Zirconia Composition for Consistent Hardness and Easier Machining
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Solution Overview
Problem
Zirconia sintered bodies used in dental prostheses and other applications face challenges in workability due to variations in color tone and hardness between production lots, which complicates machining and requires specialized techniques.
Innovation Solution
A zirconia compositional substance containing specific transition metal elements and stabilizing elements, with controlled X-ray intensity ratios and distribution widths, is used to produce calcined bodies with reduced hardness variations and improved workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different compositions are used to achieve different color tones, then color tone variety is improved, but hardness variation and workability deterioration occur
Solution Approach 1:
The invention changes the chemical composition parameters by introducing specific transition metal elements (Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag) as color components with controlled content ratios. This allows achieving different color tones while maintaining consistent thermal shrinkage behavior and hardness, thereby improving color tone variety without sacrificing workability
Solution Approach 2:
The invention creates composite zirconia materials by combining zirconia base material with specific transition metal elements and stabilizing elements. This composite approach enables independent control of color properties and mechanical properties, allowing diverse color tones while maintaining uniform hardness and good workability across different batches
2Stability of the object's composition
If calcining conditions are adjusted according to composition, then hardness consistency is improved, but production process complexity increases
Solution Approach 1:
The invention applies local quality by specifically controlling the content and state of transition metal elements within the zirconia composition. By ensuring transition metal content is 100 mass ppm or more and controlling their distribution state, the invention achieves consistent thermal shrinkage and hardness across batches without requiring complex adjustments to calcining conditions for each composition variant
3Measurement precision
If transition metal element content is increased, then color tone control is improved, but thermal shrinkage behavior variation increases
Solution Approach 1:
The invention optimizes the parameter range of transition metal element content to 100 mass ppm or more, which provides sufficient color tone control capability while maintaining stable thermal shrinkage behavior. This parameter optimization ensures that color components are present in adequate amounts for coloring without causing significant variations in thermal properties
Solution Approach 2:
The invention ensures homogeneous distribution and consistent state of transition metal elements within the zirconia matrix. By controlling the uniformity of transition metal element distribution, the invention achieves both good color tone control and stable thermal shrinkage behavior, eliminating the trade-off between these two requirements
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 results in calcined bodies that are easier to machine and have consistent hardness across production lots, facilitating efficient production of sintered bodies with desired color tones.
Implementation Method 1
the thermal shrinkage behavior changes by controlling the state of the transition metal elements contained in a particular amount or more without changing the essential composition
Data Source
AI summary
Provided is at least one selected from a calcined body that is easier to work than existing calcined bodies and that has a smaller difference in hardness between the production lots, a method for producing the same, a sintered body obtained therefrom and a zirconia compositional substance used as a raw material of this calcined body. A zirconia compositional substance comprises at least one first transition metal element selected from the group consisting of manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd) and silver (Ag); a coloring element that is either or both of a lanthanoid rare earth element and a second transition metal element different from the first transition metal element; and stabilizing element-containing zirconia, wherein a content of the first transition metal element is 100 mass ppm or more, a content of the second transition metal element is less than 100 mass ppm, and the zirconia compositional substance satisfies either or both of the following conditions: when a characteristic X-ray of a zirconium element therein and a characteristic X-ray of the first transition metal element are measured, a percentage of measurement points at which a ratio of an intensity of the characteristic X-ray of the first transition metal element to an intensity of the characteristic X-ray of the zirconium element is 0.05 or more is 3% or less of all measurement points; and when the characteristic X-ray of the zirconium element therein and the characteristic X-ray of the first transition metal element are measured, a distribution width of the ratio of the intensity of the characteristic X-ray of the first transition metal element to the intensity of the characteristic X-ray of the zirconium element is 0.3 or less.