KNN Sputtering Target Material for Low-Density Fracture Resistance
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Solution Overview
Problem
Existing KNN target materials face issues with density and fracture resistance, leading to composition deviations and mechanical weaknesses during preparation and sputter deposition, which affect the quality of the resulting piezoelectric films.
Innovation Solution
A sputtering target material with a density of 4.2 g/cm3 or less, Vickers hardness of 30 to 200, and an area-weighted mean grain size of 3.0 µm or more is produced by separately preparing NaNbO3 and KNbO3 powders with controlled firing temperatures and pressures, followed by oxidation treatment to ensure uniform oxygen and potassium composition throughout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the density of KNN target material is reduced, then the resistance to fracture is improved, but the mechanical strength may be compromised
Solution Approach 1:
The patent applies parameter changes by precisely controlling the density of the sintered ceramics to 4.2 g/cm³ or less, while simultaneously controlling Vickers hardness to 30-200 and area-weighted mean grain size to 3.0 µm or more. This multi-parameter optimization resolves the contradiction between low density and high fracture resistance, achieving both goals through coordinated parameter control in the sintering process.
2Strength
If the density of KNN target material is reduced, then the mechanical weaknesses are improved, but the composition uniformity may deteriorate
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges: density ≤4.2 g/cm³, Vickers hardness 30-200, and area-weighted mean grain size ≥3.0 µm. These parameter changes ensure both improved mechanical strength and maintained composition uniformity, as the controlled grain size and density prevent composition deviations during preparation and sputter deposition.
3Strength
If the Vickers hardness is increased, then the resistance to fracture is improved, but the density may increase
Solution Approach 1:
The patent applies parameter changes by decoupling the relationship between hardness and density through precise control of both parameters within specific ranges. By controlling Vickers hardness to 30-200 while maintaining density at 4.2 g/cm³ or less, the patent achieves high fracture resistance without the penalty of increased density, resolving the technical contradiction through multi-parameter optimization.
4Strength
If the area-weighted mean grain size is increased, then the resistance to fracture is improved, but the sintering temperature may need to be increased
Solution Approach 1:
The patent applies parameter changes by controlling the area-weighted mean grain size to 3.0 µm or more while maintaining density at 4.2 g/cm³ or less. This grain size control achieves high fracture resistance without requiring excessive sintering temperatures, as the specific grain size range optimizes both mechanical strength and energy efficiency in the sintering process.
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 target material achieves low density with high fracture resistance, ensuring consistent composition and mechanical strength, resulting in reliable piezoelectric films with predetermined properties.
Implementation Method 1
heating same in an oxygen-containing atmosphere to prepare a fired powder containing sodium and niobium
Implementation Method 2
heating same in an oxygen-containing atmosphere to prepare a fired powder containing sodium and niobium
Implementation Method 3
heating (calcinating) same in an oxygen-containing atmosphere to prepare a raw material powder containing potassium, sodium, and niobium
Implementation Method 4
heating (calcinating) same in an oxygen-containing atmosphere to prepare a raw material powder containing potassium, sodium, and niobium
Implementation Method 5
applying a predetermined pressure to the fired powder prepared in (c) to form a powder compact
Implementation Method 6
applying a predetermined pressure to the fired powder prepared in (c) to form a powder compact while also heating the powder compact to produce a sintered ceramics
Data Source
Figure 1~2
Figure 3(a)~3(b)
Figure 4(a)~4(b)
AI summary
A sputtering target material constituted from a sintered ceramics of an oxide containing potassium, sodium, niobium, and oxygen, wherein the sputtering target material has a density of 4.2 g/cm3 or less, a Vickers hardness of 30 or more and 200 or less, and an area-weighted mean grain size of 3.0 µm or more for a plurality of crystal grains observed on a sputtering surface.