliconization of Porous Carbon Using Rotating Rollers

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Solution Overview

Problem

Existing siliconization processes for carbon materials are inefficient due to long heating and cooling times, energy wastage, and inhomogeneous impregnation caused by uneven silicon distribution, particularly in batch processes.

Innovation Solution

A continuous process using externally porous rollers to supply liquid silicon to carbon workpieces, allowing for controlled temperature and pressure conditions, and spatial separation of process steps in chambers for uniform treatment and reduced energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If batch processes are used for siliconization, then the carbon materials can be converted into materials with silicon carbide matrix, but the heating and cooling times are long and energy use is high

Engineering Contradiction:
Improvesilicon carbide formationVSAvoidheating and cooling times
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements a continuous siliconization process where carbon materials are continuously fed through a reaction zone with liquid silicon, eliminating the heating and cooling cycles inherent in batch processes. The continuous movement of materials through the reaction zone maintains constant operating conditions, achieving silicon carbide formation without repeated thermal cycles.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The continuous process is divided into distinct functional zones: a feeding zone for material introduction, a reaction zone with liquid silicon for silicon carbide formation, and a discharge zone for product removal. This segmentation allows each zone to be optimized independently while maintaining continuous operation.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If batch processes are used for siliconization, then the carbon materials can be converted into materials with silicon carbide matrix, but energy consumption is high

Engineering Contradiction:
Improvesilicon carbide formationVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The continuous process maintains steady-state operating conditions in the reaction zone, eliminating the repeated heating and cooling energy expenditures of batch processes. Heat is applied continuously only where needed for silicon carbide formation, rather than cycling the entire system through temperature changes.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If wicks are used for silicon supply, then the carbon workpieces can be impregnated with liquid silicon, but the silicon supply is unevenly distributed leading to inhomogeneity

Engineering Contradiction:
Improvesilicon impregnationVSAvoidimpregnation uniformity
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent introduces porous rollers as intermediary carriers that uniformly distribute liquid silicon across the carbon workpiece surface. The rollers act as mediating elements between the silicon reservoir and the workpiece, ensuring even silicon supply through their rotating motion and porous structure that facilitates controlled silicon release.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stationary wick system is replaced with rotating porous rollers that dynamically distribute silicon. The rotation of the rollers ensures continuous movement and uniform contact between the silicon-laden roller surface and the workpiece, preventing localized over- or under-impregnation that occurs with static wicks.

Inventive Principle:
Principle #15Dynamics

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

This method achieves uniform silicon carbide formation with reduced energy consumption and improved product consistency by maintaining consistent operating conditions and avoiding contact with the silicon bath during cooling.

Implementation Method 1

The porous rollers act like wicks that absorb liquid silicon, for example from a bath, and transfer it to the workpieces

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

supplying liquid silicon to the porous carbon workpieces at an operating pressure pB2

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Implementation Method 3

The elementary silicon reacts with the carbon to form silicon carbide through heat treatment

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 4

Gassing of the workpieces with inert gas and cooling from the operating temperature TB3 to a conditioning temperature Tk

Methodology Applied
Scientific EffectGas cooling: Convection

Data Source

PatentEP2039666B1Method and device for siliconising materials containing carbon
Publication Date: 2016.08.10 AUDI AG
  • EP2039666B1 patent drawingFigure 1
  • EP2039666B1 patent drawingFigure 2~5

AI summary

The method for treating workpieces out of porous carbon material with liquid silicon (25) under formation of silicon carbide, comprises pre-heating the reinforced carbon work pieces, if necessary with fibers under inert gas coming from room temperature at a selected processing temperature (TB 1>), introducing liquid silicon to the workpieces at a processing pressure (PB 2>) and a processing temperature (TB 2>) and soaking the workpiece with liquid silicon, and reacting the liquid silicon penetrated in the workpiece with carbon in the workpiece at a temperature (TB 3>). The method for treating workpieces out of poorhouse carbon material with liquid silicon (25) under formation of silicon carbide, comprises pre-heating the reinforced porous carbon work pieces, if necessary with fibers under inert gas coming from room temperature at a selected processing temperature (TB 1>), introducing liquid silicon to the workpieces at a processing pressure (PB 2>) and a processing temperature (TB 2>) and soaking the workpiece with liquid silicon, reacting the liquid silicon penetrated in the workpiece with carbon in the workpiece at a temperature (TB 3>) under formation of silicon carbide, charging the workpiece with inert gas, cooling the workpiece from the processing temperature (TB 3>) to a conditioning temperature (T k) under continuation of the reaction, removing the tension emerged in the workpiece, and cooling the workpiece at room temperature. The introduction of silicon and transporting of the workpiece are carried out over rotatably arranged cylindrical rollers in outside area. The rotating speed of the cylindrical rollers determines the dwell time for the introduction of silicon and the reaction of the silicon with carbon under formation of silicon carbide. The temperature (TB 3>) is greater than or equal to the temperature (TB 2>). The workpiece is no longer in contact with liquid silicon outside of the workpiece. The processing temperature (TB 2>) is 1450-1700[deg] C. The silicon mass received through the workpiece is measured through weighing of basin (22) before mounting the workpiece and after infiltration and removal of the workpiece. The roller wicks are implemented in the form of prism with polygonal cross section and are rotated in clock-like manner. An independent claim is included for a device for treating workpieces out of porous carbon material with liquid silicon under formation of silicon carbide.