Laser-Tuned Lanthanum Boride Coatings for Multicolor Durable Surfaces
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Solution Overview
Problem
Existing methods for creating decorative surfaces for luxury items like watches and jewelry lack the ability to produce multicolored, corrosion-resistant, and abrasion-resistant finishes effectively.
Innovation Solution
A layer of lanthanum boride (LaBx) is deposited on a substrate using PVD and then treated with a laser to alter its stoichiometry to LaBy, changing its color based on laser parameters, allowing for the creation of multicolored surfaces with high resistance to corrosion and abrasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing methods are used to create decorative surfaces, then the manufacturing process is simple, but the ability to produce multicolored, corrosion-resistant, and abrasion-resistant finishes is insufficient
Solution Approach 1:
The patent applies local quality by depositing a uniform LaB6 layer that is then selectively laser-treated in specific regions. Different laser parameters (power, pulse duration, scanning speed) are applied to different zones of the same layer, creating locally distinct colors (blue, violet, green, yellow) while maintaining the same base material composition. This allows multicolored decorative surfaces to be produced from a single material system through localized parameter variation.
Solution Approach 2:
The invention utilizes parameter changes by varying laser processing parameters (power density, pulse duration, scanning speed, number of passes) to transform the stoichiometry of LaB6 in different regions. These parameter variations cause controlled changes in boron content, creating different lanthanum boride phases (LaB12, LaB9, LaB6, LaB4, LaB2) that exhibit distinct colors. This enables a single material to produce multiple colors through parameter control rather than requiring multiple materials or complex coating processes.
2Adaptability or versatility
If laser treatment is applied to modify stoichiometry and create colors, then multicolored surfaces are achieved, but the process complexity increases
Solution Approach 1:
The patent demonstrates universality by using a single laser device with adjustable parameters to achieve multiple functions: heating, stoichiometry modification, color creation, and pattern formation. The same laser system, by varying only operational parameters (power, pulse duration, scanning speed), can produce different colors and patterns without requiring additional equipment or material layers. This multi-functional approach simplifies the overall system while achieving complex decorative effects.
3Adaptability or versatility
If higher laser power is used to remove LaBx layer, then the substrate color is revealed, but the corrosion and abrasion resistance is reduced
Solution Approach 1:
The patent applies partial action by using laser parameters that modify stoichiometry and create colors without completely removing the protective LaB6 layer. The laser treatment is controlled to achieve sub-surface modifications where the layer remains intact but its chemical composition and optical properties are altered. This allows color variation while preserving the protective function of the coating, avoiding the need to remove the layer entirely to achieve different colors.
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 produces decorative surfaces with varying colors and maintains high hardness and resistance to corrosion and abrasion, suitable for luxury items, as demonstrated by nano-indentation and tropical climate testing.
Implementation Method 1
subsequently treated with a laser, so as to modify said stoichiometry of said portion of the layer of LaBx subjected to the laser treatment
Implementation Method 2
the layer of LaBx is deposited by PVD (Physical Vapour Deposition)
Implementation Method 3
preferentially by cathode sputtering, using a LaB6 target
Data Source
AI summary
A layer of lanthanum boride of stoichiometry LaBx where x is between 9 and 12 is deposited on substrate, for example a stainless steel watch dial, and subsequently treated with a laser, such that the portion(s) of the layer treated with the laser change colour according to the laser power. This produces multicoloured surfaces having high resistance to corrosion and abrasion. The layer of LaBx is deposited by PVD and by cathode sputtering, using a LaB6 target of purple-violet colour, such that the colour of the deposited layer differs from the colour of the target. The laser treatment at specific powers changes the stoichiometry of the layer in the treatment portions, such that the colour of these portions changes according to the stoichiometry obtained. At higher powers, the laser will remove the layer of LaBx. Thus the colour of the treated portions is determined by the material of the substrate.