AlON Powder Synthesis via High-Pressure Direct Nitridation
Solution Overview
Problem
Current methods for preparing high-quality AlON transparent ceramic powder face challenges such as residual carbon contamination, high sintering temperatures, and high production costs due to the use of expensive starting materials, with existing direct nitridation processes resulting in average sintering activity and requiring extensive carbon removal processes.
Innovation Solution
A method involving direct nitridation under high pressure using aluminum and alumina powders as starting materials, with a pressure range of 1-3 MPa, involving mixing, drying, loading, and calcination steps to produce pure-phase AlON powder with improved sintering activity and reduced carbon content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If direct nitridation is used to simplify the process, then carbon removal steps are eliminated, but the synthesized powder has average sintering activity requiring high sintering temperatures
Solution Approach 1:
The patent applies parameter changes by introducing high pressure (1-3 MPa) during the direct nitridation process to alter the reaction conditions. This pressure parameter modification enables the synthesis of AlON powder with enhanced sintering activity, thereby reducing the sintering temperature requirement while maintaining process simplicity through direct nitridation without carbon removal steps.
2Manufacturing precision
If expensive starting materials like AlN are used to achieve high-quality AlON powder, then synthesis quality is improved, but production cost increases
Solution Approach 1:
The patent replaces expensive AlN starting material with cheaper aluminum powder and alumina powder. Although aluminum powder has limited reactivity, the high pressure condition (1-3 MPa) activates the direct nitridation reaction, enabling the production of high-quality AlON powder through inexpensive, readily available materials, thus significantly reducing production cost.
Solution Approach 2:
By changing the pressure parameter to 1-3 MPa during nitridation, the patent enables the use of low-cost aluminum powder and alumina powder as starting materials. This parameter modification overcomes the low reactivity of these inexpensive materials, allowing them to effectively synthesize high-quality AlON powder without requiring expensive AlN precursors.
3Productivity
If carbothermic reduction is used to prepare AlON powder, then synthesis is achieved, but residual carbon contamination occurs requiring additional carbon removal processing
Solution Approach 1:
The patent converts the potential harm of carbon contamination into a benefit by using direct nitridation with high pressure. Instead of using carbothermic reduction that introduces carbon, the method directly introduces nitrogen under pressure to form AlON powder. The high pressure ensures complete nitridation without carbon involvement, eliminating carbon contamination while maintaining efficient synthesis.
Solution Approach 2:
The patent changes the reaction parameter from carbon-based reduction to nitrogen-based direct nitridation under high pressure (1-3 MPa). This parameter change fundamentally eliminates the source of carbon contamination while maintaining synthesis efficiency, as the high pressure drives the nitridation reaction to completion without requiring carbon removal steps.
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 achieves high-purity AlON powder with enhanced sintering activity and reduced sintering temperature requirements, facilitating the production of high-performance AlON transparent ceramics with improved optical and mechanical properties, suitable for large-scale production.
Implementation Method 1
synthesizing pure-phase AlON powder by direct nitridation under high pressure with aluminum powder and alumina powder as starting materials
Implementation Method 2
the high pressure refers to a pressure of the gas in the direct nitridation system of 1-3 MPa
Implementation Method 3
calcining the mixed powder to obtain the AlON powder
Data Source
AI summary
Aluminum oxynitride (AlON) powder, a synthesis method thereof by direct nitridation under high pressure and use thereof, which belongs to the field of ceramic powder are presented. In the method, pure-phase AlON powder is synthesized by direct nitridation under high pressure with aluminum powder and alumina powder as starting materials. The powder has a spherical-like morphology, with a particle size ranging from 5 μm to 15 μm. The powder has good dispersibility and uniformity, and higher sintering activity. AlON transparent ceramic (1.2 mm thick) prepared from the AlON powder has a linear transmittance of more than 84%. The batch yield is on kilogram-scale; therefore, the method is suitable for large-scale production of the AlON powder.