Silicon Carbide-Diboride Rotary Anode Base Body
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current rotary anodes for X-ray tubes, made of materials like titanium-zirconium-molybdenum alloys or ceramics, are limited to rotational frequencies of 200 Hz to 250 Hz due to thermal stress and mechanical failure at higher speeds, which restricts the achievement of high radiation intensities and focal spot sharpness.
Innovation Solution
A rotary anode with a ceramic base body made of a mixture of silicon carbide and high temperature-resistant diborides, such as titanium diboride, tantalum diboride, or zirconium diboride, which provides enhanced thermal resistance, mechanical strength, and thermal conductivity, allowing rotational frequencies up to 400 Hz by effectively managing heat distribution and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotational frequency is increased to achieve higher radiation intensities, then X-ray production efficiency is improved, but thermal stress and mechanical failure increase
Solution Approach 1:
The patent employs a composite material consisting of silicon carbide matrix reinforced with diboride particles (such as titanium diboride, tantalum diboride, zirconium diboride, or hafnium diboride). This composite structure combines the high thermal conductivity and thermal shock resistance of silicon carbide with the high-temperature strength and creep resistance of diboride reinforcements, enabling the base body to withstand the thermal and mechanical stresses at rotational frequencies of 300-400 Hz while maintaining structural integrity.
2Measurement precision
If rotational frequency is increased to improve focal spot sharpness, then energy density is improved, but thermal stress increases
Solution Approach 1:
The silicon carbide-diboride composite material provides superior thermal management properties. The silicon carbide matrix ensures high thermal conductivity to rapidly conduct heat away from the focal spot, while the diboride reinforcements maintain structural stability under thermal stress. This composite structure enables the rotary anode to operate at high rotational frequencies (300-400 Hz) which are necessary for achieving sharp focal spots and high energy densities without suffering from excessive thermal stress.
Solution Approach 2:
The patent optimizes the composition parameters of the composite material, specifically controlling the volume fraction of diboride particles (1-50 vol%) and the grain size of silicon carbide (0.1-10 µm). These parameter changes tailor the thermal and mechanical properties of the base body to withstand the thermal stresses generated at high rotational frequencies while maintaining the ability to achieve sharp focal spots and high energy densities.
3Ease of manufacture
If conventional materials are used, then ease of manufacture is maintained, but rotational frequency is limited to 200-250 Hz
Solution Approach 1:
The patent uses a composite material system (silicon carbide matrix with diboride particles) that can be manufactured using conventional ceramic processing techniques such as slip casting, pressureless sintering, or hot pressing. The raw materials (silicon carbide powder and diboride powder) are readily available, and the processing steps follow established ceramic manufacturing routes, maintaining ease of manufacture while achieving the high rotational frequencies of 300-400 Hz that conventional materials cannot sustain.
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 use of silicon carbide-diboride ceramics enables rotary anodes to operate at higher rotational frequencies with increased mechanical strength and thermal conductivity, preventing mechanical failure and ensuring efficient heat dissipation, thus achieving higher energy densities and improved X-ray production.
Implementation Method 1
Mixed silicon carbide-diboride ceramics of this kind have a very high thermal capacity, so the base body may absorb great quantities of energy during operating of the rotary anode
Implementation Method 2
A high thermal conductivity remains with this class of material even in the high temperature range, so the heat may be distributed particularly well during operation, and no warping occurs
Implementation Method 3
Such mixed ceramics have thermal coefficients of expansion that lie in the range of the thermal coefficients of expansion of tungsten, so stresses do not form between the base body and the focal path
Data Source
AI summary
A rotary anode for an X-ray tube includes a ceramic base body that carries a focal path for emitting X-rays during electron irradiation. The ceramic base body is made of a mixture of silicon carbide and at least one high temperature-resistant diboride.