Oriented AlN Sintered Body Using Plate-Like Powder Templates
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Solution Overview
Problem
Producing an aluminum nitride (AlN) sintered body with high c-axis orientation is costly and not sufficiently oriented when using a rotating magnetic field, as reported in existing methods.
Innovation Solution
A method involving the preparation of a mixture with plate-like AlN powder and a sintering aid, where the plate surface of the AlN powder is disposed along the surface of a formed body, followed by hot-press sintering in a non-oxidizing atmosphere with applied pressure, promoting sintering and achieving high c-plane orientation without the need for a rotating magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rotating magnetic field is used to form AlN powder, then c-axis orientation is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent replaces the complex rotating magnetic field system with a simple uniaxial pressing mechanical system. The plate-like AlN powder particles are oriented during uniaxial pressing without requiring magnetic fields, thereby achieving c-axis orientation while significantly reducing manufacturing cost and device complexity.
Solution Approach 2:
The patent uses inexpensive plate-like AlN powder as a raw material that provides orientation functionality inherently, replacing the need for expensive rotating magnetic field equipment. The plate-like morphology of the powder itself serves as the orientation mechanism, making the process cost-effective.
2Manufacturing precision
If a rotating magnetic field is used to form AlN powder, then c-axis orientation is improved, but device complexity increases
Solution Approach 1:
The patent replaces the complex rotating magnetic field system with a simple uniaxial pressing mechanical system. The plate-like AlN powder particles are oriented during uniaxial pressing without requiring magnetic fields, thereby achieving c-axis orientation while significantly reducing manufacturing cost and device complexity.
3Ease of manufacture
If conventional sintering is used without applied pressure, then processing is simpler, but sintering promotion is insufficient
Solution Approach 1:
The patent applies uniaxial pressure during the sintering process as a critical parameter change. This applied pressure promotes sintering of the plate-like AlN powder particles, enabling effective densification and grain growth while maintaining the oriented structure, thereby improving productivity without excessive complexity.
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
This method results in an AlN sintered body with a high degree of c-plane orientation, exceeding 70%, offering improved plasma resistance and piezoelectric properties at a lower cost compared to methods using rotating magnetic fields.
Implementation Method 1
since the plate surface (c-plane) of the plate-like AlN powder is arranged along the surface of the formed body, the sintering proceeds while the plate-like AlN powder functions as a template
Implementation Method 2
sintering of an AlN raw-material powder containing the plate-like AlN powder is promoted by the sintering aid
Implementation Method 3
the formed body is subjected to hot-press sintering in a non-oxidizing atmosphere while applying a pressure to the surface of the formed body
Data Source
AI summary
A method for producing an oriented AlN sintered body includes a first step of preparing a formed body by forming a mixture obtained by mixing a sintering aid with an AlN raw-material powder containing a plate-like AlN powder whose plate surface is a c-plane and which has an aspect ratio of 3 or more and an average thickness of 0.05 to 1.8 μm, wherein the mixture is formed such that the plate surface of the plate-like AlN powder is disposed along a surface of the formed body; and a second step of obtaining an oriented AlN sintered body by subjecting the formed body to hot-press sintering in a non-oxidizing atmosphere while applying a pressure to the surface of the formed body.