Initial Wetting Aid for Ceramic Vaporiser Body
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Solution Overview
Problem
In PVD metallization systems, the initial wetting of the evaporator surface by aluminum is incomplete, leading to reduced evaporation rates and increased thermal stress on the evaporator body, which affects the coating quality and service life.
Innovation Solution
An auxiliary wetting material containing aluminum and a wetting agent, such as boron nitride and zirconium/molybdenum/titanium compounds, is applied to the evaporator surface, forming an aluminum nitride layer that enhances wetting and reduces the surface tension, allowing for improved distribution and evaporation of aluminum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the evaporator body is heated to high temperature for aluminum evaporation, then the evaporation rate increases, but the initial wetting is incomplete leading to reduced evaporation rates and increased thermal stress
Solution Approach 1:
The patent applies a coating containing aluminum and wetting agents (such as boron nitride, zirconium, molybdenum, or titanium compounds) to the evaporator surface before operation. This preliminary coating ensures immediate wetting when heating begins, allowing the aluminum to spread uniformly across the surface from the start, completing the wetting process before high-temperature evaporation commences.
Solution Approach 2:
The patent modifies the surface properties of the evaporator body by applying a coating with specific chemical composition (aluminum plus wetting agents). The wetting agents lower the surface tension and react with aluminum to form aluminum nitride or similar compounds, changing the wetting parameters and enabling complete wetting at lower temperatures, thus resolving the contradiction between achieving good initial wetting and maintaining high evaporation rates.
2Stability of the object's composition
If the evaporator body uses standard ceramic material, then the structural stability is maintained, but the thermal stress increases due to incomplete initial wetting
Solution Approach 1:
By applying the wetting-promoting coating before heating, the aluminum achieves complete surface coverage early in the heating process. This preliminary wetting action distributes thermal stress uniformly across the entire evaporator surface, preventing localized stress concentration and reducing overall thermal stress on the ceramic structure while maintaining its structural stability.
3Device complexity
If the evaporator surface is not pre-treated, then the device complexity is reduced, but the coating quality decreases due to spatter formation
Solution Approach 1:
The patent applies a relatively simple coating process involving aluminum and wetting agents before evaporation. This preliminary treatment creates a uniform aluminum nitride layer that prevents spatter formation during subsequent evaporation, significantly improving coating quality without requiring complex additional equipment or processes.
Solution Approach 2:
The wetting agents (boron nitride, zirconium, molybdenum, or titanium compounds) act as intermediaries between the aluminum and the evaporator surface. These substances facilitate uniform aluminum distribution and prevent spatter by mediating the interaction between molten aluminum and the ceramic surface, thereby improving coating quality.
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 solution achieves a significant increase in evaporation rates, reduces spatter formation, and extends the service life of the evaporator body by ensuring uniform wetting and reducing thermal stress through improved initial wetting and coating quality.
Implementation Method 1
Aluminum as the first component in a condition that after the start of the operation of the evaporator body melts on its evaporator surface
Implementation Method 2
reacts with the nitrogen of the evaporator body to form an aluminum nitride layer on the evaporator surface
Implementation Method 3
a wetting agent (wetting agent) as the second component, by means of which a uniform and large-area distribution of molten aluminum on the evaporator surface is promoted
Implementation Method 4
exposed to a metal vapor that is deposited on the substrate surface as a thin metal layer. Electrically heatable evaporator bodies are used to generate the necessary constant steam flow
Implementation Method 5
heated to around 1450-1600°C
Implementation Method 6
the substrate to be coated is guided over a cooled roller and exposed to a metal vapor that is deposited on the substrate surface as a thin metal layer
Data Source
Figure 1~4
Figure 5~7
AI summary
The invention relates to an initial wetting auxiliary material which is applied to the vaporiser surface of an electrically heatable ceramic vaporiser body (1), which is to be used in a PVD-metallisation installation to vaporise aluminium, and which contains nitrogen, in particular, in the form of boron nitride, as material components. The initial wetting auxiliary material comprises aluminium which melts on the vaporiser surface thereof after operating the vaporiser body (1) and reacts with the nitrogen of the vaporiser body (1) by forming an aluminium nitride layer on the vaporiser surface, when in the melted state. Said initial wetting auxiliary material also comprises a wetting agent which distributes the melted aluminium in a regular manner and over a large surface of the vaporiser surface.