Zirconium Titanium Alloy Thermal Oxidation for Dark Surface
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Solution Overview
Problem
Existing methods for forming protective coatings on zirconium and titanium alloys do not effectively combine high tensile strength, hardness, scratch resistance, and color control from dark grey to black, while also being cost-effective and simple to produce, especially for binary alloys.
Innovation Solution
A method involving heating binary zirconium titanium alloys with specific atomic weight ratios in an oxygen-containing atmosphere at controlled temperatures, optionally with multiple heating steps and quenching, to form a hardened, darkened surface with a selectable shade from grey to black, primarily comprising a zirconium oxide layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If anodizing is used to alter surface color and appearance, then color variety is improved, but surface durability deteriorates (layer wears off readily and is easily scratched)
Solution Approach 1:
The patent changes the oxidation parameters by using elevated temperatures (500-900°C) and controlled oxygen atmospheres to form a dense, adherent oxide layer with controlled thickness and color, replacing the conventional anodizing process that produces less durable coatings
2Strength
If thermal oxidation is used to form protective oxide layers on zirconium, then surface hardness and scratch resistance are improved, but the alloy composition must be restricted (at least 80% zirconium)
Solution Approach 1:
The patent changes the compositional parameters by expanding the acceptable alloy range to include binary zirconium-titanium alloys with 20-80% zirconium, utilizing the beneficial effects of titanium while maintaining oxidation resistance through controlled thermal processing parameters
3Strength
If conventional thermal oxidation is used to darken zirconium surfaces, then scratch resistance is improved, but friction reduction is limited
Solution Approach 1:
The patent changes the oxidation parameters by using higher temperatures (500-900°C) and extended times to form a thicker, more complex oxide layer structure that provides both scratch resistance and reduced friction through surface smoothing and lower coefficient of friction
4Illumination intensity
If hazardous chemical treatments are used to color titanium surfaces, then color variety is improved, but safety requirements and complexity increase
Solution Approach 1:
The patent converts the potentially harmful effect of high-temperature oxidation into a beneficial process by controlling the atmosphere and parameters to form a protective, adherent oxide layer while achieving color control, eliminating the need for hazardous chemicals
Solution Approach 2:
The patent replaces chemical treatment methods with a thermal-oxidation process, substituting hazardous chemical reagents with controlled thermal energy and oxygen atmosphere to achieve the same coloring effect with improved safety and simplicity
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 articles with enhanced mechanical properties, improved wear resistance, and hypoallergenicity, offering a cost-effective and simple process for achieving a durable, darkened surface suitable for various applications, including stealth and medical uses.
Implementation Method 1
heating the article in an oxygen containing atmosphere at a temperature of between about 250 and about 880 degrees Celsius for between about 10 and about 110 minutes to form a hardened, darkened surface
Implementation Method 2
heating the article in an oxygen containing atmosphere at a temperature of between about 250 and about 880 degrees Celsius for between about 10 and about 110 minutes to form a hardened, darkened surface, which primarily comprises a zirconium oxide layer
Implementation Method 3
oxygen diffusion into the substrate metal, which also improved the fatigue properties of the metal
Implementation Method 4
heating the article in an oxygen containing atmosphere in a first heating step and a second heating step with a quenching step interposed
Data Source
AI summary
A method and a product made through it by utilizing Zirconium alloys containing Titanium in the manufacture of metal articles of sports, night stealth compatible articles for law enforcement and military equipment, night-stealth personal and body adornments for members of such forces, garden and household implements, fashion accessories, body art articles, and medical and dental implants, and other articles. The articles benefit from any combination of properties from being hypo-allergenic, possessing high tensile strength, abrasion resistance, and hardness, having low ductility and elasticity and of having the outer appearance within the scale of dark grey to blackness. In this method an alloy of components in their respective ratios from within the method's stipulated preferred range is shaped into a work piece by conventional metal forming devices and methods, and then subjected to an oxidation process and optional quenching steps. The oxidation is achieved through heating the work piece that is made out in the alloy in oxygen containing atmospheric ambience in one or two cycles.